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- 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
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Porter, Lauren, Reeves, Robert H., Kostka, Joel, Herrnkind, William, Keller, Laura, Quadagno, David, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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Poulton, John, Deng, Wu-Min, Horabin, Jamila I., Epstein, Lloyd, III, Thomas Keller, Tang, Hengli, Department of Biological Science, Florida State University
- Abstract/Description
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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
- Studies of the Capacity for Creatine Biosynthesis in the Protochordate Ciona Intestinalis.
- Creator
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Deligio, James Thomas, Ellington, W. Ross, Chase, P. Bryant, Moerland, Timothy S., Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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Smith, Christopher Ryan, Tschinkel, Walter R., Winn, Alice A., Inouye, Brian D., Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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Tawde, Pallavi D., Roux, Kenneth, Sathe, Shridhar, Keller, Tom, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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Zhang, Xiaojun, Fajer, Piotr G., Logan, Timothy, Chase, P. Bryant, III, Thomas Keller, Blaber, Michael, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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Albright, James Christopher, Steppan, Scott, Levitan, Don, Swofford, David, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Adreani, Mia Susan, Levitan, Don, Travis, Joseph, Wang, Zuoxin, Houle, David, Koenig, Christopher, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
- Composition and Stability of Single-Stranded DNA Viral Populations in Wastewater Treatment Plants.
- Creator
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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
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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
- Philosophical, Historical, and Empirical Investigations into the Concept of Biological Fitness.
- Creator
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Takacs, Peter, Ruse, Michael, Travis, Joseph, Bishop, Michael A., Justus, James, Florida State University, College of Arts and Sciences, Department of Philosophy
- Abstract/Description
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While undeniably one of the central explanatory concepts in biology, fitness is deployed in an ambiguous or even inconsistent manner by evolutionary biologists as well as philosophers. This sort of foundational confusion is a plea for conceptual clarity and has, thereby, presented a wonderful opportunity for philosophers of science to ply their trade. After engaging with the topic, however, several influential philosophers of science (e.g., Mohan Matthen, Dennis Walsh, and Andre Ariew) and...
Show moreWhile undeniably one of the central explanatory concepts in biology, fitness is deployed in an ambiguous or even inconsistent manner by evolutionary biologists as well as philosophers. This sort of foundational confusion is a plea for conceptual clarity and has, thereby, presented a wonderful opportunity for philosophers of science to ply their trade. After engaging with the topic, however, several influential philosophers of science (e.g., Mohan Matthen, Dennis Walsh, and Andre Ariew) and biologists (Richard Lewontin and Massimo Pigliucci) have reached the conclusion that biological fitness is not in fact the cause of natural selection but instead a mere statistical artifact or redescription of systematic transgenerational change. It is, as they see matters, a label best reserved for abstract trait types rather than the organisms that bear such traits. This poses a serious challenge to the working intuitions of most biologists and many philosophers of biology. Moreover, it is but one of many challenges to the explanatory and ontological primacy of natural selection in recent memory. For at least three decades, some practitioners in the burgeoning subdiscipline of evolutionary developmental biology have been outspoken in insisting that the tools of population biology are insufficient for describing or explaining observations of adaptive evolutionary change both past and present. In this dissertation, I examine these recent challenges to orthodox conceptions of fitness and natural selection, as well as the rejoinders given in defense. Ultimately, I defend a conception of fitness as a probabilistic dispositional property (i.e., a propensity) of token organisms that causes natural selection.
Show less - Date Issued
- 2017
- Identifier
- FSU_FALL2017_Takacs_fsu_0071E_14240
- Format
- Thesis
- Title
- Investigating the role of the e(y)1 gene in the Notch signaling pathway.
- Creator
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Alvarado, Francisco, Department of Chemistry and Biochemistry
- Abstract/Description
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Drosophila melanogaster serve as an excellent model to study the highly conserved notch signaling pathway, which is involved in a broad array of developmental events. The Notch signal transduction pathway in Drosophila is vastly complex and involves a large number of proteins and genes that positively or negatively influence Notch signaling. In this study we analyze a gene that may be affecting the Notch pathway in follicle cell development. We provide not only new information about e(y)1,...
Show moreDrosophila melanogaster serve as an excellent model to study the highly conserved notch signaling pathway, which is involved in a broad array of developmental events. The Notch signal transduction pathway in Drosophila is vastly complex and involves a large number of proteins and genes that positively or negatively influence Notch signaling. In this study we analyze a gene that may be affecting the Notch pathway in follicle cell development. We provide not only new information about e(y)1, but also the notch signaling pathway itself and add onto the understanding of germline-follicle cell signaling during oogenesis.
Show less - Date Issued
- 2013
- Identifier
- FSU_migr_uhm-0284
- Format
- Thesis
- Title
- Identification and Characterization of Mutants That Affect Stem Cell Renewal in the Arabidopsis Root.
- Creator
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Fleming, Monica, Department of Biological Science
- Abstract/Description
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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
- The Seasonal Natural History of Pheidole morrisi Forel.
- Creator
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Murdock, Tyler, Department of Biological Science
- Abstract/Description
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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
- Analysis of Chromatin Structure Indicates a Role for Fluoxetine in Altering Nucleosome Distribution.
- Creator
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Gracia, Ely
- Abstract/Description
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An interesting stimulus for chromatin structural changes is the generic and popular anti-depressant drug Fluoxetine, commonly known as Prozac. Generally accepted as a Selective Serotonin Reuptake Inhibitors (SSRI's), recent work has emerged suggesting that this antidepressant also functions as a Histone Deaceylase Inhibitors (HDIs). Studies have also come out indicating that Fluoxetine acts as an immunosuppressant drug. Treatment with Fluoxetine is believed to reduce the over-activation of...
Show moreAn interesting stimulus for chromatin structural changes is the generic and popular anti-depressant drug Fluoxetine, commonly known as Prozac. Generally accepted as a Selective Serotonin Reuptake Inhibitors (SSRI's), recent work has emerged suggesting that this antidepressant also functions as a Histone Deaceylase Inhibitors (HDIs). Studies have also come out indicating that Fluoxetine acts as an immunosuppressant drug. Treatment with Fluoxetine is believed to reduce the over-activation of the immune system associated with depression. We have used an innovative microarray technology to measure changes in nucleosomal positioning that stem from Fluoxetine treatment. With the use of the microarray, we were able to show that Fluoxetine regulated chromatin structure, that Fluoxetine induced nucleosomal changes show time-dependent kinetics, and targeted genes responsible for the regulation of immune system processes. These results give new and important insights into non-SSRI roles of this highly prescribed class of drugs.
Show less - Date Issued
- 2012
- Identifier
- FSU_migr_uhm-0087
- Format
- Thesis
- Title
- Chromatin Structural Changes Linking Flavonoid Luteolin's Function to Genomic Targets.
- Creator
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Koerner, Joshua, Biological Science
- Abstract/Description
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Many non-inherited factors play a role in the epidemiology of cancer. Several studies have suggested that a dietary increase in fruits and vegetables containing compounds such as Luteolin, used in this study, would reduce the new instances of cancer by 20% and potentially prevent 200,000 cancer-related deaths annually. One hallmark of cancer is the reorganization of DNA inside the cell. Each cell in the human body contains approximately four meters of DNA organized into a compartment, the...
Show moreMany non-inherited factors play a role in the epidemiology of cancer. Several studies have suggested that a dietary increase in fruits and vegetables containing compounds such as Luteolin, used in this study, would reduce the new instances of cancer by 20% and potentially prevent 200,000 cancer-related deaths annually. One hallmark of cancer is the reorganization of DNA inside the cell. Each cell in the human body contains approximately four meters of DNA organized into a compartment, the nucleus, that is five one-hundredths of a millimeter. This almost unbelievable compaction is facilitated by the combination of negatively charged DNA with positively charged proteins to make a complex called chromatin. The organization of chromatin regulates access to DNA sequences. This project aimed to investigate factors that regulate the organization of chromatin, thereby regulating access to the genome. In this study we highlight five genomic locations where the structure of DNA changes in response to Luteolin treatment. We have potentially identified a new promoter region for the Abelson murine leukemia viral oncogene homolog 2, (ABL2) gene. Luteolin places a nucleosome in a transcriptionally active region of hydroxytryptamine receptor 2B (HTR2B) to inhibit the possible production of the gene product. Luteolin may be establishing transcriptional competence of cyclin-dependent kinase inhibitor 2A (CDKN2A) through regulation of chromatin structure around Sp1 binding sites in the promoter. Luteolin alters chromatin structure around the Sp1 binding sites in the promoter region of kisspeptin-1 (KiSS1), which could be a preliminary step to achieving transcriptional competence. Luteolin treatment alters the chromatin structure of the myelocytomatosis viral oncogene homolog (Myc) promoter in order to potentially re-establish steady state expression in a previously deregulated gene.
Show less - Date Issued
- 2012
- Identifier
- FSU_migr_uhm-0079
- Format
- Thesis
- Title
- Phosphorylation of the Transcription Factor YY1.
- Creator
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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
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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
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Davila, Gabriel Nestor, Trombley, Paul, Ouimet, Charles, Freeman, Marc, Gaffney, Betty, Meredith, Michael, Department of Biological Science, Florida State University
- Abstract/Description
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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
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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
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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
- 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
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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
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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
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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
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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
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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
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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
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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
- The Effect of Environmental Stressors on Anxiety-like Behavior Assessed in Two Distinct Behavioral Tests.
- Creator
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Labat, Sarah, Department of Biological Science
- Abstract/Description
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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
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Lebowitz, Joseph, Department of Biological Science
- Abstract/Description
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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
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Spangler, Abby, Department of Biological Science
- Abstract/Description
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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
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Milthorpe, Hannah, Department of Biological Science
- Abstract/Description
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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
- Phylogeographic Patterns in the Eastern Diamondback Rattlesnake (Crotalus adamanteus).
- Creator
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Aronow, Karalyn, Biological Science
- Abstract/Description
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The aim of this project was to analyze relationships among populations of Crotalus adamanteus (Eastern Diamondback Rattlesnake) and to compare phylogeographic patterns across different classes of genes. The objective was to determine the effect of selective pressures on the detection of barriers to gene flow. For example, venom genes are under strong positive selection and allow an analysis of the rate of allele exchange in a gene that directly affects the fitness of an individual. This...
Show moreThe aim of this project was to analyze relationships among populations of Crotalus adamanteus (Eastern Diamondback Rattlesnake) and to compare phylogeographic patterns across different classes of genes. The objective was to determine the effect of selective pressures on the detection of barriers to gene flow. For example, venom genes are under strong positive selection and allow an analysis of the rate of allele exchange in a gene that directly affects the fitness of an individual. This selection might drive alleles through phylogeographic barriers that limit the spread of neutral alleles. The relationship between nontoxin genes and fitness is not as clear and can be difficult to establish. However, most variation in these genes is neutral and determined by stochastic events. The type of selection on a gene will affect the phylogeographic pattern displayed. Prior phylogeographic studies have used either neutral markers (e.g., microsatellites) or genes not directly involved in specific adaptations (e.g., mitochondrial genes). One venom gene, two mitochondrial genes, one nuclear gene, and one pseudogene were compared for patterns of adaptation and the presence of geographic barriers to gene flow. This novel approach to studying gene flow could have an impact on defining taxonomic groups and conservation efforts, as well as serve as a guide for choosing appropriate genetic markers for other species. In the venom gene that was analyzed, it appeared the high level of selection led to alleles being driven across the barriers to gene flow of alleles under neutral selection.
Show less - Date Issued
- 2011
- Identifier
- FSU_migr_uhm-0002
- Format
- Thesis
- Title
- Role of signaling pathways in hindsight overexpression.
- Creator
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Anderson, Rhiannon, Department of Biological Science
- Abstract/Description
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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
- Determining cis-acting elements necessary for regulation of replication timing.
- Creator
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Davis, Caroline, Department of Biological Science
- Abstract/Description
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Many diseases such as DiGeorge syndrome, leukemia and likely all cancers display abnormal replication timing, the temporal order in which segments of chromosomes are replicated. However, the elements that regulate normal replication timing are poorly understood. DNA replicates during S phase of the cell cycle and does so in a spatio-temporal pattern. DNA replicating early in S phase localizes within the nuclear interior and is highly correlated with transcriptionally active euchromatin. On...
Show moreMany diseases such as DiGeorge syndrome, leukemia and likely all cancers display abnormal replication timing, the temporal order in which segments of chromosomes are replicated. However, the elements that regulate normal replication timing are poorly understood. DNA replicates during S phase of the cell cycle and does so in a spatio-temporal pattern. DNA replicating early in S phase localizes within the nuclear interior and is highly correlated with transcriptionally active euchromatin. On the other hand, DNA replicating late in S phase localizes at the nuclear and nucleolar periphery and is highly correlated with transcriptionally inactive heterochromatin. Taken together, this pattern of replication shows that DNA replication is likely involved in higher chromosome structure and function. To continue progressing within the field, replication timing regulatory elements must be identified. Uncovering these elements will allow a greater understanding of higher chromosome structure and function organization as well as elucidating the relationship between abnormal replication timing and disease. In order to show necessity of suspected candidate regulatory elements, each must be removed and a dramatic effect on replication timing must be observed. This thesis focuses on two means of showing element necessity: the development of a targeting vector to generate small deletions of DNA that harbor suspected regulatory elements and the confirmation that puromycin reconstitution to generate and identify large deletions is feasible.
Show less - Date Issued
- 2014
- Identifier
- FSU_migr_uhm-0303
- Format
- Thesis
- Title
- Sponge Regeneration and Food Abundance.
- Creator
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Vasbinder, Kelly, Department of Biological Science
- Abstract/Description
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Sponges are an integral part of marine ecosystems, especially coral reefs, because they perform many functions necessary to keeping the ecosystems healthy. The most important of these functions is the filtration of the water around them. Sponges feed by filtering bacteria and other small plankton from the surrounding water, which keeps the water clean for the rest of the organisms that live on the reef. When a sponge is wounded, it has a decreased filtering ability and can also lose its...
Show moreSponges are an integral part of marine ecosystems, especially coral reefs, because they perform many functions necessary to keeping the ecosystems healthy. The most important of these functions is the filtration of the water around them. Sponges feed by filtering bacteria and other small plankton from the surrounding water, which keeps the water clean for the rest of the organisms that live on the reef. When a sponge is wounded, it has a decreased filtering ability and can also lose its ability to perform other important functions such as participating in mutualisms, gluing corals to the reef frame, and stabilizing broken coral. Sponges are able to regenerate after wounding, and this study compares the regeneration and growth rates of sponges in two different habitats. This is relevant because different habitats have different concentrations of bacteria, and sponge food abundance in a single habitat can change based on many different factors, including factors that influenced by humans, such as nutrient concentrations. Mangrove habitats have a higher concentration of sponge food in the water than reef sites, making it possible to compare growth and regeneration of sponges with different food concentrations available in the field. Individual reef sponges from the species Ircinia felix, Verongula rigida, Callyspongia vaginalis, and Niphates digitalis were placed on mangrove and reef sites. Genotype and initial size was controlled in the experiments by cutting two nearly identical pieces from the same sponge and attaching them to stable substrata until the cut edges healed, so each piece of an individual was identical genetically and had a similar size and shape. Each sponge was wounded using a stainless steel razor blade to mimic bites of spongivorous fishes such as angelfishes and trunkfishes. Sponges of the same species were wounded in the same way. The sponges were then allowed to regenerate these wounds, and the regeneration and growth rates of each individual were calculated and compared. V. rigida, and C. vaginalis both regenerated faster in the mangrove habitat than on the reef. I. felix, and V. rigida grew faster in the mangroves than they did on the reef. In the mangroves, N. digitalis was able to reorganize itself to begin re-growing its vase shape faster when there was more food available in the water. The tissue at the wounding sites in N. digitalis and V. rigida reorganized and regenerated differently in the two different habitats. Sponges of three Caribbean and three Florida Keys species were weighed, dried, and ashed to determine the amount of each sponge that is water, tissue, and inorganic matter, and to give a better understanding of how the amount of each material corresponds to a sponge volume or a regenerated volume. Two tough Caribbean sponges, V. rigida and I. felix showed a significant difference in the dry weight and ash weight to volume ratios when compared to C. vaginalis, but not when compared with each other. Three species from the Florida Keys, H. implexiformis, T. ignis, and Ircinia spp showed a significant difference in wet and dry weight to volume ratios between one another but no difference in ash weight to volume ratios. In addition to field wounding experiments, a pilot study on tank wounding experiments were performed to assess regeneration with different concentrations of sponge food. These experiments were designed to determine whether or not sponge regeneration experiments could be performed in tanks. Some of the sponges showed regeneration after a period of twenty days, indicating that tank experiments mimicking the field experiments on regeneration are possible. This set of experiments also allowed the public to learn about sponges.
Show less - Date Issued
- 2014
- Identifier
- FSU_migr_uhm-0429
- Format
- Thesis
- Title
- The Effects of Multiple Drivers of Global Change on Caterpillar Abundances.
- Creator
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Griffith, Kaitlin, Department of Biological Science
- Abstract/Description
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Anticipating the effects of anthropogenic global change on organisms is a major challenge for ecologists today. While there have been many studies on the independent effects of global change factors, few studies have considered the potential interactive effects. Additionally, studies to date have focused on how global change factors influence plants; effects on higher trophic levels remain poorly understood and are often ignored, even though they can feedback to influence plants. We asked...
Show moreAnticipating the effects of anthropogenic global change on organisms is a major challenge for ecologists today. While there have been many studies on the independent effects of global change factors, few studies have considered the potential interactive effects. Additionally, studies to date have focused on how global change factors influence plants; effects on higher trophic levels remain poorly understood and are often ignored, even though they can feedback to influence plants. We asked whether nitrogen (N) deposition, precipitation, and predators had interactive effects on herbivorous caterpillars in a field experiment with two species of tobacco (Nicotiana tabacum, low nicotine defense-level; Nicotiana rustica, high nicotine defense-level). Our research questions were: (1) do higher N and higher precipitation alter herbivore abundances either independently or synergistically, (2) do higher N and precipitation affect spider suppression of herbivores, and (3) will global change drivers have greater effects on herbivores living on plants with low levels of anti-herbivore defenses as opposed to high defense levels? On N. tabacum, N enrichment significantly decreased caterpillar abundances under high precipitation, but had no significant effect on caterpillars when precipitation was low. We also found that spiders significantly suppressed caterpillar abundances on N. tabacum across all resource levels. For N. rustica, we found that spiders significantly suppressed caterpillars under low precipitation, but spiders had no significant effect on caterpillars under high precipitation. Our results indicate that global change drivers have interactive effects on herbivores, and can alter predator-prey interactions, and that these effects will depend on plant resistance to herbivores. Understanding ecological responses to global change may require consideration of multiple global change factors and multiple trophic levels.
Show less - Date Issued
- 2014
- Identifier
- FSU_migr_uhm-0430
- Format
- Thesis
- Title
- The Effect of Physical and Emotional Stress on Nicotine Consumption in Male Mice.
- Creator
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Sattler, Carley, Department of Psychology
- Abstract/Description
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This experiment was designed to examine the impact of chronic stress exposure on nicotine consumption. Adolescent (postnatal days, PD 38-75) male mice underwent 10 days of social defeat, were treated with one month (long-term) of forced nicotine consumption (160 mg/l), and their reactivity to various behavioral paradigms (social interaction test (SIT), elevated plus maze (EPM), and forced swim test (FST)) was assessed. Findings indicate that chronic nicotine exposure following social defeat...
Show moreThis experiment was designed to examine the impact of chronic stress exposure on nicotine consumption. Adolescent (postnatal days, PD 38-75) male mice underwent 10 days of social defeat, were treated with one month (long-term) of forced nicotine consumption (160 mg/l), and their reactivity to various behavioral paradigms (social interaction test (SIT), elevated plus maze (EPM), and forced swim test (FST)) was assessed. Findings indicate that chronic nicotine exposure following social defeat may effectively buffer against some anxiety- and depression-like symptoms later in life.
Show less - Date Issued
- 2014
- Identifier
- FSU_migr_uhm-0345
- Format
- Thesis
- Title
- Amygdala Mechanisms Involved in Chemosensory Communication.
- Creator
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Stroe, Ioana, Biological Science
- Abstract/Description
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The amygdala is an almond-shaped region of the brain present in many vertebrates such as human, hamsters and mice. The amygdala is composed of several parts, of which the following are most relevant to my research: the basolateral amygdala (BLA) and the posterior medial amygdala (MeP). The BLA functions in learning and shows increased activation after the mouse has learned a behavior. The lateral paracapsular nuclei of the intercalated nucleus (ICNlpcn) project inhibitory neurons into the BLA...
Show moreThe amygdala is an almond-shaped region of the brain present in many vertebrates such as human, hamsters and mice. The amygdala is composed of several parts, of which the following are most relevant to my research: the basolateral amygdala (BLA) and the posterior medial amygdala (MeP). The BLA functions in learning and shows increased activation after the mouse has learned a behavior. The lateral paracapsular nuclei of the intercalated nucleus (ICNlpcn) project inhibitory neurons into the BLA and mediate its activity. Dopamine has been shown to inhibit the lpcn group and therefore relieve inhibition of the BLA (disinhibition). Dopamine also acts directly in the BLA to increase activation. Therefore, if a mouse is conditioned to prefer a particular odor (in this case steer urine), dopamine injection will cause an increase in BLA activation after learning due to both disinhibition and direct excitatory response. The medial posterior amygdala in the mouse mostly responds to olfactory stimuli from the same species (conspecific stimuli). The MeP is also thought to be under control of another ICN group, the caudal ICN (ICNc). If the same inhibitory relationship is seen between ICNc and MeP, the dopamine injection may cause disinhibition in the MeP and therefore the conditioned steer urine stimulus may show increased activation in the MeP despite being a stimulus from another species (heterospecific stimulus). My experiment tests whether the ICNc has inhibitory control over the MeP, and whether dopamine will cause inhibition in the ICNc and therefore cause disinhibition in the MeP.
Show less - Date Issued
- 2011
- Identifier
- FSU_migr_uhm-0040
- Format
- Thesis
- Title
- The Cost of Safety: Negotiating the Trade-Off between Safety and Growth.
- Creator
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Matechik, Christopher, Biological Science
- Abstract/Description
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To avoid the threat of predation, prey can alter their behavior such as moving from habitats where predation risk is high to those where it is low. However, such behaviors may involve a tradeoff if the low risk habitats are suboptimal feeding locations for the prey compared to the high risk ones. In seagrass, pinfish (Lagodon rhomboides) often move from low- to high-blade density patches in the presence of the predatory Gulf flounder (Paralichthys albigutta). However, restricted movements in...
Show moreTo avoid the threat of predation, prey can alter their behavior such as moving from habitats where predation risk is high to those where it is low. However, such behaviors may involve a tradeoff if the low risk habitats are suboptimal feeding locations for the prey compared to the high risk ones. In seagrass, pinfish (Lagodon rhomboides) often move from low- to high-blade density patches in the presence of the predatory Gulf flounder (Paralichthys albigutta). However, restricted movements in high-blade habitats may lead to reduced foraging efficiency and growth rates. I used a field experiment that ran for 28 days to examine this potential tradeoff between survival and growth. Neither predator presence nor seagrass blade density affected survival or growth in pinfish. However, after accounting for the loss of experimental replicates at lower grass-blade densities, the change in pinfish biomass was greater in the predator-present treatment compared to the controls, suggesting higher mortality, increased vigilance or both when flounder were present. Unfortunately, loss of experimental replicates and high variance in the measured responses hindered my ability to address the potential tradeoff, but suggestive results support further examination.
Show less - Date Issued
- 2011
- Identifier
- FSU_migr_uhm-0025
- Format
- Thesis
- Title
- Characterization of Maize Transgene-Reactivated Mutants.
- Creator
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Mills, Erica, Biological Science
- Abstract/Description
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Epigenetic gene regulation results from heritable changes in chromatin structure, DNA methylation, and/or histone modifications associated with different expression levels for endogenous genes and transgenes. The silent b1 transgene (Btg-s) can be used to study epigenetic gene regulation in maize. A forward genetics screen based on the reactivation of Btg-s was conducted using EMS mutagenized maize. Through this screen, several mutants reactivating the transgene, designated transgene...
Show moreEpigenetic gene regulation results from heritable changes in chromatin structure, DNA methylation, and/or histone modifications associated with different expression levels for endogenous genes and transgenes. The silent b1 transgene (Btg-s) can be used to study epigenetic gene regulation in maize. A forward genetics screen based on the reactivation of Btg-s was conducted using EMS mutagenized maize. Through this screen, several mutants reactivating the transgene, designated transgene reactivated (tgr), were identified. Published work demonstrates that mutations affecting proteins involved in the RNA-dependent DNA methylation pathway cause transgene reactivation. Such mutations result in characteristic phenotypes, such as a loss of DNA methylation, loss of siRNA accumulation, and loss of transcriptional silencing. To investigate Btg promoter methylation in the tgr mutants, bisulfite sequencing was performed on plants with silenced and reactivated transgenes from four lines of tgr mutants (tgr1-3,11). Results show that in three mutant lines, the promoter region had higher methylation levels in silenced plants compared to reactivated plants, while another mutant had similar levels of methylation in both phenotypes. For tgr2, siRNA levels were assayed and transcript abundance was evaluated for genes encoding proteins possibly involved in the methylation pathway. It was found that tgr2 showed no loss of siRNA production and no difference in transcript levels were observed between silenced and reactivated individuals for the genes evaluated. This work aided in characterizing the tgr mutants which are potentially strong tools for understanding epigenetic regulation of transgenes.
Show less - Date Issued
- 2011
- Identifier
- FSU_migr_uhm-0028
- Format
- Thesis
- Title
- Chromatin Structural Changes in the Innate Immune Response.
- Creator
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Welch, Alexandra, Department of Biological Science
- Abstract/Description
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Eukaryotic nucleosomes have critical regulatory roles in mediating access to DNA. Differential regulation of nucleosome distribution is necessary for generating a rapid response to pathogens in the innate immune response and other stimuli. However, this genomic reorganization event is largely uncharacterized. Our lab has proposed that early, widespread, and transient reorganization of the genomic structure potentiates the appropriate responses of the cell to insult. We have identified...
Show moreEukaryotic nucleosomes have critical regulatory roles in mediating access to DNA. Differential regulation of nucleosome distribution is necessary for generating a rapid response to pathogens in the innate immune response and other stimuli. However, this genomic reorganization event is largely uncharacterized. Our lab has proposed that early, widespread, and transient reorganization of the genomic structure potentiates the appropriate responses of the cell to insult. We have identified chromatin structural changes in THP-1 human macrophage-like cell line induced by S. aureus stimulation. We measured nucleosome distribution high temporal resolution through the course of infection at more than 800 inflammation and immunity related genes. Herein we show that S. aureus indeed does induce rapid widespread changes in nucleosome distribution. This work supports a new model in which widespread changes potentiate a robust immune response.
Show less - Date Issued
- 2014
- Identifier
- FSU_migr_uhm-0416
- Format
- Thesis