Biology Graduate Students  2015-2016 

These are some of our current graduate students and their research interests.

• Debra Brunson

  Graduate Advisor Dr. Terri Ellis   Research Interests My graduate research focuses on the pathogen, Klebsiella pneumoniae, a gram negative, rod shaped bacteria prevalant in nosocomial infections. This includes pneumonia and systemic infections. I am interested in observing the relationship between the bacteria and immune cells, particularly alveolar macrophages. I use confocal microscopy as a tool to observe phagocytosis of different strains of K. pneumoniae by macrophages. This allows me to analyze the different ways in which the strains of K. pneumoniae are able to evade the immune system due to characteristics such as porin loss, capsule production, and O antigen loss. I hope to further explore this relationship through other molecular methods as my research continues, here and UNF.  Education B.S. Microbiology, Idaho State University, Pocatello, Idaho

• Cohen Carpenter

  Graduate Advisor Dr. Eric Johnson Research Interests My interests are in the community ecology of coastal marine and estuarine systems with a closer look at sharks. My graduate research consists of surveying shark populations along the southeastern coast in order to provide information such as species richness, relative abundance, distribution and breeding populations of these top predators. More specifically, we are focusing on the scalloped hammerhead (Sphyrna lewini) and the Carolina hammerhead (Sphyrna gilberti​), the two of which are morphologically indistinguishable. Until recently, they were both considered scalloped hammerheads, and endangered at that. This research will allow for a better understanding of all species involved and subsequently a greater ability to practice sustainable management of them. Education B.S. Biology, Georgia Southern University

   

• Corey Corrick

  Graduate Advisor Dr. Eric Johnson Research Interests I am interested in the ecology, population dynamics, and life history of marine and estuarine species.  My current research focuses on spatial variation in fishing mortality of blue crab populations in subestuaries of the upper Chesapeake Bay, which have observed sustained declines over the last 25 years. This project, in coordination with other ongoing research efforts, will help to understand the relative impacts of recreational and commercial fishing on blue crab populations and help to quantify the contribution of individual subestuaries to the Chesapeake Bay spawning stock. Education A.S. Biology, Santa Fe College B.S. Biology, Coastal Biology, University of North Florida

   

• Kaylin Crosby

  Graduate Advisor Dr. Terry Maple and Dr. Quincy Gibson Research Interests My research focuses on the social dynamics of captive western lowland gorillas. Specifically, I am assessing the effectiveness of training protocols which aim to strengthen group cohesion. This will be done through a comparative analysis examining the change in social interactions and the levels of fecal glucocorticoids (a biological stress marker) before and after training implementation. The study has the potential to determine a successful method that can give zoological intituations a means to improve the social stability of their primate populations.   Education B.S. Animal Behavior, Purdue University, 2012 M.S. Biology, Ball State University, Muncie, 2015

• Paige Duffin

   

  Graduate Advisor Dr. Cliff Ross Research Interests "In the broadest sense, I am driven by the idea of finding an interface between awareness through scientific inquiry and striving for a sustainable future for the marine environment through the use of that knowledge. The foundation of my thesis work aligns with this interest, as I seek to elucidate the dynamics of the host-pathogen interaction that leads to seagrass wasting disease, whose periodic decimation of regional seagrass species throughout history is so substantial that it frequently triggers ecosystem wide collapses. The causative agent of the epidemic is Labyrinthula, a group of parasitic slime molds. I’ve chosen to focus on wasting disease prevalence in Thalassia testudinum (turtle grass), due to its fundamental role as a primary producer in shallow tropics around the world and whose populations have been historically plagued by Labyrinthula infection. More specifically, the overarching goal of my research is to define and draw correlations between host immune measures, site-specific environmental variability, pathogen prevalence, and host genotype. This study is especially meaningful when we place it within the context of anthropogenic impact and the compounding associated stressors it imposes on coastal ecosystems in particular. The expectation is that host susceptibility to Labyrinthula will be intimately linked to the condition of its environment. Bleak projections concerning the health of our coastal ecosystems the near future demand advances in our understanding of this complex interaction to facilitate the development of more informed conservation management techniques." Education B.S. Biology, University of North Florida

• Samantha Ehnert

  Graduate Advisor Dr. Jim Gelsleichter   Research Interests The goal of my research is to determine if high levels of mercury accumulation that have been observed in shark muscle also occurs in their brain, the main target for mercury toxicity, and if these levels are associated with damage to their nervous system. This study will focus on mercury concentrations in the brain, and S-100, a protein marker of brain damage, in the cerebrospinal fluid of the Atlantic sharpnose shark (Rhizoprionodon terraenovae). Additional markers of oxidative stress and lipid peroxidation will be tested as well.   Education B.S. Marine Biology with honors, University on North Carolina Wilmington, 2011

• Joseph Fong

  Graduate Advisor Dr. Judith Ochrietor Research Interests My graduate thesis research is directed at the study of cell adhesion molecules in the brain, specifically Neuroplastins. The goal of my thesis research is to characterize the interactions between the transmembrane domain of Neuroplastins and monocarboxylate transporters (MCTs) in the brain. Neuroplastins are important cell adhesion molecules in synapses, allowing for neurite outgrowth, synaptic maturation and plasticity, and may be useful as a drug target for treatment of mental disorders. MCTs are used to transport pyruvate, lactate, and ketone by means of facilitated diffusion for use as an energy source by parts the brain, in addition to glucose which is also utilized by the rest of the body. The interactions of other members of the Immunoglobulin Superfamily (IgSF) of cell adhesion molecules (Basigin, and Embigin) with MCTs have been well characterized. However, the interactions between Neuroplastins and MCTs have not yet been characterized. This project will provide insight into the potential for the interactions between these molecules within the brain. Education B.S. Biology, University of North Florida

• Caleb Hayes

  Graduate Advisor Dr. David Waddell Research Interests My research focuses on the isolation and functional analysis of Tetratricopeptide 39c (Ttc39c), a novel gene expressed during skeletal muscle. This gene's expression has been shown to be transcriptionally regulated by the E3 ubiquitin ligase MuRF1. While having virtually no expression in differentiated skeletal muscle, Ttc39c expression is upregulated by MuRF1 under neurogenic atrophy conditions. Understanding Ttc39c's function within this atrophy pathway will further elucidate the molecular mechanisms of neurogenic skeletal muscle atrophy.  Education B.S. Biology, Western Kentucky University

• Matt Heck

  Graduate Advisor Dr. John Hatle Research Interests My research interests lie in the characterization of experimental laboratory techniques that prolong lifespan. With the advent of modern medicine and infectious disease prevention, selection’s limitation on promoting post-reproductive survival has manifested itself through age-related disorders. The associated decline in healthspan observed late in life has been linked with the accumulation of damage to macromolecules (e.g., catalytic proteins, lipid membranes, and DNA), which are thought to contribute to cellular dysfunction, the induction of age-related diseases, and eventual death. Dietary restriction (DR), a reduction of caloric intake without malnutrition, significantly extends median and maximum lifespans in most animals. While the DR response is multifaceted, hope remains that a discrete pattern of differential expression can be attributed to its salutary effects on healthspan. Using RNAi-mediated knockdown of neuropeptide F (a homolog of neuropeptide Y) upon a DR regimen, I intend to test the orexigenic hormone’s effects on reducing macromolecular damage (protein carbonylation, lipid peroxidation, and oxidative DNA adduction), enhancing resistance to stress (e.g., ultraviolet radiation and oxidizing agents), and extending lifespan. Molecular assays will measure oxidative damage in postmitotic tissues such as muscle and brain, and qPCR will be utilized to assess changes in DR-related gene expression.   Education B.S. Biology, University of North Florida

   

• Karina Kakareka

  Graduate Advisor Dr. David Waddell Research Interests My graduate research focuses on the molecular mechanisms of neurogenic skeletal muscle atrophy. Previous literature has shown an up-regulation of MuRF1, an E3 ubiquitin ligase, under atrophy conditions. Although MuRF1 is typically characterized to function in tagging proteins for degradation, unpublished data suggests that it has a possible role as a transcriptional regulator. I am interested in how myogenic regulatory factors, namely MyoD and myogenin, coordinate with MuRF1 to transcriptionally regulate atrogenes differentially expressed under MuRF1 KO conditions during neurogenic atrophy. Additionally, I am interested in characterizing the expression and activity of a novel atrogene, Calcoco1 (Calcium Binding and Coiled-Coil Domain 1), in muscle. Characterizing a potential mechanism of MuRF1 as a transcriptional regulator may help to alleviate the absence of identified targets of E3 ubiquitin ligases. In a broader context, a potential mechanism of how E3 ligases act as transcriptional regulators in neurogenic atrophy may aid in targeting muscle atrophy in diseases and injuries.  Education B.S. Biology, University of North Florida

• Carissa King

  Graduate Advisor Dr. Quincy Gibson Research Interests My research interests are on the social development and behavior of infant bottlenose dolphins in the St. John’s River. As part of this, I will be analyzing the dolphins’ vocalizations and the river’s soundscape in order to determine potential impacts of noise pollution on mother-infant behavior.  Education B.S. Biology, University of Northern Colorado, 2014

• Sydney Labuzan

  Graduate Advisor Dr. David Waddell   Research Interests My research interests lie in better elucidating the cellular pathway involved in the process of skeletal muscle atrophy. My research in particular focuses on the isolation and functional analysis of dihydrousidine synthase 2 (Dus2), a gene that is expressed in skeletal muscle cells. This gene’s expression has been shown to be transcriptionally regulated by MuRF1, an E3 ubiquitin ligase. Dus2 expression has already been seen to be upregulated by MuRF1 under conditions of neurogenic atrophy, and is hypothesized to be a regulator of translational machinery and involved in cell viability in pulmonary cells. However, its role has never been functionally analyzed in skeletal muscle, so better understanding its function within the atrophy pathway will help to better understand the underlying molecular mechanisms of neurogenic skeletal muscle atrophy.   Education  B.S. Biology, Rollins College

   

• Clark Morgan

  Graduate Advisor Dr. Jim Gelsleichter Research Interests My primary research interests lie within the conservation and management of elasmobranchs, particularly large coastal sharks. My thesis work aims to establish new blood biomarkers to quantify the physiological stress response of sharks to both commercial and recreational capture, and to better understand how stress impacts survivability. Specifically, I am investigating how indicators of oxidative stress can help predict post-release mortality. By better understanding the varying factors of capture-induced stress, we can more accurately determine the number of released sharks that survive which will result in more accurate analysis of fishery catch data, and thus more effective fisheries management.   Education B.S. in Biology, Minor in Marine Biology, Florida State University

• Kat Mowle

  Graduate Advisor Dr. Jim Gelsleichter Research Interests Broadly, my research interests lie in understanding the reproductive cycle of various shark species, information which is critical to conducting stock assessments and making management decisions concerning shark populations. Here at UNF, my master's research focuses on characterizing the cycle of the protein vitellogenin in the bonnethead shark, Sphyrna tiburo. Vitellogenin is a precursor to yolk proteins and its synthesis is regulated by the hormone estradiol; better understanding of the cycle of this protein will aid in a more detailed understanding of the overall reproductive cycle, particularly of female individuals. Additionally, this project focuses on using nonlethal methods to assess the reproductive cycle of sharks via the measurement of proteins and hormones in plasma samples. This reduces the need to sacrifice individuals while learning about their biology. Education B.S. in Marine Biology, Hawaii Pacific University

   

• Jennifer Raabe

  Graduate Advisor Dr. Matthew Gilg Research Interests My research interests include larval behavior, recruitment, and the study of invasive species with an emphasis on marine invertebrates. My current project investigates the potential range of the invasive Asian green mussel, Perna virdis. In order to do this I will be looking into the vertical migration patterns of P. viridis larvae in conjunction with settlement data. The information collected from this study will allow us to better predict larval movement and determine which environmental factors will be key in determining whether larvae will settle at certain locations. Education B.S. Biology with an emphasis on Environmental Biology, University of Southern Mississippi

• David Reynolds

  Graduate Advisor Cliff Ross Research Interests My research interests focus on conservation biology and marine ecology. The aim of my graduate research is to identify the effects of the seasonal red tide producing dinoflagellate, Karenia brevis, on reef building coral in the Gulf of Mexico. By analyzing sub-lethal stress in coral at different life stages following exposure to K. brevis and their associated brevetoxins, I hope to determine if these algae blooms have the potential to cause recruitment failure and coral bleaching. The results of this research will help us understand the impact of a potential local stressor on coral in the Gulf of Mexico and allow us to more accurately project coral decline.  Education B.S Biology, University of North Florida

   

• Chelsea Shields

  Graduate Advisor Dr. Jim Gelsleichter Research Interests My research focuses on the reproductive endocrinology of the southern stingray, Dasyatis americana. I am examining associations between reproductive stage and circulating concentrations of reproductive hormones using non-lethal approaches, such as the measurement of plasma sex hormones and assessments of pregnancy via ultrasonography. This information is important because recent studies have shown that captive D. americana held in public aquaria appear to be exhibiting reproductive abnormalities associated with hormonal regularities, but virtually no information is available on how hormones regulate reproduction in this species.  Education B.S. Marine Science, Stockton University, New Jersey

   

• Chelsea Villanueva

  Graduate Advisor Dr. Dale Casamatta Research Interests The focus of my research is identifying and classifying novel cyanobacteria, isolated from terrestrial habitats in Northeast Florida. A diverse and ubiquitous group of microbes, cyanobacteria are primary producers across much of the world, and are major contributors to global carbon and nitrogen cycles. However cyanobacterial taxonomy and ecology have been vastly understudied and they are still poorly understood organisms. The goal of my research is to provide data that will clarify cyanobacterial taxonomy and help to catalog the plethora of unknown cyanobacterial populations. The applications of my research benefit not only Biology but Anthropology as well. Microbial communities inhabiting stonework in culturally significant human landscapes must be biologically defined, before they can be individually addressed in terms of cultural preservation. Biocrusts inhabiting stone are complex microbial consortia and the results of my research will potentially guide preservation efforts often undertaken by anthropologists. Education B.S. Biology, University of North Florida

• John Whalen

  Graduate Advisor Dr. Jim Gelsleichter Research Interests My research interests focus on the adverse effects of xenobiotics in the environment on biological organisms. The goal of my graduate research is to examine the potential health effects of pollutant exposure on Atlantic stingray (Dasyatis sabina) populations in the St. Johns River. Special emphasis is placed on identifying the effects of polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) exposure on stingrays due to known contaminated sites in the lower St. Johns River basin. We use molecular and cellular biomarkers as quantifiable indicators that link environmental exposure to a specific health outcome. Exposure to PAHs can cause the formation of toxicopathic lesions, while exposure to PCBs can cause alterations in endocrine and immune function. The level of biomarkers in Atlantic stingrays can be used as a proxy for environmental health because stingrays interact with the sediment, where these contaminants settle and persist, allowing for continued exposure. It is critical to collect baseline data for stingrays in the St. Johns River, especially since there are eminent plans to dredge the shipping channel, which can resuspend and redistribute the contaminated sediments.  Education B.S. Zoology, B.S. Environmental Science with Honors, Miami University, 2013

   

• Kelsey Yetsko

  Graduate Advisor Dr. Matthew Gilg Research Interests My research focuses on the heritability of thermal tolerance in corals and their ability to adapt to rising ocean temperatures with climate change. I am currently investigating the heritability of thermal tolerance in the staghorn coral, Acropora cervicornis, as well as how mortality correlates to cellular levels of stress biomarkers. The results of this study will aid in conservation of this threatened species and will provide a useful management tool for identifying temperature tolerant colonies in the field. Education A.B. Marine Biology, The College of Charleston, South Carolina

   

• Casey Zender

   

  Graduate Advisor Dr. Jim Gelsleichter Research Interests My research focuses on discovering tertiary biomarkers of stress in the blood of sharks.  These biomarkers will be used to determine the impact of stress on the shark during capture and also to predict the threshold of stress that results in post-release mortality.  This will be accomplished by testing for indicators of oxidative stress and lipid peroxidation in Blacktip sharks (Carcharhinus limbatus). By understanding the physiological consequences caused by capture on sharks, more accurate calculations can be made in regards to stock assessment, ultimately achieving more effective management of sharks in fisheries. Education B.S. Biology, Coastal Biology, University of North Florida, 2016