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Title: Effects of cGMP-dependent protein kinase signaling in Drosophila S2 cells subjected to anoxia and oxidative stress.
Creator: Makhnyeva, Olena, Milton, Sarah L., Dawson-Scully, Ken, Graduate College
Abstract/Description: Ischemic stroke is one of the leading causes of human death worldwide. It occurs due to high susceptibility of neurons to anoxia and reoxygenation. Unlike mammals, invertebrate Drosophila melanogaster withstands low oxygen levels without showing pathology. In the present study, Drosophila Schneider (S2) cells were employed to investigate the role of the cGMP-dependent Protein Kinase (PKG) signaling pathway in Drosophila anoxia-tolerance in vitro. This was accomplished by subjecting cells to...
Show moreIschemic stroke is one of the leading causes of human death worldwide. It occurs due to high susceptibility of neurons to anoxia and reoxygenation. Unlike mammals, invertebrate Drosophila melanogaster withstands low oxygen levels without showing pathology. In the present study, Drosophila Schneider (S2) cells were employed to investigate the role of the cGMP-dependent Protein Kinase (PKG) signaling pathway in Drosophila anoxia-tolerance in vitro. This was accomplished by subjecting cells to chemical anoxia and oxidative stress concurrently with treatments by pharmacological agents affecting specific targets of the PKG pathway and assessing cytotoxicity. In this study, activation of the PKG pathway protected S2 cells from the aforementioned stresses. The results of this study may lead to a better understanding of fruit fly’s innate anoxia-tolerance strategies. Consequently, this knowledge may be used to identify potential therapeutic targets to prevent detrimental neurological effects of an ischemic stroke in humans.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00005837
Format: Document (PDF)

Title: Rapid neuroprotection from acute oxidative stress.
Creator: Caplan, Stacee Lee, Dawson-Scully, Ken, Milton, Sarah L., Graduate College
Date Issued: 2011-04-08
PURL: http://purl.flvc.org/fcla/dt/3164512
Subject Headings: Stress --physiology, Protein kinases, Neuroprotective agents
Format: Document (PDF)

Title: Sex determination of loggerhead sea turtles (Caretta caretta) via hormonal analysis by high performance liquid chromatography.
Creator: Botterill, Brooke L., Florida Atlantic University, Milton, Sarah L.
Abstract/Description: Sea turtles have temperature-dependent sex determination, with males being produced at cooler temperatures and females at warmer ones. Thus, sex ratios are often estimated on average nest temperatures, but this is unreliable. Therefore, many studies have begun to look to alternative methods to identify sex ratios. Other methods used to determine sex require hatchling sacrifice or are labor intensive. This study utilized high performance liquid chromatography (HPLC) to investigate correlations...
Show moreSea turtles have temperature-dependent sex determination, with males being produced at cooler temperatures and females at warmer ones. Thus, sex ratios are often estimated on average nest temperatures, but this is unreliable. Therefore, many studies have begun to look to alternative methods to identify sex ratios. Other methods used to determine sex require hatchling sacrifice or are labor intensive. This study utilized high performance liquid chromatography (HPLC) to investigate correlations between steroid hormone levels in hatchling plasma and allantoic fluid, nest temperature and sex. Hatchling sex was determined laparoscopically to ground-truth hormone profiles. No correlation was found between hormones, nest temperature and sex. However, as hormones were readily detectable by HPLC, the technique may be applicable to juvenile or adult turtles with mature profiles.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13284
Subject Headings: Sea turtles--Nests--United States, Loggerhead turtle--Breeding, Sex (Biology), High performance liquid chromatography
Format: Document (PDF)

Title: Markers of Hypoxic Stress in Fishes of the Kissimmee River.
Creator: Dirk, Lynda J., Milton, Sarah L., Florida Atlantic University
Abstract/Description: The channelized Kissimmee River experiences seasonally low dissolved oxygen levels which have changed the ecosystem to favor air-breathing species, while gamefish populations have declined greatly. In 2001 , the central portion of the river (Pool C) was physically restored. To evaluate the usefulness of various stress markers and assess the success of the partial restoration, the stress responses were analyzed (brain monoamines, heat shock proteins, and plasma cortisol) of air-breathing fish ...
Show moreThe channelized Kissimmee River experiences seasonally low dissolved oxygen levels which have changed the ecosystem to favor air-breathing species, while gamefish populations have declined greatly. In 2001 , the central portion of the river (Pool C) was physically restored. To evaluate the usefulness of various stress markers and assess the success of the partial restoration, the stress responses were analyzed (brain monoamines, heat shock proteins, and plasma cortisol) of air-breathing fish (bowfin, Florida gar), versus gamefish (largemouth bass and bluegill sunfish). Fish were collected from hypoxic and normoxic water at three sites in the Kissimmee River. Statistical analysis (MANOV A) showed overall significantly higher stress response in hypoxic gamefish than those in normoxia, with higher hsp72 levels, DOPAC, and Dopamine turnover (DOPAC:DA). Hsp60 and cortisol was significantly higher only in hypoxic bass while serotonin and 5-HIAA were significantly higher in hypoxic bluegill sunfish. Air-breathers did not show higher stress levels during hypoxia.
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Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00000747
Subject Headings: Kissimmee River (Fla )--Ecology, Restoration ecology--Florida--Kissimmee River Watershed, Adaptation (Biology), Fishes--Effect of stress on
Format: Document (PDF)

Title: Stress protein expression and green turtle fibropapillomatosis.
Creator: McGarrity, Monica E., Florida Atlantic University, Milton, Sarah L.
Abstract/Description: Green turtle fibropapillomatosis (GTFP) is a highly debilitating disease that affects several species of marine turtles worldwide. This study evaluated stress protein expression in red blood cells (RBCs), skin and tumors of green turtles (Chelonia mydas) from a GTFP-prevalent site and a more pristine, GTFP-free site. Levels of expression of HSP72 were significantly higher in healthy turtles from the GTFP-prevalent site compared to healthy turtles from the GTFP-free site, suggesting that these...
Show moreGreen turtle fibropapillomatosis (GTFP) is a highly debilitating disease that affects several species of marine turtles worldwide. This study evaluated stress protein expression in red blood cells (RBCs), skin and tumors of green turtles (Chelonia mydas) from a GTFP-prevalent site and a more pristine, GTFP-free site. Levels of expression of HSP72 were significantly higher in healthy turtles from the GTFP-prevalent site compared to healthy turtles from the GTFP-free site, suggesting that these turtles are, indeed stressed. Levels of HSP72 expression were also significantly higher in the nucleated RBCs than in skin tissues of turtles from both sites. These results demonstrate the utility of RBC stress protein evaluation as a new, minimally invasive method of evaluating stress loads in marine turtles as a factor in the potentially multifactorial etiology of GTFP. In addition, HSP72 and GP96 were present and detectable in tumors of diseased turtles, and thus show potential for use in treatment of GTFP.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13269
Subject Headings: Green turtle--Diseases, Green turtle--Immunology, Stress (Physiology), Environmental monitoring
Format: Document (PDF)

Title: Stress Protein and Anti-Apoptotic Protein Expression in Green Turtle (Chelonia mydas) Fibropapillomatosis.
Creator: Deming, Alissa C., Milton, Sarah L., Florida Atlantic University
Abstract/Description: Fibropapillomatosis (FP) is a devastating pandemic characterized by benign cutaneous neoplasias that is afflicting marine turtles worldwide. This study evaluated the expression of HSP72, GRP96, and Bcl-2 in tumor and healthy biopsies. These proteins are found in high levels in some tumors and prevent apoptosis, allowing tumor cells to survive. HSP72 and GRP96 are also known to initiate an immune response and may contribute to the regression often observed in FP tumors. Results were found that...
Show moreFibropapillomatosis (FP) is a devastating pandemic characterized by benign cutaneous neoplasias that is afflicting marine turtles worldwide. This study evaluated the expression of HSP72, GRP96, and Bcl-2 in tumor and healthy biopsies. These proteins are found in high levels in some tumors and prevent apoptosis, allowing tumor cells to survive. HSP72 and GRP96 are also known to initiate an immune response and may contribute to the regression often observed in FP tumors. Results were found that showed all three protective proteins had significantly higher levels in actively growing tumor tissue compared to healthy tissue. Specifically, cauliflower-like tumors, thought to be actively growing, were found to have higher levels of HSP72 and GRP96 compared to healthy skin, whereas smooth tumors, thought to be regressing, did not. These results offer insight into the molecular mechanisms behind the development of FP tumors and open a number of avenues for future research.
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Date Issued: 2008
PURL: http://purl.flvc.org/fau/fd/FA00000740
Subject Headings: Stress (Physiology), Green turtle--Diseases, Environmental monitoring, Green turtle--Immunology
Format: Document (PDF)

Title: A cGMP-dependent protein kinase (PKG) controls synaptic transmission tolerance to acute oxidative stress at the Drosophila larval neuromuscular junction.
Creator: Caplan, Stacee Lee, Milton, Sarah L., Dawson-Scully, Ken
Date Issued: 2013-02-01
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1152_jn.00784.2011_1644861569
Format: Document (PDF)

Title: RNAi-Mediated Gene Silencing in a Gonad Organ Culture to Study Sex Determination Mechanisms in Sea Turtle.
Creator: Sifuentes-Romero, Itzel, Merchant-Larios, Horacio, Milton, Sarah L., Moreno-Mendoza, Norma, Díaz-Hernández, Verónica, García-Gasca, Alejandra
Date Issued: 2013-06-07
PURL: http://purl.flvc.org/fau/fd/FAUIR000173
Format: Citation

Title: Beach dynamics, beachfront development, and climate change: Interactions that impact sea turtle nesting beaches.
Creator: Bladow, Rachel A., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Climate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher...
Show moreClimate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher rates of mortality compared to green turtles at temperatures above 34°C. Only loggerhead nests were exposed to inundation, but embryonic mortality did not differ from noninundated nests. Beach profiles across the nesting season were also determined. A major storm altered the beach more in areas of coastal development; however, this was impacted by a nourishment project and the presence of a structured inlet. Future management strategies may need to protect sea turtle nests from extended periods at elevated temperatures.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00005926
Subject Headings: Dissertations, Academic -- Florida Atlantic University, Sea turtles--Ecology., Loggerhead turtle--Florida., Sea turtles--Nests., Climate change
Format: Document (PDF)

Title: Assessing the Effects of Incubation Temperature on the Cognitive Ability of Hatchling Loggerhead (Caretta caretta) Sea Turtles.
Creator: Serra, Ivana, Milton, Sarah, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Under the expected warmer temperatures due to climate change, sea turtle embryos may be subjected to thermal conditions detrimental to nest success and hatchling quality; one trait which may be negatively affected is cognitive ability. In this study, loggerhead sea turtle eggs were acquired from Boca Raton, FL and lab incubated under two female-producing temperatures: an “optimal” temperature of 31°C and a sublethal temperature of 33°C. Cognitive ability of post-hatchlings, assessed via...
Show moreUnder the expected warmer temperatures due to climate change, sea turtle embryos may be subjected to thermal conditions detrimental to nest success and hatchling quality; one trait which may be negatively affected is cognitive ability. In this study, loggerhead sea turtle eggs were acquired from Boca Raton, FL and lab incubated under two female-producing temperatures: an “optimal” temperature of 31°C and a sublethal temperature of 33°C. Cognitive ability of post-hatchlings, assessed via associative learning and reversal was investigated using a y-maze. The sublethal temperature decreased incubation duration, hatch success, hatchling growth rates and produced smaller hatchlings with significantly more scute anomalies. Hot hatchlings performed worse on the reversal, taking longer to train, and thus hint at an effect of incubation temperature on cognitive flexibility in loggerhead turtles. With temperatures rising on beaches in South Florida, this study provides evidence of further potential threats to hatchling quality and potentially even survival.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013559
Subject Headings: Loggerhead turtle, Eggs--Incubation, Temperature, Cognition
Format: Document (PDF)

Title: Brevetoxin Metabolism and Physiology - A Freshwater Model of Morbidity in Endangered Sea Turtles.
Creator: Cocilova, Courtney Christine, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The dinoflagellate Karenia brevis is one organism responsible for harmful algal blooms (HABs) that severely impact marine life. K. brevis produces a suite of neurotoxins referred to as brevetoxins (PbTx) which bind to voltage-gated sodium channels (VGSCs) in excitable tissues, affecting cellular permeability leading to a suite of symptoms and potentially cell death. Brevetoxicosis is difficult to treat in sea turtles as the physiological impacts have not been investigated and the magnitude...
Show moreThe dinoflagellate Karenia brevis is one organism responsible for harmful algal blooms (HABs) that severely impact marine life. K. brevis produces a suite of neurotoxins referred to as brevetoxins (PbTx) which bind to voltage-gated sodium channels (VGSCs) in excitable tissues, affecting cellular permeability leading to a suite of symptoms and potentially cell death. Brevetoxicosis is difficult to treat in sea turtles as the physiological impacts have not been investigated and the magnitude and duration of brevetoxin exposure are generally unknown. Due to their threatened and endangered status, experimental exposures cannot be performed to determine the fate of brevetoxin in sea turtle tissues, making it difficult to design appropriate treatments. The freshwater turtle, Trachemys scripta, was utilized as a model for brevetoxin exposure in turtles. Turtles were exposed to intratracheal instillation (10.53μg/kg) or oral dosing (33.48μg/kg) of PbTx-3 3x weekly over a period of 2-4 weeks. Tissues and fluids were collected for ELISA to determine PbTx-3 uptake and distribution, routes of excretion and rates of clearance (1h-1wk post-exposure). Tissues were also preserved for histopathology. Primary turtle neuronal cell cultures were exposed to PbTx-3 in the presence and absence of various agonists and antagonists to determine brevetoxin’s mode of action. PbTx-3 was widely distributed in all tissues and fluids following both intratracheal and oral exposures, but was largely cleared from the system within 24 hours; PbTx-3 moved into the bile and feces over 48h post exposure indicating that this is the main route of excretion. While exposed animals showed clear behavioral symptoms of toxicity including muscle twitching, swimming in circles, and ataxia, there was no evident tissue pathology. Despite the evident behavioral effects, turtle neurons are surprisingly resistant to PbTx-3, with an EC50 significantly higher than is seen in mammalian neurons. While PbTx-3 exposure resulted in significant Ca2+ influx, various antagonists prevented Ca2+ influx when added with PbTx-3 confirming the mechanism of action through VGSCs. Upregulation of Hsp72 in the turtle brain could be enhancing cell survival. Based on results, intralipid treatment post PbTx-3 exposure rapidly decreases symptoms and proves to be a suitable treatment for toxin exposure.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004812
Subject Headings: Sea turtles--Mortality., Sea turtles--Physiology., Marine toxins., Neurotoxic agents--Analysis.
Format: Document (PDF)

Title: Ecosystem health and environmental influences on innate immune function in the loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle.
Creator: Sposato, Patricia L., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Loggerhead (Caretta caretta) and green (Chelonia mydas) turtles recruit to nearshore environments as juveniles. These often degraded habitats are associated with emerging diseases such as green turtle fibropapillomatosis (GTFP), however there are few studies on immune function in sea turtles. The objective of this research was to quantify phagocytosis of the innate immune system by flow cytometry and compare levels between animals from a degraded habitat (the Indian River Lagoon, FL) to a...
Show moreLoggerhead (Caretta caretta) and green (Chelonia mydas) turtles recruit to nearshore environments as juveniles. These often degraded habitats are associated with emerging diseases such as green turtle fibropapillomatosis (GTFP), however there are few studies on immune function in sea turtles. The objective of this research was to quantify phagocytosis of the innate immune system by flow cytometry and compare levels between animals from a degraded habitat (the Indian River Lagoon, FL) to a more pristine environment (the Trident Basin, Port Canaveral, FL), and across a range of temperatures. While in vitro temperatures did not alter rates of phagocytosis, it was higher in samples obtained in the summer than winter. Rates of phagocytosis in sea turtles with GTFP and from degraded environments with increased prevalence of GTFP were low compared to animals from the more pristine environment, suggesting that the environment can alter innate immunological function and thus contribute to the development of disease.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004333, http://purl.flvc.org/fau/fd/FA00004333
Subject Headings: Developmental biology, Ecosystem management -- Florida, Loggerhead turtle -- Habitat -- Environmental aspects, Marine biodiversity conservation, Sea turtles -- Immunology
Format: Document (PDF)

Title: Incubation Temperature Effects on Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtle Hatchling Vigor.
Creator: Henaghan, Christopher, Milton, Sarah, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Climate change has the potential to expose sea turtle nests to higher temperatures, which may negatively impact sea turtle hatchling vigor. In this study, loggerhead and green hatchlings were sampled from the Boca Raton, Florida beach and via lab incubation, and hatchling vigor was determined. Elevated nest temperatures decreased loggerhead and green turtle hatchling performance and corticosterone levels, with the most significant effects found in hatchlings exposed to maximum incubation...
Show moreClimate change has the potential to expose sea turtle nests to higher temperatures, which may negatively impact sea turtle hatchling vigor. In this study, loggerhead and green hatchlings were sampled from the Boca Raton, Florida beach and via lab incubation, and hatchling vigor was determined. Elevated nest temperatures decreased loggerhead and green turtle hatchling performance and corticosterone levels, with the most significant effects found in hatchlings exposed to maximum incubation temperatures above 35°C during late development. Lab-incubated loggerhead post-hatchling corticosterone levels and growth rates were also determined. The differences seen in corticosterone levels with overall nest incubation temperatures, mean temperatures during early, middle or late stages of development, and its negative correlation with hatchling performance improves our understanding of the underlying physiological mechanisms linking elevated incubation temperatures and sub-lethal physiological effects that may significantly impact hatchling survival, a critical step for sea turtle conservation in south Florida and elsewhere.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013157
Subject Headings: Loggerhead turtle--Florida, Caretta caretta, Chelonia mydas, Green turtle, Temperature, Eggs--Incubation
Format: Document (PDF)

Title: Plasma Steroid Hormones in Loggerhead and Green Sea Turtle Hatchlings.
Creator: Reis, Andrea, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Florida’s sea turtle populations are increasing due to conservation efforts; however, sea turtle species are vulnerable to climate change. Turtles exhibit temperaturedependent sex determination, in which nest environment influences sex. Environmental changes may produce altered sex ratios that limit reproduction potential; therefore hatchling sex ratios should be monitored. Hatchlings are not externally sexually dimorphic, making sex identification difficult. This study established baseline...
Show moreFlorida’s sea turtle populations are increasing due to conservation efforts; however, sea turtle species are vulnerable to climate change. Turtles exhibit temperaturedependent sex determination, in which nest environment influences sex. Environmental changes may produce altered sex ratios that limit reproduction potential; therefore hatchling sex ratios should be monitored. Hatchlings are not externally sexually dimorphic, making sex identification difficult. This study established baseline plasma hormone concentrations in hatchling and post-hatchling green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles using High Performance Liquid Chromatography. Five hormones were assayed and were present in the majority of samples (testosterone: N.D.-10.12, progesterone: N.D.-0.43, estradiol: N.D.-4.78, estriol: N.D.-5.55 and estrone: N.D.-1.67 μg/mL). Plasma hormones did not distinguish hatchling sex because male and female ranges overlapped. Hormone concentrations varied with sex but also with incubation temperature, indicating that climate change could impact hatchling and posthatchling hormone profiles and thus could impact future fitness.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004626
Subject Headings: Sea turtles--Embryology., Sea turtles--Habitat--Conservation., Sex determination, Genetic., Loggerhead turtle--Effect of temperature on., Developmental genetics.
Format: Document (PDF)

Title: Physiological Effects of Disorientation in Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtle Hatchlings.
Creator: Pankaew, Karen, Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Following nest emergence, sea turtle hatchling dispersal can be disrupted by artificial light or skyglow from urban areas. Mis- or disorientation increases exposure to predation, thermal stress, and dehydration, could consume valuable energy, and thus influence the likelihood of survival. This study utilized laboratory simulations of extended crawl distances and field observations to investigate the energy cost of disorientation crawling on loggerhead (Caretta caretta) and green (Chelonia...
Show moreFollowing nest emergence, sea turtle hatchling dispersal can be disrupted by artificial light or skyglow from urban areas. Mis- or disorientation increases exposure to predation, thermal stress, and dehydration, could consume valuable energy, and thus influence the likelihood of survival. This study utilized laboratory simulations of extended crawl distances and field observations to investigate the energy cost of disorientation crawling on loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle hatchlings and the impact on the subsequent swim frenzy. Extended crawls increased oxygen consumption, decreased plasma glucose, and reduced green hatchling swim performance following a 200m crawl. Surprisingly, plasma lactate concentrations did not increase with crawl distance, likely due to frequent rest periods that would, however, increase time on the beach and thus exposure to predators. This research may provide managers with physiological data to determine best practices for sea turtle conservation and adds to the biological knowledge of these animals.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004619
Subject Headings: Predation (Biology), Sea turtles--Life cycles., Sea turtles--Nests--Protection., Wildlife conservation., Exterior lighting--Environmental aspects.
Format: Document (PDF)

Title: cGMP/PKG-regulated mechanisms of protection from low oxygen and oxidative stress.
Creator: Mahneva, Olena, Milton, Sarah L., Dawson-Scully, Ken, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Stroke is one of the leading causes of human death in the United States. The debilitating effects of an ischemic stroke are due to the fact that mammalian neurons are highly susceptible to hypoxia and subsequent oxygen reperfusion. From studies in Drosophila melanogaster, cGMP-dependent Protein Kinase (PKG) enzyme is thought to affect anoxia tolerance by modifying the electrical current through potassium ion channels. In this research, two animal models were employed: Drosophila melanogaster...
Show moreStroke is one of the leading causes of human death in the United States. The debilitating effects of an ischemic stroke are due to the fact that mammalian neurons are highly susceptible to hypoxia and subsequent oxygen reperfusion. From studies in Drosophila melanogaster, cGMP-dependent Protein Kinase (PKG) enzyme is thought to affect anoxia tolerance by modifying the electrical current through potassium ion channels. In this research, two animal models were employed: Drosophila melanogaster and mammalian neurons exposed to stroke-like conditions. First, in vivo studies using Drosophila were performed to further our knowledge about the differences between the naturally occurring variants of the Drosophila foraging gene, which shows different protein levels of PKG. Mitochondrial density and metabolic activity between two fly genotypes exposed to anoxia and reoxygenation were compared. It was found that flies with less enzyme potentially showed mitochondrial biogenesis and higher metabolic rates upon reoxygenation. Next, in vivo studies where PKG enzyme was activated pharmacologically were performed; it was found that the activation of the cGMP/PKG pathway led to neuroprotection upon anoxia and reoxygenation. Furthermore, this model was translated into the in vitro model using Drosophila cells. Instead of anoxia and reoxygenation, hypoxia mimetics and hydrogen peroxide were used to induce cellular injury. After showing the cGMP/PKG pathway activation-induced cell protection, the potential downstream targets of the molecular signaling as well as underlying biochemical changes were assessed. It was found that mitochondrial potassium ion channels were involved in the protective signaling and the signaling modulated metabolic function. Furthermore, it was found that acidosis protected Drosophila cells from cell death, metabolic disruption, and oxidative stress. Finally, this research was translated to a mammalian in vitro model of neuronal damage upon stroke-like conditions; there, it was demonstrated that the cGMP/PKG pathway activation in rat primary cortical neurons and human cortical neurons was protective from low oxygen and acute oxidative stress. The results of this study lead to a better understanding of molecular mechanisms taking place during low oxygen and oxidative stresses. Consequently, this knowledge may be used to identify potential therapeutic targets and treatments that may prevent detrimental neurological effects of an ischemic stroke in humans.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013013
Subject Headings: Stroke, Cyclic GMP-Dependent Protein Kinases, Oxidative Stress
Format: Document (PDF)

Title: The impacts of nest microenvironment on sea turtle hatchling performance and their responses to thermal stress.
Creator: Seaman, Heather A., Milton, Sarah, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: As climate change threatens with sea-level rise and more storms, increased erosion could increase the need for beach nourishment. Alterations to sand characteristics may result in changes to the sea turtle nest microenvironment, impacting the temperature and oxygen levels which may affect hatchling performance. In this study, leatherback, loggerhead, and green nests were sampled from two sites with different sand characteristics in Juno Beach, Florida, USA. Gas exchange was higher in green...
Show moreAs climate change threatens with sea-level rise and more storms, increased erosion could increase the need for beach nourishment. Alterations to sand characteristics may result in changes to the sea turtle nest microenvironment, impacting the temperature and oxygen levels which may affect hatchling performance. In this study, leatherback, loggerhead, and green nests were sampled from two sites with different sand characteristics in Juno Beach, Florida, USA. Gas exchange was higher in green turtle nests with a greater mixture of sediment. Darker sediment elevated nest temperatures. Finer sediment and a greater mixture of sediment in leatherback nests elevated the nest temperatures; conversely finer sediment, and a greater mixture of sediment decreased loggerhead and green nest temperatures. Elevated nest temperatures reduced leatherback, loggerhead, and green turtle hatchling performance. Understanding the relationships between beach composition, nest environment, and hatchling performance will aid management decisions essential to sea turtle conservation.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013542
Subject Headings: Sea turtles--Nests, Thermal stress (Biology), Sea turtles--Conservation, Beach nourishment
Format: Document (PDF)

Title: Role and Regulation of Methionine Sulfoxide Reductase (Msr) in a model of oxidative stress tolerance: Trachemys scripta.
Creator: Reiterer, Melissa, Milton, Sarah, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The detrimental effects of oxidative stress caused by the accumulation of Reactive Oxygen Species (ROS) have been acknowledged as major factors in aging, senescence and several neurodegenerative diseases and conditions such as Parkinson’s disease and stroke (ischemia/reperfusion). Mammalian models are extremely susceptible to these stresses that follow the restoration of oxygen after anoxia; however, some organisms including the freshwater turtle Trachemys scripta can withstand several bouts...
Show moreThe detrimental effects of oxidative stress caused by the accumulation of Reactive Oxygen Species (ROS) have been acknowledged as major factors in aging, senescence and several neurodegenerative diseases and conditions such as Parkinson’s disease and stroke (ischemia/reperfusion). Mammalian models are extremely susceptible to these stresses that follow the restoration of oxygen after anoxia; however, some organisms including the freshwater turtle Trachemys scripta can withstand several bouts of anoxia and repeated reoxygenation without any apparent pathology. T. scripta thus provides us with an alternate vertebrate model in which we can investigate physiological mechanisms of neuroprotection without the damaging effects that come with oxidative stress. The major objective of this study was to investigate the protective mechanisms in the turtle brain under conditions of anoxia and oxidative stress. Specifically, the focus is on the Methionine Sulfoxide Reductase system (Msr), an antioxidant and cellular repair system, and how it is regulated to protect the brain against such stressors. Previous studies in my lab have demonstrated that Msr mRNA and protein levels are differentially upregulated during anoxia and reoxygenation. To investigate the regulation of Msr, FOXO3a was directly induced by transfecting a human FOXO3a plasmid into turtle brain cell cultures, as FOXO3a has been shown to regulate MsrA levels in other animal models. Pharmacological manipulation of FOXO3a was also performed using the green tea extract Epigallocatechin gallate (EGCG) as it has been shown to increase expression of FOXO3a during oxidative stress conditions in other models. I found that an induction of human FOXO3a increased FOXO3a levels and showed protection against cell death during oxidative stress. Furthermore, treatment of cells with EGCG increased expression of FOXO3a only when the cells were exposed to oxidative stress and decreased cell death. Induction of FOXO3a and EGCG treatment did not increase MsrA levels, however MsrB3 levels were upregulated under both treatments but only in the presence of oxidative stress. These results suggest that MsrA and MsrB3 protect the cells from oxidative stress damage through different molecular pathways and that EGCG may be a therapeutic target to treat diseases related to damage by oxidative stress.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013154
Subject Headings: Methionine Sulfoxide Reductases, Oxidative Stress, Trachemys scripta
Format: Document (PDF)

Title: Origins, movements, and foraging behavior of Hawksbill Sea Turtles (Eretmochelys imbricata) in Palm Beach County waters, Florida, USA.
Creator: Wood, Lawrence D., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: This dissertation examined the natal origins, home-range, and in-situ foraging behavior of an aggregation of sub-adult hawksbill turtles (Eretmochelys imbricata) found off the coast of Palm Beach County, Florida. Surveys were conducted on approximately 30 linear km of reef between 15 and 30 m in depth. Tissue samples were retrieved from 112 turtles for mtDNA haplotype determination. GPS-linked satellite transmitters were deployed on six resident sub-adults, resulting in both minimum convex...
Show moreThis dissertation examined the natal origins, home-range, and in-situ foraging behavior of an aggregation of sub-adult hawksbill turtles (Eretmochelys imbricata) found off the coast of Palm Beach County, Florida. Surveys were conducted on approximately 30 linear km of reef between 15 and 30 m in depth. Tissue samples were retrieved from 112 turtles for mtDNA haplotype determination. GPS-linked satellite transmitters were deployed on six resident sub-adults, resulting in both minimum convex polygon (MCP) and 95%, 50%, and 25% kernel density estimates (KDE) of home-range size. A foraging ethogram was developed, and sequential analysis performed on thirty videos (141 total minutes) of in-situ foraging behavior. Seventeen total haplotypes were identified in this aggregation, the majority (75%) of which represented rookeries on Mexico’s Yucatan Peninsula. Other sources, from most to least important, include Barbados, Costa Rica, Puerto Rico, Antigua, and the U.S. Virgin Islands.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004339
Subject Headings: Animal behavior, Animal orientation, Hawksbill turtle -- Ecology, Predation (Biology), Sea turtles -- Habitat, Wildlife conservation, Wildlife management
Format: Document (PDF)

Title: INFLUENCE OF UV LIGHT ON VITAMIN D AND IMMUNE FUNCTION OF GREEN (CHELONIA MYDAS) SEA TURTLES WITH FIBROPAPILLOMATOSIS.
Creator: Garefino, Victoria E., Milton, Sarah L., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Green sea turtles (Chelonia mydas) are an endangered species prone to a debilitating disease called fibropapillomatosis (FP). The aim of this study was to determine the influence of UV light on vitamin D levels and immune function in juvenile green sea turtles with FP. Phagocytosis, plasma vitamin D levels and viral load of ChHV5 were measured for FP- and FP+ turtles kept at the Gumbo Limbo Nature Center (GLNC) and for turtles caught at the St. Lucie power plant. Turtles kept at GLNC were...
Show moreGreen sea turtles (Chelonia mydas) are an endangered species prone to a debilitating disease called fibropapillomatosis (FP). The aim of this study was to determine the influence of UV light on vitamin D levels and immune function in juvenile green sea turtles with FP. Phagocytosis, plasma vitamin D levels and viral load of ChHV5 were measured for FP- and FP+ turtles kept at the Gumbo Limbo Nature Center (GLNC) and for turtles caught at the St. Lucie power plant. Turtles kept at GLNC were housed in tanks exposed to varying amounts of UV light. Turtles brought into GLNC had lower phagocytosis compared to turtles at the St. Lucie power plant. Individuals exposed to greater UV light had higher plasma vitamin D levels and a more successful recovery. The results of this project will provide rehabilitation facilities with a mechanism to improve the recovery of animals with this disease.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013467
Subject Headings: Chelonia mydas, Green turtle--Diseases, Fibropapillomatosis, Ultraviolet radiation, Vitamin D
Format: Document (PDF)

FAU Theses and Dissertations (23)	+ -
FAU College Collections (3)	+ -
FAU Graduate Student Research (2)	+ -

Adaptation (Biology) (3)	+ -
Eggs--Incubation (3)	+ -
Green turtle--Diseases (3)	+ -
Loggerhead turtle (3)	+ -
Sea turtles--Ecology (3)	+ -

Caretta caretta (2)	+ -
Chelonia mydas (2)	+ -
Environmental monitoring (2)	+ -
Green turtle--Immunology (2)	+ -
Neuroprotective agents (2)	+ -
Oxidative Stress (2)	+ -
Predation (Biology) (2)	+ -
Protein kinases (2)	+ -
Sea turtles--Nests (2)	+ -
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Temperature (2)	+ -
Wildlife conservation (2)	+ -
Animal behavior (1)	+ -
Animal orientation (1)	+ -
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Dissertations, Academic -- Florida Atlantic University (1)	+ -
Drosophila melanogaster -- Life cycles (1)	+ -
Ecosystem management -- Florida (1)	+ -
Exterior lighting--Environmental aspects. (1)	+ -
Fibropapillomatosis (1)	+ -

Electronic Thesis or Dissertation (23)	+ -
abstract (2)	+ -
article (2)	+ -
report (1)	+ -

Florida Atlantic University (23)	+ -
Milton, Sarah L. (23)	+ -
Charles E. Schmidt College of Science (20)	+ -
Department of Biological Sciences (19)	+ -
Dawson-Scully, Ken (5)	+ -

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