Immunology and Infectious Disease Commons^™

Elucidating The Role Of Interleukin-17a In West Nile Virus Infection, Dhiraj Acharya

Dissertations

West Nile virus (WNV) is a neurotropic flavivirus of significant public health importance for which no therapeutics and vaccine are currently available. Interleukin-17A (IL-17A) is an inflammatory cytokine that regulates diverse immune functions, while its role is unclear in host’s immune response to WNV. Furthermore, CD8⁺ T cells are crucial components of immunity and play a vital role in recovery from WNV infection. Here, we report a previously unrecognized function of IL-17A in regulating CD8⁺ T cell cytotoxicity. We show that WNV induces the expression of IL-17A in both mouse splenocytes and human peripheral blood mononuclear cells cultured …

Study Of Rickettsia Parkeri Colonization And Proliferation In The Tick Host Amblyomma Maculatum (Acari: Ixodidae), Khemraj Budachetri

Dissertations

Amblyomma maculatum (Gulf coast tick) ticks are prevalent across the Atlantic to Gulf Coast region of United States. These ticks are recognized vectors of Rickettsia parkeri, a spotted fever group of Rickettsia (SFGR) known to cause American boutonneuse fever associated with fever and eschar rashes localized to the site of bites. We hypothesized that Rickettsia parkeri colonization and proliferation in the tick vector involve pathogen-symbiont dynamics and tick-pathogen interactions, which influence rickettsial transmission to the victims after tick bites. The rickettsial infection is maintained across the tick life cycle for many generations due to transovarial and transstadial transmission of …

A Microbiomic Approach To The Characterization Of The Impacts And Influences Of Viral, Bacterial, And Harmful Algal Bloom Toxins On The Bottlenose Dolphin, Corey David Russo

Dissertations

As apex predators that display high site fidelity Tursiops truncatus (bottlenose dolphin) are indicators of marine ecosystem health. Bottlenose dolphins, additionally, display pathogenesis and immune response similar to that of humans. Humans and coastal bottlenose dolphins, in particular, are constantly exposed to the same industrial, agricultural and domestic toxins and pathogens, contaminants and pollutants. Thus, studies on the bottlenose dolphin are also valuable in bridging the gap between ocean and human health. Bottlenose dolphins are susceptible to viral bacterial and toxin infection. Infection in the bottlenose dolphin manifests itself in the form of mass stranding events, unusual mortality events, chronic …

Real-Time Pcr Detection And Phylogenetic Relationships Of Neorickettsia In Digeneans From Egypt, Phillipines, Thailand, Vietnam And The United States, Stephen E. Greiman, Jefferson A. Vaughan, Rasha Elmahy, Poom Adisakwattana, Nguyen Van Ha, Thomas J. Fayton, Amal I. Khalil, Vasyl V. Tkach

Student Publications

Neorickettsia (Rickettsiales, Anaplasmataceae) is a genus of obligate intracellular bacterial endosymbionts of digeneans (Platyhelminthes, Digenea). Some Neorickettsia are able to invade cells of the digenean's vertebrate host and are known to cause diseases of domestic animals, wildlife, and humans. In this study we report the results of screening digenean samples for Neorickettsia collected from bats in Egypt and Mindoro Island, Philippines, snails and fishes from Thailand, and fishes from Vietnam and the USA. Neorickettsia were detected using a real-time PCR protocol targeting a 152bp fragment of the heat shock protein coding gene, GroEL, and verified with nested PCR and sequencing …

Endohelminth Parasites Of Some Midwater And Benthopelagic Stomiiform Fishes From The Northern Gulf Of Mexico, Michael J. Andres, Mark S. Peterson, Robin M. Overstreet

Gulf and Caribbean Research

: Mesopelagic fishes represent significant ecological links between mesozooplankton and the larger pelagic squids, fishes, and marine mammals. As such, these fishes also play a significant role as intermediate or paratenic hosts for parasites that require a crustacean intermediate host and mature in marine mammals or pelagic fishes. We examined a total of 208 individuals representing 5 species of Sternoptychidae and 88 individuals representing 2 species of Phosichthyidae from 20 locations in the northern Gulf of Mexico (nGOM). Six of the 7 species we examined are mesopelagic and one species was benthopelagic. We found the larval stages of Anisakis brevispiculata …

Dollfustrema Durum N. Sp. And Heterobucephalopsis Perardua N. Sp. (Digenea: Bucephalidae) From The Giant Moray Eel, Gymnothorax Javanicus (Bleeker) (Anguilliformes: Muraenidae), And Proposal Of The Heterobucephalopsinae N. Subfam, Matthew J. Nolan, Stephen S. Curran, Terrence L. Miller, Scott C. Cutmore, Cinzia Cantacessi, Thomas H. Cribb

Faculty Publications

Two new species of bucephalid trematode (Platyhelminthes: Digenea) are described from the giant moray eel, Gymnothorax javanicus (Anguilliformes: Muraenidae), from off Lizard Island, Australia. We used a combined morphological and molecular-based approach targeting the internal transcribed spacer 2 (ITS2) of the ribosomal DNA (rDNA) and the D1–D3 region of the large subunit (28S) of rDNA to circumscribe the species. Dollfustrema durum n. sp. is distinguished from seven congeners in having 5–6 rows of enlarged body spines circling the anterior portion of the rhynchus. From the remaining 10 species, D. durum n. sp. differs in body length, and in having a …

First Record Of The Invasive Asian Fish Tapeworm Bothriocephalus Acheilognathi In Honduras, Central America, Guillermo Salgado-Maldonado, Wilfredo A. Matamoros, Brian R. Kreiser, Juan Manuel Caspeta-Mandujano, Edgar F. Mendoza-Franco

Faculty Publications

This paper provides the first report of the invasive Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934, in Honduras. The cestode was found in Profundulus portillorum (Cyprinodontiformes: Profundulidae), which represents a new host record, and which is a member of a genus faced with a variety of conservation challenges, now potentially complicated by the presence of this pathogenic cestode. Nearly complete sequence data from the ITS-1 5.8S and ITS-2 regions corroborate the determination based on morphological characteristics. Several species of carp were introduced to Honduras for aquaculture purposes in the early 1980s and the presence of the Asian fish tapeworm in …

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang

Dissertations

Embryonic stem cells (ESCs) have been recognized as a promising cell source for regenerative medicine. Intensive research over the past decade has led to the possibility that ESC-derived cells will be used for the treatment of human diseases. However, increasing evidence indicates that ESC-derived cells generated by the current differentiation methods are not fully functional. It is recently recognized that ESC-derived cells lack innate immunity to a wide range of infectious agents and inflammatory cytokines. When used in patients, ESC-derived cells would be placed in wounded sites that are exposed to various pathogens and inflammatory cytokines; therefore, their viability and …

Role Of Msa In Immune Evasion, Persistence, And Protease Regulation In The Human Pathogenic Strains Of Staphylococcus Aureus, Maria Deepa Basco

Dissertations

Opportunistic pathogens like Staphylococcus aureus on entering the host can stay colonized at the foci of infection or evade the immune system to disseminate to other sites. In this study we investigated the regulatory influence of the modulator of sarA (msa) on immune evasion and host persistence, employing the hospital-acquired strain S. aureus UAMS-1 and community-acquired strain S. aureus USA300 LAC. In the murine sepsis model, mutation of the msa gene in LAC showed no change in dissemination of infection; however, in UAMS-1 a decrease in microbial load was observed in the lungs. Differential regulation by the msa gene was …

Il-22 Signaling Contributes To West Nile Encephalitis Pathogenesis, Fengwei Bai, Penghua Wang, Lauren A. Zenewicz, Jianfeng Dai, David Gate, Gong Cheng, Long Yang, Feng Qian, Xiaoling Yuan, Ruth R. Montgomery, Richard A. Flavell, Terrence Town, Erol Fikrig

Faculty Publications

The Th17 cytokine, IL-22, regulates host immune responses to extracellular pathogens. Whether IL-22 plays a role in viral infection, however, is poorly understood. We report here that Il22^-/- mice were more resistant to lethal West Nile virus (WNV) encephalitis, but had similar viral loads in the periphery compared to wild type (WT) mice. Viral loads, leukocyte infiltrates, proinflammatory cytokines and apoptotic cells in the central nervous system (CNS) of Il22^-/- mice were also strikingly reduced. Further examination showed that Cxcr2, a chemokine receptor that plays a non-redundant role in mediating neutrophil migration, was significantly reduced in Il22^{-/- …}

Genetic Variation In Potentially Virulent Vibrio Parahaemolyticus From The Northern Gulf Of Mexico, Nicholas Felix Noriea Iii

Dissertations

Vibrio parahaemolyticus (V_p) is a gram-negative bacterium found naturally in marine and estuarine environments. V_p is found in oysters including those which are later consumed by the public. Sub-populations of potentially virulent Vp contain specific virulence factors and are relevant human pathogens capable of causing gastroenteritis, wound infection, and death. The tdh and trh genes, both encoding hemolysins, have been correlated with the majority of clinical V_p isolates but have not been shown to be the definitive virulence factors.

A total of 146 V_p isolates from the northern Gulf of Mexico were collected and probed …

Clam (Corbicula Fluminea) As A Potential Sentinel Of Human Norovirus Contamination In Freshwater, Xunyan Ye

Dissertations

The purpose of this study was to evaluate and validate the use of the clam Corbicula fluminea as a sentinel of human noroviruses (HuNoV) contamination in freshwater. The first specific aim was to develop a new method to extract HuNoV RNA from contaminated bivalves (e.g. oysters, clams) that would be much faster than existing methods. The procedure developed includes an initial total RNA extraction using TRI Reagent, followed by HuNoV RNA concentration and purification using biotinylated probe-capture technology. HuNoV RNA is finally detected by real-time RT-PCR. Using bivalve homogenates spiked with HuNoV, 100 PCR detection units of the virus was …

Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood

Master's Theses

Mosquitoes (Diptera: Culicidae) are vectors of disease in the adult stage, but understanding the factors affecting distributions of the immature stages is important to the understanding and control of adult populations. Discarded automobile tires comprise important larval mosquito habitats. The Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus) are two medically important species commonly found in tires, but factors affecting their larval distributions in tires have not been studied, nor have their interspecific interactions. I investigated the effects of chemicals associated with organic pollution on oviposition preferences and larval survival of both …

Regulation Of Biofilm And Antibiotic-Resistance By The Modulator Of Sara (Msa) In Staphylococcus Aureus, Antony Schwartz

Dissertations

Staphylococcus aureus is an important human pathogen that is the causative agent of life-threatening diseases such as endocarditis and osteomyelitis. The ability of S. aureus to thrive as a successful pathogen can be partially attributed to its ability to form biofilm. Biofilm is an extracellular polysaccharide, protein, and DNA-based slime layer that protects the bacterial community. The global regulator sarA is essential for biofilm formation. Since the modulator of sarA (msa) gene regulates several virulence factors and is required for the full expression of sarA, the capacity of the msa mutant to form a biofilm was examined. The mutation of …

The Role Of Msa In The Global Regulation Of Virulence In Staphylococcus Aureus, Vijayaraj Nagarajan

Dissertations

Staphylococcus aureus is an important pathogen causing life threatening diseases in humans. Previously we showed that msa modulates the activity of sarA (Staphylococcal accessory regulator), which is one of a major global regulator of virulence in S. aureus. The objective of this study is to characterize the role of msa (Modulator of SarA) in the global regulation of virulence in S. aureus. Structure and function predictions were done using several computational tools and approaches to understand the nature of msa. A novel S. aureus microarray meta-database (SAMMD) was designed and developed to compare and contrast other transcriptomes with msa transcriptome. …