Master of Science, The Ohio State University, 2010, Environmental Science

Hybrid striped bass (Morone chrysops x M. saxatilis) is an important sportfish in many systems across the U.S. and is often stocked into reservoirs as fry or juveniles. However, determining the success or failure of fry stocking and factors underlying fry survival in reservoirs has been difficult for fisheries managers because of the complications in collecting larvae in reservoirs. Using fish culture ponds, I was able to examine the effects of physical and biological variables on the growth and survival of larval hybrid striped bass, providing information to help fisheries managers to identify reservoir attributes that can support hybrid striped bass stocking. I conducted experiments over three years at two Ohio fish hatcheries to determine: 1) the effects of increased fish fry stocking density on larval fish growth and zooplankton availability; 2) whether the zooplankton prey base in ponds and reservoirs is adequate to support larval and juvenile growth; 3) the potential magnitude of cyclopoid copepod predation on fry in ponds and reservoirs. I found that fry stocking density did not influence fish yield (g/m3) or survival; however, a low density treatment produced larger, albeit fewer, juveniles at harvest than did a high density treatment. Therefore, stocking rates should be based upon whether managers wish to produce larger or higher numbers of juvenile hybrid striped bass. Hybrid striped bass growth and diet analyses indicate that copepod nauplii are an important prey during the first week of life and copepodites during the entire culture period, whereas Daphnia spp. were less important . My study also found that culture ponds and their source waters have similar zooplankton prey composition, size frequency and densities, suggesting that a hatchery environment can serve as a good proxy for studying reservoir ecology. Cyclopoid copepod predation on larval hybrid striped bass at copepod and larval densities found in culture ponds and reservoirs is unlikely to ca (open full item for complete abstract)

Committee: Stuart A. Ludsin (Advisor); David A. Culver (Committee Member); Harold Walker (Committee Member) Subjects: Aquaculture

Master of Science (MS), Wright State University, 2024, Biological Sciences

Emerald ash borer (EAB), Agrilus planipennis, is an invasive pest that significantly impacts olive trees (Olea europaea). This study aimed to assess the role of abiotic stress factors such as drought and salinity in influencing plant defenses and resistance to EAB, while also examining cultivar variation in resistance. The study specifically aimed to address: (1) What effects do varying degrees of abiotic stress (drought, salinity) have on olive trees' antioxidant and peroxidase activity in olive tree? (2) Do distinct olive cultivars exhibit varying levels of resistance to EAB under various stressors? We used a controlled experimental design with two stress treatments (drought and salinity) and 20 olive cultivars to conduct the bioassay. Growth metrics (height and stem diameter), peroxidase activity, and antioxidant activity were measured, while EAB survival and performance were assessed by monitoring larval feeding and growth. Results indicated no significant differences in antioxidant activity between treatments, although low salinity slightly enhanced antioxidant responses. Peroxidase activity was highest under high salinity, and growth responses varied by treatment and cultivar, with Leccino showing the highest antioxidant activity. EAB larvae performed best under drought conditions but exhibited poor survival on certain cultivars. These findings suggest that abiotic stress influences both plant defense mechanisms and pest resistance, with cultivar-specific responses to stress and pest pressure.

Committee: Don Cipollini Ph.D. (Advisor); John Stireman III Ph.D. (Committee Member); Volker Bahn Ph.D. (Committee Member) Subjects: Agriculture; Agronomy; Biology; Botany; Chemistry; Ecology; Entomology; Environmental Science; Environmental Studies; Nutrition; Plant Biology; Plant Pathology; Plant Sciences; Public Health; Soil Sciences

Doctor of Philosophy, Miami University, 2024, Biology

Midwestern North American lakes, including the Laurentian Great Lakes, are experiencing significant increases in water transparency due to invasive Dreissenid mussels and improved watershed management practices. Climate change loss of winter has reduced annual ice cover on the lakes. Increases in water transparency combined with the absence of ice cover in the winter may lead to an increased risk of exposure to damaging ultraviolet radiation (UV), which is known to regulate the early life stages of fish. Despite these potential increases in underwater UV, very little is known of the current day UV transparency throughout the Great Lakes, nor the UV tolerance or mechanisms of protection of the early life stages of a culturally, economically, and ecologically important subfamily of native Great Lakes fish: Coregonine (i.e., Lake Whitefish [Adikameg; Coregonus clupeaformis], Cisco [Otoonapi; C. artedi], and Bloater [C. hoyi]), nor an economically important invasive prey species of fish: Alewife (Alosa pseudoharengus). This dissertation investigated 1) the spatial and temporal UV transparency patterns across the Great Lakes, 2) the ability for UV to accelerate the hatching of native Cisco eggs, 3) the UV tolerance, mechanisms of protection, and sublethal consequences of exposure to UV among two life stages, four species and multiple populations of fish and 4) the influence of UV on the vertical distribution of larval Alewife and Bloater within Lake Michigan. Although long-term offshore UV data does not exist, long-term nearshore UV data suggest shallower UV exposure correlated with increasing dissolved organic carbon concentrations. Laboratory experiments revealed that developing Cisco embryos exposed to UV have the potential to hatch 30 days earlier than embryos unexposed to UV, the egg life stage of all native coregonines tested had a higher UV tolerance than the larval life stages, and the UV tolerance among species and populations of the same species varied. Field s (open full item for complete abstract)

Committee: Craig Williamson (Advisor); David Bunnell (Committee Member); Jennifer Schumacher (Committee Member); Michael Vanni (Committee Member); Thomas Fisher (Committee Member) Subjects: Biology; Ecology; Freshwater Ecology; Limnology; Organismal Biology

Master of Science, Miami University, 2022, Biology

As habitat loss and degradation continually threaten biodiversity, understanding the habitat requirements of species is as important as ever for wildlife management and conservation. All species require certain habitat features to persist, whether that be at the microhabitat scale or the landscape scale. Here I aimed to determine habitat features important for spotted salamanders, a cryptic species with a complex life cycle. My central hypothesis is that microhabitat features and landscape-level features will both impact spotted salamander individuals and populations. I used an experimental study to assess impacts on individuals and a field survey to assess populations. Overall, I found that larval density and pond cover both impact captive reared spotted salamander metamorphosis, and that leaf litter impacts the recapture of individuals after overwintering. Finally, I found that the prevalence and abundance of wild spotted salamanders are associated with the amount of leaf litter, the amount of shrub/scrub habitat surrounding breeding ponds, and the distance of the breeding pond to the nearest pond. This research demonstrates the importance of studying habitat features at various scales to accurately study species occupancy and manage natural areas in a way that best accommodates wildlife.

Committee: Michelle Boone (Advisor); Tereza Jezkova (Committee Member); Nancy Solomon (Committee Member) Subjects: Biology; Conservation; Ecology; Freshwater Ecology; Wildlife Conservation; Wildlife Management; Zoology

Master of Science (MS), Ohio University, 2021, Biological Sciences (Arts and Sciences)

Parkinson's disease (PD) is a progressive neurodegenerative movement disorder characterized by the loss of dopaminergic (DA) neurons in substantia nigra pars compacta and the formation of Lewy Bodies (LBs), cytoplasmic protein deposits of α-Synuclein (αSyn). In recent years, an intriguing concept of prion-like spreading of pathogenic proteins such as αSyn has emerged. Released αSyn spreads between neurons causing neurodegeneration, but the actual propagation mechanism is still under investigation. In order to test cell-to-cell propagation of αSyn, I investigate αSyn release. In my project, I develop a larval neuromuscular junction (NMJ) model in order to study αSyn release mechanisms. I hypothesize that neuronal activity regulates pathological αSyn release. Thus, using optogenetics to stimulate neurons that co-express αSyn and Channel Rhodopsin (ChR2) in Drosophila melanogaster larvae, I examine αSyn release induced by neuronal depolarization. I use ELISA technique to detect and compare released αSyn levels in the hemolymph of different fly lines. Results show activity-dependent αSyn release. This activity-dependent αSyn release is also influenced by synaptic transmission, mutations, and phosphorylation of αSyn. Hence, αSyn release might be induced in some regions of PD brain in response to excitability, and this αSyn release might underlie the disease progression. Therefore, targeting αSyn release could be further studied in hope of establishing new therapeutic interventions to stop or slow PD pathology.

Committee: Daewoo Lee (Advisor); Corinne Nielsen (Committee Member); Robert Colvin (Committee Member) Subjects: Biology; Neurobiology; Neurosciences

Master of Science (MS), Ohio University, 2021, Geological Sciences

Studies of the relationship between extant trace makers, known environmental conditions, and the morphology of their biogenic structures allow for the interpretation of continental ichnofossils. This study examined the burrowing techniques, behaviors, and trace morphologies of three extant species of burrowing beetles, Tenebrio molitor, Zophobas morio, and Phyllophaga sp., from their larval to adult life stages under normal and stressed environmental conditions in a laboratory setting. Tenebrio molitor and Z. morio burrowed using their mandibles to compact the substrate, while Phyllophaga sp., burrowed by excavation and backfilling. The three species primary behaviors were locomotion, mobile deposit feeding, intermittent resting, and pupation. Larvae burrows of T. molitor and Z. morio included open boxworks, while Phyllophaga sp. larvae generated elongate backfilled burrows which terminated in an open chamber. All three species created ovoid to ellipsoidal chambers when preparing for pupation. During their adult stage, T. molitor and Z. morio created conical traces and chambers, while Phyllophaga sp. produced loosely backfilled burrows. The environmental stresses tested were related to sediment sand and water content as well as sediment compactness. Higher trace abundance was produced in sediments with decreased sand content, increased water content, and low compactness, although trace morphologies did not change. Highly compacted substrates had little activity, but distinct trace morphologies. The total level of bioturbation, quantified with the ichnofabric index, produced by multiple specimens of each species in large enclosures filled with layered sediment varied from 1 (T. molitor and Phyllophaga sp.) to 2-5 (Z. morio). Quantitative analyses of the quantitative properties of the different traces showed that, despite having similar morphologies, the traces produced by the three species were dissimilar, but also showed variation within species. Understanding extan (open full item for complete abstract)

Committee: Daniel Hembree Ph.D (Advisor); Alycia Stigall Ph.D (Committee Member); Xizhen Schenk Ph.D (Committee Member) Subjects: Geology; Paleontology

Master of Science, Miami University, 2020, Biology

Zooplankton in reservoirs within agricultural landscapes exhibit unique dynamics due to highly variable discharge as well as elevated nutrient inputs and productivity. Here we explore the long-term response of crustacean zooplankton biomass and phenology and relate these to long-term trends and interannual variability (IAV) in environmental factors in a eutrophic reservoir over a 24-year period. We also investigated bidirectional effects among zooplankton taxa, chlorophyll, and larval fish using convergent cross mapping (CCM). Cyclopoids increased and rotifers decreased over time, while the center of gravity (COG, week of peak biomass) of calanoids advanced over time. We detected the largest number of significant correlations between the IAVs of crustacean taxa and temperature, and between the IAVs of crustacean taxa COG and chlorophyll COG. CCM identified numerous interspecific relationships among zooplankton taxa and effects of inorganic turbidity, temperature, and food quality. Bottom-up effects of chlorophyll on cyclopoids and rotifers as well as rotifers on copepods were significant, while top-down effects were marginally significant. Our findings suggest phytoplankton and temperature likely drove long-term changes in the zooplankton community. Management of eutrophic reservoirs should consider the temporal scale and complexity of food web dynamics to understand effects from climatic factors and watershed inputs.

Committee: María González Dr. (Advisor); Michael Vanni Dr. (Committee Member); Craig Williamson Dr. (Committee Member); Thomas Fisher Dr. (Committee Member) Subjects: Aquatic Sciences; Biology; Ecology; Environmental Science; Limnology

Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Bighead carp (Hypophthalmichthys nobilis) is native to Asia and was introduced to the United States as a species of interest for aquaculture in the 1970s but escaped from captivity soon after. This species is currently widely spread throughout the Mississippi River Basin and may already be present in the Great Lakes, which could impact this important sport fishery. Current control efforts have focused on preventing further spread through constructing barriers and physical removal of adults from rivers. Alternative methods for biocontrol of invasive fish species are becoming increasingly attractive and show promise as another tool that can be used to control or eliminate invasive populations. These methods rely on genetic technology designed and implemented in aquaculture, such as sex reversal, polyploidy and mass offspring production for stocking. A series of experiments were conducted to investigate novel aspects of sperm storage to perform in vitro fertilization and intensive larval/juvenile rearing of bighead for application in biocontrol stocking programs. The first experiment addressed the short term storage of sperm on ice and cryopreservation. There is a lack of available information on the short term storage of silver carp (Hypophthalmichthys molitrix) and bighead carp sperm. The quality of fresh silver carp sperm stored without dilution in a sperm motility inhibiting (extender) solution was found to decrease rapidly after 24 hours becoming agglutinated or forming clumps by the third day. When sperm was stored in an extender solution, 45 % motility was maintained after 3 days. The trials involving cryopreservation investigated the applicability of utilizing original or modified protocols previously described for common carp and silver carp. The trials conducted with modified protocols were not successful, as post-thaw motility was sporadic or absent. However, the trials with original protocols using koi carp sperm identified post-thaw motility of at least 1 (open full item for complete abstract)

Committee: Konrad Dabrowski (Advisor); Lauren Pintor (Committee Member); Roman Lanno (Committee Member) Subjects: Aquaculture; Aquatic Sciences; Fish Production

Doctor of Philosophy, The Ohio State University, 2018, Environment and Natural Resources

Sustainable management of fisheries and improvement of aquaculture production depends on an increased scientific understanding of fish physiology, nutrition, genetics, and ecology. With over 33,000 described fish species, and hundreds of these species being commercially fished or farmed, it is impractical to develop scientific resources and thoroughly investigate the biology of each species. One solution to this problem is the utilization of model organisms. The zebrafish Danio rerio is a widely used model organism in the larger experimental biology community. However, several areas of research need to be addressed for its utility to increase, particularly for fisheries and aquaculture research. First, rearing methods need to be improved, with an emphasis on larval and early juvenile stages. The sex determination system is controversial, but has been suggested to be polygenic. Finally, interspecies hybridization, which is a key tool in genetic improvement for aquaculture species, has not been thoroughly explored in the Danio genus. We present a series of studies addressing these areas of research in order to increase the utility of the zebrafish model system with an emphasis on applications to fisheries and aquaculture research. First, we designed and evaluated a rearing method utilizing a novel set of environmental parameters (3 parts per thousand salinity, high densities of live food, algal turbidity, 24L:0D photoperiod) from 5 to 21 days post-fertilization (dpf) that led to rapid growth rates (mean ± SD lengths of 19.4 ± 1.0 mm and 30.4 ± 1.5 mm at 21 and 42 dpf, respectively) and high fertility (232 ± 124 oocytes/female at 66 ± 3 dpf) (chapter 2). Next, we evaluated this protocol at temperatures close to the lower thermal limit for embryonic development (23°C) and observed no significant decrease in survival compared to a control group kept at optimum temperature (28.5°C) (chapter 3). We then utilized this rearing protocol to perform a series of investigati (open full item for complete abstract)

Committee: Konrad Dabrowski (Advisor); Wick Macdonald (Committee Member); Ottobre Joseph (Committee Member) Subjects: Agriculture; Aquaculture; Aquatic Sciences; Biology; Evolution and Development; Fish Production; Livestock; Organismal Biology; Zoology

Doctor of Philosophy, The Ohio State University, 2018, Environment and Natural Resources

Bighead carp are characterized by many morphological and physiological adaptations that allow them to survive and grow in wide range of environmental conditions. However, information on how this species withstands environmental change is contradictory. To address this issue a set of experiments were conducted with the aim of determining the effects of two major environmental factors (temperature and oxygen saturation) on the growth of bighead carp under laboratory conditions. Small (S; 2.5±0.3g) and large (L; 5.7±0.5g) bighead carp juveniles were reared in temperatures that were gradually increased by 5°C. Overall, environmental factors significantly (P<0.0001) affected specific growth rate (SGR, %/day), feed conversion ratio (FCR), survival (%) and temperature quotient (Q10) of bighead carp. The change of temperatures and feeding conditions significantly affected the body composition of small and large bighead carp juveniles. The fatty acid compositions (FA) of total lipids (TL), neutral lipids (NL), and polar lipids (PL) were altered from the initial level by the change of temperatures as well as feeding conditions. Fatty acid compositions of NL and PL were subdivided into saturated (SFA), unsaturated (UFA), Omega-3 (n-3) and Omega-6 (n-6) fatty acids, as well as the ratio of n-3: n-6. Overall, the highest SFA content was found at higher temperature and UFA at a lower temperature and they differed significantly (P<0.05). Hypoxia tolerance of koi and bighead carps were examined under laboratory conditions. Dissolved oxygen concentration was gradually reduced in a 3L volume respirometry flask and measured at 15 min intervals until reaching the threshold levels, aquatic surface respiration (ASR) and loss of equilibrium (LOE). The results indicated that hypoxia tolerance of koi and bighead carps varies depending on the threshold considered (ASR and LOE). The ontogenetic (size) impact in hypoxia tolerance indicates that oxygen consumption from water (WO) and a (open full item for complete abstract)

Committee: Konrad Dabrowski Dr. (Advisor) Subjects: Environmental Science

MS, Kent State University, 2017, College of Arts and Sciences / Department of Biological Sciences

Great Lakes coastal wetlands are of significant ecological and economic importance. These wetlands collect runoff from surrounding land, mitigate natural disasters, and provide habitat for plants and animals at all life stages. There is a growing literature describing the factors effecting spatial and temporal patterns in fish diversity in brackish coastal wetlands that surround marine waters, but similar studies are lacking in freshwater estuaries and little is known about these patterns in larval fishes. Adult fishes were collected weekly between May and October 2015 using fyke nets set in monotypic stands of vegetation. Larval fishes were collected weekly between May and October 2015, and biweekly from April to August 2016. Water depth was measured at all fyke nets and all traps. A suite of abiotic variables was also measured during 2016. Patterns in fish distribution and diversity were assessed using univariate and multivariate statistics. Fish did not appear to choose specific types of vegetation, but preferred the presence of vegetation to open water areas. Patches of submerged aquatic vegetation and water lily/lotus had a significant effect on larval community structure, as did dissolved oxygen, pH, and secchi depth. Larvae peaked in abundance in mid-July in 2015, and early June in 2016, but the 2016 peak had over 1000 more individuals than the 2015 peak. Further, abundance values from 2015 were similar to those from the same dates in 2016. This suggests that spawning periods of Lake Erie fishes are predictable from year to year within the same estuary. These studies suggested that fish prefer macrophytic cover, and they improved understanding of the effects of water level on fish distributions. The studies also identified spawning patterns as constant from year-to-year. Future studies should examine whether larval fish actively choose habitats following spawning, as well as whether abiotic variables influence hatching and growth rates. Finally, the work on (open full item for complete abstract)

Committee: Mark Kershner Ph.D (Advisor); Ferenc de Szalay Ph.D (Committee Member); Kristin Arend Ph.D (Committee Member) Subjects: Biology; Ecology

Doctor of Philosophy, University of Toledo, 2014, College of Natural Sciences and Mathematics

Migratory fish are globally harvested by humans and are important to ecosystem function. The management of migratory fish depends on an ability to monitor populations and a sound understanding of the role of fish migrations in an ecosystem context. Lake Erie is a highly productive freshwater fishery and many of Lake Erie's fishes are potamodromous, migrating from Lake Erie into tributaries to spawn. The goal of this dissertation was to improve methods for monitoring migratory fishes and examine the role of fish migrations in ecosystem processes. First, I developed techniques for monitoring spawning stocks of migratory fishes in the Maumee River, one of Lake Erie's largest tributaries, using hydroacoustic sampling, gill net sampling, and Bayesian state-space modeling. I determined that the spawning stock abundance for Walleye was approximately 650,000 fish in 2011 and 550,000 individuals in 2012. Second, I examined the importance of fish migrations as a material subsidy to upstream riverine consumers using stable isotope analysis. I found that although migratory fish inputs (eggs and carcasses) were a negligible pool of carbon relative to other sources. However, migratory fish biomass had low carbon to nitrogen ratios, indicating high nutritional quality, and stable isotope analysis supported the hypothesis that some riverine fishes and invertebrates consume these inputs. Third, I estimated detection probabilities for larval fishes in the Maumee and Detroit rivers and demonstrated how detection information can be used to inform indices of abundance and taxonomic richness estimates. Detection probabilities varied among taxa and were generally greater in the Maumee River than the Detroit River. Taxa with the greatest detection probabilities were those with high fecundities, small hatching lengths, and no nesting behaviors. Accounting for incomplete detection greatly increased an index of abundance for a species with low detection probability but had a relatively minor (open full item for complete abstract)

Committee: Christine Mayer (Committee Chair); Thomas Bridgeman (Committee Member); Johan Gottgens (Committee Member); Patrick Kocovsky (Committee Member); Edward Roseman (Committee Member) Subjects: Ecology; Freshwater Ecology; Wildlife Management

MS, University of Cincinnati, 2010, Arts and Sciences: Biological Sciences

Spadefoot toad species display extreme variation in larval period duration, due in part to evolution of thyroid hormone (TH) physiology. In particular, previous studies using an in-vitro tail tip shrinkage assay showed tissue responsiveness to TH was increased in species with shorter larval periods. To explain larval period differences at the molecular level, we hypothesized species differences in TH receptor (TR) expression consistent with the dual function model for the role of TR in development. Specifically, low TR expression prior to the production of endogenous TH and greater induction of TR when endogenous TH becomes available could contribute to shorter larval periods. We cloned fragments of TRα and TRβ genes from S. couchii, S. multiplicata, and P. cultripes and measured their mRNA levels using quantitative PCR in the absence (premetamorphosis) or presence (metamorphosis) of TH. We found that S. couchii, which has the shortest larval period, had no or little fold change in TRα or TRβ compared to the other species, S. multiplicata and P. cultripes during premetamorphosis, but had the highest fold changes during natural and induced metamorphosis. The higher fold change during natural metamorphosis in S. couchii suggests greater signaling through the TR to enable shorter larval periods. Indeed, the higher fold-change in TRβ (which is a direct TH response gene) in the T3-induction assay supported the increased TR signalling capacity in S. couchii. Our study provides evidence for changes in TR expression that may contribute to divergent larval period durations in spadefoot toads.

Committee: Daniel Buchholz PhD (Committee Chair); John Layne PhD (Committee Member); Kenneth Petren PhD (Committee Member) Subjects: Biology

Master of Science, The Ohio State University, 2010, Evolution, Ecology, and Organismal Biology

Management of aquaculture systems should be based on ecologically sound principles and experimentation to determine species- and site-specific management practices that both optimize fish production and extend our understanding. Herein, we exemplify an approach to meet this goal, evaluating the effectiveness of three common management levers: pond fertilization regimen, pond filling and stocking schedule, and fry stocking rate, on larval production of two popular percid fish, walleye (Sander vitreus) and saugeye (S. vitreus x S. canadense), at Senecaville State Fish Hatchery in Ohio. These levers are based on established ecological principles and hypotheses concerning fish recruitment, including resource-driven or “bottom-up” control, the match-mismatch hypothesis, and predator-driven or “top-down” control, respectively. Our experiments demonstrate that “top-down” effects (i.e., fish predation on zooplankton) drive fish growth, and we recommend that fry stocking density be reduced to les than 20 percid fry/m3 to yield suitable fish size at harvest. At higher stocking rates, percid planktivory can deplete zooplankton prey resources, resulting in poor fish growth and unacceptably small percid size at harvest. The other two management levers (i.e., manipulating fertilization rate and pond filling and stocking schedules) had little impact on percid production; however, these ecological management levers may be critical for successful fish production at other hatcheries, given different environmental conditions (e.g., source water productivity) or fish taxa. Overall, we illustrate an ecologically sound approach to assess management protocols for fish production in aquaculture settings that can be broadly applied to culture of many species at a variety of culture locations.

Committee: Stuart Ludsin PhD (Advisor); David Culver PhD (Advisor); Roy Stein PhD (Committee Member) Subjects: Aquaculture; Ecology; Fish Production; Freshwater Ecology

Doctor of Philosophy (PhD), Ohio University, 2012, Biological Sciences (Arts and Sciences)

Changes in synaptic plasticity are thought to be the basis of information storage leading to memory formation. In both vertebrates and invertebrates, the cAMP signaling pathway has been shown to be critical for learning and memory. The combined use of advanced genetic tools and behavioral learning assays in Drosophila has helped define the role for cAMP signaling in olfactory associative learning. However, very little is known about how cAMP mediated changes in synaptic transmission, especially at central synapses, contribute to behavioral learning. In this thesis I have used a combination of electrophysiology on Drosophila primary neuronal cultures and behavioral larval learning assays to explore if cAMP mediated changes in synaptic plasticity can contribute to behavioral learning. I demonstrate that cAMP signaling activates PKA and thus leads to an increase in the frequency of excitatory cholinergic synaptic currents and a supression of inhibitory GABAergic synaptic currents. I also observe that cAMP modulates the inhibitory GABAergic synapses in two distinct ways. It increases pre-synaptic GABA release and also decreases post-synaptic GABAA-receptor response possibly through PKA mediated phosphorylation, thus resulting in an overall reduction of GABAergic synaptic transmission. This regulation of post-synaptic GABAA-receptors by cAMP is altered in the mushroom body (MB) neurons of cAMP mutants (e.g. dunce and rutabaga). These flies have physiologically opposite levels of cAMP and show defects in olfactory learning. I further demonstrate that a biogenic amine (5-HT) increases cholinergic EPSC frequency and decreases GABAergic IPSC frequency. My work shows that 5-HT acts through the d5-HT7 receptor to activate cAMP-PKA signaling as its effect on cholinergic and GABAergic currents is similar to that observed with cAMP alone. I further note that the d5-HT7 receptor is expressed in the mushroom body neurons, which is critical for both olfactory appetitive and aversive (open full item for complete abstract)

Committee: Daewoo Lee (Advisor); Ralph DiCaprio A (Committee Member); Robert Colvin A (Committee Member); Jung Peter (Committee Member) Subjects: Neurosciences

Master of Science (MS), Ohio University, 2005, Biological Sciences (Arts and Sciences)

The CG4749 gene in Drosophila melanogaster is predicted to encode a methyltransferase, and its homologue in humans (p120) is directly related to growth rate of cancer cells. In Drosophila, it has been shown previously that CG4749 is a gene regulated by the Toll pathway, which parallels the NF-κB pathway in mammals. In this study, in order to elucidate the function of CG4749 and its connection to the Toll pathway, a study on the CG4749 gene has been performed using molecular, genetic, and histological approaches. We found that CG4749 is necessary for normal development in Drosophila, in that the CG4749 mutants are embryonic to larval recessive lethal and the development is retarded in the CG4749 mutant larvae. Loss of CG4749 function leads to autophagic cell death in the Drosophila larval hindgut epithelium, suggesting that CG4749 is indispensable for cell survival of Drosophila larval hindgut epithelium. The CG4749 gene is essential for hemocyte overproduction stimulated by overactive Toll and JAK/STAT pathways. In addition, CG4749 is essential for maintaining En protein expression in the Drosophila larval hindgut. This is the first study demonstrating that the CG4749 gene, one gene regulated by the Toll pathway, is related to autophagic cell death in Drosophila.

Committee: Soichi Tanda (Advisor) Subjects: Biology, Genetics

Master of Science, Miami University, 2010, Zoology

This thesis discusses how multiple environmental stressors affect both a native and a non-native fish species in Lake Tahoe. Stressors include both natural ultraviolet radiation (UVR) and a phototoxic polycyclic aromatic hydrocarbon (PAH), fluoranthene (FLU). Due to human activities, both UVR attenuation and PAH levels are increasing, potentially affecting natural processes of the lake. The objective of this study was to understand the individual and population level effects of exposure to different levels of UVR and photo-activated FLU in the two species. Responses to these changes in the native Lahontan redside minnow (Richardsonius egregius) and the non-native warm-water bluegill sunfish (Lepomis macrochirus) were compared in controlled outdoor exposures. Tests were conducted to determine the sensitivity/tolerance of each species, and microscopy techniques were utilized to determine the extent of skin damage, serving as biomarkers of exposure and effect. Natural defenses were also investigated; clarifying in what ways each species may tolerate exposure. This research will help determine the potential for invasive success of the bluegill and similar species in Lake Tahoe and other oligotrophic, montane lakes that are susceptible to habitat alteration, nutrient inputs, and recreational activity.

Committee: James Oris PhD (Advisor); Richard Edelmann PhD (Committee Member); Lori Isaacson PhD (Committee Member); Craig Williamson PhD (Committee Member) Subjects: Ecology; Environmental Science; Toxicology

Master of Science, University of Akron, 2012, Biology

Embryonic ethanol exposure is known to cause birth defects and neurodevelopmental disorders in many vertebrates, including humans. In this study, zebrafish (D. rerio) were used to investigate the affects of embryonic ethanol exposure on embryo/larval development and the subsequent adult behavior. Although zebrafish have become a widely used model for prenatal alcohol exposure, in many cases the concentrations used are high and the period of observation is short. In order to record both larval and adult measures, this study utilized a low concentration of ethanol (0.4%) throughout the embryonic period of development (0-72 days post fertilization). Anatomical and physiological data was collected from larvae (including eye and heart measures) to investigate the affects of ethanol on embryonic development and an aggression/avoidance assay was used to determine if embryonic ethanol exposure influenced adult behavioral phenotypes. Exposure to ethanol throughout embryonic development resulted in decreased eye size, increased ventricle area, increased cardiovascular function, and reduced size in the larvae. In the adult fish, neither measures of size nor behavior of the treatment group were found to be significantly different from that of the control. In conclusion, low levels of embryonic ethanol exposure can result in changes in both form and function of larval anatomy and physiology. However, this affect does not seem to carry into adulthood through size or behavioral aggression/avoidance behaviors.

Committee: Brian Bagatto Dr. (Advisor); Francisco Moore Dr. (Committee Member); Richard Londraville Dr. (Committee Member) Subjects: Anatomy and Physiology; Animals; Behavioral Sciences; Biology; Developmental Biology; Physiology

Bachelor of Sciences, Ohio University, 2013, Biological Sciences

Cancer is a leading cause of death in the United States. Cancer arises due to the accumulation of multiple mutations. These mutations can occur in signaling transduction pathways that then impact other pathways through crosstalk. Crosstalk between pathways is an expanding area of research as it demonstrates how one mutation can affect other systems downstream. The identification of proteins that mediate crosstalk also allows for the potential development of therapeutic drugs to interrupt the crosstalk, potentially nullifying the initial mutation. Two pathways that are involved in many types of human cancers are the Jak-Stat and Wnt (Wingless, Wg) pathways. These two pathways are also involved in the development of a leukemia-like disease seen in Hop[Tum-l] mutants in Drosophila. Here I show that these two pathways crosstalk in vivo, mediated by the protein Mad. I show that this crosstalk is important to the proliferation of larval hemocytes and their differentiation into a specialized cell type, the lamellocyte. I propose and test a model whereby the Jak-Stat pathway activates proliferation and differentiation while the Wnt pathway activates proliferation and inhibits differentiation. I examine if differentiation in an overactive Jak-Stat mutant, Hop[Tum-l], requires activity of Mad. Additionally, I examine if Mad inhibits Wg pathway activity in hematopoiesis. From my results, I propose a system where the protein Mad mediates the crosstalk between the Jak-Stat and Wnt pathways by inhibiting the Wnt pathway.

Committee: Soichi Tanda (Advisor) Subjects: Biology; Cellular Biology; Genetics; Molecular Biology

Master of Science, University of Toledo, 2012, Biology (Ecology)

The estimation of abundance is complicated by factors contributing to spatial and temporal variability. Many organisms are highly variable across both of these scales, thereby violating assumptions of conventional abundance estimation methods. Larval walleye in the Maumee River are extremely variable; however estimates of abundance and mortality are important in understanding anthropogenic impacts on this spawning group and their role in Lake Erie walleye recruitment. Bayesian hierarchical models were used to quantify spatial and temporal variability, and estimate abundance and mortality within the river while accounting for spatial and temporal uncertainty. We sampled larval walleye at the river mouth and in the intake canal of a water-cooled power plant in 2010 and at an additional upstream site near the spawning grounds in 2011. Temporal variability and uncertainty was greater than spatial variability at all sites and years during the study. Daily abundance at each site and year was related to patterns in river discharge and temperature. Larval walleye abundance decreased in a downstream fashion, with an estimated annual natural mortality rate of 63.7% in 2011. Downstream (B) and power plant abundance (C) varied between years leading to a decrease in power plant entrainment mortality from 2010 to 2011, 11.1 to 2.8% respectively. Total in-river mortality was estimated at 64.8% when entrainment mortality was included. Quantifying sources of variability lead to an adjustment in sampling protocol, which increased precision in estimated values. Bayesian hierarchical models provided an optimal framework for understanding sources of variability and estimating larval fish abundance and mortality in this large river system.

Committee: Christine Mayer PhD (Committee Chair); Craig Stow PhD (Committee Member); Edward Roseman PhD (Committee Member); Jonathan Bossenbroek PhD (Committee Member) Subjects: Applied Mathematics; Aquatic Sciences; Biology; Ecology; Environmental Science; Freshwater Ecology; Statistics