The goal of this study was to examine the potential health effects of organochlorine (OC) and polycyclic aromatic hydrocarbon (PAH) exposure on Atlantic stingray populations in Florida’s St. Johns River (SJR). Special emphasis was placed on identifying OC- and/or PAH-related effects in stingrays from areas of the lower (LSJR) and middle (MSJR) basins shown to possess elevated levels of these compounds, as well as characterizing baseline levels of pollutant exposure in the SJR shipping channel, which may be subjected to dredging in the near future, potentially resuspending and redistributing contaminated sediments and increasing pollutant-associated effects. To accomplish this, we measured OC and PAH biomarker levels in stingrays collected from contaminated and reference sites. We specifically examined the phase I detoxification enzyme, cytochrome P4501a1 (CYP1a1); the phase II detoxification enzymes, glutathione-S-transferase (GST) and uridine 5’-diphosphate glucuronosyltransferase (UGT); fluorescent aromatic compounds, PAH bile metabolites; and lipid peroxidation (LPO), cell membrane damage. Biomarker values collected between 2014 and 2016 were compared by site. Detoxification enzyme activity and LPO values from individuals collected from the three MSJR lakes between 2002 and 2005 were compared to those collected between 2014 and 2016. The data suggested that biomarker values from the SJR were variable, with elevated levels from Lake Jesup. Compared to reference estuaries, the LSJR has low biomarker values. This indicates that residing in certain portions of the MSJR is detrimental to stingray health, while residing in the LSJR is not. Lake Monroe and Lake George biomarker levels indicated reduced contaminant input over time, whereas Lake Jesup biomarker levels suggested the opposite. This study has developed a baseline for biomarker levels in the LSJR, allowing for the identification of dredging-induced changes to the system, and has identified temporal changes in biomarker levels from three MSJR lakes.

Klebsiella pneumoniae is an opportunistic pathogen responsible for lobar pneumoniae, liver abscess, and septicemia. Clinical isolates are found to be extended spectrum beta lactamase positive with differential expression of the two classical porins, OmpK35 and OmpK36. Porin loss is associated with increased minimum inhibitory concentrations of beta lactam, cephalosporin, and carbapenem antibiotics that target the peptidoglycan. However, little is known about how porin loss affects other aspects of the cell envelope. The focus of this study was to characterize clinical isolates exhibiting differential porin expression and determine if the cumulative changes altered the resistance to phagocytosis by macrophages. The results support the hypothesis that porin loss significantly impacts the overall cell envelope composition, which in turn alters interactions with macrophages.

In animals, the accepted model of carbohydrate digestion and absorption involves reduction of disaccharides into the simple sugars glucose, fructose and galactose. Previous studies have shown the presence of disaccharides maltose and trehalose in the blood of several crab species, the crayfish and the American lobster. In 2011, a gene for a distinct disaccharide sucrose transporter (SCRT) was first found in Drosophila melanogaster and characterized using a yeast expression system. The purpose of the current study was to identify and characterize a putative disaccharide transporter analog in crustaceans using the American lobster, Homarus americanus. Brush border membrane vesicles purified from the hepatopancreas were utilized. After identification of a sucrose transporter in the brush border membrane of the hepatopancreas, transport kinetics experiments were used to characterize it using 14C radio-labeled sucrose and a Millipore filter isolation technique. Lack of glycyl-sarcosine inhibition of sucrose uptake into vesicles indicated that the highly non-specific dipeptide transporter PEPT1 was not the functional transporter of sucrose. A more acidic pH of 4 was shown to drive sucrose transport in the absence of sodium. Sodium was then shown to also significantly stimulate sucrose uptake, which resulted in an overshoot at 1 minute over a hyperbolic potassium uptake curve, suggesting that both sodium and acidic pH were capable of driving disaccharide transport. Experiments that used a variety of monosaccharides and polysaccharides indicated that the disaccharides maltose and trehalose were the only sugars to significantly inhibit carrier-mediated sucrose transport (maltose P = 0.017, trehalose P = 0.023 using a one-way ANOVA) (Km = 0.1951 ± 0.0630 mM sucrose, Jmax = 0.5884 ± 0.0823 nmol/mg protein x 1 minute), suggesting specificity of the transporter. Sucrose in the presence of 20 mM maltose had a Km of 0.5847 ± 0.1782 mM sucrose (P = 0.030) and a Jmax of 0.6536 ± 0.1238 nmol/mg protein x 1 minute (P = 0.006). ANOVA P-values indicate the difference between the sucrose control curve and the maltose curve. The highly significant reduction between the Km values of the control sucrose curve and the maltose curve suggests competitive inhibition between the two sugars. These two disaccharides could utilize the same transporter, and are appropriate for the physiology of the animal in this case, as lobsters commonly digest glycogen and chitin, polymers of maltose and trehalose, respectively. These findings suggest there is a brush-border proton-, or sodium-dependent, hepatopancreatic carrier process, shared by sucrose, maltose, and trehalose, that may function to absorb disaccharides that occur from digestion of naturally-occurring dietary constituents.

Based on recognized life history traits and ecology, zoos strive to house their gorillas (Gorilla gorilla gorilla) in mixed-sex groups with one mature male or silverback, multiple females, and their offspring. However, successful captive breeding programs and a nearly 50:50 birth sex ratio has created the need to house surplus males in solitary conditions or all-male groups. It is commonly believed that male western gorillas will not tolerate one another in the presence of females; however, multi-male, mixed-sex groups have been observed in the wild. For this reason, some zoos have begun experimenting with this scenario. At the time of data collection, only four of the 51 institutions housing gorillas in the North American Species Survival Plan® population housed multi-male, mixed sex groups. Chapter one documents the activity budgets of two of these multi-male groups and compares them to those of two traditional family troops. Overall behavior repertoire was similar between group type, though more locomoting and aberrant behaviors were exhibited by individuals in the multi-silverback groups. Interaction between the silverbacks varied greatly between the multi-male groups which suggests there could be multiple models of success for these groups. However, further insight is needed to determine why some multi-male groups are successful while others are not. Therefore, the second chapter outlines the results of a multi-institutional survey which covered the recent history of multi-male, mixed-sex groups in North American zoos. The goal of the survey was to determine potential factors associated with silverback compatibility. Results indicate that there is an association between successful multi-male, mixed-sex groups and some life history factors including the relatedness of the males, their rearing histories, and the time at which they were introduced. This research offers insight into a potential gorilla social assemblage that has been underutilized in zoo settings.

From 2008 to 2012, the total U.S. commercial landings of blue crabs (Callinectes sapidus Rathbun, 1896) averaged over 173 million lbs. Chesapeake Bay and its tributaries are important contributors to this fishery, providing greater than 30% of national commercial landings annually. In Chesapeake Bay, C. sapidus exhibits a complex life cycle in which mated females migrate to the saline waters of the Bay mouth to spawn. During migration, females can traverse multiple management jurisdictions, complicating effective management of this important fishery. Sustained declines in harvest have led to management strategies focused on protecting the female spawning stock in an attempt to enhance recruitment back into the Bay. This study presents the results of a broad scale mark-recapture study (n=7,072) in 11 Chesapeake Bay subestuaries and one coastal embayment, designed to track female migration and quantify spatial variation in exploitation rates of mature female blue crabs. Tagging was conducted in fall 2014 (September and October), when most females have matured and begin to migrate to the spawning grounds, and in summer 2015 (July), when additional females mature and migrate to the spawning grounds. Approximately 8.1% of tagged females were recaptured within one year of release. Overall, the exploitation rate of the 2015 blue crab spawning stock in Chesapeake Bay was 10.5%; however exploitation varied widely among systems (4.0-28.5%). This estimate is below both the management target and threshold exploitation rates and the population grew in subsequent years, suggesting recruitment overfishing of blue crabs was not occurring in Chesapeake Bay at this time.

The St. Johns River (SJR; Jacksonville, FL, USA) is a large, brackish, estuarine system characterized by considerable anthropogenic pollution, recurrent harmful algal blooms (HABs), and diverse toxin-producing cyanobacteria. The most prevalent toxins in SJR water samples are microcystins/nodularins (MCs/NODs). Additionally, the SJR provides critical habitat for a genetically and behaviorally distinct estuarine community of bottlenose dolphins (Tursiops truncatus) that routinely uses and strands in low mesohaline and oligohaline areas of the river. This population has been subject to two unusual mortality events (UME) since 2010 and has since been described as having substantial declines in population health, characterized by widespread dermatitis and emaciation. Additionally, three dolphins have been recovered from low salinity habitats with epidermal algal mats. Because dolphin illness and strandings overlapped temporally and spatially with confirmed cyanobacterial blooms in the SJR, there is concern that estuarine dolphin health may be declining due to exposure to toxic cyanobacteria and HAB events. Specific to this study, the SJR estuarine community was considered a high-risk group for cyanotoxin exposure in relation to coastal animals. This study analyzed all available hepatic tissues for estuarine dolphins, and used samples from coastal individuals that stranded outside of the known cyanotoxin bloom season as controls. Three analytical methods were used to determine MCs/NODs presence in dolphin liver and epidermal algal mat samples. An Adda ELISA and LC-MS/MS were used to determine free MCs/NODs presence while the MMPB technique was used to determine total (bound and free) concentrations and as confirmatory analyses. ELISA analyses produced high values that were not supported by concurrent LC-MS/MS or MMPB analyses, indicative of false positives. MMPB testing resulted in low-level total MCs/NODs detection in some specimens. Results indicate that both estuarine and coastal dolphins are exposed to MCs/NODs, with potential toxic and immune health impacts.

Although it was once thought that neurons solely rely on glucose as a substrate for cellular energy production, it is now known that small monocarboxylate molecules, like pyruvate, lactate, and ketone bodies, are also utilized. Monocarboxylates are transported across plasma membranes via facilitated diffusion using a family of transport proteins known as monocarboxylate transporters (MCTs). Four MCTs (MCT1, MCT2, MCT3, and MCT4) are expressed within neural tissues. Expression of the MCTs has been tied to co-expression of a cell adhesion molecule belonging to the Basigin subset of the immunoglobulin superfamily (IgSF). Basigin gene products are known to interact with MCT1 and MCT4 in the mammalian neural retina and this association is essential to support the cellular energy needs of photoreceptors. A previous study indicated that Basigin gene products use hydrophobic amino acids within specific regions of the transmembrane domain to interact with MCT1. In the present study, it is hypothesized that the same amino acids within the transmembrane domain are used to interact with MCT4, but that no association exists with MCT2, which typically interacts with a different member of the IgSF subset. Therefore, the purpose of the present study was to assess the association between Basigin gene products and MCT4, and with MCT2. Recombinant proteins corresponding to the transmembrane domain of Basigin gene products were used in in vitro binding assays with endogenous MCT2 and MCT4 from mouse brain protein lysates. Contrary to the hypothesis, it was determined that the transmembrane domain of Basigin gene products binds to both MCT2 and MCT4 in vitro. Different amino acids within the transmembrane domain of Basigin gene products are used for each association and the pattern is different from that used in the association with MCT1. The data suggest that Basigin plays multiple roles in the nervous system.

Although tiger sharks are an important apex predator in many ecosystems, little is known about their reproduction. The goal of this study was to determine the size-at-maturity and the reproductive seasonality of tiger sharks in the western Atlantic Ocean. This was achieved using a combination of ultrasonography and measurements of plasma hormone concentrations; in particular, testosterone for males and estradiol and progesterone for females. Steroid hormone concentrations were measured using chemiluminescent assays (CLIA). Maturity was also examined through histology of reproductive organs in females and clasper calcification in males. Females were found to mature between 270 and 310 cm total length and males were found to mature between 260 and 300 cm total length. Mating was determined to occur in October/November, based on the presence of mating wounds on females and increased concentrations of testosterone in males. Some females were shown to exhibit increased plasma estradiol concentrations also during October/November; however, we do not believe that ovulation takes place until May or June based on ultrasonography data. This suggests a period of sperm storage although histological examination of the oviducal gland was not able to confirm this. Ultrasonography data, showing increasing embryo size over the course of a year, and data on minimum size of tiger sharks caught in longline surveys suggested that parturition occurs between June and September with pups being born as small as 56 cm fork length. The findings from this study show that some tiger sharks reach reproductive maturity at sizes smaller than what has been previously suggested. Additionally, the possibility of tiger sharks storing sperm suggests that their reproductive cycle is a minimum of two years long and could be up to three years in duration. This information is important for management of the species in the future. Additionally, this study adds to the limited knowledge about reproduction of elasmobranchs and how patterns of reproductive steroids can correlate with different reproductive events.

Vitellogenin (Vtg) is a precursor to yolk-proteins produced in the liver of many invertebrates and non-mammalian vertebrates; its synthesis is stimulated by the hormone estradiol (E2). This study is the first to characterize vitellogenin synthesis in a placental viviparous elasmobranch, the yolk-sac placental bonnethead shark, Sphyrna tiburo. This study focused on determining where and when Vtg is produced, as well as what hormonal factors regulate Vtg production. The liver was confirmed as the site of Vtg production via immunohistochemistry. Immunoreactivity was also observed within granulosa cells of ovarian follicles; further experimentation is needed to determine if this is indicative of Vtg production by these cells. Using immunoblotting, the highest proportions of Vtg positive females were found in March, with Vtg production continuing into April and May. Putative Vtg production was found to begin in August for some individuals, with production continuing throughout the fall and winter months. In regards to hormonal regulation, immunohistochemical analysis identified receptors for E2 and progesterone (P4) within the liver. Comparison of the monthly E2 and Vtg cycles provides evidence that E2 stimulates Vtg production in S. tiburo, as high or increasing concentrations of E2 correlated with Vtg presence in the plasma. Preliminary results also suggest in vitro production of Vtg by liver tissue when exposed to E2. Comparison of the monthly P4 and Vtg cycles suggests P4 may inhibit Vtg synthesis, with higher levels of P4 found in the months when Vtg production declines. Additionally, the methods developed for this study were able to identify Vtg in the plasma of other elasmobranch species. Vtg detection in plasma may thus be an ideal new, nonlethal method for characterizing elasmobranch reproductive periodicity, which will aid in assessing population growth and allow for managers to possess more accurate information to make appropriate decisions for the populations.

If we want to understand how meroplankton utilize the water column and how their vertical distribution may influence horizontal advection, it is important to study their behavior in the various environments where they exist. In a well-mixed system with physical cues dampened, and no vertical layering, these organisms will have to depend on environmental cues such as light, tidal current, and tide cycle, as well as their own swimming ability to migrate vertically. Plankton and water samples were collected at three depths (near surface, midwater, near bottom) during the summers of 2013 and 2014 from sites within the main channel of the Intracoastal Waterway. Six taxonomic groups were collected including polychaetes, bivalves, gastropods, barnacles, tunicates, and crabs, and fell into one of three categories of vertical distribution. Certain preferences for vertical distribution, and habitat, of sessile invertebrates can increase, or provide refuge from, competition. To assess the potential competition for spatial resources between native and nonnative bivalves in the Guana Tolomato Matanzas estuary, settlement collectors with settlement plates at different depths were deployed for one month periods during the summers of 2013 and 2014 at two main channel sites and two feeder creek sites. Competition would likely be highest subtidally and within the main channel due to all species occurring in that habitat in higher numbers than the feeder creek.