Search results

Title: The Microbiology and Pathology of Shell Disease in the Florida Spiny Lobster, Panulirus Argus with a Comparison to Shell Disease in the American Lobster, Homarus Americanus.
Creator: Porter, Lauren, Reeves, Robert H., Kostka, Joel, Herrnkind, William, Keller, Laura, Quadagno, David, Department of Biological Science, Florida State University
Abstract/Description: Shell disease is a common affliction in marine crustaceans. It manifests as necrotic lesions on the exoskeleton that are caused by bacteria producing extracellular enzymes capable of degrading crustacean cuticle. Prior to 1998, shell disease was not reported in the Florida spiny lobster, Panulirus argus. Since that time it has been seen in P. argus in the Florida Keys. In 1999, an outbreak of severe shell disease occurred in the American lobster, Homarus americanus. Shell disease has been...
Show moreShell disease is a common affliction in marine crustaceans. It manifests as necrotic lesions on the exoskeleton that are caused by bacteria producing extracellular enzymes capable of degrading crustacean cuticle. Prior to 1998, shell disease was not reported in the Florida spiny lobster, Panulirus argus. Since that time it has been seen in P. argus in the Florida Keys. In 1999, an outbreak of severe shell disease occurred in the American lobster, Homarus americanus. Shell disease has been reported in this species for almost a century. To determine if shell disease etiology is the same between the species, a comparative study was undertaken. Healthy and shell-diseased cuticle was sampled in P. argus and H. americanus to determine if a consistent culturable bacterial flora exists on the exoskeleton, and if it the same flora found in lesions. Bacteria were identified by 16S ribosomal DNA sequencing. At least 600 bases of the ribosomal RNA gene were aligned with sequences of identified marine bacteria and phylogenetic relationships were determined. Seven groups of bacteria, six of which are in the gamma proteobacteria, emerged consistently on healthy and diseased cuticle. No primary pathogen was isolated from either species. Six of the groups were isolated from both lobster species and one group was isolated only from P. argus. The association of the bacterial groups with both healthy and shell-diseased cuticle suggests that the normal bacterial flora is in part responsible for shell disease lesions. For each lobster species, histological, scanning electron microscope, and transmission electron microscope observations were made of lesions. In both species, Gram-negative rods were the predominant bacterial morphology present, but cocci and pleomorphic bacteria were also seen. The pathology of the disease appeared to be very different between the lobster species. In P. argus, lesions appear to spread laterally via formation of an extracellular matrix that encapsulates the bacteria. The bacteria seem to secrete degradative enzymes into the matrix, which breaks down surrounding cuticle. Many lesions appeared to be initiated by trauma in P. argus. In H. americanus, the lesions appear to spread by direct bacterial contact with and degradation of the cuticle.
Show less
Date Issued: 2004
Identifier: FSU_migr_etd-0475
Format: Thesis

Title: Phylogeny and Historical Biogeography of Hadrosaurid Dinosaurs.
Creator: Prieto-Marquez, Albert, Erickson, Gregory M., Parker, William C., Steppan, Scott J., Swofford, David L., Ronquist, Fredrik, Department of Biological Science, Florida State...
Show morePrieto-Marquez, Albert, Erickson, Gregory M., Parker, William C., Steppan, Scott J., Swofford, David L., Ronquist, Fredrik, Department of Biological Science, Florida State University
Show less
Abstract/Description: Hadrosaurids were the most diverse and abundant dinosaurs at the end of the Cretaceous. However, their phylogeny is incompletely known and the relationships of many taxa, particularly European and South American, remains unresolved. Questions remain regarding the timing of their origin and which attributes might have allowed these animals to diversify and colonize nearly all continents by the late Campanian. Likewise, the center of origin and subsequent biogeographical history of hadrosaurids...
Show moreHadrosaurids were the most diverse and abundant dinosaurs at the end of the Cretaceous. However, their phylogeny is incompletely known and the relationships of many taxa, particularly European and South American, remains unresolved. Questions remain regarding the timing of their origin and which attributes might have allowed these animals to diversify and colonize nearly all continents by the late Campanian. Likewise, the center of origin and subsequent biogeographical history of hadrosaurids has remained contentious. With the goal of elucidating the evolutionary history of hadrosaurids, I present the most comprehensive and resolved phylogeny of these animals ever estimated, using a complete taxonomic sampling at specific level. I also report the results of a biogeographic analysis seeking to establish the ancestral area of Hadrosauridae, testing whether they originated in Asia, North or South America. In addition I used the same method to track their diversification in relation to intercontinental connections throughout their tenure. Parsimony and Bayesian methods were implemented to elucidate the phylogenetic relationships of all hadrosaurid species. These included specimens of 41 hadrosaurids from Europe, Asia and North and South America. Outgroup taxa included twelve iguanodontoidean species from Europe, North America and Asia. New characters were defined and old ones revised on the basis of new data collected from first hand examination of specimens. Traditional and geometric morphometrics were applied to discover patterns of variation containing phylogenetic information. Continuous geometries were studied using the Analysis of Planar Shapes Using Geodesic Paths, a novel landmark-free method that considers the continuous non-linear geometry of the bones. In this way, a total of 299 phylogenetically informative characters (205 cranial and 94 postcranial) were defined and documented, the most extensive character data set ever constructed for hadrosaurid dinosaurs. In general, parsimony and Bayesian analyses confirmed the dichotomic evolution of hadrosaurids into Saurolophinae and the hollow-crested Lambeosaurinae. Saurolophines consisted of "saurolophs" and "kritosaurs". Lambeosaurines consisted of a succession of Eurasian outgroups to two major clades, "parasaurolophs" and "amurosaurs" ("hypacrosaurs" and "corythosaurs"). Hadrosauridae was redefined as the clade stemming from the most recent common ancestor of Hadrosaurus foulkii and Parasaurolophus walkeri. Its monophyly was unambiguously supported by an iliac supraacetabular process that projects lateroventrally between half and three quarters of the dorsoventral depth of the central plate of the ilium and a craniocaudally short supraacetabular process that is less than 55% the length of the central plate of the ilium. The closest outgroup taxa to Hadrosauridae lived in eastern North America. The hadrosaurid radiation and the divergence of saurolophines from lambeosaurines occurred no later than the Santonian and was coincident with the evolution of a suite of mandibular characters (i.e., increased number of tooth families, presence of three teeth forming the dentary occlusal plane, ventral offset of the oral predentary-premaxilla contact). These characters may have been key innovations. These results suggest that feeding adaptations might have played a central role in the diversification of hadrosaurids. Circumnarial fossae and cranial crests evolved prior to the hadrosaurid radiation. Both of these characters were reconstructed to have evolved at the same time. Ancestral areas were reconstructed on the phylogeny derived from the weighted parsimony analysis of Hadrosauridae. Fitch parsimony and the Dispersal-Vicariance (DIVA) method were implemented to reconstruct ancestral areas for all clades of Hadrosauria. The results show that the genesis of Hadrosauridae occurred in eastern North America during the late Santonian. Soon after their origin, hadrosaurids dispersed to Asia, the ancestral area for the major Saurolophinae-Lambeosaurinae divergence. Lambeosaurines and saurolophines dispersed to North America and underwent major cladogenesis during the late Campanian. Within Saurolophinae, "maiasaurs" and "saurolophs" returned to Asia, while "kritosaurs" colonized South America by the late Campanian. Within Lambeosaurinae, "tsintaosaurs" dispersed to Europe no later than the late Campanian. The North American radiations of "hypacrosaurs", "parasaurolophs" and "corythosaurs" may have represented independent dispersal events from the Asian continent or, alternatively, were part of a single dispersal in the late Campanian with posterior occupations of Asia by a few species from those clades. Vicariant events may have occurred following several of the inferred hadrosaurid dispersals. Thus, both vicariance and dispersal may have been instrumental in shaping the recorded distribution of hadrosaurids. Two additional studies were conducted on European and South American hadrosaurids. Although well represented in Asia and North America, the presence of this animals in Europe and South America is known only from rare and fragmentary remains that are poorly documented and mostly unstudied. As a result, the impact of these animals on the phylogenetics and biogeography of hadrosaurids as a whole are not known. Here, I provide a revised and complete osteology of the type specimens and hypodigms for the only two taxa known from South America, Secernosaurus koerneri and Kritosaurus australis. K. australis is regarded as a junior synonym of S. koerneri, based on a combination of iliac and pubic characters unique to these two taxa. Inclusion of S. koerneri within the genus Kritosaurus is not supported by the phylogenetic analysis. S. koerneri is inferred to be a member of the "kritosaur" clade within Saurolophinae, as the sister taxon to the Argentinean OTU from Salitral Moreno. Another unnamed hadrosaurid, an OTU from Big Bend National Park, Texas, is positioned as the closest outgroup to the South American clade. The results of this biogeographical analysis indicates that the Secernosaurus clade originated in South America during the late Campanian after a dispersal event (probably followed by vicariance) from southern North America before the end of that geologic stage. Finally, and regarding European hadrosaurids, the observation of previously unrecognized characters in the maxilla and dentary of Tsintaosaurus spinorhinus (Campanian of China) and Pararhabdodon isonensis (Maastrichtian of Spain) led to a revision of the taxonomy and phylogenetic relationships of the latter. In particular, the extreme elongation of the symphyseal region of the type and only material of Koutalisaurus kohlerorum (a dentary from the Maastrichtian of Spain) was also observed in T. spinorhinus. This implied that K. kohlerorum is indistinct from T. spinorhinus. This, in combination with the fact that P. isonensis and T. spinorhinus share a maxilla with elevated jugal joint continuous with the ectopterygoid ridge (a character not seen among Iguanodontoidea), led me to the conclusion that K. kohlerorum as a junior synonym of P. isonensis. The incorporation of those new characters in Bayesian and parsimony phylogenetic analyses of Hadrosauridae resulted in the inference that Pararhabdodon isonensis and Tsintaosaurus spinorhinus form a clade of basal lambeosaurines—the "tsintaosaurs". Fitch parsimony and Dispersal-Vicariance reconstruction of ancestral areas on the resulting phylogeny indicated that "tsintaosaurs" originated in eastern Asia during the middle or late Campanian and that P. isonensis represents a dispersal event (followed by vicariance) to Europe that occurred before the end of that geologic stage.
Show less
Date Issued: 2008
Identifier: FSU_migr_etd-0460
Format: Thesis

Title: Cell Signaling and the Regulation of Axis Formation, Cell Proliferation, and Differentiation in Drosophila Melanogaster.
Creator: Poulton, John, Deng, Wu-Min, Horabin, Jamila I., Epstein, Lloyd, III, Thomas Keller, Tang, Hengli, Department of Biological Science, Florida State University
Abstract/Description: The development of multicellular animals involves a diverse array of cellular processes, including cell differentiation, proliferation, and polarization. The control of these processes is largely governed by communication between different cells. This intercellular communication, known as cell signaling, is therefore a fundamental aspect of developmental and cellular biology. Despite a wealth of knowledge regarding the canonical cell signaling pathways, many questions remain regarding the...
Show moreThe development of multicellular animals involves a diverse array of cellular processes, including cell differentiation, proliferation, and polarization. The control of these processes is largely governed by communication between different cells. This intercellular communication, known as cell signaling, is therefore a fundamental aspect of developmental and cellular biology. Despite a wealth of knowledge regarding the canonical cell signaling pathways, many questions remain regarding the mechanistic nature of the communication taking place during specific developmental events, as well as questions regarding the control of activation of cell signaling. In this dissertation I will use the egg chamber of Drosophila melanogaster as a model system to investigate the genetics and cellular biology surrounding two important developmental events involving cell signaling. In the first part I describe a role for an adhesion molecule, Dystroglycan (DG), in the communication between two important cell types present in the egg chamber (the follicle cells and the oocyte). This communication is of great developmental significance because it creates the foundation for the polarization of the oocyte. The finding that DG is involved in this process suggests that changes in cell adhesion are important in the communication that establishes oocyte polarity. In the second part of the dissertation I identify a novel role for the gene, Belle (Bel), in controlling the activation of a key cell signaling pathway known as Notch. Notch activation in the follicle cells is essential for many aspects of egg chamber development. I also demonstrate that the regulation of Notch by Bel occurs through Bel's role in the microRNA pathway, possibly through regulation of levels of another protein, Delta. Together my research sheds new light on two key facets of egg chamber development that will potentially elucidate similar mechanisms present in other aspects of development in Drosophila, as well as other organisms.
Show less
Date Issued: 2009
Identifier: FSU_migr_etd-0459
Format: Thesis

Title: Thermal Sensitivity of Calcium and Magnesium Binding for Parvalbumins from Teleost Fish.
Creator: Erickson, Jeffrey Robert, Moerland, Timothy S., Logan, Timothy M., Chase, P. Bryant, Ellington, W. Ross, Gaffney, Betty J., Department of Biological Science, Florida State...
Show moreErickson, Jeffrey Robert, Moerland, Timothy S., Logan, Timothy M., Chase, P. Bryant, Ellington, W. Ross, Gaffney, Betty J., Department of Biological Science, Florida State University
Show less
Abstract/Description: Parvalbumin is an abundant divalent cation binding protein of fast vertebrate skeletal muscle. Its proposed function is to sequester calcium after contraction, thus facilitating relaxation. Calcium and magnesium equilibrium dissociation constants and instantaneous rate constants of parvalbumins from two Antarctic teleosts (Gobionotothen gibberifrons and Chaenocephalus aceratus), two temperate zone teleosts (Cyprinus carpio and Micropterus salmoides), and one Arctic teleost (Boreogadus saida)...
Show moreParvalbumin is an abundant divalent cation binding protein of fast vertebrate skeletal muscle. Its proposed function is to sequester calcium after contraction, thus facilitating relaxation. Calcium and magnesium equilibrium dissociation constants and instantaneous rate constants of parvalbumins from two Antarctic teleosts (Gobionotothen gibberifrons and Chaenocephalus aceratus), two temperate zone teleosts (Cyprinus carpio and Micropterus salmoides), and one Arctic teleost (Boreogadus saida) were determined to assess potential differences in protein function. PV was isolated by homogenization followed by gel filtration and ion exchange chromatography. Sample purity was checked by 2-D PAGE. Dissociation constants were determined by a competitive binding assay between parvalbumin and either fluo-3 or Magnesium Green. Thermodynamic parameters were determined by calorimetry. Instantaneous rate constants were determined by stopped-flow spectrometry. Deduced amino acid sequences were also determined for several teleost parvalbumins. Functional data showed that parvalbumins from different teleost fish can exhibit markedly different patterns of thermal sensitivity. However, a general pattern of conservation for several binding parameters at native temperature was observed. Sequence data indicated that the major structural features, including the coordinating residues of the binding loops, were conserved in parvalbumins. Substitutions leading to variability of thermal function are likely to have occurred outside the binding loops of the protein.
Show less
Date Issued: 2005
Identifier: FSU_migr_etd-0553
Format: Thesis

Title: Studies of the Capacity for Creatine Biosynthesis in the Protochordate Ciona Intestinalis.
Creator: Deligio, James Thomas, Ellington, W. Ross, Chase, P. Bryant, Moerland, Timothy S., Department of Biological Science, Florida State University
Abstract/Description: Creatine kinase (CK) catalyzes the reversible transfer of the gamma-terminal phosphate of MgATP to the guanidine creatine (Cr) forming MgADP and phosphocreatine (PCr). The CK reaction plays a central role in both temporal and spatial ATP buffering in cells displaying high and variable rates of ATP turnover. There is a constant, non-enzymatic conversion of Cr to creatinine that must be compensated for by biosynthesis and/or dietary uptake. In all true vertebrate craniates, there is a capacity...
Show moreCreatine kinase (CK) catalyzes the reversible transfer of the gamma-terminal phosphate of MgATP to the guanidine creatine (Cr) forming MgADP and phosphocreatine (PCr). The CK reaction plays a central role in both temporal and spatial ATP buffering in cells displaying high and variable rates of ATP turnover. There is a constant, non-enzymatic conversion of Cr to creatinine that must be compensated for by biosynthesis and/or dietary uptake. In all true vertebrate craniates, there is a capacity for de novo biosynthesis of Cr as evidenced by the presence of the two enzymes of the biosynthetic pathway- arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT). In these organisms the bulk of Cr biosynthesis is partitioned between the pancreas, kidney and liver for subsequent transport to muscle fibers and other cells expressing CK. Many protochordates and a broad spectrum of invertebrates, including the basal metazoan sponges, express CK and contain significant pools of Cr/PCr, particularly in primitive-type spermatozoa. However, repeated attempts at demonstrating the enzymes of Cr biosynthesis in these organisms have failed and it has been suggested that Cr is derived from the diet and/or by direct uptake from seawater. I show in this thesis that the protochordate tunicate Ciona intestinalis expresses what appear to be three unique, but very similar to one another, transcripts for GAMT. To validate that these transcripts code for GAMT, the full length cDNA for one of these was generated by PCR amplification and ligated into an expression vector. Expression resulted in the production of a large amount of soluble protein that was purified to homogeneity by low pressure chromatography. The resulting recombinant enzyme had an experimentally determined N-terminal amino acid sequence and relative molecular mass as predicted by the deduced amino acid sequence from the cDNA. Catalytic studies of this recombinant GAMT showed that it indeed had the capacity to methylate guanidinocetate to Cr with an apparent Km and maximal velocity comparable to GAMTs from vertebrates. Real-time PCR showed that this GAMT is primarily expressed in the stomach and gonad but also is expressed in two other tissue complexes. Analysis of the C. intestinalis genome and EST sequencing projects showed that the AGAT gene is present and is expressed demonstrating that this species has the complete Cr biosynthetic pathway. Perusal of other EST and genome sequencing projects reveal that true GAMTs are present in the lancelet Branchiostoma, the sea urchin Strongylocentrotus and the hydroid Hydractinia and AGAT genes are present in both Branchiostoma and Strongylocentrotus. Given the present experimental results and the emerging EST/genome sequencing data, it is clear that the capacity for de novo Cr biosynthesis is widespread in organisms expressing CK and that the genes for GAMT/AGAT evolved coincident with CK.
Show less
Date Issued: 2005
Identifier: FSU_migr_etd-0777
Format: Thesis

Title: Self-Organization and the Superorganism: Functional Ecology of the Obligate Mutualism Between a Fungus Gardening Ant and Its Symbiotic Fungus.
Creator: Seal, Jon Nicholas, Tschinkel, Walter R., Johnson, Frank, James, Frances C., Levitan, Don R., Winn, Alice A., Department of Biological Science, Florida State University
Abstract/Description: This dissertation investigated the evolutionary ecology of a type of obligate mutualism, the form of agriculture found in ants. It presents the results of two laboratory experiments with the fungus-gardening ant species, Trachymyrmex septentrionalis, a species occurring in the Apalachicola National Forest in Florida that is closely related to mostly tropical leaf-cutting ants in the genera Atta and Acromyrmex. Fungus-gardening ants supply substrates to their fungus garden and feed the...
Show moreThis dissertation investigated the evolutionary ecology of a type of obligate mutualism, the form of agriculture found in ants. It presents the results of two laboratory experiments with the fungus-gardening ant species, Trachymyrmex septentrionalis, a species occurring in the Apalachicola National Forest in Florida that is closely related to mostly tropical leaf-cutting ants in the genera Atta and Acromyrmex. Fungus-gardening ants supply substrates to their fungus garden and feed the products of the fungus to their larvae. Because ants make choices in the substrates they collect, an interesting topic is the relationship between the choice of substrates and the quality and amounts of fungus and ants produced. No previous studies have measured the consequences of these choices on the relative sizes of fungus gardens or the quality and quantity of ants produced. The first experiment indicated a positive relationship between subtrate preference and both ant and fungal performance but it was not perfect. The ants preferred bluejack oak (Quercus incana) catkins and caterpillar frass over oak leaves or flowers (Gaylussacia dumosa). Colonies on the high catkin diet produced more fungal biomass than could be subsequently used, indicating only indirect feedback between forager activity and the colony's nutritional demands. The biomass of ant produced was similarin all groups, with the exception of being low in colonies that received only flowers. Colonies that had rejected tussock caterpillar frass were later able to produce as much ant biomass on a low catkin diet as those on the high catkin diet. In the second experiment, the successful replacement of T. septentrionalis's fungal cultivar, with a foreign fungus obtained in Louisiana from colonies of A. texana, did not change the substrate preference of the ants or the amount or quality of the ants produced. However, T. septentrionalis colonies with A. texana fungus produced more fungal biomass. Under the conditions of these experiments, the relationship between T. septentrionalis and its native fungal cultivar appear to be mutually adaptive, but that mutualism does not seem to be the product of a tight feedback mechanism on an ecological scale.
Show less
Date Issued: 2006
Identifier: FSU_migr_etd-0289
Format: Thesis

Title: Florida Harvester Ants and Their Charcoal.
Creator: Smith, Christopher Ryan, Tschinkel, Walter R., Winn, Alice A., Inouye, Brian D., Department of Biological Science, Florida State University
Abstract/Description: Harvester ants of the genus Pogonomyrmex collect and deposit many items on top of their nests. Although these deposits, or depots, may be colossal there is very little known about them. This research is a case study of the depots in the Florida harvester ant, P. badius, describing the depot contents, distributions of different components within the depots, the ontogeny of the depots, a stimulus for their creation, testing hypotheses of their function, evaluating their effect on a measure of...
Show moreHarvester ants of the genus Pogonomyrmex collect and deposit many items on top of their nests. Although these deposits, or depots, may be colossal there is very little known about them. This research is a case study of the depots in the Florida harvester ant, P. badius, describing the depot contents, distributions of different components within the depots, the ontogeny of the depots, a stimulus for their creation, testing hypotheses of their function, evaluating their effect on a measure of colony level fitness, and providing an overview of information on depots of other species throughout the genus. The depots of P. badius consist mostly of small charcoal fragments, while those of other species are primarily pebbles. Mature colonies can have millions of objects in their depot, each of which is the result of a single foraging trip by a worker. In P. badius, the distributions of midden and charcoal about the mound are not completely overlapping, but are positively correlated in areas of overlap. Charcoal depots are isometric with colony size, increasing proportionately with the number of mature workers in the nest. Moreover, the amount of charcoal per colony size varies with season (they are larger in fall compared to spring), and site. The absence of the depot stimulates collection of non-food objects. The depots do not appear to function as territorial markers, roofs (preventing chamber collapse), or mulch (preventing water evaporation). Depots had a moderate effect on temperature (2°C, but only in the top 2cm), but it is not known whether the ants exploit this temperature difference. And finally, the effect of charcoal on the seasonal fitness of colonies was not statistically significant, but colonies with charcoal depots did produce more sexuals and workers, indicating that the effect of charcoal on fitness may accumulate over multiple seasons.
Show less
Date Issued: 2004
Identifier: FSU_migr_etd-0340
Format: Thesis

Title: Ecological Relationships of Turtles in Northern Florida Lakes: A Study of Omnivory and the Structure of A Lake Food Web.
Creator: Aresco, Matthew Joseph, James, Frances C., Deyle, Robert, Travis, Joseph, Miller, Thomas, Houpt, Thomas, Means, D. Bruce, Department of Biological Science, Florida State University
Abstract/Description: Lakes in the southeastern United States support a high diversity of reptiles and amphibians, including many species of turtles. Reptilian omnivores are abundant and their role in lake food webs must be important. In Leon County, Florida, I studied 17 lakes and the abundances of 3 species of turtles - yellow-bellied slider, Trachemys scripta, Florida cooter, Pseudemys floridana, and Florida softshell, Apalone ferox. I found that lakes in northern Florida range from low-nutrient, sand-bottom...
Show moreLakes in the southeastern United States support a high diversity of reptiles and amphibians, including many species of turtles. Reptilian omnivores are abundant and their role in lake food webs must be important. In Leon County, Florida, I studied 17 lakes and the abundances of 3 species of turtles - yellow-bellied slider, Trachemys scripta, Florida cooter, Pseudemys floridana, and Florida softshell, Apalone ferox. I found that lakes in northern Florida range from low-nutrient, sand-bottom lakes to moderately eutrophic, muck-bottom lakes with abundant macrophytes, but one of the best predictors of turtle abundances was periphyton. Abundances of all three focal species were strongly correlated with a mud and muck substrate and both top-down (no alligator predation) and bottom-up (high periphyton productivity) factors. On a finer scale, abundances of the individual species were correlated with additional factors that may be related to trophic position: T. scripta – high phosphorus and high chironomid abundance, P. floridana – low macrophyte cover and high chironomid abundance, and A. ferox – high macroinvertebrate abundance, high snail abundance, and high phosphorus. An experiment revealed that intraspecific competition may be more important than interspecific competition in partitioning resources between the omnivorous, T. scripta, and specialist algivore, P. floridana. In low resource environments, inefficient digestive physiology and intraspecific competition may limit density of an omnivore compared to that of a low trophic position specialist. Stable isotope analysis of the entire food web of Lake Jackson, Leon County, Florida, revealed that filamentous macroalgae were the foundation of the web despite the much greater biomass of macrophytes. The turtle assemblage consisted of one herbivore and five omnivores. The diets of the three focal species differed: P. floridana was a specialist algivore (trophic position [TP] = 2.3), T. scripta was a generalist omnivore (TP = 3.3), and A. ferox was an omnivore with some specialization on insects and snails (TP = 3.8). There were few specialists (TP ³ 4.0) and few strict primary consumers. Omnivory was prevalent (90% of consumers), and the food web is one trophic level shorter than those in fish-dominated, north temperate lake webs that have few turtles, less species diversity, and lower productivity.
Show less
Date Issued: 2005
Identifier: FSU_migr_etd-0230
Format: Thesis

Title: Allergenic Cross-Reactivity Between Cashew and Pistachio Nuts.
Creator: Tawde, Pallavi D., Roux, Kenneth, Sathe, Shridhar, Keller, Tom, Department of Biological Science, Florida State University
Abstract/Description: Title: Allergenic cross-reactivity between cashew and pistachio nuts Rationale: Cashew and pistachio belong to Anacardiaceae family and strong allergenic cross-reactivity between nuts of these two species has been reported. The aim of our study was to identify the cross-reactive allergenic proteins from cashew and pistachio nuts. Methods: Extracted cashew and pistachio nut proteins were separated by means of 1- and 2-dimensional PAGE. Pooled human sera from cashew-allergic patients was tested...
Show moreTitle: Allergenic cross-reactivity between cashew and pistachio nuts Rationale: Cashew and pistachio belong to Anacardiaceae family and strong allergenic cross-reactivity between nuts of these two species has been reported. The aim of our study was to identify the cross-reactive allergenic proteins from cashew and pistachio nuts. Methods: Extracted cashew and pistachio nut proteins were separated by means of 1- and 2-dimensional PAGE. Pooled human sera from cashew-allergic patients was tested for reactivity to soluble cashew and pistachio proteins by IgE immunoblotting after one-dimensional (1-D) and 2-D electrophoresis. The identities of the IgE-reactive bands from the pistachio immunoblot were further analyzed by means of N-terminal amino acid sequencing and comparison to previously published data from the cashew. ELISAs were performed using individual sera from subjects with cashew and tree nut allergy to assess the degree of IgE reactivity to cashew and pistachio nut extracts. Inhibition ELISA studies were conducted to assess the degree of allergenic cross-reactivity between cashew and pistachio nuts. Results: IgE immunoblots of cashew and pistachio extract probed with cashew-allergic sera identified proteins of 35kDa, 22kDa, and 7-9kDa. N-terminal amino acid sequencing of the IgE-reactive spots from pistachio immunoblot identified them as the acidic subunit, basic subunit of 11S globulin and 2S albumin seed storage proteins respectively. Seed storage proteins are known food allergens in cashew and have been designated as Ana o 1 (7S globulin), Ana o 2 (11S globulin) and Ana o 3 (2S albumin). ELISA results with ten individual cashew-allergic sera (two out of the ten patients have pistachio allergy, and the remaining eight patients had never eaten pistachio) showed IgE reactivity to both cashew and pistachio nut. Inhibition ELISA demonstrated that pre-incubation of sera with pistachio extract resulted in a marked decrease in IgE binding to cashew extract, and vice versa indicating allergenic cross-reactivity. Conclusion: The results demonstrate the presence of cross-reactive B cell epitopes on cashew and pistachio nut allergens. The plant taxonomic classification of cashew and pistachio nuts does appear to predict allergenic cross-reactivity.
Show less
Date Issued: 2004
Identifier: FSU_migr_etd-0358
Format: Thesis

Title: Hypoallergenic Mutants of Ana O 2, a Major Cashew Allergen & Identification and Characterization of Tree Nut Allergens.
Creator: Tawde, Pallavi Dattatray, Roux, Kenneth H., Sathe, Shridhar K., III, Thomas C.S. Keller, Blaber, Michael, Reeves, Robert, Department of Biological Science, Florida State University
Abstract/Description: Allergic diseases are a heterogeneous group of type I IgE-mediated hypersensitivity reactions affecting more than 25% of the world's population of developed countries becoming a major clinical and public health issue. According to the American Academy of Allergy, Asthma and Immunology (AAAAI), allergies affect as many as 40-50 million people in the United States, making it the sixth most common cause of chronic illness. Recent studies have estimated that food allergies occur in 6 - 8% of...
Show moreAllergic diseases are a heterogeneous group of type I IgE-mediated hypersensitivity reactions affecting more than 25% of the world's population of developed countries becoming a major clinical and public health issue. According to the American Academy of Allergy, Asthma and Immunology (AAAAI), allergies affect as many as 40-50 million people in the United States, making it the sixth most common cause of chronic illness. Recent studies have estimated that food allergies occur in 6 - 8% of children under 3 years of age and in 4% of adults in the US population. The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) proposed that milk, shellfish, egg, fish, peanut, soybean, tree nuts and wheat are eight major sources of food allergens and the causes of most food allergies. Peanut, tree nuts, and seafood allergies predominate in adults, whereas milk and egg allergies are important in children. Tree nut allergies, in particular, affect about 0.5% of the US population. The commonly consumed tree nuts in the US include walnuts, almonds, cashews, pistachios, and pecans, all of which are allergenic to predisposed individuals of the consuming population. The major allergenic proteins associated with tree nut allergies include the seed storage proteins belonging to the 7S and 11S globulin, and 2S albumin gene families. Complementary DNA expression libraries were created from English walnut, cashew and almond. To identify the almond profilin, almond and walnut 60S ribosomal protein P2, 7S and 11S globulin genes in cashew and pistachio nuts, the libraries were used either directly as targets for degenerate primers in PCR 'fishing' experiments or transferred to nitrocellulose membranes and screened with tree nut allergenic patient sera. Upon identification and amplification of the respective coding genes, they were modified with restriction enzymes, ligated into an expression vector, and expressed as fusion proteins. These purified fusion proteins were used to screen for tree nut-allergic patient IgE-reactivity in direct immunoblots and to identify the native counterparts of these proteins in crude nut extracts via inhibition immunoblots and/or inhibition ELISA. Information on the linear epitopes and homology modeling of 7S and 11S globulins from cashew and pistachio would provide structural insight into the issue of serological and clinical cross-reactivity between these two nuts from the Anacardiaceae family. The 11S globulins represent a family of most abundant seed storage proteins, and have been shown to be the most allergenic (i.e., react with high percentage of patients sera) of the seed storage proteins (allergenic in cashew, pistachio, almond, walnut, Brazil nut, and hazelnut). Linear IgE-reactive epitopes on the primary amino acid sequence of major cashew allergen and protein --11S globulin, Ana o 2 were located by overlapping synthetic peptide analysis using cashew allergic sera. Additionally, alanine scanning mutagenesis of the immunodominant IgE reactive linear epitopes was used in the identification of key amino acid residues critical for IgE binding. The identified critical amino acids would serve as targets to create hypoallergenic variants of Ana o 2, by introducing point mutations of those critical amino acids using site-directed mutagenesis in the Ana o 2 cDNA and unaltering the overall structural fold of the molecule. The biological potential of the hypoallergenic engineered Ana o 2 mutants would be analyzed using an ex vivo basophil activation assay. Thus, by reducing the anaphylactic potential of Ana o 2 while preserving T cell epitopes, we could potentially use these hypoallergens for allergen specific immunotherapy in cashew sensitized individuals.
Show less
Date Issued: 2008
Identifier: FSU_migr_etd-0346
Format: Thesis

Title: Conformational Change of Troponin I Upon Muscle Activation.
Creator: Zhang, Xiaojun, Fajer, Piotr G., Logan, Timothy, Chase, P. Bryant, III, Thomas Keller, Blaber, Michael, Department of Biological Science, Florida State University
Abstract/Description: Unraveling the detailed molecular mechanisms involved in muscle contraction is a prerequisite for understanding the molecular basis of muscular disorders. Troponin (Tn) plays a key role in muscle regulation, and it is composed of three subunits: TnC, TnI and TnT. This study is aimed at understanding conformational changes occurring in TnI during muscle activation and force generation. The primary experimental technique used is site specific spin labeling combined with electron paramagnetic...
Show moreUnraveling the detailed molecular mechanisms involved in muscle contraction is a prerequisite for understanding the molecular basis of muscular disorders. Troponin (Tn) plays a key role in muscle regulation, and it is composed of three subunits: TnC, TnI and TnT. This study is aimed at understanding conformational changes occurring in TnI during muscle activation and force generation. The primary experimental technique used is site specific spin labeling combined with electron paramagnetic resonance (SDSL-EPR). In present study, we used SDSL EPR technique to observe the orientational changes of TnI-TnT coiled-coil domain and the conformational changes of TnI C-terminal domain between different thin filament states. The fiber tilts spectra of TnI133-MTSSL reconstituted fibers showed that in this domain, TnI is well ordered and oriented at a specific angle with respect to the actin filament. After simulations using a nonlinear-least-squares (NLS) approach, we found that TnI-TnT coiled-coil undergoes a significant orientational change between different states: from "Blocked" to "Closed" state, TnI re-orients itself ~50° axially; from "Closed" to "Open" state, TnI re-orients itself 90° azimuthally. In order to examine the conformational change of TnI C-terminal region upon Ca2+ binding, DEER distance measurements between two residues in TnI C-terminal region (residue 170 and residue 202) were performed. The broad distance distribution between residue 170 and 202 indicates that the TnI C-terminal region is flexible. Unlike TnC and other regions of TnI, in solution, this region is not affected by Ca2+ binding. The reconstitution of the troponin complex to Tm/actin does not change the flexibility of the TnI C-terminal region. By using both DEER and FRET techniques to monitor the distance change between TnI and actin upon Ca2+ binding, we discovered that this region shifts away from actin in thin filaments when Ca2+ is bound. This is the first direct observation of such a conformational change.
Show less
Date Issued: 2008
Identifier: FSU_migr_etd-0539
Format: Thesis

Title: Elucidation of the Catalytic Mechanism of Two Fatty Acid-Metabolizing Enzymes Using EPR Spectroscopy.
Creator: Wu, Fayi, Gaffney, Betty J., Levenson, Cathy W., Fadool, Debra A., Outlaw, William H., Roux, Kenneth H., Department of Biological Science, Florida State University
Abstract/Description: Coral allene oxide synthase (cAOS), a hemoprotein with sequence similarity to bovine liver catalase (BLC), is the N-terminal domain of a fusion protein with an 8R-lipoxygenase in coral Plexaura homomalla. A radical having a g-value of 2.004-2.005 is formed in cAOS upon reaction with peracetic acid. The radical has been shown to be tyrosyl by deuterium substitution of tyrosines and by EPR. The radical site was located at Y193 by mutagenesis of several tyrosines, which are included in the...
Show moreCoral allene oxide synthase (cAOS), a hemoprotein with sequence similarity to bovine liver catalase (BLC), is the N-terminal domain of a fusion protein with an 8R-lipoxygenase in coral Plexaura homomalla. A radical having a g-value of 2.004-2.005 is formed in cAOS upon reaction with peracetic acid. The radical has been shown to be tyrosyl by deuterium substitution of tyrosines and by EPR. The radical site was located at Y193 by mutagenesis of several tyrosines, which are included in the regions of sequence similarity of cAOS and BLC. The kinetics of enzyme reacting with peracetic acid and 13R-HPODE, a nonoptimal substrate, demonstrated that oxidized heme intermediates form and radical formation has a role in recovery of the enzyme. The heme ligand of cAOS was determined to be Y353 by mutagenesis, based on the changed UV-vis spectra of the mutant. Lipoxygenase (LOX) is a family of non-heme iron-containing enzymes that catalyze the dioxygenation of polyunsaturated fatty acids. How LOX interacts with fatty-acid substrates is still not clear although the interaction is critically important in determining the regio- and stereo-specificity of the enzyme. We employed an EPR spectroscopic approach, combined with fatty-acid spin labels, to obtain insight into this question. The fatty-acid spin labels are labeled on carbons 5-, 8-, 10-, 12- and 16- of stearic acid (doxyl stearic acid, DSA). The affinity of DSA for soybean lipoxygenase-1 (LOX-1) increases as the chain length between the labeled carbon and the methyl end increases except in the case of the one labeled on carbon 16. The EPR lineshape suggests that 16-DSA binds to the cavity in a different mode from the others. Iron in LOX-1 enhances relaxation of all the DSA probes similarly. Enzyme kinetics showed that 5-DSA is a competitive inhibitor of LOX-1 with a Ki 9 ?M while the dissociation constant Kd determined by EPR is 10 ?M. These results indicate that all the probes bind to the fatty acid substrate-binding site of LOX-1 or to a portion of it. Room-temperature EPR spectra show local mobility of probes bound to LOX-1. Those probes labeled at the methyl or carboxyl end experienced more motion than those labeled in the middle of the chain. This suggests that the binding site does not accommodate the whole chain, but that doxyl portion resides near the entrance to the substrate cavity, with only the hydrocarbon portion of the spin label occupying the substrate site.
Show less
Date Issued: 2006
Identifier: FSU_migr_etd-0706
Format: Thesis

Title: Phylogeography of the Sigmodontine Rodent, Phyllotis Xanthopygus, and a Test of the Sensitivity of Nested Clade Analysis to Elevation-Based Alternative Distances.
Creator: Albright, James Christopher, Steppan, Scott, Levitan, Don, Swofford, David, Department of Biological Science, Florida State University
Abstract/Description: I undertook a phylogenetic and phylogeographic study of the widespread Andean rodent, Phyllotis xanthopygus. My goals were to obtain general information about the history of the species and to explore some issues of Nested Clade Analysis (NCA) sensitivity in an empirical framework. The mitochondrial marker, cytochrome-b, was sequenced to produce an intraspecific maximum-likelihoo phylogeny of Phyllotis xanthopygus. I assessed the sensitivity of NCA to alternative distances by incorporating...
Show moreI undertook a phylogenetic and phylogeographic study of the widespread Andean rodent, Phyllotis xanthopygus. My goals were to obtain general information about the history of the species and to explore some issues of Nested Clade Analysis (NCA) sensitivity in an empirical framework. The mitochondrial marker, cytochrome-b, was sequenced to produce an intraspecific maximum-likelihoo phylogeny of Phyllotis xanthopygus. I assessed the sensitivity of NCA to alternative distances by incorporating physiognomic information in the form of two elevation distances based on isolines. The elevation distances were largely congruent, but they both differed from the standard great-circle distance metrics. Only three out of nine phylogeographic inferences were the same for the different approaches.
Show less
Date Issued: 2004
Identifier: FSU_migr_etd-0026
Format: Thesis

Title: The Life History, Reproductive Ecology, and Demography of the Red Porgy, Pagrus Pagrus, in the Northeastern Gulf of Mexico.
Creator: Devries, Douglas Alan, Travis, Joseph, Koenig, Christopher C., Meeter, Duane, Elam, John S., Grimes, Churchill B., Levitan, Don R., Department of Biological Science, Florida...
Show moreDevries, Douglas Alan, Travis, Joseph, Koenig, Christopher C., Meeter, Duane, Elam, John S., Grimes, Churchill B., Levitan, Don R., Department of Biological Science, Florida State University
Show less
Abstract/Description: This study examined the reproductive ecology of the red porgy Pagrus pagrus (Sparidae) in the NE Gulf of Mexico and the temporal, bathymetric, and small scale spatial variability of its life history traits and demographics. Almost 4000 specimens were collected using standardized hook and line gear year-round, Mar 1998-Sep 2001, in the NE Gulf - most (n=2,586) at 9 sites off NW Florida in 30-68 m. Spawning grounds were widespread, spawning occurred primarily Dec – Feb, and 50% of females...
Show moreThis study examined the reproductive ecology of the red porgy Pagrus pagrus (Sparidae) in the NE Gulf of Mexico and the temporal, bathymetric, and small scale spatial variability of its life history traits and demographics. Almost 4000 specimens were collected using standardized hook and line gear year-round, Mar 1998-Sep 2001, in the NE Gulf - most (n=2,586) at 9 sites off NW Florida in 30-68 m. Spawning grounds were widespread, spawning occurred primarily Dec – Feb, and 50% of females matured at 211 mm and sites, and were 206 - 417 mm TL and ages 2 - 9 yr, strong evidence the process is socially controlled. Red porgy are permanently sexually dichromatic, pair spawners, and do not form large, predictable spawning aggregations. Neither protogyny nor their reproductive ecology appears to make them more sensitive than gonochorists to exploitation - they are probably less so in some cases. Traits such as widespread spawning grounds, no tendency to form spawning aggregations, absence of behaviorally-related size or sex selectivity, socially controlled sex change, co-occurrence of sexes year-round, and an extended period of transition, should stabilize or enable rapid compensation of sex ratios in red porgy (preventing sperm limitation or disruption of mating). Size and age composition, size at age, survival rates, transition rates, sizes and ages at transition, and sex ratios all differed significantly at a scale of only 10's of km. Environmental heterogeneity and site fidelity probably explain most of those differences, which likely reflect phenotypic, not genetic, effects. Habitat patches likely have variable hydrological, geological, biological, exploitation, and ecological characteristics. Once recruited to a patch, philopatric adults are exposed to a unique suite of factors which could affect growth, mortality, and reproduction. Such small spatial scale differences in many traits suggests a complex structure of local subpopulations; these resemble Crowder et al.'s (2000) sources and sinks or the broadly - defined metapopulation of Kritzer and Sale (2004). Pooled data from such a complex population structure could introduce excessive variability to parameter estimates and bias stock assessments.
Show less
Date Issued: 2006
Identifier: FSU_migr_etd-0076
Format: Thesis

Title: Dendritic Spines and Deacetylases.
Creator: Dietz, Karen C., Ouimet, Charles C., Wang, Zuoxin, Kabbaj, Mohamed, Trombley, Paul Q, III, Thomas C.S. Keller, Department of Biological Science, Florida State University
Abstract/Description: The work presented in this dissertation represents investigations into the mechanism of two neurological disorders. The first set of experiments was aimed at examining the morphology of post-synaptic structures called dendritic spines in a mouse model of Down's syndrome. The second set of experiments was aimed at examining the regional pattern and cellular distribution of possible therapeutic targets, histone deacetylases, in treating the symptoms of Huntington's disease. In the first set of...
Show moreThe work presented in this dissertation represents investigations into the mechanism of two neurological disorders. The first set of experiments was aimed at examining the morphology of post-synaptic structures called dendritic spines in a mouse model of Down's syndrome. The second set of experiments was aimed at examining the regional pattern and cellular distribution of possible therapeutic targets, histone deacetylases, in treating the symptoms of Huntington's disease. In the first set of experiments, we examined a mouse model of Down's syndrome, the Ts65Dn mouse, to determine if it mimics the dendritic spine abnormalities in area CA1 of hippocampus that have been documented in human individuals with the disorder. The Ts65Dn mouse represents a partial trisomy of the murine chromosome homologous to a large portion of human chromosome 21, which is present in 3 copies rather than 2 in Down's syndrome. These mice show behavioral abnormalities and learning deficits that are thought to replicate the mental retardation that is a prominent characteristic of Down's syndrome. As many of the behavioral and learning paradigms used to test these mice require hippocampal function, and neurons from hippocampal tissue taken from Down's syndrome individuals show a reduction in the density of dendritic spines, we sought to determine if Ts65Dn mice exhibit the same morphological abnormality. Dendritic spine densities on the apical branches of CA1 hippocampal neurons in Ts65Dn animals were not significantly different when compared to those from euploid (normal chromosome number) littermates. In addition, morphological analysis of dendritic spine shape demonstrated that the proportion of dendritic spines in each of the four major spine shape categories (stubby, thin, filopodia and mushroom) was not different between the two conditions. As the environment for cells in a cultured slice are most likely very different from those experienced in the intact animal, we examined if neurons in the intact brain exhibited signs of abnormal dendritic spine density in the Ts65Dn mouse. Analysis of dendritic spine densities on apical branches of CA1 hippocampal neurons from mice sacrificed at 2 weeks, 3 months or 6 months of age showed no significant differences between the euploid and trisomic conditions. Furthermore, Western blot analysis showed that Ts65Dn do not have reduced expression of a dendritic spine protein, drebrin, as has been reported in Down's syndrome. The second set of experiments that are described concern the immunohistochemical localization of two enzymes involved in the transcriptional regulation of genes. These enzymes, called histone deacetylases, or HDACs, aid in the regulation of histone acetylation levels as a mechanism to control access of transcription factors to gene sequences. Recently, it was found that compounds that inhibit enzymes that remove acetyl groups demonstrate therapeutic effects in animal models of Huntington's disease, a neurodegenerative disorder that targets brain regions important for movement control. The work presented here describes the immunohistochemical localization of a HDAC2 and HDAC7. HDAC7 immunohistochemistry was consistent with biochemical studies demonstrating that HDAC7 can be present in both the cytoplasm and the nucleus. A finding of interest is that not all neurons of the murine brain express HDAC7, nor is it localized to the same subcellular compartment in all cell types. Granule cells of the hippocampal dentate gyrus and of the cerebellum showed very little immunoreactivity for HDAC7. Apical dendrites of the CA1 and CA3 regions of hippocampus showed very heavy cytoplasmic staining. Deeper cortical layers showed pyramidal neurons with heavier staining than superficial pyramidal layers in almost all cortical regions, except for the orbital, insular and piriform cortices which showed heavy staining in superficial layers as well. In general, staining of the olfactory system appeared more intense than other sensory system regions. Fibers along the striatonigral bundle, from the caudate to the substantia nigra reticulata showed heavy immunoreactivity. These data suggest that targeting therapeutics to HDAC7 activity may indeed be useful, as the striatonigral pathway is a key component of movement control. HDAC2 immunoreactivity confirmed that HDAC2 is strictly a nuclear localized protein. In addition, it appeared that HDAC2 is ubiquitously expressed throughout the murine brain in all brain regions. Interestingly, HDAC2 staining occurred only in neurons that showed NeuN staining, demonstrating that it is a neuron-specific protein. Therefore, therapeutic inhibition of HDACs that include inhibition of HDAC2 may affect many aspects of neurologic functioning in multiple brain regions. It is our hope that this work will provide some added detail and knowledge to the greater neuroscience community, and will aid in the greater understanding of the organization and function of the brain and ultimately aid in development of treatments for and ultimately the cure of neurological diseases and disorders.
Show less
Date Issued: 2008
Identifier: FSU_migr_etd-0082
Format: Thesis

Title: Construction and Analysis of a Transgenomic Cytogenetic Sorghum (Sorghum Propinquum) BAC Fish Map of Maize (Zea Mays L.) Pachytene Chromosome 9.
Creator: Amarillo, Ferdinand Enginco, Bass, Hank W., Levenson, Cathy W., Bates, George W., Fadool, James M., Keller, Laura R., Department of Biological Science, Florida State University
Abstract/Description: Large-scale cytogenetic mapping in maize has been a major challenge primarily due to fact that the maize genome has a low gene density and an abundance of repetitive sequence elements. Using a unique combination of biological and genome resources for maize, sorghum, and oat, we have solved this problem and produced a cytogenetic FISH map of maize pachytene-stage chromosome 9 with 32 maize markers. The genetically mapped markers used are distributed along the linkage maps at an average spacing...
Show moreLarge-scale cytogenetic mapping in maize has been a major challenge primarily due to fact that the maize genome has a low gene density and an abundance of repetitive sequence elements. Using a unique combination of biological and genome resources for maize, sorghum, and oat, we have solved this problem and produced a cytogenetic FISH map of maize pachytene-stage chromosome 9 with 32 maize markers. The genetically mapped markers used are distributed along the linkage maps at an average spacing of 5 centiMorgans. Each locus was mapped by means of multicolor direct FISH with a fluorescently labeled probe mix containing a whole chromosome paint, a single sorghum BAC clone, and the centromeric sequence, CentC. A maize-chromosome-addition line of oat was used for bright unambiguous identification of the maize 9 fiber within pachytene chromosome spreads. The locations of the sorghum BAC FISH signals were determined, and each new cytogenetic locus was assigned a centiMcClintock position on the short (9S) or long (9L) arm. Nearly all of the markers appeared in the same order on linkage and cytogenetic maps but at different relative positions on the two. The CentC FISH signal was localized between tda66 (at 9S.03) and cdo17 (at 9L.03). Several regions of genome hyperexpansion on maize chromosome 9 were found by comparative analysis of relative marker spacing in maize and sorghum. This transgenomic cytogenetic FISH map creates anchors between various maps of maize and sorghum integrating genetic markers, BAC fingerprints, and BAC hybridization data. It will provide tools for validating sequenced genomes, a foundation for exploring genomic diversity among related species, and a framework for comparative mapping of other plants with large and complex genomes.
Show less
Date Issued: 2007
Identifier: FSU_migr_etd-0189
Format: Thesis

Title: Gene Expression Profiling of Flagellar Length Control in Chlamydomonas Reinhardtii.
Creator: Chamberlain, Kara Lista, Keller, Laura R., Levenson, Cathy W., Bass, Hank W., Epstein, Lloyd M., Houpt, Thomas A., Department of Biological Science, Florida State University
Abstract/Description: Complex organelles, such as cilia and flagella, play an integral part in how a cell interacts with the environment. The model system Chlamydomonas reinhardtii is a biflagellate alga that uses its flagella for swimming and sensing the environment. C. reinhardtii monitor and respond to environmental cues through changes in cellular morphology and gene expression. I used gene expression profiling to characterize the global response of stimulus-induced changes in flagellar morphology and gene...
Show moreComplex organelles, such as cilia and flagella, play an integral part in how a cell interacts with the environment. The model system Chlamydomonas reinhardtii is a biflagellate alga that uses its flagella for swimming and sensing the environment. C. reinhardtii monitor and respond to environmental cues through changes in cellular morphology and gene expression. I used gene expression profiling to characterize the global response of stimulus-induced changes in flagellar morphology and gene expression in C. reinhardtii. Previous investigations have demonstrated coordination between changes in flagellar morphology with changes in gene expression. When C. reinhardtii encounters various stimuli the cell responds through changes in flagellar length, such as assembly, disassembly, and elongation. I created a custom microarray assay to examine the transcript regulation associated with these changes in flagellar length. Using this technique, approximately 1000 genes were evaluated in a single experiment to create a global gene expression profile. While the transcriptional regulation of flagellar assembly is well characterized, that of flagellar disassembly and elongation is less understood. Using high throughput microarrays, I analyzed the changes in gene expression associated with flagellar assembly, disassembly and elongation. Microarrays were probed with fluorescently labeled cDNAs synthesized from RNA extracted from cells before and during stimulation. Evaluation of the gene expression profiles identified ~100 clones showing at least a 2-fold change in expression during changes in flagellar length. Products of these genes are associated not only with flagellar structure and motility but also with other cellular responses including signal transduction and metabolism. Expression of specific genes from each category was further characterized with high resolution quantitative real-time PCR (qRT-PCR). Comparison of the gene expression profiles demonstrated coordinate expression of cell motility component genes during flagellar assembly and disassembly; whereas comparison of the assembly and elongation expression profiles demonstrated that these morphological changes are very different responses at a transcriptional level. Furthermore, transcript regulation of genes involved in other cellular activities revealed a new and uncharacterized whole cell response to stimulation. This analysis lays the groundwork for a more comprehensive understanding of the cellular and molecular networks regulating flagellar length changes.
Show less
Date Issued: 2007
Identifier: FSU_migr_etd-0158
Format: Thesis

Title: Sexual Selection, Fertilization Dynamics and the Use of Alternative Mating Tactics in the Hermaphroditic Seabass Serranus Subligarius.
Creator: Adreani, Mia Susan, Levitan, Don, Travis, Joseph, Wang, Zuoxin, Houle, David, Koenig, Christopher, Department of Biological Science, Florida State University
Abstract/Description: The use of an alternative male mating tactic is frequently discussed as an option that makes the best of a bad situation for disadvantaged males and not as part of an adaptive system that can produce equal average levels of reproductive success for individuals using each tactic. It is easy to develop scenarios in which some combinations of tactics produce greater success than others; the difficulty of testing hypotheses about these scenarios and the optimal distribution of tactics revolves...
Show moreThe use of an alternative male mating tactic is frequently discussed as an option that makes the best of a bad situation for disadvantaged males and not as part of an adaptive system that can produce equal average levels of reproductive success for individuals using each tactic. It is easy to develop scenarios in which some combinations of tactics produce greater success than others; the difficulty of testing hypotheses about these scenarios and the optimal distribution of tactics revolves around the difficulty of understanding how tactics are expressed. To be specific, it is unknown whether alternative behaviors are conditional and if conditional, how an individual assesses and ultimately chooses which tactic to use in any given context. Under conditions of limited mate availability, variable resource allocation or altered physiological response (e.g. temperature or poor food quality), one might expect variation in mating patterns, but the direction and extent of these variations is relatively unknown. In the simultaneously hermaphroditic marine fish, Serranus subligarius, male role individuals are known to pair spawn, group spawn and streak spawn. These mating strategies are common among marine reef fish and their behavior has been well studied. What is unclear is how each behavior translates into reproductive success and how these competing strategies are maintained within the same population. This research will focus on the use of alternative mating tactics among simultaneous hermaphrodites. The majority of simultaneous hermaphrodites mate in pairs, often cross-fertilizing each other. Alternative tactics among external fertilizers include group spawning, sneak spawning (males mimic females), or streak spawning, in which a male releases sperm over a spawning event already in progress. In this dissertation I examined the ecological and social contexts under which alternative tactics are utilized and their resulting outcomes with respect to mating behavior and fertilization success. Chapter one investigates the role of simultaneous hermaphrodites in sexual selection and reviews several studies in which sexual selection is revealed in systems with equal allocation to sex. I discuss ways in which sexual selection has been measured and suggest ways in which this may be modified in hermaphrodites. I also indicate ways in which males compete and females are chosen in these systems, despite their ability to mate with any other individual. Finally, I implicate some of the potential causes of sexual conflict in my study system; namely, that individuals vie for the male role and larger fish spawn more frequently in the male role. In chapter two, I explored the ecological and physiological contexts under which streak spawning occurs and discuss their relative importance. Size structure was characterized at each of three sites within the field study site and was subsequently used as the impetus for the experiments performed in Chapter 3 to tease out its relevance. Size structure appears to play an important role in the occurrence of streak spawning, as more streaking appears in the sites, which have greater than 20% of individuals comprised of the small size class (measured by density transects at three sites). This chapter also aims to quantify the type of habitat over which a pair spawns and whether or not this differs when additional males participate. I found that at one of the sites, there was a preference for streak spawners when macroalgae was present than when the rocks were bare. In addition, this chapter demonstrates the peak spawning times to be July and August, which were confirmed by both field observations and investigation of the gonads of actively mating individuals. In chapter three, I investigated the fertilization success of animals spawning with and without streakers participating, both in the field and in a controlled manipulation experiment. In the field I find that fertilization rates are lower in fish spawning with multiple males participating. I confirmed this finding under more controlled conditions in a field manipulation experiment. Rock rubble reef plots provided substrate on which I tested the role of density and size structure on the frequency of streak spawning and resulting fertilization success. Spawns with additional males resulted in lower fertilization success and the number of streak spawns was significantly greater when small size-class individuals were present. Thus, both field and experimental evidence suggest that small individuals predict the incidence of streak spawning and their participation lowers fertilization success. Reduced fertilization success means that both males and females incur a fitness cost. The mechanism for lowered success remains unclear but likely includes the physical disturbance created in the water column by the activity of additional males. The results of this dissertation suggest that there may be a cost to certain mating systems and the contexts under which these different tactics are utilized are dependent on ecological, social and physiological factors. It points to the complexities of individual variation in behavior and the need for more rigorous experimental work to tease apart the factors associated with variation in mating tactic. Interactions among environment, social group, and ontogeny are not often addressed simultaneously in study systems and more empirical work in these areas would help elucidate the mechanisms associated with the use of alternative mating tactics.
Show less
Date Issued: 2011
Identifier: FSU_migr_etd-0122
Format: Thesis

Title: The Batoid Tree of Life: Recovering the Patterns and Timing of the Evolution of Skates, Rays and Allies (Chondrichthyes: Batoidea).
Creator: Aschliman, Neil C., Naylor, Gavin J.P., Steppan, Scott J., Parker, William C., Mast, Austin R., Department of Biological Science, Florida State University
Abstract/Description: Batoid fishes (skates, stingrays and allies) comprise the majority of species diversity and morphological disparity among chondrichthyans, one of the two primary divisions of extant jawed vertebrates. The largely recent and growing interest in batoid evolution has emphasized the need for a well-supported phylogeny against which evolutionary changes in traits can be interpreted. While batoids are morphologically well characterized and have an excellent fossil record, there is currently no...
Show moreBatoid fishes (skates, stingrays and allies) comprise the majority of species diversity and morphological disparity among chondrichthyans, one of the two primary divisions of extant jawed vertebrates. The largely recent and growing interest in batoid evolution has emphasized the need for a well-supported phylogeny against which evolutionary changes in traits can be interpreted. While batoids are morphologically well characterized and have an excellent fossil record, there is currently no consensus on the interrelationships of family-level taxa. Patterns of evolution within the two largest groups of batoids, skates and stingrays, also remain obscure. This dissertation presents novel frameworks for interpreting the patterns and timing of batoid evolution based on molecular data, morphology, and fossils. I recovered a resolved and time-calibrated phylogeny of the major extant groups of batoids using mitochondrial genomes, two independent nuclear markers, and fossil ages. Taxon sampling included 37 ingroup species from 22 of 23 families. Data partitioning schemes, potential biases in the sequence data, the relative informativeness of each fossil, and ancestral state reconstructions were explored. The molecular data set was then expanded with additional species in order to address questions at a finer taxonomic scale, in particular among skates and stingrays. Two nuclear and two mitochondrial markers were sequenced for 87 batoid species across 52 of 81 genera. A similar analytical approach was applied to this larger data set. I also performed a morphology-based phylogenetic analysis in order to interpret accurately coded morphological characters against the molecular frameworks. I updated the data set of McEachran and Aschliman (2004) with a number of corrections and modifications, and added new characters from the synarcual and other chondroskeletal structures. The molecular phylogenies indicate that the major lineages of batoids originated in relatively rapid sequence, followed by long periods of independent evolution. These trees corroborate morphology-based hypotheses in many respects, but have strongly divergent implications in others. Lineages inferred to be distantly related, such as skates and stingrays, or sawfishes and sawsharks, are indicated to have achieved very similar, specialized body plans through convergence. Skates and stingrays are unique among batoids in exhibiting a highly depressed disc supported to the apex by fin rays, and swim by passing waves along the lateral margin of the pectoral fin without additional propulsion by lateral motion of the tail and caudal fin. The plesiomorphic mode of locomotion and body plan for most batoid groups was probably not shark-like, as in sawfishes. Instead, it is inferred to be a combination of pectoral fin undulation and shark-like axial locomotion, which is correlated with a broader pectoral disc and reduced tail compared to the sawfish body plan. The higher-resolution molecular phylogeny is in many cases congruent with previous morphological studies or biogeography. Exceptions typically suggested a potential weakness in the molecular data, suggested that a morphology-based classification scheme is likely based on convergent characters or ignores a highly divergent morphotype nested within otherwise similar taxa, or helped resolve taxonomic confusion based on informal re-assignment by authority. Potentially non-monophyletic families and genera were identified for future study with expanded taxon sampling, additional sequence data and morphological re-evaluation. The origin of Batoidea is estimated to have occurred in the Late Triassic, with the major groups diverging throughout the Jurassic and possibly into the Cretaceous. Radiations of each major crown group are indicated to have occurred from the Late Cretaceous to the Cenozoic. The tree shape recovered for all major batoid groups, with long internal branches subtending subsequent radiations around the Cretaceous/Tertiary boundary, suggests that batoid standing diversity may be due in large part to lineage pruning and/or rapid radiation into vacated niche space. This is consistent with the fossil record, which suggests that batoids were more severely affected by the end-Cretaceous extinction event than were the other neoselachians. The updated morphological phylogeny included several key changes from earlier hypotheses and more closely approximates the molecular frameworks. There remain conflicts between morphological and molecular trees, such as the phylogenetic placements of skates and thornbacks, which currently appear to be difficult to reconcile. Future attempts to reconcile molecules and morphology will require expanded data sets and investigation of potential sources of error in each.
Show less
Date Issued: 2011
Identifier: FSU_migr_etd-0242
Format: Thesis

Title: The Role of Evolution in Maintaining Coexistence of Competitors.
Creator: Pastore, Abigail I. (Abigail Ilona), Miller, Thomas E., Bertram, R. (Richard), Inouye, Brian D., Steppan, Scott J., Winn, Alice A., Florida State University, College of Arts and...
Show morePastore, Abigail I. (Abigail Ilona), Miller, Thomas E., Bertram, R. (Richard), Inouye, Brian D., Steppan, Scott J., Winn, Alice A., Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Species interactions can regulate a population’s density and therefore can act as a selective force on that population. Such evolutionary responses have the potential to feedback and change ecological interactions between species. For species that compete for resources, the interaction between ecological and evolutionary dynamics will regulate the stability of the species interactions, determining whether competing species can coexist. The outcome of competition between species is determined...
Show moreSpecies interactions can regulate a population’s density and therefore can act as a selective force on that population. Such evolutionary responses have the potential to feedback and change ecological interactions between species. For species that compete for resources, the interaction between ecological and evolutionary dynamics will regulate the stability of the species interactions, determining whether competing species can coexist. The outcome of competition between species is determined by two factors: (1) niche overlap, or the similarity in how species use resources and are affected by their environment, and (2) fitness differences, or differences in how efficiently each species uses resources in their environment. Decreasing niche overlap will decrease competitive interactions, thereby stabilizing coexistence. Decreasing fitness differences makes species more equal in their competitive abilities, facilitating coexistence. In the absence of evolutionary constraints, both niche overlap and fitness differences among species are subject to change as a consequence of evolution among competitors, and thus ecological dynamics between two species will also change. In this dissertation, I develop a broader understanding of (1) how niche overlap and fitness differences between species change after evolution in response to competition, (2) how changes in niche overlap and fitness differences are mediated through changes in resource use of protists, and (3) what role evolutionary history plays in shaping ecological and evolutionary dynamics. I address these goals with a suite of approaches including theoretical models, an experimental lab system, and comparative methods. I constructed a quantitative genetic model of trait evolution, where the trait of a species determined its resource use, and found that species are prone to change in their niche overlap as well as their fitness differences as a result of trait evolution. However, the magnitude of changes in niche overlap and fitness differences were determined by the resource availability within the environments. When resources were broadly available, species changed more in their niche overlap, whereas when resources were narrowly available, species changed more in their fitness difference. To test these predictions, I developed a system in the laboratory where protists competed for a bacterial resource. Species were allowed to evolve in either monoculture or a two-species mixture; the effects of evolution on competition, niche overlap and fitness differences were quantified using parameterized models. In general I found that species tended to converge in their niche as a result of evolution, however, changes in fitness differences between species were larger and more influential on coexistence than changes in niche differences. Both increases in niche overlap, and increases in fitness differences decreased coexistence among species pairs. By describing the bacterial communities associated with these protists before and after selection I determined that protists tended to converge or not change in which bacteria they were consuming as a result of selection. Additionally, for eleven protist species, I determined whether traits or relatedness predicted competitive ability by placing species on a molecular phylogeny and conducting pairwise competition experiments for all pairs. I found no correlations, suggesting neither traits, nor evolutionary history was informative for explaining current ecological and evolutionary interactions in this deeply divergent clade. There are two major conclusions from this dissertation: (1) when species evolve in response to competition, changes in fitness differences may often be more important than changes in niche overlap, (2) evolution can, and may be likely to, decrease the ability of species to coexist through increases in niche overlap and increases in fitness differences. This work suggests that one must simultaneously consider the role of evolutionary and ecological processes to understand community processes. Specifically, when researchers are attempting to explain mechanisms of coexistence between species, they must consider how evolutionary dynamics may change the ecological interactions within communities of competitors.
Show less
Date Issued: 2017
Identifier: FSU_FALL2017_Pastore_fsu_0071E_14135
Format: Thesis

Title: Composition and Stability of Single-Stranded DNA Viral Populations in Wastewater Treatment Plants.
Creator: Pearson, Victoria M., Rokyta, Darin, Beerli, Peter, Dennis, Jonathan Hancock, Hughes, Kimberly A., Tang, Hengli, Florida State University, College of Arts and Sciences,...
Show morePearson, Victoria M., Rokyta, Darin, Beerli, Peter, Dennis, Jonathan Hancock, Hughes, Kimberly A., Tang, Hengli, Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Regular emergence and re-emergence of viral pathogens emphasizes the importance of understanding viral biogeography and migration. Single-stranded DNA (ssDNA) viruses are among the least understood groups of microbial pathogens, yet the group contains known agricultural pathogens, which infect both livestock and crops (Circoviridae and Geminiviridae), and model organisms (Microviridae). Wastewater treatment plants (WWTPs) receive water from multiple sources, becoming reservoirs for the...
Show moreRegular emergence and re-emergence of viral pathogens emphasizes the importance of understanding viral biogeography and migration. Single-stranded DNA (ssDNA) viruses are among the least understood groups of microbial pathogens, yet the group contains known agricultural pathogens, which infect both livestock and crops (Circoviridae and Geminiviridae), and model organisms (Microviridae). Wastewater treatment plants (WWTPs) receive water from multiple sources, becoming reservoirs for the collection of many viral families that infect a large range of hosts. Investigations utilizing high-throughput sequencing have determined that local viral diversity is extremely high but does not scale to produce an exponentially higher global diversity. It follows that similar genotypes can be found great distances apart, although they may not be permanent constituents of any single population. Transient genotypes have been observed in temporal surveys of closed systems, where genotypes migrate between individual populations. This study focused on the geographic and temporal population stability of single-stranded DNA (ssDNA) viruses in open systems. Sampling from WWTPs in three neighboring cities in Northwest Florida, which receive constant inflow and potentially receive the same viruses from the local environment, was conducted across a nine-month time span. A combination of polyethylene glycol (PEG) precipitation and filter concentration was used to isolate whole viral particles from the complex wastewater samples. The ssDNA viruses were isolated from larger viruses using a sucrose gradient for size selection and rolling circle amplification was performed to both bias the sample towards ssDNA and prepare the samples for high-throughput sequencing. Amplified genomes were sequenced using Illumina platforms and de novo assembled. Given the increased potential for migration, we expected the populations would be mostly homogenous with relatively few viruses that are unique to individual WWTPs. Viral genotypes with genetic similarity to Circoviridae, Geminiviridae, and Microviridae were recovered from all three WWTPs, however <25% of recovered genes match genotypes (>80% amino acid identity) recovered from neighboring sample sites. We determined that <10% of the genotypes were present in all three plants and the majority of genotypes were specific to one WWTP. Unexpectedly, the WWTPs that were closest to each other geographically were the least similar, and the plants geographically distant from each other had the most observed genetic overlap. These results highlight the high level of diversity within each population, while the high observed heterogeneity indicates localized genetic success and limited migration opportunities between the WWTPs. Throughout time the communities experienced a large degree of genetic turnover. Only 30% of the genotypes were present in more than one time point, 5% were recovered in three of more samplings and <1% were present in all five time points. This thesis concludes that viral genomes are continually moving through the environment and their presence in any given area may be temporary. Therefore, viruses are a continual selective force on their host species through the sheer volume of genetic potential in an area at any given time.
Show less
Date Issued: 2017
Identifier: FSU_FALL2017_Pearson_fsu_0071E_14170
Format: Thesis

Title: Evolution of the Material Properties of Mineralized Dental Tissues.
Creator: Kay, David Ian, Erickson, Gregory M., Lenhert, Steven John, Oates, William, Steppan, Scott J., Florida State University, College of Arts and Sciences, Department of Biological...
Show moreKay, David Ian, Erickson, Gregory M., Lenhert, Steven John, Oates, William, Steppan, Scott J., Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: During their 473 million-year diversification, gnathostomes came to exploit an unprecedented variety of trophic niches. Modifications to dental form and mineralized tissue constituents (i.e. enamel, dentines and in a few taxa, cementum) facilitated their exploitation of novel prey and/or plant matter. In general, it has been assumed that the intra-tissue level biomechanics of these constituents had little bearing on whole-tooth functionality, aside from enamel in mammals showing dental...
Show moreDuring their 473 million-year diversification, gnathostomes came to exploit an unprecedented variety of trophic niches. Modifications to dental form and mineralized tissue constituents (i.e. enamel, dentines and in a few taxa, cementum) facilitated their exploitation of novel prey and/or plant matter. In general, it has been assumed that the intra-tissue level biomechanics of these constituents had little bearing on whole-tooth functionality, aside from enamel in mammals showing dental occlusion. Specifically, many mammals possess teeth that self-wear to functionality and show a diversity of derived dental tissues (e.g. prismatic enamel fabrics, coronal cementum) – some which have been shown to possess unique biomechanical attributes to resist wear and fracture. Here I formally test the hypothesis that the primitive gnathostome hard tissue material properties remained static prior to the cladogenesis of Mammalia. An ancillary goal is to glean initial insights on how the material properties of these dental tissues in non-mammalian and mammalian taxa may contribute to whole-tooth form, function, performance and diets. Properties were tested and examined using two standardized material science techniques, microindentation and nanoindentation, as well as a novel technique for quantifying fracture propagation from cracks formed during microindentation. The results from this investigation suggest these material properties are highly variable among gnathostome dentitions. Aside from hardness, there is not a significant relationship between most material properties and diet aside from enamel hardness. There are also complex fracture patterns seen in the enamels of mammals and chondrichthyans, showing that gnathostome lineages independently evolved properties to control fracture and damage done to tooth enamel. Overall, this study suggests that in the case of enamel hardness, natural selection operated at the tissue level to bring about shifts in tooth functionality throughout the gnathostome radiation. More material properties (i.e. fracture toughness) need to be investigated to uncover the true functional import of material properties in dental tissues and establish how the tissue complexes contributed to whole tooth function.
Show less
Date Issued: 2017
Identifier: FSU_FALL2017_Kay_fsu_0071N_14152
Format: Thesis

Title: Identification and Characterization of Mutants That Affect Stem Cell Renewal in the Arabidopsis Root.
Creator: Fleming, Monica, Department of Biological Science
Abstract/Description: SCARECROW (SCR) is a transcription factor with a pivotal role in radial patterning and stem cell renewal in the Arabidopsis root, making it a great tool for stem cell research. How SCR regulates stem cell renewal is still not clear. This research focuses on understanding stem cell renewal in the Arabidopsis root through identification and characterization of mutations that affect SCR. Understanding how these mutations regulate root growth could advance our understanding of the mechanisms that...
Show moreSCARECROW (SCR) is a transcription factor with a pivotal role in radial patterning and stem cell renewal in the Arabidopsis root, making it a great tool for stem cell research. How SCR regulates stem cell renewal is still not clear. This research focuses on understanding stem cell renewal in the Arabidopsis root through identification and characterization of mutations that affect SCR. Understanding how these mutations regulate root growth could advance our understanding of the mechanisms that control stem cell renewal in all organisms.
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0307
Format: Thesis

Title: A Multipurpose Protocol to Characterize Concussion Symptoms in College Athletes.
Creator: Galletti, Christopher, Department of Biological Science
Abstract/Description: With 1.6 to 3.8 million sports-related concussions (SRCs) per year and an uncertain definition of concussion or mild traumatic brain injury (mTBI), there is a great need for a model to clarify the diagnosis and assessment of concussions and mTBIs. In addition, the effects of post-concussion syndrome (PCS) can be debilitating if not properly treated. College athletes are at an increased risk for repetitive head injury while still suffering from PCS, which can lead to the rare and deadly second...
Show moreWith 1.6 to 3.8 million sports-related concussions (SRCs) per year and an uncertain definition of concussion or mild traumatic brain injury (mTBI), there is a great need for a model to clarify the diagnosis and assessment of concussions and mTBIs. In addition, the effects of post-concussion syndrome (PCS) can be debilitating if not properly treated. College athletes are at an increased risk for repetitive head injury while still suffering from PCS, which can lead to the rare and deadly second impact syndrome (SIS). To improve the management and assessment of concussions, a comprehensive approach will provide objective and quantitative measures using novel methods including postural stability and aerobic exercise testing to complement existing measures of standard assessment of concussion (SAC), concussion grading scale (CGS), and ImPACT. This pilot study collected baseline data from subjects using this multipurpose protocol, which will serve as a reference when comparing concussed subjects. This study provides the framework to diagnose and manage the treatment of concussed college athletes in order to provide an accelerated, yet safe return-to-play (RTP).
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0309
Format: Thesis

Title: The Effect of Selection on Early and Late Age Mating Proportion in Drosophila melanogaster.
Creator: Heinrichs, Erica, Hughes, Kimberly, Department of Biological Science
Abstract/Description: Within a population, organisms show variation in longevity and age- associated performance. In addition, experimental evolution studies and comparative analyses often reveal trade-offs between lifespan and early-age reproduction. For example, a recent analysis of experimentally evolved Drosophila melanogaster indicated that flies that had evolved longer life had also evolved lower early-age fecundity (Remolina et al. 2012). Other experimentally evolved populations of flies have shown similar...
Show moreWithin a population, organisms show variation in longevity and age- associated performance. In addition, experimental evolution studies and comparative analyses often reveal trade-offs between lifespan and early-age reproduction. For example, a recent analysis of experimentally evolved Drosophila melanogaster indicated that flies that had evolved longer life had also evolved lower early-age fecundity (Remolina et al. 2012). Other experimentally evolved populations of flies have shown similar patterns (Rose 1984; Luckinbill et al. 1984) To determine if this tradeoff is potentially due to decreased investment in early-age reproductive behavior in populations with increased longevity, I measured the mating rate in replicated selection and control lines. In this study, I determined the effects of selection, age and selection by age interaction on the proportion mated within twenty minutes. The effect of age and selection by age interaction were not significant, however the overall effect of selection approached significance. Therefore, the difference between selection and control populations in the proportion of mating is not age-specific. Thus, these results do not support the hypothesis that the tradeoff between longevity and fecundity is mediated by reproductive behavior. However, the selection population tends to have higher mating proportion late in life compared to the control population. This increase in mating proportion at late ages in the selection population could underlie the higher in fecundity at late ages seen in the selected populations.
Show less
Date Issued: 2013
Identifier: FSU_migr_uhm-0212
Format: Thesis

Title: The Seasonal Natural History of Pheidole morrisi Forel.
Creator: Murdock, Tyler, Department of Biological Science
Abstract/Description: The small golden ant Pheidole morrisi Forel is the most common ant of the Apalachicola National Forest, a typical longleaf pine flat-woods ecosystem and is found in pine forests across the eastern U.S. P. morrisi likely plays a significant role in these important North American ecosystems, yet many aspects of the ant's life history, including its annual cycle, remain un-investigated. To determine the annual cycle and life history of P. morrisi a range of colony sizes were censused by wax...
Show moreThe small golden ant Pheidole morrisi Forel is the most common ant of the Apalachicola National Forest, a typical longleaf pine flat-woods ecosystem and is found in pine forests across the eastern U.S. P. morrisi likely plays a significant role in these important North American ecosystems, yet many aspects of the ant's life history, including its annual cycle, remain un-investigated. To determine the annual cycle and life history of P. morrisi a range of colony sizes were censused by wax-casting entire nests, excavating the casts, segregating sections of the casts by their depth from the surface, and retrieving the ants by melting the wax. This technique provided data on the numbers of the different colony members as well as their locations in the nest. This procedure was repeated throughout the year to capture major phases of the seasonal cycle, along with changes in colony demography. P. morrisi produced two cohorts of brood annually and overwintered larvae. These phases of worker brood are separated by a phase of alate production. Soil temperatures at the time of casting showed that the brood were usually kept in the warmest regions of the nest, which varied seasonally from 18 to 26 oC. The proportion of the colony composed of majors was different between colonies at different stages of growth, but did not change seasonally. A number of other colony-level attributes were related to season, depth, or colony size.
Show less
Date Issued: 2013
Identifier: FSU_migr_uhm-0190
Format: Thesis

Title: The Standardization of Animal Markers for Mild Traumatic Brain Injury.
Creator: Glickman, Jaisyn, Department of Biological Science
Abstract/Description: Mild Traumatic Brain Injury (mTBI) is the most common type of TBI leading to other long-term neurodegenerative disorders. mTBI is known to effect a significant percentage of the men and women in athletics, military and motor vehicle accidents to name a few. TBI is credited with multiple neurological disorders. To date, the majority of research and development on the issue of mTBI has been focused on protection and detection. At present, there is no clinically validated specific brain-targeted...
Show moreMild Traumatic Brain Injury (mTBI) is the most common type of TBI leading to other long-term neurodegenerative disorders. mTBI is known to effect a significant percentage of the men and women in athletics, military and motor vehicle accidents to name a few. TBI is credited with multiple neurological disorders. To date, the majority of research and development on the issue of mTBI has been focused on protection and detection. At present, there is no clinically validated specific brain-targeted pharmacotherapy that will ameliorate the neurobehavioral effects associated with mTBI. The goal of this work was to establish the differences in behavioral and molecular markers for mTBI compared to uninjured animals as a foundation for future drug development work. Male Sprague-Dawley rats were given anesthesia and a closed-head cortical injury was induced using an electrically controlled device. Groups included; uninjured shams and brain-injury-vehicle (β-cyclodextrin). Vehicle injections were given intraperitoneal at 15 minutes, 6 and 24hr. Neurobehavioral testing was performed at 24 and 48hr following injury. Brain extractions were performed at the same time periods and assayed for protein expression. Protein markers were chosen to analyze edema, inflammation, demyelination and oxidative stress. An assessment for memory using the Morris Water Maze showed a significant injury effect. Measurements for thigmotaxic behavior, indicating anxiety, showed a significant injury effect. Sensory and motor performance using composite neuroscoring showed a significant injury effect. Balance testing revealed a significant deficit in injured animals. Molecular markers chosen also showed a significant injury effect. This work has provided both behavioral and molecular measures for a rat model of mTBI. Future work will use these same measures and include neuroprotective drug treated groups. The first class of drugs to be analyzed for protective effects will be steroidal.
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0311
Format: Thesis

Title: The role of salivary proline rich proteins in the acceptance of quinine.
Creator: Martin, Laura, Department of Biological Science
Abstract/Description: Not much is known about the effects of saliva on bitter taste modulation, although there has been evidence suggesting a relationship between proline-rich proteins and increased acceptance of tannin-containing diets. This experiment was designed to determine if there is a similar relationship between proline-rich proteins and acceptance of other bitter taste stimuli, namely quinine. In this experiment, we monitored the microstructure of feeding behavior in rats exposed to a control diet, and...
Show moreNot much is known about the effects of saliva on bitter taste modulation, although there has been evidence suggesting a relationship between proline-rich proteins and increased acceptance of tannin-containing diets. This experiment was designed to determine if there is a similar relationship between proline-rich proteins and acceptance of other bitter taste stimuli, namely quinine. In this experiment, we monitored the microstructure of feeding behavior in rats exposed to a control diet, and compared this to the feeding behavior of rats that were given a 0.375% quinine-containing diet. We simultaneously monitored the protein expression of these animals via a saliva collection method that alters neither the protein expression, nor the behavior. This allowed us to look for predictive relationships between protein expression and changes in the rat's behavior. We found a protein band at 35 kDa, a PRP, and cystatin S, a cistine protease inhibitor, were upregulated in response to the quinine-containing diet. Changes in cystatin S predicted increases in both meal size (g) and rate of feeding (g/min), while changes in the band at 35 kDa predicted increases in rate of feeding (g/min). These data suggest that PRPs may not only play a role in the acceptance of tannins, but also in the acceptance of other bitter taste stimuli.
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0352
Format: Thesis

Title: Cell Adhesion and Motility on Biocompatible Polyelectrolyte Multilayers.
Creator: Martinez, Jessica Susanne, Keller, Thomas C. S., Schlenoff, Joseph B., Keller, Laura R., Ma, Teng, Lenhert, Steven, Florida State University, College of Arts and Sciences,...
Show moreMartinez, Jessica Susanne, Keller, Thomas C. S., Schlenoff, Joseph B., Keller, Laura R., Ma, Teng, Lenhert, Steven, Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: To improve the design of prostheses surfaces, our research group investigates how biocompatible polyelectrolyte multilayers (PEMUs) can be constructed to serve as coatings for biomedical implants, providing a versatile, inexpensive, and potentially efficient solution to create anti-bacterial, anti-inflammatory, and biologically selective surfaces. More specifically, this dissertation research investigates how individual cells and cell sheets adhere and migrate on PEMUs constructed to have...
Show moreTo improve the design of prostheses surfaces, our research group investigates how biocompatible polyelectrolyte multilayers (PEMUs) can be constructed to serve as coatings for biomedical implants, providing a versatile, inexpensive, and potentially efficient solution to create anti-bacterial, anti-inflammatory, and biologically selective surfaces. More specifically, this dissertation research investigates how individual cells and cell sheets adhere and migrate on PEMUs constructed to have uniform and gradients of modulus and how individual cells and gram negative bacteria, Escherichia coli, adhere to PEMUs constructed to have an anti-adhesive surface chemistry. In this investigation, PAH/PAA PEMUs are shown to be biocompatible compared to the soluble polycation PAH at concentrations above 0.1mM. Soluble PAH concentrations at 1 and 10mM cause irreversible damage to the plasma membrane of smooth muscle, A7r5, and bone, U2OS, cells. Additionally, adhesive and motile responses of cells are dependent on PEMU surface chemistry. Cells on PEMUs terminated with the polycation PAH relocalize their focal adhesions to their cell periphery and are highly motile compared to cells cultured on PAA terminated PEMUs and uncoated glass coverslips. To investigate effects of PEMU modulus on cell adhesion and motility, PEMUs were made with the polyanion PAA (poly(acrylic acid)) modified with a photosensitive 4-(2-Hydroxyethoxy) benzophenone (PAABp) and the polycation PAH (poly(allylamine hydrochloride)). UV irradiating PAH/ PAABp PEMUs forms covalent bonds between PE layers and consequently increases its Young's Elastic Modulus, while retaining innate surface chemistry. Individual cells and cell sheets detect differences in PEMU modulus and respond by varying morphology and behavior. These PAH/PAABp PEMUs modulate the adhesion, spreading, and migration of individual cells, specifically smooth muscle, bone, and fibroblast cells. PAABp containing PEMUs were constructed to have either a shallow (~5MPa mm-1) or a steep (~50MPa mm-1) modulus gradient. Only smooth muscle cells durotax along steep modulus gradients toward increasing modulus and orient toward increasing modulus on shallow modulus gradients. In contrast, bone cells discriminately adhere to the stiffest region of both steep and shallow modulus gradients and fibroblasts show no difference in behavior along any region of the gradients. Epithelial sheets, isolated as primary explants of fish epithelial tissue from the scales of fish Poecilia sphenops (Black Molly) and Carassius auratus (Comet Goldfish), orient toward increasing modulus on steep modulus gradient. Cell sheets collectively durotax near the ~90MPa region of the gradient toward increasing modulus. Surfaces with substantial zwitterionic functionality (possessing a net neutral surface charge due to equal contribution of both positive and negative charges in polymer side groups) have been shown to effectively prevent cell and protein attachment. PEMUs built with PAH (poly(allylamine hydrochloride)) and PAA (poly(acrylic acid)) containing the AEDAPS zwitterionic group 3-(2-(acrylamido)-ethyldimethyl ammonio) propane sulfonate (PAH/PAA-co-AEDAPS PEMUs) and a new benzophenone crosslinker to stiffen the thin film were shown to prevent rat aortic smooth muscle (A7r5) and mouse fibroblast (3T3) cells attachment, but failed to prevent irreversible attachment of biofilm-forming gram-negative bacteria Escherichia coli, strain ATCC-8739. AEDAPS containing PEMUs are hydrophilic and have increased nanoroughness of ~10nm. 'Super soaking' AEDAPS PEMUs incorporates more zwitterions into the PEMU and significantly maximizes the surface presentation of PAA-co-AEDAPS, which promotes early attachment of bacteria, but eventually, causes a gradual decrease in bacteria attachment with increasing incubation time. This investigation provides further insight into the possible application of PEMUs as bioselective thin film coatings, which may have potential for use in biomedical applications.
Show less
Date Issued: 2015
Identifier: FSU_2015fall_Martinez_fsu_0071E_12894
Format: Thesis

Title: Proteomic and Funcational Analysis of ORF45 Interactome during the Lytic Cycle of Kaposi’s Sarcoma-Associated Herpesvirus.
Creator: Gillen, Joseph G. (Joseph Gerald), Zhu, Fanxiu, Stagg, Scott, Tang, Hengli, Keller, Thomas C. S., Jones, Kathryn M. (Kathryn Marjorie), Florida State University, College of Arts...
Show moreGillen, Joseph G. (Joseph Gerald), Zhu, Fanxiu, Stagg, Scott, Tang, Hengli, Keller, Thomas C. S., Jones, Kathryn M. (Kathryn Marjorie), Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: ORF45 of Kaposi's sarcoma–associated herpesvirus (KSHV) is a gamma herpesvirus-specific, immediate-early, and tegument protein. Our previous studies have revealed its crucial roles in both early and late stages of KSHV infection. In this study, we surveyed the interactome of ORF45 using a panel of monoclonal antibodies. In addition to the previously identified extracellular regulated kinase (ERK) and p90 ribosomal S6 kinase (RSK) proteins, we found several other co-purified proteins,...
Show moreORF45 of Kaposi's sarcoma–associated herpesvirus (KSHV) is a gamma herpesvirus-specific, immediate-early, and tegument protein. Our previous studies have revealed its crucial roles in both early and late stages of KSHV infection. In this study, we surveyed the interactome of ORF45 using a panel of monoclonal antibodies. In addition to the previously identified extracellular regulated kinase (ERK) and p90 ribosomal S6 kinase (RSK) proteins, we found several other co-purified proteins, including prominent ones of ~38 kDa and ~130 kDa. Mass spectrometry revealed that the 38 kDa protein is viral ORF33 and the 130 kDa protein is cellular USP7 (ubiquitin-specific protease 7). We mapped the ORF33-binding domain to the highly conserved carboxyl terminal 19-aa of ORF45, and the USP7-binding domain to the reported consensus motif in the central region of ORF45. Using immunofluorescence staining, we observed colocalization of ORF45 with ORF33 or USP7, in both transfected conditions and KSHV-infected cells. Moreover, we noticed an ORF45-dependent relocalization of a portion of ORF33/USP7 from the nucleus to the cytoplasm. We found that ORF45 caused an increase in ORF33 protein accumulation, which was abolished if either the ORF33- or USP7-binding domain in ORF45 was deleted. Furthermore, deletion of the conserved carboxyl terminus of ORF45 in the KSHV genome drastically reduced the level of ORF33 protein in KSHV-infected cells and abolished production of progeny virions. To determine if the binding of ORF33 is a critical function of C19, we used co-precipitation with point mutants of the C19 region and identified two required residues: tryptophan 403 and tryptophan 405. We then engineered KSHV genomes containing these mutants and transfected them into iSLK cells. Similar to the C19 deletion mutant, we found that both binding-deficient mutants exhibited decreased ORF33 accumulation and viral particle production. Since C19 is sufficient for binding ORF33, we hypothesized that introduction of a C19 analogue could inhibit binding and may lead to a similar decrease in viral particle production. We used ELISA to measure the binding of ORF33 to ORF45 in the presence of TAT-C19 and found that TAT-C19 inhibited binding in a dose-dependent manner. To measure the analogue's effect on viral particle production, we treated KSHV-infected cells with TAT-C19 and found that TAT-C19 inhibited viral particle production in a dose-dependent manner. In conclusion, binding of ORF33 and ORF45 during the lytic cycle is required for accumulation of the ORF33 and production of viral particles. In addition to forming a complex with ORF33 and USP7, we also found a strong association of ORF45 to RSK and ERK during the lytic cycle, matching previous reports that ORF45 bound ERK and RSK in a single complex. During that study, ORF45 was found to form a complex with ERK and RSK and the formation of this complex lead to accumulation of active ERK and RSK. While the binding site of RSK was mapped to aa 55-70, it was unclear if ERK bound to ORF45 directly or through RSK. Using in vitro binding analysis, we identified an ERK binding site in aa 16-35. Using T-Coffee analysis, we compared the sequences of gamma-2 herpesvirus homologues of ORF45 and found two highly conserved phenylalanine residues at aa 32 and 34. After generating point mutants of each residue to alanine, we measured their effect on the activation of ERK and RSK induced by ORF45 and found that either mutation lead to decreased activation of ERK and RSK. We are currently evaluating their effect upon the activation of ERK and RSK during the lytic cycle and the production of progeny virions.
Show less
Date Issued: 2015
Identifier: FSU_2015fall_Gillen_fsu_0071E_12935
Format: Thesis

Title: Modulation of Kinase Signaling by ORF45 during the Lytic Cycle of Kaposi's Sarcoma-Associated Herpesvirus.
Creator: Avey, Denis R., Zhu, Fanxiu, Sang, Qing-Xiang Amy, Tang, Hengli, Gilbert, David M., Dennis, Jonathan Hancock, Florida State University, College of Arts and Sciences, Department...
Show moreAvey, Denis R., Zhu, Fanxiu, Sang, Qing-Xiang Amy, Tang, Hengli, Gilbert, David M., Dennis, Jonathan Hancock, Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Kaposi's Sarcoma-Associated Herpesvirus (KSHV) is an oncogenic virus that has adapted unique mechanisms to modulate the cellular microenvironment of its human host. The pathogenesis of KSHV is intimately linked to its manipulation of cellular signaling pathways, including the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. We have previously shown that KSHV ORF45 contributes to the sustained activation of both ERK and p90 ribosomal S6 kinase (RSK,...
Show moreKaposi's Sarcoma-Associated Herpesvirus (KSHV) is an oncogenic virus that has adapted unique mechanisms to modulate the cellular microenvironment of its human host. The pathogenesis of KSHV is intimately linked to its manipulation of cellular signaling pathways, including the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. We have previously shown that KSHV ORF45 contributes to the sustained activation of both ERK and p90 ribosomal S6 kinase (RSK, a major functional mediator of ERK/MAPK signaling) during KSHV lytic replication. ORF45-activated RSK is required for optimal KSHV lytic gene expression and progeny virion production, though the underlying mechanisms downstream of this activation are still unclear. We hypothesized that the activation of RSK by ORF45 causes differential phosphorylation of cellular and viral substrates, affecting biological processes essential for efficient KSHV lytic replication. Accordingly, we observed widespread and significant differences in protein phosphorylation upon induction of lytic replication. Mass-spectrometry-based phosphoproteomic screening identified putative substrates of ORF45-activated RSK in KSHV-infected cells. Bioinformatic analyses revealed that nuclear proteins, including several transcriptional regulators, were overrepresented among these candidates. We validated the ORF45/RSK-dependent phosphorylation of several putative substrates by employing KSHV BAC mutagenesis, kinase inhibitor treatments, and/or CRISPR-mediated knockout of RSK in KSHV-infected cells. Furthermore, we assessed the consequences of knocking out these substrates on KSHV progeny virion production. Importantly, we investigated the regulation of gene expression by ORF45-actvated RSK by performing RNA-seq of KSHV-infected cells. We show data to support that ORF45 regulates the translational efficiency of a subset of viral/cellular genes with complex secondary structure in their 5' UTR. One of the few viral substrates of ORF45-activated identified by our mass spectrometry analysis was ORF36. KSHV ORF36 encodes a serine/threonine viral protein kinase, which is conserved throughout all herpesviruses. Although several studies have identified the viral and cellular substrates of conserved herpesvirus protein kinases (CHPKs), the precise functions of KSHV ORF36 during lytic replication remain elusive. We report that ORF36 interacts with another lytic protein, ORF45, in a manner dependent on ORF36 kinase activity. We mapped the regions of ORF36 and ORF45 involved in their binding. Their association appears to be mediated by electrostatic interactions, since deletion of either the highly basic N-terminus of ORF36 or an acidic patch of ORF45 abolished the binding. Additionally, dephosphorylation of ORF45 protein dramatically reduced its association with ORF36. Importantly, ORF45 enhances both the stability and kinase activity of ORF36. Consistent with previous studies of CHPK homologs, we detected ORF36 protein in extracellular virions. To investigate the roles of ORF36 in the context of KSHV lytic replication, we employed BAC mutagenesis to engineer both ORF36-null and kinase-dead (KD) mutants. We found that ORF36-null/mutant virions are moderately defective in viral particle production and are further deficient in primary infection. In summary, our results uncover a functionally important interaction between ORF36 and ORF45, and indicate a significant role of ORF36 in the production of infectious progeny virions. Altogether, these data shed light on the mechanisms by which KSHV ORF45 manipulates viral and cellular kinase signaling to optimize lytic replication. The findings reported here have important implications for the pathobiology of KSHV and other diseases in which RSK activity is missregulated.
Show less
Date Issued: 2016
Identifier: FSU_2016SP_AVEY_fsu_0071E_13145
Format: Thesis

Title: Phosphorylation of the Transcription Factor YY1.
Creator: Rizkallah, Raed, Hurt, Myra M., Levenson, Cathy W., Epstein, Lloyd Mark, Keller, Thomas C. S., Bass, Hank, Department of Biological Science, Florida State University
Abstract/Description: Reversible phosphorylation plays an integral role in the regulation of eukaryotic cellular proteins, especially transcription factors. YY1 is a multifunctional transcription factor involved in the regulation of a wide spectrum of essential cellular processes. YY1 has been proposed to be a phosphoprotein and several studies have reported that phosphorylation affects its DNA binding activity. However, these results were indirect and contradictory. In this study, we provide direct evidence that...
Show moreReversible phosphorylation plays an integral role in the regulation of eukaryotic cellular proteins, especially transcription factors. YY1 is a multifunctional transcription factor involved in the regulation of a wide spectrum of essential cellular processes. YY1 has been proposed to be a phosphoprotein and several studies have reported that phosphorylation affects its DNA binding activity. However, these results were indirect and contradictory. In this study, we provide direct evidence that YY1 is a phosphoprotein in normally cycling HeLa cells. Using purified YY1, we present direct evidence that phosphorylation has a negative effect on its DNA binding activity, using several binding sites. We have mapped three phosphorylated sites on YY1 in vivo. The phosphorylated serine residue 247 was detected in asynchronously growing HeLa cells. A phosphomimetic substitution at this site had no effect on the sub-cellular localization of YY1 and only a moderate negative effect on the DNA binding activity of YY1. The other two phosphorylated sites, at threonines 348 and 378, were detected in nocodazole–arrested HeLa cells. Threonines 348 and 378 are located in the linker peptides between the zinc finger motifs of the DNA binding domain of YY1. Phosphorylation at these two residues was correlated with cytoplasmic distribution of YY1 away from the condensed DNA. Moreover, diminished DNA binding activity was observed for YY1 in whole cell extracts from nocodazole-arrested HeLa cells, in in vitro electrophoretic mobility shift assays (EMSA). This diminished binding activity was reversed by dephosphorylation of YY1 with phosphatases. Consistent with these results, phosphomimetic substitutions at threonines 348 and 378 resulted in the loss of YY1 DNA binding activity. However, these mutations caused no observable effect on the subcellular localization of YY1 in interphase HeLa cells. We also show that YY1 is excluded from the condensing chromosomes at prophase in normally growing cells and it remains dispersed away from DNA until telophase. At this stage of mitosis, YY1 is recruited back to DNA in the nucleus at the same time of chromosome decondensation. These observations propose a mechanism for the inactivation of YY1 DNA binding activity in mitosis, through phosphorylation of its DNA binding domain. To identify kinases that phosphorylate YY1, we have tested bacterially expressed and purified YY1 against one hundred kinases in vitro. Several kinases were shown to highly phosphorylate YY1. Polo-like kinase 1 (Plk1) and Casein Kinase 2á1 (CK2á1) showed the highest activity in phosphorylating YY1 of the kinases examined. Using deletion and point-substitution mutants of YY1, we have shown that Plk1 specifically phosphorylates threonine 39 in the acidic trans-activation motif in the N-terminal domain of YY1. Phosphorylation at this site could play a role in the regulation of the transcriptional activity of YY1. In addition, CK2á1 was shown to phosphorylate YY1 at serine 118, located in the caspase consensus cleavage site. Phosphorylation at serine 118 may play an important role in regulating the cleavage of YY1 during apoptosis.
Show less
Date Issued: 2008
Identifier: FSU_migr_etd-4622
Format: Thesis

Title: Ecological Effects of Red Grouper (Epinephelus Morio) in Florida Bay.
Creator: Ellis, Robert Dodge, Coleman, Felicia C., Huettel, Markus, DuVal, Emily H., Inouye, Brian D., Miller, Thomas E., Florida State University, College of Arts and Sciences,...
Show moreEllis, Robert Dodge, Coleman, Felicia C., Huettel, Markus, DuVal, Emily H., Inouye, Brian D., Miller, Thomas E., Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Ecosystem engineers can have complex effects on communities through a variety of direct and indirect pathways. Describing these effects is a necessary step in understanding and predicting the effects of engineer species. Red Grouper (Epinephelus morio) manipulate habitats by excavating sediment and detritus from karst solution holes in Florida Bay; they are also predators that consume a variety of crustaceans and benthic fish prey. As both a habitat manipulator and predator, the effects of...
Show moreEcosystem engineers can have complex effects on communities through a variety of direct and indirect pathways. Describing these effects is a necessary step in understanding and predicting the effects of engineer species. Red Grouper (Epinephelus morio) manipulate habitats by excavating sediment and detritus from karst solution holes in Florida Bay; they are also predators that consume a variety of crustaceans and benthic fish prey. As both a habitat manipulator and predator, the effects of Red Grouper on communities associated with the habitats they modify will likely be complex and difficult to predict. Here I present the results of observational and experimental work investigating the community and species-level effects of Red Grouper on faunal communities associated with Florida Bay solution holes. By measuring solution holes and conducting diver surveys of faunal communities associated with a fixed set of solution holes over time, I was able to show how the communities and the solution holes themselves were different in the presence and absence of Red Grouper. In general, solution holes were deeper, and communities were both more abundant and diverse when Red Grouper were present. However, while many species changed in abundance and occurrence from year-to-year, short term experiments, on the order of weeks, indicated that these effects were primarily driven by a small set of species that interacted strongly with the Red Grouper. Caribbean Spiny Lobster (Panulirus argus) was a common and abundant member of the solution-hole communities, and were more abundant in solution holes with Red Grouper, despite the fact that Red Grouper are known lobster predators. Investigating the Red Grouper-lobster interaction across lobster ontogeny indicated that Red Grouper positively affected the abundance of large lobsters, but negatively affected the abundance of smaller lobsters. To determine if this result was due to predation or avoidance behavior by juvenile lobsters, I conducted an experiment to test relative predation risk of lobsters adjacent to solution holes with Red Grouper, and another experiment at artificial dens to test lobster avoidance in the presence and absence of Red Grouper. The results of both experiments confirmed the hypothesis that size-selective predation by Red Grouper maintains the observed distribution of lobsters in solution holes, and not avoidance behaviors by lobsters. The community level analysis also showed a strong positive effect of Red Grouper on the abundance of juvenile coral reef fishes. I hypothesized that this effect was caused by a behaviorally-mediated indirect interaction (BMII) between Red Grouper and juvenile reef fishes via solution-hole associated piscivores. A recent addition to the suite of solution-hole associated piscivores is the Indo-Pacific lionfish (Pterois volitans and P. miles). As resident piscivores with high site fidelity in relatively high abundance in the bay, lionfish served as a focal species to test the BMII hypothesis. Juvenile reef fishes were most abundant at solution holes with Red Grouper present, least abundant in solution holes with lionfish present, and at intermediate abundances when both predators were present. These results confirmed the strong negative effects that lionfish have on native reef fish communities, and also suggest that Red Grouper can ameliorate some of these negative effects through a BMII that results in higher native fish abundance. Overall, Red Grouper had largely positive effects on the abundance and diversity of the fish and crustacean communities found inside and around solution holes in Florida Bay. The results presented here suggest that Red Grouper have strong effects on a wide range of species which together shape the ecosystems they manipulate.
Show less
Date Issued: 2015
Identifier: FSU_2015fall_Ellis_fsu_0071E_12879
Format: Thesis

Title: Characterization of Dopamine and Kainate Receptors in Olfactory Bulb Neurons and Their Efffects on Glutamatergic Transmission.
Creator: Davila, Gabriel Nestor, Trombley, Paul, Ouimet, Charles, Freeman, Marc, Gaffney, Betty, Meredith, Michael, Department of Biological Science, Florida State University
Abstract/Description: The main olfactory bulb (OB) receives odorant information from the nasal epithelium, interprets much of that information, and transmits the results to higher cortical regions. The predominant excitatory neurotransmitter in the OB and throughout the brain is glutamate. Modulators of glutamatergic activity influence synaptic transmission of intrabulbar circuits profoundly; therefore, the effects of neuromodulators must be thoroughly characterized in order to understand fully how OB circuits...
Show moreThe main olfactory bulb (OB) receives odorant information from the nasal epithelium, interprets much of that information, and transmits the results to higher cortical regions. The predominant excitatory neurotransmitter in the OB and throughout the brain is glutamate. Modulators of glutamatergic activity influence synaptic transmission of intrabulbar circuits profoundly; therefore, the effects of neuromodulators must be thoroughly characterized in order to understand fully how OB circuits function. Investigations performed here address the capacity of dopamine receptor (DAR) and kainate receptor (KAR) activation to modulate glutamate transmission from principal cells to interneurons in OB primary cultures. Initially, I obtained immunocytochemical evidence for DARs expressed in principal cells. Subsequent electrophysiological analyses revealed that the D2-like receptor subtype (D2Rs) attenuated both spontaneous and evoked glutamatergic transmission. Information gleaned from studies of input resistances and calcium currents allowed me to determine that the site of modulation is located on the presynaptic cell. My research into KARs demonstrated the existence of functional KARs in OB neurons and began to elucidate their physiological roles in OB neurotransmission. First, I gathered immunocytochemical evidence to visualize KARs expressed both at and near synapses. In situ hybridization (ISH) was employed to map which OB neurons express mRNA for each KAR subunit. Expression levels for each subunit were quantified in parallel studies using the reverse transcriptase-polymerase chain reaction (RT-PCR). Electrophysiological approaches were used to determine whether or not KARs participate in synaptic transmission between OB neurons in primary cultures. I provide evidence for KAR-mediated modulation of both spontaneous and evoked glutamatergic transmission between OB neurons. Taken together, this work supports the notion that synaptic transmission of OB neurons can be modulated by either metabotropic or ionotropic ligand-gated ion channels. In addition, this is the first thorough characterization of KAR expression and physiology in OB neurons.
Show less
Date Issued: 2003
Identifier: FSU_migr_etd-0817
Format: Thesis

Title: The Effects of D-Cycloserine, an Nmda Receptor Agonist, on Conditioned Taste Aversion Learning.
Creator: Davenport, Rachel A., Houpt, Thomas A., Ouimet, Charles C., III, Thomas C. S. Keller, Department of Biological Science, Florida State University
Abstract/Description: Conditioned taste aversion (CTA) learning occurs as a result of the pairing of a novel taste with a malaise-inducing substance. This is a robust associative learning paradigm that has been shown to be N-methyl-D-Aspartic acid (NMDA) receptor-mediated, as NMDA receptor antagonists attenuate CTA learning. This work presents four experiments that examine the role of an NMDA receptor agonist, d-Cycloserine (DCS), in CTA learning. The first experiment showed that DCS enhanced CTA learning but only...
Show moreConditioned taste aversion (CTA) learning occurs as a result of the pairing of a novel taste with a malaise-inducing substance. This is a robust associative learning paradigm that has been shown to be N-methyl-D-Aspartic acid (NMDA) receptor-mediated, as NMDA receptor antagonists attenuate CTA learning. This work presents four experiments that examine the role of an NMDA receptor agonist, d-Cycloserine (DCS), in CTA learning. The first experiment showed that DCS enhanced CTA learning but only under certain constraints. Namely, DCS enhanced CTA when there was a short delay between the taste and toxin pairing (10 minutes), but not when there was a longer delay (45 minutes). We next tried to explain this phenomenon by probing three possibilities: (1) DCS fails to enhance CTA after a long delay because its activity is short-lived, (2) during the long delay, DCS enhances learned safety towards the taste that would counteract CTA acquisition or (3) enhancement of CTA by DCS depends upon the temporal proximity of taste and toxin. Our data showed that DCS was effective at enhancing short-delay CTA for at least one hour after administration; thus a short half-life is not sufficient to explain why DCS fails to enhance long-delay CTA. DCS did not enhance learned safety, even though learned safety is NMDA receptor-mediated; therefore it is unlikely that learned safety during the long delay masked enhancement of CTA learning. DCS enhanced CTA only when there was a short period of taste processing; longer temporal delays between initial taste processing and LiCl, even with an immediate taste-toxin pairing, did not support DCS enhancement. Thus the lack of an effect of DCS on long-delay CTA is not due to a short half-life of DCS nor a build-up of learned safety during the long-delay, nor the temporal distance between the taste and toxin stimuli. The duration of time since initiation of the taste stimuli appears critical, however. There are a few potential neural mechanisms that may explain this short- vs. long-delay phenomenon. The most relevant finding in recent literature suggests that NMDA receptors can become internalized after activation. It is possible that NMDA receptors become activated after the initial taste and may internalize during the delay between taste and toxin causing less enhancement of DCS on long-delay CTA.
Show less
Date Issued: 2006
Identifier: FSU_migr_etd-0826
Format: Thesis

Title: Molecular Events Underlying the Enhancement of Conditioned Taste Aversion by D-Cycloserine.
Creator: Davenport, Rachel A., Houpt, Thomas A., Kelley, Colleen M., III, Thomas C. S. Keller, Ouimet, Charles C., Trombley, Paul Q., Department of Biological Science, Florida State...
Show moreDavenport, Rachel A., Houpt, Thomas A., Kelley, Colleen M., III, Thomas C. S. Keller, Ouimet, Charles C., Trombley, Paul Q., Department of Biological Science, Florida State University
Show less
Abstract/Description: Conditioned taste aversion (CTA) is a form of associative learning in which an animal avoids and reacts aversively to a taste (conditioned stimulus, CS) that has been previously paired with a toxin or other malaise-inducing stimulus (unconditioned stimulus, US). CTA is unique among Pavlovian learning paradigms because conditioning is supported across long delays (minutes to hours) between taste and toxin [Garcia et al., 1966; Kalat & Rozin, 1973; Smith & Roll, 1967] and is robust in that an...
Show moreConditioned taste aversion (CTA) is a form of associative learning in which an animal avoids and reacts aversively to a taste (conditioned stimulus, CS) that has been previously paired with a toxin or other malaise-inducing stimulus (unconditioned stimulus, US). CTA is unique among Pavlovian learning paradigms because conditioning is supported across long delays (minutes to hours) between taste and toxin [Garcia et al., 1966; Kalat & Rozin, 1973; Smith & Roll, 1967] and is robust in that an animal can form a strong aversion that can last for months [Houpt et al., 1996; Martin & Timmins, 1980; Steinert et al., 1980] after only a single trial of a taste-toxin pairing [Garcia & Koelling, 1967]. CTA learning is easily manipulated, as the strength or magnitude of the aversion is dependent on the concentration, saliency, and duration of the CS, as well as the amount or strength of the US [Barker, 1976; Dragoin, 1971; Nachman & Ashe, 1973]. The anatomical pathway involved in CTA is well characterized and includes the nucleus of the solitary tract, parabrachial nucleus, amygdala, and gustatory cortex [for a review, see Yamamoto, 2006]. The two forebrain regions, the amygdala and gustatory cortex, are particularly important as lesions of these areas cause deficits in CTA learning [Josselyn et al., 2004; Nerad et al., 1996], and both structures exhibit cellular changes during and after CTA acquisition, such as induction of long-term potentiation [Escobar & Bermudez-Ratoni, 2000], activation of immediate early genes such as c-fos [Lamprecht and Dudai, 1995], phosphorylation of markers such as MAPK [Berman et al., 1998], phosphorylation of NMDAR subunits such as NR2B [Rosenblum et al., 1997], and changes in the activation and expression of genes such as CREB, fra-2, and fen-1 [Desmedt et al., 2003; Kwon et al., 2008; Saavedra-RodrÃguez et al., 2009]. As with other forms of associative learning, CTA is N-methyl-D-aspartate receptor (NMDAR)-dependent [Jimenez & Tapia, 2004]. Pharmacological inactivation of NMDARs attenuates or blocks CTA [e.g. Gutierrez et al., 1999] while activation by NMDAR agonists enhances CTA learning [Land & Riccio, 1997]. Data from our lab show that the NMDAR agonist, D-cycloserine (DCS), dose-dependently enhances taste learning, but only under certain parameters [Nunnink et al., 2007].
Show less
Date Issued: 2011
Identifier: FSU_migr_etd-0825
Format: Thesis

Title: Characterization of HDAC4's Role in Brain.
Creator: Darcy, Michael, Ouimet, Charles C., Kelley, Colleen, Kabbaj, Mohamed, Bolaños, Carlos, Keller, Laura, Department of Biological Science, Florida State University
Abstract/Description: Epigenetic regulation of gene expression involves a steady-state balance of acetylation carried about by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs act as transcriptional co-activators and HDACs interact with large multi-protein complexes to promote transcriptional repression. HDACs have only recently been characterized in mammalian cells, and most work has focused on the function of HDACs in vitro using biochemical analysis, inhibitors, and cultured cell types....
Show moreEpigenetic regulation of gene expression involves a steady-state balance of acetylation carried about by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs act as transcriptional co-activators and HDACs interact with large multi-protein complexes to promote transcriptional repression. HDACs have only recently been characterized in mammalian cells, and most work has focused on the function of HDACs in vitro using biochemical analysis, inhibitors, and cultured cell types. HDAC4, a class II HDAC, displays the ability to shuttle between the cytoplasm and the nucleus where it can regulate transcriptional programs. HDAC4 plays a key role in calcium-dependent transcriptional regulation of many non-neuronal cell processes including cardiac hypertrophy and bone formation. HDAC4 mRNA is also highly expressed in brain; however protein expression and its underlying biological role in brain is still unclear. HDAC4 localization in cultured neurons is dependent on neural activity and calcium-dependent signaling pathways. Mechanisms governing long-term changes in synaptic plasticity and learning and memory take place on dendritic spines, a site affected by many cognitive disorders. Dendritic spines act to compartmentalize calcium signaling and second messenger cascades leading to activation of enzymes and proteins associated with transcriptional regulation. Inhibition of HDACs has become a prevalent tool in exploring the role of HDACs in brain and has proven useful in many models of psychiatric and neurodegenerative disorders with more recent implication in the recovery or enhancement of synaptic plasticity and learning and memory. HDAC inhibition, however, is non-specific, and the localization of specific HDACs in brain and their role in these neuronal functions needs to be addressed. The similarity between HDAC4 regulation in non-neuronal cells and the processes initiated within a dendritic spine led to the hypothesis that HDAC4 may be present at the dendritic spine, where it can relay alterations of synaptic activity to the nucleus in order to regulate transcriptional programs affecting synaptic plasticity or other cell function. For this dissertation, I report findings which establish the regional and novel subcellular localization pattern of HDAC4 expression in brain, identify a mechanism specific to synaptic activity at the dendritic spine which results in HDAC4 trafficking, and attempt to establish a direct interaction of HDAC4 to a key member of the scaffolding network within a dendritic spine. In additional studies, I report the effects of HDAC inhibition on learning and memory and lesion size using a model of traumatic brain injury (TBI) as well as the effects of amyloid plaque level on the localization pattern of HDAC4 in the hippocampus. These studies failed to illicit a significant change in the conditions tested and are not discussed in the main text, however, useful information regarding the role of HDAC inhibition and HDAC4 was obtained. In brief, I report the localization of HDAC4 across brain regions germane to many pathological conditions such as Huntington's, Parkinson's, and Alzheimer's disease. HDAC4 was found to be present in dendritic spines, enriched at the level of the post-synaptic density (PSD), and partially colocalized with post-synaptic density protein 95 (PSD-95), a key scaffolding protein for the formation and maintenance of dendritic spines. Furthermore, using hippocampal slice cultures to more closely represent in vivo synaptic connections, exogenous overexpression of HDAC4 localized to the cytoplasm and in dendritic spines. Dendritic spines, synaptic activity, and the ability to form memories are tightly regulated through the activation of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Blockade of both NMDA and AMPA receptors together was necessary to induce the nuclear localization of HDAC4 in these cultures, a shift that was reversed upon removal of the antagonists or reduced by HDAC inhibition. Finally, HDAC4 was expressed along with PSD-95 in vitro as well as extracted from hippocampal tissue to explore whether HDAC4 was a direct member of the PSD-95 scaffolding network in vivo. HDAC4 failed to show a complex with PSD-95, however, indirect interactions may still exist which anchor HDAC4 to the PSD. Together, these results suggest HDAC4 can act as a synaptic monitor, translocating to the nucleus during synaptic blockade where it can alter transcriptional programs and gene expression. Isolating the biological role for individual HDAC isoforms remains a critical step in understanding the mechanisms behind therapeutic candidates such as HDAC inhibitors, which have been used clinically in non-neuronal disruption of cancerous cells, and show much promise in the alleviation of many symptoms resulting from various psychiatric and neurodegenerative disorders.
Show less
Date Issued: 2010
Identifier: FSU_migr_etd-0848
Format: Thesis

Title: Why Dominant Individuals Cooperate — Fitness Consequences of Cooperative Courtship in a System with Variable Cooperative Display Coalitions.
Creator: Jones, Megan Anlis, DuVal, Emily H., Mesterton-Gibbons, Mike, Hughes, Kimberly A., Houle, David C., Steppan, Scott J., Florida State University, College of Arts and Sciences,...
Show moreJones, Megan Anlis, DuVal, Emily H., Mesterton-Gibbons, Mike, Hughes, Kimberly A., Houle, David C., Steppan, Scott J., Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Understanding the evolution of cooperative behaviors is a major goal of evolutionary biology, but the majority of research in this field has focused on why helpers assist others. Helpers’ reproductive costs introduce a clear paradox to our understanding of natural selection as helpers in cooperative systems apparently sacrifice reproductive opportunities to increase others’ fitness. This puzzle in cooperative behaviors has led to significant advances in our understanding of indirect and...
Show moreUnderstanding the evolution of cooperative behaviors is a major goal of evolutionary biology, but the majority of research in this field has focused on why helpers assist others. Helpers’ reproductive costs introduce a clear paradox to our understanding of natural selection as helpers in cooperative systems apparently sacrifice reproductive opportunities to increase others’ fitness. This puzzle in cooperative behaviors has led to significant advances in our understanding of indirect and delayed fitness benefits for helpers. However, as cooperation results from the interaction of individuals that may have very different incentives for participation it is equally important to understand whether and how cooperation benefits the dominant recipients of this help. There has been relatively little attention paid to why the recipient of the apparent help participates in the cooperative relationship, in part because the advantage to the dominant individual seems apparent in many systems. Existing work reveals a variety of potential benefits for dominant individuals and that the benefits for dominants may be less obvious than assumed. To date investigations into costs and benefits of cooperation to dominant individuals have been largely limited to cooperative breeding behavior. My dissertation research investigates the fitness consequences of cooperative courtship display for dominant individuals, in the White-ruffed Manakin, Corapipo altera. Manakins (Aves: Pipridae) are small, primarily lekking passerines, and, in some species, males cooperate in their courtship displays. Previous work on manakin cooperative display behavior has focused on benefits to subordinate males. The fitness consequences of cooperation for dominant individuals has not yet addressed in a system with variation in cooperative strategies. I found strong evidence of cooperation among male C. altera. I also found that, within a single population of C. altera on the Atlantic slope of Costa Rica, some males participate in coordinated display with other males (45.4±20% were classified as cooperative in any given year), while other males appear to only display singly. My dissertation research investigated the causes and consequences of cooperation by dominant C. altera males by quantifying aspects of the males' fitness including how inclusive fitness benefits may facilitate the maintenance of cooperative display coalitions and the consequences of cooperative display coalitions for males’ annual reproductive success, survival, and social status — important parts of lifetime fitness for long-lived, iteroparous species including C. altera. I found that cooperative males were not more closely related than expected at random from the population. Males that cooperated did not have higher annual reproductive success than males that displayed solo nor was there a significant difference in the frequency of copulations after a solo courtship display and a courtship display by multiple males. In a survival analysis, cooperation did not significantly affect the survival of dominant males. There was no consistent pattern of cooperation (or non-cooperation) among males across their tenure as dominant male: some were always cooperative, some always non-cooperative, but many males with multi-year tenures switched between cooperative and non-cooperative statuses. However, more males than expected employed strictly solo strategies across their tenure as dominant individuals, given the population-wide rates of survival and cooperation. The degree to which males cooperated, defined as the proportion of tenure classified as cooperative, was unrelated to variation in lifespan or length of tenure as a dominant male. Additionally, the proportion of total tenure classified as cooperative did not explain the patterns of lifetime reproductive success. Together, these results reject the hypotheses that dominant males in cooperative partnerships gain indirect or direct fitness benefits from their associations with subordinate males. Seeking to understand processes underlying patterns of fitness consequences from cooperative behaviors, I conducted three experiments to determine if males at sites where the dominant male was cooperative were faster or more intense in their response to an experimental stimulus. Cooperative males were not faster to respond to a female at the display site nor were they faster to respond to the vocalization of an unknown male conspecific at the display site. Cooperative males were not significantly more likely to respond to a predator model, however, they were significantly more likely to spend time near the snake and lizard models. There could be benefit of sociality in the detection of terrestrial predators. This research addresses previously unexplored aspects of cooperative courtship display, and therefore represents a significant contribution to the more general understanding of the costs and benefits of cooperation. The variation in the amount of cooperation expressed by different individuals of this species offers a unique opportunity to separate the fitness consequences of cooperation by comparing differences in success not only among individuals, but also those among displays in different cooperative contexts by the same individual.
Show less
Date Issued: 2017
Identifier: FSU_SUMMER2017_Jones_fsu_0071E_13625
Format: Thesis

Title: Reproductive Dynamics of Gulf Black Sea Bass in the Northeastern Gulf of Mexico.
Creator: Mckenzie, Ryan Wilson, Coleman, Felicia C., DuVal, Emily H., Travis, Joseph, Florida State University, College of Arts and Sciences, Department of Biological Science
Abstract/Description: Our knowledge of the reproductive dynamics of many economically important marine fish species is remarkably poor. This limits our ability to assess and manage the effects of exploitation on their reproductive potential. The Gulf Black Sea Bass Centropristis striata melana is a temperate serranid that contributes to both recreational and commercial fisheries in the state of Florida, however, the reproductive dynamics of this species is not well understood. To fill this gap, I conducted a...
Show moreOur knowledge of the reproductive dynamics of many economically important marine fish species is remarkably poor. This limits our ability to assess and manage the effects of exploitation on their reproductive potential. The Gulf Black Sea Bass Centropristis striata melana is a temperate serranid that contributes to both recreational and commercial fisheries in the state of Florida, however, the reproductive dynamics of this species is not well understood. To fill this gap, I conducted a fisheries-independent survey to explore the spatial and demographic scales of spawning populations in the northeastern Gulf of Mexico. To ensure effective and non-biased sampling, I assessed gear type and fish behavior sampling biases for the Gulf Black Sea Bass. Baited fish traps and hook-and-line were equally selective for fish size, however, hook-and-line had a higher catch efficiency. Body size was strongly correlated to social dominance in the Gulf Black Sea Bass, however, larger individuals in the population were not more susceptible to hook-and-line gears. These results indicated that hook-and-line was the optimal sampling method with relatively high efficiency and low sampling bias. Using hook-an-line fishery-independent surveys, I assessed the spatial and temporal dynamics of the Gulf Black Sea Bass spawning populations to test whether spawning populations were consistent across spawning habitats and describe demographic trends in spawning. Spawning populations were not consistent across available spawning habitat and displayed a high degree of spatial variability over scales of no more than 10 kilometers. These patterns were likely influenced by juvenile recruitment rates. Demography was a clear factor in the timing of reproduction as the proportion and average size of females and males significantly changed over the course of the spawning season. Larger females began spawning earlier in the spawning season and larger males were present on spawning habitats for longer periods. Overall, the findings of this study highlighted the important roles of spatial and demographic variation in the reproduction of the Gulf Black Sea Bass, and warrant future investigation due to their implications into the conservation and management of this economically important fishery.
Show less
Date Issued: 2017
Identifier: FSU_SUMMER2017_Mckenzie_fsu_0071N_14086
Format: Thesis

Title: The Role of Seasonal and Geographic Temperature Variation in the Life Cycle of the Clonal Sea Anemone Diadumene Lineata (Verrill).
Creator: Ryan, Wilbur Helcat, Miller, Thomas E. (Professor of Biological Science), Huettel, Markus, Hughes, Kimberly A., Levitan, Donald R., Wulff, Janie L., Florida State University,...
Show moreRyan, Wilbur Helcat, Miller, Thomas E. (Professor of Biological Science), Huettel, Markus, Hughes, Kimberly A., Levitan, Donald R., Wulff, Janie L., Florida State University, College of Arts and Sciences, Department of Biological Science
Show less
Abstract/Description: Clonality is the general term that encompasses all manner of pinching, splitting, budding, and fragmenting behaviors by which organisms divide their somatic body tissues into more or less independent units. It can be as straight forward as fragments of a sponge surviving after being rent apart by a hurricane or as convoluted as the telescoping generations of parthenogenic aphids. Clonality is a widespread feature of animal life cycles and the degree of clonal investment is expected to affect...
Show moreClonality is the general term that encompasses all manner of pinching, splitting, budding, and fragmenting behaviors by which organisms divide their somatic body tissues into more or less independent units. It can be as straight forward as fragments of a sponge surviving after being rent apart by a hurricane or as convoluted as the telescoping generations of parthenogenic aphids. Clonality is a widespread feature of animal life cycles and the degree of clonal investment is expected to affect everything from spatial genotypic and genetic structure to evolutionary dynamics and ecology interactions. Yet, the shear diversity and complexity of clonal behavior has hampered efforts to develop a general understanding of how and why clonality evolves as the adaptive benefits of these behaviors may be as idiosyncratic as the mechanisms by which cloning occurs. Contrary to some past formulations of the problem, the production of clonal progeny is not typically an alternative to sexual reproduction, as most clonal organisms also reproduce sexually. While there is often an immediate tradeoff where a unit of energy can either be invested in gametes or clonal progeny at any given time, there is not inherently a tradeoff between asexual and sexual reproduction over the span of a lifetime. Dividing somatic tissue in to separate units can be a way of increasing total lifetime fecundity by increasing total biomass, more efficiently colonizing open space or promoting longevity by spreading the risk of mortality over spatially-separated somatic units. With this perspective, understanding the adaptive value of clonality becomes a matter of analyzing the holistic suite of fitness effects that arise from variation in allocating energy among unitary growth, clonal propagation and gametogenesis. The amount of energy available and the fitness value of a particular investment strategy are governed in large part by the environment and so understanding the environmental context is key to understanding the forces shaping life cycle evolution. Temperature, in particular, affects the metabolic cost of maintaining body tissues and is key in determining the energetically optimal body size for a unitary animal. Where temperatures fluctuate seasonally or where clonal replicates may spread across a heterogeneous landscape, the reaction norm of fission rate, body size or traits associated with gamete production may be an important target of selection, influencing which life cycle patterns can evolve. In this dissertation I examine the influence of seasonal and geographic temperature variation on fission rate, body size and gamete production of the clonal sea anemone, Diadumene lineata (Verrill 1869), to better understand the constraints and tradeoffs that govern the evolution of resource allocation strategy; and ultimately, the factors that drive the evolution of clonality in this species. Through a combination of laboratory experiments, field observations, optimality modeling and genetic tools I demonstrate that (1) fission rates are strongly temperature dependent, resulting in seasonal and geographic variation in clonal behavior, (2) the production of gametes is closely tied to body size and shows an inverse latitudinal pattern with fission rate, (3) the observed reaction norm of fission rate with temperature is consistent with selection to maximize gamete production across the locally experienced range of temperatures, as opposed to selection for maximum clonal proliferation, per se, and (4) there is a latitudinal decrease in genotypic richness and diversity that corresponds with changes in fission rate, suggesting that variation in fission rate leads to changes in the spatial structure of genetic variation among sites. Together, these results are consistent with the hypothesis that clonality is adaptive under conditions where individual body size is constrained by the environment. Under these conditions more gametes may be produced over a lifetime by genets dividing somatic tissue into multiple small units rather than remaining a single large unit. In this species, there is an immediate cost to dividing a large body into two pieces as the number of gametes produced by two small individuals sums to less than those produced by a large individual, yet, the lost reproductive potential may be able to be compensated for over time by an increased growth rate at a smaller body size. Additional costs and benefits imposed by changes in mortality rate, competitive ability or mate choice as fission rate changes remain to be investigated and may be equally important in understanding and predicting the evolution of clonal behavior in this and other species.
Show less
Date Issued: 2017
Identifier: FSU_SUMMER2017_Ryan_fsu_0071E_13999
Format: Thesis

Title: Assortative Mating in the Tropical Sea Urchin Lytechinus Variegatus.
Creator: Nunez, Jose Alberto Moscoso, Levitan, Donald R., Hughes, Kimberly A., Burgess, Scott C., Florida State University, College of Arts and Sciences, Department of Biological Science
Abstract/Description: Non-random mating is presumed to be an important mechanism that allows for the maintenance of genetic variation. Assortative mating has been studied extensively in organisms that possess defined ways in which sperm is transferred to eggs (e.g. via copulation, courtship or vector assisted pollination in plants), but rarely in broadcast spawners. Broadcast spawning is perceived as a mating event that allows for mixing of gametes and promotes random mating. However, there are multiple pathways...
Show moreNon-random mating is presumed to be an important mechanism that allows for the maintenance of genetic variation. Assortative mating has been studied extensively in organisms that possess defined ways in which sperm is transferred to eggs (e.g. via copulation, courtship or vector assisted pollination in plants), but rarely in broadcast spawners. Broadcast spawning is perceived as a mating event that allows for mixing of gametes and promotes random mating. However, there are multiple pathways in which spawning adults can affect fertilization of gametes in non-random ways. For example, positive assortative mating can occur in broadcast spawners if similar phenotypes spawn closer together in space or time, or possess similar gamete recognition proteins that expedite fertilization. Here, I propose to examine assortative fertilization, patterns of aggregation and gamete recognition protein genotype of the sperm bindin gene as a function of spine color in the sea urchin Lytechinus variegatus as well as evaluating deviations from Hardy-Weinberg Equilibrium (HWE) based on color. Results indicate that laboratory crosses of urchins within color morphs yielded higher fertilization success than crosses between color morphs. Field surveys determined that these sea urchins are aggregating by color at times of their reproductive season when they are more likely to spawn. Tests for HWE using field data of urchin phenotypes suggest strong deviations from HWE. However, DNA sequences of regions of the sperm bindin gene for sea urchins of different color do not show evidence of genetic structure of the population. Paternal success in broadcast spawners is largely determined by the proximity of males to spawning females and the compatibility between them at the time they release their gametes. Selection is predicted to favor traits and behaviors that increase the likelihood of spawning near a more compatible neighbor. These results provide strong evidence for assortative mating and an explanation for the maintenance of color variation in this species.
Show less
Date Issued: 2017
Identifier: FSU_SUMMER2017_Moscoso_fsu_0071N_14093
Format: Thesis

Title: CRISPR-Cas9 Utility in Genome Engineering.
Creator: McCullers, Michelle R., Department of Biological Science
Abstract/Description: The field of genomic engineering and manipulation has made great strides in recent years with the development of genome-altering techniques to alleviate disease by flexing control on an epigenetic scale. Facioscapulohumeral muscular dystrophy (FSHD) poses a series of points within its pathophysiology where it is possible to examine the utility of these manipulation techniques. This paper specifically focuses on how three approaches can be applied to ultimately stop the expression of the full...
Show moreThe field of genomic engineering and manipulation has made great strides in recent years with the development of genome-altering techniques to alleviate disease by flexing control on an epigenetic scale. Facioscapulohumeral muscular dystrophy (FSHD) poses a series of points within its pathophysiology where it is possible to examine the utility of these manipulation techniques. This paper specifically focuses on how three approaches can be applied to ultimately stop the expression of the full length double homeobox 4 DUX4 gene transcript which is thought to be responsible for the upper body muscular atrophy exhibited in most FSHD cases. With this information, we can surmise what the future holds for epigenetics, including the purpose of repetitive DNA, the role of epigenetics in disease manifestation, and how to apply new genetic engineering techniques in creative ways.
Show less
Date Issued: 2015
Identifier: FSU_migr_uhm-0450
Format: Thesis

Title: Genetic Analysis of the Role of Mps3 in Centrosome Separation in Budding Yeast.
Creator: Abblett, Rebecca L., Department of Biological Science
Abstract/Description: The spindle pole body (SPB) is the functional equivalent of the mammalian centrosome in budding yeast Saccharomyces cerevisiae and is important for chromosome segregation and cell division. Paralleling how chromosome duplication and segregation are important for accurate cell division, the SPB must duplicate and segregate for successful chromosome segregation. Yet, while the process of SPB duplication has been highly characterized, the mechanism of SPB segregation remains poorly understood....
Show moreThe spindle pole body (SPB) is the functional equivalent of the mammalian centrosome in budding yeast Saccharomyces cerevisiae and is important for chromosome segregation and cell division. Paralleling how chromosome duplication and segregation are important for accurate cell division, the SPB must duplicate and segregate for successful chromosome segregation. Yet, while the process of SPB duplication has been highly characterized, the mechanism of SPB segregation remains poorly understood. Mps3, a SUN-domain protein, is a component of the SPB and plays an important role in SPB dynamics. To study Mps3 and its interactions with other relevant factors, we have conducted both genetic and cellular biology based experiments. We have observed through live-cell microscopy that Mps3 localizes to the SPB as well as to the nuclear envelope. We then found, through a combined biochemical and genetic approach, that a phosphorylation as well as a cleavage event exist to potentially regulate the function of Mps3 at the SPB and nuclear envelope, and we conducted multiple genetic screens in order to further classify the novel cleavage event. We propose that modification of Mps3 initiates SPB segregation, which catalyzes or parallels Mps3 degradation in the nuclear envelope. Understanding the mechanism of SPB separation will contribute to our knowledge of chromosome segregation and cell division, which has implications in developing treatments for chromosomal birth defects.
Show less
Date Issued: 2015
Identifier: FSU_migr_uhm-0459
Format: Thesis

Title: The Effect of Environmental Stressors on Anxiety-like Behavior Assessed in Two Distinct Behavioral Tests.
Creator: Labat, Sarah, Department of Biological Science
Abstract/Description: The elevated plus maze, a behavioral test commonly used with rodents, has been successfully used with prairie voles in previous studies to assess anxiety-like behaviors. However, whether or not the light-dark box, another common behavioral test, can be used to assess anxiety-like behaviors in prairie voles is still unknown. For this study, we used female prairie voles to measure the effects of an acute severe stressor and a chronic mild stressor on anxiety-like behaviors in the elevated plus...
Show moreThe elevated plus maze, a behavioral test commonly used with rodents, has been successfully used with prairie voles in previous studies to assess anxiety-like behaviors. However, whether or not the light-dark box, another common behavioral test, can be used to assess anxiety-like behaviors in prairie voles is still unknown. For this study, we used female prairie voles to measure the effects of an acute severe stressor and a chronic mild stressor on anxiety-like behaviors in the elevated plus maze and light-dark box to determine whether or not the light-dark box test can be used to assess anxiety-like behaviors. Our data showed that the light-dark box can detect an increase in anxiety-like behaviors in response to an acute severe stressor but not a chronic mild stressor.
Show less
Date Issued: 2013
Identifier: FSU_migr_uhm-0217
Format: Thesis

Title: Protecting Against Rod Degeneration In A Model Of Retinitis Pigmentosa.
Creator: Lebowitz, Joseph, Department of Biological Science
Abstract/Description: Retinitis Pigmentosa (RP) is a heritable disease that affects the retina, the photosensitive neural tissue lining the back of the eye. RP results in the gradual degeneration of rod photoreceptor cells, but secondarily cone cells degenerate and all visual input is lost. Mutations in nearly 100 genes have been associated with this disease and related disorders, however little is known about the series of cellular events that precede photoreceptor death. Taking advantage of a transgenic...
Show moreRetinitis Pigmentosa (RP) is a heritable disease that affects the retina, the photosensitive neural tissue lining the back of the eye. RP results in the gradual degeneration of rod photoreceptor cells, but secondarily cone cells degenerate and all visual input is lost. Mutations in nearly 100 genes have been associated with this disease and related disorders, however little is known about the series of cellular events that precede photoreceptor death. Taking advantage of a transgenic zebrafish model of rod degeneration, a small molecule screen and morpholino injections were used to identify modifiers of the cell death typically observed in RP. Rod photoreceptors in the developing zebrafish larvae express a fluorescent reporter gene. This leads to rod degeneration similar to that seen in RP, but cell death can easily be observed under a microscope. Live larvae were observed under the fluorescence microscope to determine if a compound has slowed or altered the degeneration of the rod cells at 4 days post fertilization. A gene-dosage dependent rate of degeneration was uncovered when comparing larvae that were hetero- and homozygous for the transgene. Modulation of the retinoic acid pathway modestly altered cell death. Knocking down Nr2e3 and p53 expression also showed protective effects that were stronger than those following chemical treatment. p53 codes for a key regulator of apoptosis, and Nr2e3 codes for a transcription factor of the rhodopsin gene. These results suggest further study of genetic and chemical manipulation of photoreceptor degeneration, and genotype-phenotype correlations in such diseases.
Show less
Date Issued: 2013
Identifier: FSU_migr_uhm-0269
Format: Thesis

Title: Oviposition site preference and reproductive seasonality in Nerita scabricosta.
Creator: Spangler, Abby, Department of Biological Science
Abstract/Description: The developmental stages of plants and animals are critical as well as highly susceptible to environmental conditions and predation. Organisms have evolved many different methods for dealing with problems such as larval exposure to physical stress and predation. Two commonly studied solutions to these problems are when a species reproduces in relation to environmental cycles (phenology) and wherea species reproduces (oviposition site selection). This project makes use of a species of snail...
Show moreThe developmental stages of plants and animals are critical as well as highly susceptible to environmental conditions and predation. Organisms have evolved many different methods for dealing with problems such as larval exposure to physical stress and predation. Two commonly studied solutions to these problems are when a species reproduces in relation to environmental cycles (phenology) and wherea species reproduces (oviposition site selection). This project makes use of a species of snail that lives and reproduces in a particularly stressful environment; the tropical high intertidal zone. In attempts to further understand the adaptive evolution caused by larval susceptibility, I investigate what kinds of environmental and physical characteristics dictate oviposition site selection, and which other seasonal environmental cycles are closely correlated with the reproductive season of the species. The results of this study seem to indicate that the environmental conditions of the tide pools do not elicit an oviposition site preference. However, results of the phenology portion of the study do show some fairly strong relationships among annual environmental cycles and the reproductive season.
Show less
Date Issued: 2013
Identifier: FSU_migr_uhm-0252
Format: Thesis

Title: A Comparison of Past and Present Pseudacris feriarum and Pseudacris nigrita Populations: Reproductive Character Displacement in Areas of Sympatry Over Time.
Creator: Milthorpe, Hannah, Department of Biological Science
Abstract/Description: Jack Fouquette (1975) observed reproductive character displacement between the chorus frogs, Pseudacris feriarum and Pseudacris nigrita, with P. feriarum increasing its pulse rate and number in areas of sympatry. Extensions of Fouquette's original study by Lemmon (2009 and 2010) observed this similar displacement along the contact zone in the southeastern United States and found that the displacement was occurring due to female preference pressures on male P. feriarum in order to avoid...
Show moreJack Fouquette (1975) observed reproductive character displacement between the chorus frogs, Pseudacris feriarum and Pseudacris nigrita, with P. feriarum increasing its pulse rate and number in areas of sympatry. Extensions of Fouquette's original study by Lemmon (2009 and 2010) observed this similar displacement along the contact zone in the southeastern United States and found that the displacement was occurring due to female preference pressures on male P. feriarum in order to avoid maladaptive hybridization. In this study, which is an extension of Fouquette (1975) and Lemmon (2009), I compare the acoustic recordings from Fouquette's original study to present-day populations of P. feriarum and P. nigrita across the contact zone. Randomization test results show that different populations from around the contact zone have changed over time in regards to dominant frequency and call duration, but have not changed in regards to pulse rate or number, possibly indicating that female preference selection pressures are still strong on P. feriarum males in sympatry for higher energy calls.
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0328
Format: Thesis

Title: Role of signaling pathways in hindsight overexpression.
Creator: Anderson, Rhiannon, Department of Biological Science
Abstract/Description: The interaction between various signaling pathways and their spatial and temporal regulation during growth and development remains largely unknown. The purpose of this thesis is to investigate the role of signaling pathways involved in hindsight (hnt) overexpression in wing imaginal discs of Drosophila. Hindsight is a transcription factor involved in cell-cycle programs and cell adhesion. Because of hindsight's role in the mitotic/endocycle switch, I wanted to investigate whether this...
Show moreThe interaction between various signaling pathways and their spatial and temporal regulation during growth and development remains largely unknown. The purpose of this thesis is to investigate the role of signaling pathways involved in hindsight (hnt) overexpression in wing imaginal discs of Drosophila. Hindsight is a transcription factor involved in cell-cycle programs and cell adhesion. Because of hindsight's role in the mitotic/endocycle switch, I wanted to investigate whether this overgrowth was caused by cell proliferation or prolonged endocycle. I used markers for DNA replication and mitotic division and found that the overgrowth was caused by cell proliferation. I also tested whether Notch, JNK, DPP, Hippo or EGFR signaling pathways were involved in the overgrowth by observing their gene expression. JNK and EGFR pathways were both found to be involved in the tumorigenic growth. Finally, the interaction between hindsight and giant lethal larvae (lgl), a tummor suppressor gene, was tested.
Show less
Date Issued: 2014
Identifier: FSU_migr_uhm-0410
Format: Thesis

Title: The Effects of Testosterone on zif268 Expression and Its Potential Role in Learning and Memory.
Creator: Bunn, Corinne, Department of Biological Science
Date Issued: 2013
Identifier: FSU_migr_uhm-0185
Format: Thesis

Title: Characterization of the Role of Eco1 in Chromosome Segregation During Meiosis in Budding Yeast.
Creator: Reynolds, Torrie, Department of Biological Science
Abstract/Description: To ensure accurate chromosome segregation, sister chromatid cohesion must be properly established at S-phase when DNA is replicated. The protein Eco1/Ctf7 is responsible for establishing this cohesion, and is the focus of this Thesis work. The conserved protein complex cohesin acts as the "molecular glue" that mediates this sister chromatid cohesion. Cohesin is loaded onto the chromosomes before DNA replication, and when the acetyltransferase Eco1 acetylates cohesin at S-phase, the sister...
Show moreTo ensure accurate chromosome segregation, sister chromatid cohesion must be properly established at S-phase when DNA is replicated. The protein Eco1/Ctf7 is responsible for establishing this cohesion, and is the focus of this Thesis work. The conserved protein complex cohesin acts as the "molecular glue" that mediates this sister chromatid cohesion. Cohesin is loaded onto the chromosomes before DNA replication, and when the acetyltransferase Eco1 acetylates cohesin at S-phase, the sister chromatids become entrapped in the cohesin ring. This Thesis aimed to elucidate the roles of Eco1 in cohesin-mediated sister chromatid cohesion, specifically during meiosis. A novel eco1 meiosis-specific mutant was constructed in the budding yeast Saccharomyces cerevisiae. Fluorescence microscopy techniques were used to assay sister chromatid cohesion, nuclear division, and chromosome structure in cells depleted of Eco1 in meiosis. This work shows that meiotic Eco1 and its establishment of sister chromatid cohesion regulates recombination and chromosome segregation during meiosis.
Show less
Date Issued: 2012
Identifier: FSU_migr_uhm-0137
Format: Thesis

Theses and Dissertations (265)	+ -
Undergraduate Honors Theses (53)	+ -

Biology (235)	+ -
Life sciences (66)	+ -
Ecology (28)	+ -
Cytology (24)	+ -
Molecular biology (23)	+ -

Neurosciences (18)	+ -
Evolution (Biology) (17)	+ -
Genetics (17)	+ -
Developmental biology (10)	+ -
Biochemistry (9)	+ -
Medical sciences (9)	+ -
Marine biology (8)	+ -
Botany (7)	+ -
Neurobiology (7)	+ -
Virology (6)	+ -
Biophysics (5)	+ -
Evolution (5)	+ -
Zoology (5)	+ -
Aquatic ecology (4)	+ -
Psychobiology (4)	+ -
Behavior (3)	+ -
Biodiversity (3)	+ -
Communicable diseases (3)	+ -
Human behavior (3)	+ -
Immunology (3)	+ -
Neuropsychology (3)	+ -
Population biology (3)	+ -
Animal behavior (2)	+ -
Animal culture (2)	+ -
Aquaculture (2)	+ -

text (318)	+ -
doctoral thesis (33)	+ -
master thesis (7)	+ -

Florida State University (265)	+ -
College of Arts and Sciences (78)	+ -
Travis, Joseph (40)	+ -
Bass, Hank W. (32)	+ -
Keller, Thomas C. S. (26)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Owner