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Development And Use Of An Environmental Dna Tool To Monitor Recovery Of The Critically Endangered Smalltooth Sawfish, Pristis Pectinata, In The Northwest Atlantic, Ryan N. Lehman

Master's Theses

The Critically Endangered Smalltooth Sawfish, Pristis pectinata, was once common in the tropical and subtropical waters of the Atlantic Ocean; however, following global declines in range and abundance over the past century, individuals were restricted to the waters of south and southwest Florida (SWFL) by about the 1980’s. Recently, public encounter reports have emerged in historically occupied habitats in United States waters, suggesting individuals are present in, or re-occupying, these areas, although the status of P. pectinata outside of SWFL is not currently well understood. Targeted environmental DNA (eDNA) surveys were chosen to assess the occurrence of P …

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing

Master's Theses

The Critically Endangered Largetooth Sawfish, Pristis pristis, experienced global declines in range and abundance over the past century and Australia is now their last stronghold. This research aimed to understand whether these declines have been accompanied by a reduction in levels of genetic diversity. Using P. pristis tissue samples sourced from natural history specimens, three fragments (616-bp, 386-bp, 141-bp) in the mitochondrial DNA (mtDNA) control region were PCR-amplified. At each fragment, significant genetic structure was found in P. pristis overall (Φ_ST=0.946, N=9; 0.813, N=54; 0.771, N=99). The Indo-West Pacific and Atlantic/Eastern Pacific each harbor genetically distinct lineages of …

Microplastic Abundance, Distribution And Impacts On Sargassum-Associated Juvenile Fishes In The Gulf Of Mexico, Olivia Lestrade

Master's Theses

Microplastics are a concern in marine environments because they are highly durable, ubiquitous, and can be mistaken for food and ingested by small organisms. Pelagic Sargassum, an important habitat for larval and juvenile stages of many fish species, is found in large surface aggregations, and may provide complex structure in which microplastics become trapped. This could lead to greater risk of microplastic ingestion by fish early life stages associated with Sargassum habitats. To better understand the impacts of microplastics within Sargassum communities, this study examined 1) microplastic concentrations and ingestion by juvenile fishes associated with Sargassum; 2) the microbial …

Assessing The Nursery-Role Function Of Pelagic Sargassum For Juvenile Fishes In The Northern Gulf Of Mexico, Courtney Stachowiak

Master's Theses

Sargassum, a genus of holopelagic brown algae, floats at the ocean’s surface using air-filled bladders and forms a complex comprised of two species, S. natans and S. fluitans. Oceanic processes (e.g., Langmuir circulation, etc.) aggregate Sargassum into mats and weedlines, and primarily distribute the algal complex throughout the North Atlantic Ocean and the Gulf of Mexico (GOM). These floating habitats provide shelter and feeding opportunities for a diverse community of invertebrates and fishes. Sargassum is a presumed nursery habitat for juvenile stages of commercially- and recreationally-targeted fishery species. In this study, I estimated the standardized abundances of juvenile …

Determining The Trophic Role Of Red Snapper (Lutjanus Campechanus) In Mississippi State Waters Using Stomach Content And Stable Isotope Analysis, Branden Kohler

Master's Theses

The goal of this study was to determine the diet composition, trophic position and ecological role of red snapper (Lutjanus campechanus) in Mississippi state waters utilizing stable isotopes (δ¹³C and δ¹⁵N) and stomach content analysis. Stable isotope analysis of fish and their prey can provide information on species-specific basal resource utilization, diet composition and trophic position which can improve food web models and inform fisheries management decisions. Particulate organic matter (POM), the presumed base of the food web, red snapper muscle tissue, and red snapper stomach contents were collected from 25 sites in 2016 and …

Effects Of Infection Of The Protist Parasite, Dermomycoides Sp., In Dusky Gopher Frog Tadpoles, Jaime Smith

Master's Theses

Infections of the protist parasite, Dermomycoides sp. are thought to have caused several years of low recruitment in the dusky gopher frog (Rana sevosa) populations. I evaluated the effects of density of the infective zoospores, host developmental stage, and tadpoles' ability to acquire resistance to Dermomycoides sp. on dusky gopher frog tadpoles. Tadpoles were exposed to zoospore densities of 0, 250, 500, and 750 zoospores/µL at Gosner stage 25, and we found no significant differences among treatments in tadpole mortality. In evaluating susceptibility by development stage, I exposed R. sevosa to 50 zoospores/µL as eggs, embryos, hatchlings, and …

A Management Strategy Evaluation Of The Impacts Of Interspecific Competition And Recreational Fishery Dynamics On Vermilion Snapper (Rhomboplites Aurorubens) In The Gulf Of Mexico, Megumi C. Oshima

Dissertations

In the Gulf of Mexico (GOM), Vermilion Snapper (Rhomboplites auroruben), are believed to compete with Red Snapper directly for prey and habitat. The two species share similar diets and have significant spatial overlap in the Gulf. Red Snapper are thought to be the dominate competitor, forcing Vermilion Snapper to feed on less nutritious prey when local resources are depleted. In addition to ecological pressures, GOM Vermilion Snapper support substantial commercial and recreational fisheries. Over the past decade, recreational landings have steadily increased, reaching a historical high in 2018. One cause may be stricter regulations for similar target species such as …

An Examination Of The Influence Of Multi-Scale Processes And Connectivity On The Population And Assemblage Dynamics Of Headwater Fishes, Josh P. Hubbell

Dissertations

Typified by their branching pattern, headwaters are numerically abundant as the density of these habitats increases with increasing distance from the base of a dendritic river system. Connectivity among headwaters is complex, resulting in the spatial isolation of populations. Headwater specialists have evolved a suite of traits that permit these species to permanently reside within these habitats. The spatial configuration and connectivity of headwaters has repercussions for metapopulations and meta-assemblages. I investigated how multi-scale processes and connectivity influenced the patch occupancy, coexistence, movement ecology, population structure, and gene flow of headwater specialists. In chapter two, I used occupancy modeling to …

Do Mosquito Pesticides Harm Their Natural Enemies? Ecological Impacts And Non-Target Effects Of Larvicides On Mosquito Predators, Joseph Nelsen

Master's Theses

Larvicides are chemicals used to kill juvenile mosquitoes. When applied to an area, other aquatic organisms are exposed to these chemicals. The removal or impairment of top insect predators could be beneficial to mosquito populations once harmful pesticide levels dissipate. Two common larvicides were examined: growth regulators (IGRs) and surface films (SFs). The goal of this project was to determine if larvicides harm mosquito predators common to southern Mississippi. I surveyed aquatic sites before and after IGR and SF treatments, and then compared changes in insect community structure. Community evenness was lower in SF treated habitats. When analyzing prey taxa …

Interrelationships Among Monorchiid Trematodes With Special Emphasis On Some Northwestern Atlantic Genera, Apryle Panyi

Master's Theses

The Monorchiidae Odhner, 1911 is a cosmopolitan family of flukes (Trematoda: Digenea) comprising species that parasitize the digestive tract of estuarine and marine fishes as adults. Compared with other oceans, recent morphological or molecular taxonomic work conducted on monorchiid species from the northwestern Atlantic Ocean has been sparse (Manter, 1931; Overstreet, 1969; Andres et al., 2018; Wee et al., 2018, 2019, 2020). Therefore, the present work investigated the interrelationships of some monorchiids from the northwestern Atlantic Ocean with emphasis on several genera and investigated if Lasiotocus minutus (Manter, 1931) Thomas, 1959 constitutes a complex of cryptic species. New morphological and …

The Effect Of Constant Relative Growth Rate Versus Constant Specific Growth Rate On Oocystis Sp, Rachel Kriner

Master's Theses

In this study, a strain of Oocystis sp. (S002) was grown using two different growth strategies at three different temperatures (15°C, 20°C, 25°C). One strategy (GS1) kept a constant specific growth rate (µ) and the other (GS2) kept a constant relative growth rate (µ/µ_max). In both strategies, the cultures were grown following the protocols of a hybrid growth system. The Dilution Phase is an initial semi-continuous growth phase that involves daily dilutions until set growth criteria are met. Followed by a batch culture growth protocol where the cultures were diluted at the onset of the first day and …

Comparison Of Retention Rates Between Traditional On-Ground And Online Biology Laboratory Courses In The Community College Setting, Megan Davis Winborne

Dissertations

Community colleges provide vital educational resources to students across the nation. Online learning has become an integral part of the course offerings for community colleges. With regards to online learning, there is a lack of empirical evidence and research focused on community college offered biology laboratories, particularly concerning retention rates of these students. Means, Toyama, Murphy, and Bakia. (2013) found that even though there are copious amounts of studies dedicated to evaluation of evidence-based practices in online learning formats, many of them neglected to review retention rates associated with online educational courses.

The purpose of this study was to determine …

Generating Zika Vaccine Candidates Using Nhumirim Virus As A Backbone, Mariam A. Atobiloye

Honors Theses

Zika virus (ZIKV) is a mosquito-transmitted flavivirus that is causing significant world-wide health concern. There are currently no treatments or vaccines available for this virus, thus, there is an urgent need to develop a safe and effective vaccine to combat ZIKV infection. Nhumirim virus (NHUV) is also a mosquito-transmitted flavivirus, but it is unable to infect humans and other vertebrate animals, making it an ideal candidate to develop chimeric viral vaccines against other disease-causing flaviviruses, such as ZIKV. In this study, we generated chimeric viruses by replacing envelope (E) gene in the genome of NHUV with ZIKV E gene, which …

Molecular Characterization Of Wolbachia And Its Impact On The Microbiome Of Exotic And United States Ticks, Cailyn G. Bobo

Honors Theses

Wolbachia endosymbionts are obligate intracellular bacteria in the phylum α-Proteobacteria. They infect approximately two-thirds of arthropods including insects and nematodes. These bacteria manipulate host reproductive biology through a series of mechanisms that include feminization of male progeny, parthenogenesis, male killing, and cytoplasmic incompatibility. These features make Wolbachia an effective agent of controlling insect populations, as previously reported in different mosquito species. Likewise, the bacteria have also shown promising ability to interfere with the ability of mosquitoes to transmit several viral pathogens. This study was conducted to fill an existing knowledge gap on the prevalence of Wolbachia in different tick species …

Mosquito Communities And Insect-Specific Viruses In A Heterogenous, Urban Landscape In Puerto Rico, Nicole Scavo

Master's Theses

The goal of my thesis was to investigate the relationships between mosquito diversity, Aedes aegptyi populations, and socioeconomic factors (SEF) in an urban setting and to characterize the virome of Ae. aegypti in San Juan, Puerto Rico. Mosquitoes were collected in three periods during late 2018 and early 2019 and were identified to the species level. Socioeconomic factors were measured using foot surveys and U.S. Census data. Some Ae. aegypti females were processed for sequencing and sent to Quick Biology for RNA sequencing to identify viruses. Results showed a link between SEF and Ae. aegypti abundance as well as between …

Elucidating The Molecular Pathways Involved In The Fitness And Water Stress Response Of Pseudomonas Synxantha 2-79 In The Plant Rhizosphere, Clint Henry D. Pablo

Master's Theses

Pseudomonas synxantha 2-79 is a biocontrol agent that represents beneficial indigenous rhizobacteria that are broadly distributed in the Pacific Northwest, USA and flourish in the rhizosphere of commercially grown wheat under surprisingly arid conditions. The molecular adaptation of 2-79-like bacteria to plants growing in dry soils is poorly understood. We hypothesized that the ability of 2-79 to colonize and persist in the rhizosphere of water-stressed plants is underpinned by the formation of hydrating biofilms and the utilization of root exudates that contain plant-derived osmoprotectants called quaternary ammonium compounds (QACs). We tested this hypothesis by identifying waters stress response pathways in …

Characterizing Erad And Antioxidant Response In Ixodes Scapularis Ise6 Cells During Borrelia Infection, Latoyia Downs

Master's Theses

Ticks are hematophagous ectoparasites that transmit a multitude of diseases to humans. Borrelia burgdorferi (BB) and Borrelia miyamotoi (BM) are both tick-borne pathogens that cause disease in humans and are transmitted by the black-legged tick (Ixodes scapularis). A byproduct of blood digestion generates reactive oxygen species that are toxic and cause oxidative stress which promotes cellular damage and dysfunction. The endoplasmic reticulum (ER) is especially affected by oxidative stress, resulting in a buildup of improperly folded proteins in the ER lumen called ER stress. To prevent cellular damage, the tick utilizes an antioxidant system to neutralize ROS and mechanisms …

Historical And Contemporary Variables Affecting The Range And Distribution Of Aedes Aegypti, The Yellow Fever Mosquito, In The United States, Nicole Mackey

Master's Theses

Aedes aegypti, the primary mosquito vector of the yellow fever virus, threatens global health by passing on this virus, as well as chikungunya, dengue, and Zika viruses. Through its natural tendency to live in highly urban areas and bite human hosts; understanding the factors that affect the historical and current range of the pest is invaluable (Gubler, 1998). Although these viruses are not normally found in the United States, lack of vaccinations and wide-spread presence of the mosquito could lead to these diseases being reintroduced with potentially devastating effects (Monath, 2001). To determine a partial historical range of A. aegypti …

Development Of An Attenuated Zika Virus By Editing The 5’ Untranslated Region, E. Ashley Thompson

Master's Theses

Zika Virus (ZIKV) is a mosquito-transmitted flavivirus that usually causes no symptoms to mild febrile in humans, and it has been regarded as an insignificant pathogen to public health. However, recent outbreaks of ZIKV infection have revealed that ZIKV can cause severe neurological effects in adults, such as Guillain-Barre Syndrome (GBS), and in infants whose mothers acquired the virus during pregnancy, causing Congenital Zika Syndrome (CZS). Currently, no approved vaccine is available and there is a critical need to develop an effective and safe vaccine. While most vaccine developmental strategies target the viral prM-E protein of ZIKV, we aimed to …

Cloning And Expression Of Human Synaptosome Associated Protein 29 In E. Coli, Logan M. Ryals

Honors Theses

Acting as the chief mediators of vesicular fusion, soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) play a role in many intracellular trafficking events by moving opposing membranes into close proximity. One such event takes place in the process of autophagy. A key SNARE involved in autophagy is Synaptosome Associated Protein 29 (SNAP-29), which acts on the autophagosome membrane to promote autophagosome and lysosome fusion. Kaposi’s Sarcoma Herpesvirus (KSHV) proteins ORF33 and ORF38 were demonstrated to interact with SNAP-29. The exact mechanism of this interaction is yet to be elucidated but it is hypothesized that these interactions allow KSHV to modulate …

Vegetative Community And Health Assessment Of A Constructed Juncus-Dominated Salt Marsh In The Northern Gulf Of Mexico, Nickolas R. Murphy

Master's Theses

Deer Island is a coastal habitat which provides a buffer from storm and flood damage as well as shore-line stabilization to the mainland of Biloxi, Mississippi. A third of the land has been lost since 1850, largely driven by tropical storm and hurricane impacts as well as sea level rise. The United States Army Corps of Engineers and Mississippi Department of Marine Resources have targeted the shores of the island as sites for restoration using beneficial use dredged material, and two sites of differing age have since been planted with Spartina alterniflora, Juncus roemerianus, Uniola paniculata, S. patens, and Panicum …

The Effect Of Truncated Complement Constructs On Biofilm Formation, Protease Production, And Pigmentation, Cara L. Cothern

Honors Theses

The msaABCR operon regulates virulence factors in Staphylococcus aureus, a Gram-positive commensal organism that colonizes healthy individuals but can also be a human pathogen. These virulence factors include biofilm development, pigmentation, and extracellular protease production. The operon consists of the msaB gene, which produces a coding transcript, the msaA gene and the msaC gene, which produce noncoding RNAs, and msaR, which produces an antisense RNA. The latter three transcript regions of the operon are referred to as untranslated regions (UTRs) and are essential for the function of the operon, but only msaB encodes a protein. The mechanism of …

Amplification And Potential Transformation Of Human Syntaxin-17 Into Model E. Coli, Taylor H. Gore

Honors Theses

Membrane fusion is key to organism homeostasis and occurs when a transport vesicle fuses with a target compartment, merging the two membranes into one while releasing the contents of the transport vesicle into the target compartment. This process is controlled by SNARE proteins. Syntaxin-17 protein plays a crucial role in the fusion of the autophagosome membrane with the lysosome membrane, allowing for degradation of misfolded intracellular components and pathogens. Intriguingly, Syntaxin 17 has been identified as a target of herpesvirus tegument proteins, although the pathological significance of the Syntaxin 17 and tegument protein interaction is unclear. As a first step …

Evaluating Biogenesis Of 5’-Tailed Mirtrons, Jonathan D. Hoover

Honors Theses

MicroRNAs are 22 nucleotide, non-coding RNAs that serve as substrates for Argonaute proteins to induce RNA interference pathways. Intron-derived miRNA precursors called “mirtrons” have been identified and classified primarily through deep sequencing methods. Unlike most miRNAs, mirtrons are derived from splicing events and also exhibit high levels of post-transcriptional nucleotide addition to hairpin precursors. Most relevant among these modifications is 3’ uridylation as it inhibits mirtron biogenesis in multiple model systems. Mirtrons may also possess additional nucleotides adjacent to the pre-miRNA hairpin at the 3’ and/or 5’ ends. These nucleotide “tails” are removed prior to Dicer cleaving the hairpin. In …

Assessing The Effect Of Bile And Oxygen Availability On The Redox Status Of Listeria Monocytogenes Strain F2365, Sukriti Bhattarai

Honors Theses

Although bile is a bactericidal agent able to disrupt membrane structure and cellular homeostasis, including the induction of oxidative stress, Listeria can tolerate bile and also utilize it as a signal to enhance infection and virulence. Preliminary findings showed that under anaerobic conditions, exposure to bile significantly lowered the amount of oxidative damage present in bile-resistant strain F2365 cells. Similarly, Listeria further elicits an adaptive immune response, wherein pre-exposure of the bacterium to stress during food processing or in the host prior to entry into the intestine increases bile tolerance. Based on these previous studies, we hypothesized that bile induces …

A Comparison Of Egg Desiccation Tolerance And Development Under Different Temperatures For Three Common Aedes Mosquitoes, Shelby A. Hosch

Honors Theses

With the rise in global temperatures, invasive mosquito species like Aedes albopictus may be able to reach regions that were previously inhospitable to these species. Therefore, if A. albopictus were to potentially reach Puerto Rico, it would come into contact with the species of Aedes aegypti and Aedes mediovittatus in local containers, and it is unclear how the tropical temperatures and precipitation patterns would affect the co-occurrence of these three species. Egg desiccation and temperature dependent growth among the species were measured to test how these species hatched and developed during different humidity and temperature. It was hypothesized that there …

Alpha-Gal Syndrome: Molecular Characterization Of Amblyomma Americanum Α-D-Galactosidase In Α-Gal Metabolism And Onset Of Red Meat Allergy, Ahmed A. Mohamed

Honors Theses

Tick-borne red meat allergy is an IgE-mediated delayed hypersensitivity reaction, increasingly widespread in tick endemic areas in the United States of America, and worldwide. Bites from the lone-star tick (Amblyomma americanum) are believed to be involved as the source of the sensitization of humans to the oligosaccharide galactose-⍺-1,3-galactose (α-gal), which is found in most mammal-derived food products, including gelatin, broths, and red meat. The purpose of this study is to functionally characterize the lone-star tick α-D-galactosidase (AGS) enzyme and assess its role in α-gal metabolism. This enzyme cleaves terminal α-galactose moieties from glycoproteins and glycolipids. Hence, I hypothesized …

Investigating Roles For Rna Turnover Processes In Cell Signaling Through Drosophila Melanogaster Genetic Mosaics, Sudiksha Rathan Kumar

Honors Theses

The process of cell signaling is vital in organisms for proper development as it determines the fate and function of cells. This process is highly regulated by myriad interactions between signaling pathway components and gene expression mechanisms. RNA turnover is a type of RNA processing that degrades RNA. It plays an essential role in homeostasis and environmental changes; however, its influence on signaling pathways is currently unknown. In the present study, the effect of RNA turnover processes on cell signaling was analyzed using the genetic mosaics in Drosophila melanogaster. Fly mosaics were created by breeding RNAi lines targeting cellular …

Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray

Honors Theses

Hybridization and introgression are two important evolutionary mechanisms that can increase genetic diversity. Interesting introgression patterns can form when parental species have genes that confer some adaptive benefit to the organism. The Fundulus notatus species complex contains species with various identifying characterisics. Fundulus notatus, the blackstripe topminnow, and Fundulus olivaceus, the blackspotted topminnow, are closely related and occupy many of the same rivers in their preferred niches. These two species often hybridize and form hybrid zones where their niches overlap. We studied two hybrid zones located in the Tombigbee River and Spring River. Within each hybrid zone, we …

Mouse Embryonic Stem Cells Are Sensitive To The Cytotoxicity Of Nitric Oxide: Biological Implications For Early Embryogenesis, Mckenzie C. Hargis

Honors Theses

The early embryo, before implantation, is at a very vulnerable stage in development where it faces various inflammatory cytokines throughout the implantation process. In this stage, the cells in the blastocyst, the preimplantation stage embryo, must proliferate rapidly for tissue formation. However, it is known that inflammatory cytokines can inhibit cell proliferation. Previous studies have shown that embryonic stem cells (mESCs), the major cell component in the blastocyst, are unresponsive to treatments of tumor necrosis factor ⍺ (TNF⍺) and interferon 𝛾 (IFN𝛾), two inflammatory cytokines involved in the implantation process. Treatment of mESC-differentiated fibroblasts (mESC-FBs) with TNF⍺ and IFN𝛾 in …