Digital Commons Network^™

Comparative Genomic Analysis Of Two Serotype 1/2b Listeria Monocytogenes Isolates From Analogous Environmental Niches Demonstrates The Influence Of Hypervariable Hotspots In Defining Pathogenesis, Aidan Casey, Kieran Jordan, Aidan Coffey, Edward M. Fox, Olivia Mcauliffe

Department of Biological Sciences Publications

The vast majority of clinical human listeriosis cases are caused by serotype 1/2a, 1/2b, 1/2c, and 4b isolates of Listeria monocytogenes. The ability of L. monocytogenes to establish a systemic listeriosis infection within a host organism relies on a combination of genes that are involved in cell recognition, internalization, evasion of host defenses, and in vitro survival and growth. Recently, whole genome sequencing and comparative genomic analysis have proven to be powerful tools for the identification of these virulence-associated genes in L. monocytogenes. In this study, two serotype 1/2b strains of L. monocytogenes with analogous isolation sources, but …

The Vibrio Cholerae Minor Pilin Tcpb Initiates Assembly And Retraction Of The Toxin- Coregulated Pilus, Dixon Ng, Tony Harn, Tuba Altindal, Subramania Kolappan, Jarrad M. Marles, Rajan Lala, Ingrid Spielman, Yang Gao, Caitlyn A. Hauke, Gabriela Kovacikova, Zia Verjee, Ronald K. Taylor, Nicolas Biais, Lisa Craig

Publications and Research

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent …

Salvinia Molesta: An Assessment Of The Effects And Methods Of Eradication, Arti Lal

Master's Projects and Capstones

Salvinia molesta is an invasive aquatic fern. It is now the second worse aquatic invader in the world. Since the 1930s, it has invaded most tropical and some temperate countries. S. molesta plants grow vegetatively and can increase in size rapidly. S. molesta can form thick mats of up to 1-meter-thick. There are a number of ways these thick mats negatively affect the environment: 1) reduce light to benthic organisms, 2) reduce oxygen in the water column for other organisms, 3) accumulate as organic matter at the bottom of the water column, 4) decrease nutrients for other organisms, and 5) …

Anthropogenic Disturbance Modulates Mammal Community Diversity, Assembly, & Abundance: Emerging Infectious Disease Risk In The Greater Yellowstone Ecosystem, Leticia Andrea Gutiérrez Jiménez

Dissertations

This dissertation examines the role of mammalian biodiversity in maintaining overall ecosystem health in the Greater Yellowstone Ecosystem (GYE). The study explores the pathways by which anthropogenic disturbance prevents or promotes the emergence of human infectious diseases. I studied two paramount research questions: Question 1: What are the direct effects of anthropogenic disturbance on rodent community assemblages and the consequent indirect effects on public health? I first surveyed the GYE rodent community and their pathogens by using land use as a measure of anthropogenic disturbance (e.g., human settlements, horseback ranches, pastures, undisturbed). I identified pathogens in rodent blood samples by …

Synthetic Ion Channels: A New Class Of Membrane Disruptor And Efflux Pump Inhibitor For The Recovery Of Antibiotic Potency, Mohit Bharatkumar Patel

Dissertations

Antibiotic resistance has become a world-wide health care crisis. In 2013 there were 50,000 deaths in U.S. and EU, associated with hospital acquired bacterial infections. This problem is exacerbated by the lack of new antibiotics in development. Here, we report that synthetic amphiphiles represent a new class of adjuvants that rescue antibiotic potency against multidrug resistant bacteria. Hydraphiles are amphiphiles, designed and synthesized in Gokel lab, that show many of the same properties as protein ion channels. Hydraphiles were previously shown to have antimicrobial activity against Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae. Here, we report that hydraphiles recover the …

Historical Biogeography, Spatial Distribution, And Within-Host Interactions Of Avian Haemosporidian Parasites (Apicomplexa, Haemosporida), Leticia De Souza Soares

Dissertations

This dissertation addresses several aspects of the biogeography and evolution of avian malarial parasites (Haemosporida: Plasmodium and Haemoproteus), and the interactions of these pathogens with their hosts and other avian blood parasites. In Chapter 1, I investigate change in haemosporidian assemblages on the West Indies over millennial time scales, taking advantage of the historical isolation of islands by postglacial rising sea levels. I found that, the prevalence of parasite lineages is highly dynamic over periods from decades to thousands of years. Turnover of lineages requires more time than variation in lineage prevalence, suggesting that competitive exclusion of parasite lineages, likely …

The Effect Of Varying Environmental Conditions On The Growth Of Stenotrophomonas Maltophilia, Norah Alqahtani

Theses & Dissertations

Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen in the debilitated host. It possesses the ability to target and colonize respiratory-tract epithelial cells and grow on the surface of medical devices. It is associated with a significant case-fatality ratio in cystic fibrosis patients. S. maltophilia species have the ability to grow in bacterial biofilms, which further complicates these infections by providing the opportunity for acquisition of antibiotic resistant genes. This study investigated the effects on the growth of different strains of the same species of S. maltophilia, ATCC 51331 and 13637, when the selected environmental factors are varied. …

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 …

Tlr8 Couples Socs-1 And Restrains Tlr7-Mediated Antiviral Immunity, Exacerbating West Nile Virus Infection In Mice, Amber M. Paul, Dhiraj Acharya, Linda Le, Penghua Wang, Dobrivoje S. Stokic, A. Arturo Leis, Lena Alexopoulou, Terrence Town, Richard A. Flavell, Erol Fikrig, Fengwei Bai

Faculty Publications

West Nile virus (WNV) is a neurotropic ssRNA flavivirus that can cause encephalitis, meningitis, and death in humans and mice. Human TLR7 and TLR8 and mouse TLR7 recognize viral ssRNA motifs and induce antiviral immunity. However, the role of mouse TLR8 in antiviral immunity is poorly understood. In this article, we report that TLR8-deficient (Tlr8−/−) mice were resistant to WNV infection compared with wild-type controls. Efficient WNV clearance and moderate susceptibility to WNV-mediated neuronal death in Tlr8−/− mice were attributed to overexpression of Tlr7and IFN-stimulated gene-56 expression, whereas reduced expression of the proapoptotic gene coding Bcl2-associated X protein was observed. …

Functional And Structural Characterization Of The Mevalonate Diphosphate Decarboxylase And The Isopentenyl Diphosphate Isomerase From Enterococcus Faecalis, Chun-Liang Chen

Open Access Dissertations

Enterococcus faecalis causes a diverse range of nosocomial infections (in wounds, the gastrointestinal tract, the blood stream and the endocardium), and multidrug-resistant strains have become a serious issue across countries. Vancomycin, a FDA-approved drug for the disruption of the bacterial cell wall biosynthesis, has been utilized to treat infectious diseases caused by Enterococci; however, the prevalence of vancomycin-resistant enterococci (VRE) threatens communities all over the world. We aim at developing novel therapeutic strategies to control bacterial growth of Enterococci, and we focus on targeting two essential enzymes involved in poly-isoprenoid biosynthesis in Enterococcus faecalis; one is the mevalonate diphosphate decarboxylase …

Murine Models Of Splenic Marginal Zone Lymphoma: A Role For Cav1?, Chelsey L. Patten, Christine E. Cutucache

Biology Faculty Publications

Dozens of murine models of indolent and aggressive B-cell lymphomas have been generated to-date. These include those manifesting chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) as well as xenografts of mantle cell lymphoma (MCL). These models have led to an improved understanding of disease etiology, B-cell biology, immunomodulation, and the importance of the tumor microenvironment. Despite these efforts in CLL, DLBCL, and MCL, considerably little progress toward a model of splenic marginal zone lymphoma (SMZL) has been accomplished. Herein, we describe the similarities and differences between CLL, MCL, and SMZL, and highlight effective murine models that mimic disease …

Nucelotide Substitution Rates In Hantavirus Cd8+ T-Cell Epitopes, Brian Gerald Sikes

Graduate Theses

Hantaviruses pathogenic to humans are exclusive to rodents. Typically each hantavirus is associated with only one host species. Due to their close association, the geographical distributions are the same. Old World species, such as Hantaan hantavirus and Puumala hantavirus, induce symptoms described as the Hemorrhagic Fever with Renal Syndrome (HFRS). The New World hantaviruses, such as Andes hantavirus and Sin Nombre hantavirus, share a suite of symptoms that have been described as Hantavirus Pulmonary Syndrome (HPS). In this study, 16 well-characterized cytotoxic T lymphocytes (CTL) epitopes of the nucleocapsid (N) protein were identified from the literature.

These 16 …

Expression Of Glycine-Rich Proteins Found In Salivary Glands Of The Lone Star Tick (Amblyomma Americanum) Using A Mammalian Cell Line, Annabelle Clark

Honors Theses

Ticks play an important ecological role as well as a growing role in human health and veterinary care. Ticks are hosts to a plethora of microbial pathogens that can be transferred during feeding to cause tick-borne diseases in humans and many animals. Ticks may in large part owe the success of the transfer of these pathogens between hosts to their complex saliva. The saliva secreted upon a tick’s attachment to a host serves the following, among other, functions: anti-hemostasis of the blood pool, preventing an inflammatory response at the bite site, and serving as a natural anti-microbial substance. An important …

Influence Of Tick And Mammalian Physiological Temperatures On Borrelia Burgdorferi Biofilms, Shafiq Shaikh, Venkata Arun Timmaraju, Jason Torres, Kayla Socarras, Priyanka A. Theophilus, Eva Sapi

Biology and Environmental Science Faculty Publications

The spirochaete bacterium Borrelia burgdorferi sensu lato is the aetiologic agent of Lyme disease. Borrelia is transmitted to mammals through tick bite and is adapted to survive at tick and mammalian physiological temperatures. We have previously shown that B. burgdorferi can exist in different morphological forms, including the antibiotic-resistant biofilm form, in vitro and in vivo. B. burgdorferi forms aggregates in ticks as well as in humans, indicating potential of biofilm formation at both 23 and 37 °C. However, the role of various environmental factors that influence Borrelia biofilm formation remains unknown. In this study, we investigated the effect …

Hiv Glycoprotein Gp120 Impairs Fast Axonal Transport By Activating Tak1 Signaling Pathways, Sarah H. Berth, Nichole Mesnard-Hoaglin, Bin Wang, Hajwa Kim, Yuyu Song, Maria Sapar, Gerardo Morfini, Scott T. Brady

Publications and Research

Sensory neuropathies are the most common neurological complication of HIV. Of these, distal sensory polyneuropathy (DSP) is directly caused by HIV infection and characterized by length-dependent axonal degeneration of dorsal root ganglion (DRG) neurons. Mechanisms for axonal degeneration in DSP remain unclear, but recent experiments revealed that the HIV glycoprotein gp120 is internalized and localized within axons of DRG neurons. Based on these findings, we investigated whether intra-axonal gp120 might impair fast axonal transport (FAT), a cellular process critical for appropriate maintenance of the axonal compartment. Significantly, we found that gp120 severely impaired both anterograde and retrograde FAT. Providing a …

Fluctuating Temperatures Alter Environmental Pathogen Transmission In A Daphnia–Pathogen System, Tad Dallas, John M. Drake

Faculty Publications

Environmental conditions are rarely constant, but instead vary spatially and temporally. This variation influences ecological interactions and epidemiological dynamics, yet most experimental studies examine interactions under constant conditions. We examined the effects of variability in temperature on the host–pathogen relationship between an aquatic zooplankton host (Daphnia laevis) and an environmentally transmitted fungal pathogen (Metschnikowia bicuspidata). We manipulated temperature variability by exposing all populations to mean temperatures of 20°C for the length of the experiments, but introducing periods of 1, 2, and 4 hr each day where the populations were exposed to 28°C followed by periods of …

One Health Interactions Of Chagas Disease Vectors, Canid Hosts, And Human Residents Along The Texas-Mexico Border, Melissa N. Garcia, Sarah O’Day, Susan P. Fisher-Hoch, Rodion Gorchakov, Ramiro Patino, Teresa Patricia Feria-Arroyo, Susan T. Laing, Joe E. Lopez, Alexandra Ingber, Kathryn M. Jones, Kristy O. Murray

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Background

Chagas disease (Trypanosoma cruzi infection) is the leading cause of non-ischemic dilated cardiomyopathy in Latin America. Texas, particularly the southern region, has compounding factors that could contribute to T. cruzi transmission; however, epidemiologic studies are lacking. The aim of this study was to ascertain the prevalence of T. cruzi in three different mammalian species (coyotes, stray domestic dogs, and humans) and vectors (Triatoma species) to understand the burden of Chagas disease among sylvatic, peridomestic, and domestic cycles.

Methodology/Principal Findings

To determine prevalence of infection, we tested sera from coyotes, stray domestic dogs housed in public …

Pyruvate Oxidase Of Streptococcus Pneumoniae Contributes To Penumolysin Release, Joseph C. Bryant, Ridge C. Dabbs, Katie L. Oswalt, Lindsey R. Brown, Jason W. Rosch, Keun S. Seo, Janet R. Donaldson, Larry S. Mcdaniel, Justin A. Thornton

Faculty Publications

Background

Streptococcus pneumoniae is one of the leading causes of community acquired pneumonia and acute otitis media. Certain aspects of S. pneumoniae’s virulence are dependent upon expression and release of the protein toxin pneumolysin (PLY) and upon the activity of the peroxide-producing enzyme, pyruvate oxidase (SpxB). We investigated the possible synergy of these two proteins and identified that release of PLY is enhanced by expression of SpxB prior to stationary phase growth.

Results

Mutants lacking the <>spxB gene were defective in PLY release and complementation of spxB restored PLY release. This was demonstrated by cytotoxic effects of sterile filtered …

Overlap In The Seasonal Infection Patterns Of Avian Malaria Parasites And West Nile Virus In Vectors And Hosts, Matthew Medeiros, Robert Ricklefs, Jeffrey Brawn, Marilyn Ruiz, Tony Goldberg, Gabriel Hamer

Biology Department Faculty Works

Multiple vector-borne pathogens often circulate in the same vector and host communities, and seasonal infection dynamics influence the potential for pathogen interactions. Here, we explore the seasonal infection patterns of avian malaria (Haemosporida) parasites (Plasmodium and Haemoproteus) and West Nile virus (WNV) in birds and mosquitoes in suburban Chicago. We show that both pathogens vary seasonally in Culex mosquitoes and avian hosts, but that patterns of covariation are complex. Different putative Plasmodium species varied asynchronously across the season in mosquitoes and birds, suggesting that different forces may govern their transmission. Infections of Culex mosquitoes with Plasmodium parasites were positively associated …

Abiotic Factors Contributing To The Survival Of Three Tick Species In Southeastern Virginia, Amblyomma Americanum (Lone Star Tick), Dermacentor Variabilis (American Dog Tick), And Amblyomma Maculatum (Gulf Coast Tick), Lindsey A. Bidder

Biological Sciences Theses & Dissertations

Amblyomma americanum, Amblyomma maculatum, and Dermacentor variabilis are hard-bodied ticks in the Hampton Roads area of southeastern Virginia. This study consisted of two field projects focused on these tick species. To estimate the off-host survival of local tick species, a capture-mark-recapture (CMR) study was performed. An environmental survival study was performed to quantify the ability of these three tick species to survive in situ. Four field sites were used in the Hampton Roads region covering a variety of habitat types and vegetation; specifically two drier, upland field sites and two flood-prone sites. CMR was conducted from May through …

Computerized Classification Of Surface Spikes In Three-Dimensional Electron Microscopic Reconstructions Of Viruses, Younes Benkarroum

Dissertations, Theses, and Capstone Projects

The purpose of this research is to develop computer techniques for improved three-dimensional (3D) reconstruction of viruses from electron microscopic images of them and for the subsequent improved classification of the surface spikes in the resulting reconstruction. The broader impact of such work is the following.

Influenza is an infectious disease caused by rapidly-changing viruses that appear seasonally in the human population. New strains of influenza viruses appear every year, with the potential to cause a serious global pandemic. Two kinds of spikes – hemagglutinin (HA) and neuraminidase (NA) – decorate the surface of the virus particles and these proteins …

Ifn-G Induces Histone 3 Lysine 27 Trimethylation In A Small Subset Of Promoters To Stably Silence Gene Expression In Human Macrophages, Yu Qiao, Kyuho Kang, Eugenia Giannopoulou, Celeste Fang, Lionel B. Ivashkiv

Publications and Research

The mechanisms by which IFN-g activates expression of interferon-stimulated genes that have inflammatory and host defense functions are well understood. In contrast, little is known about how IFN-g represses gene expression. By using transcriptomic and epigenomic analysis, we found that stable repression of a small group of genes by IFN-g is associated with recruitment of the histone methyltransferase EZH2 and deposition of the negative mark histone 3 lysine 27 trimethylation (H3K27me3) at their promoters. Repressed genes included MERTK, PPARG, and RANK, which have anti-inflammatory functions and promote osteoclast differentiation. Gene repression and H3K27me3 persisted after IFN-g signaling was terminated, and …

Receptor-Type Guanylyl Cyclase At 76c (Gyc76c) Regulates De Novo Lumen Formation During Drosophila Tracheal Development, Monn Monn Myat, Unisha Patel

Publications and Research

Lumen formation and maintenance are important for the development and function of essential organs such as the lung, kidney and vasculature. In the Drosophila embryonic trachea, lumena formde novo to connect the different tracheal branches into an interconnected network of tubes. Here, we identify a novel role for the receptor type guanylyl cyclase at 76C (Gyc76C) in de novo lumen formation in the Drosophila trachea.We show that in embryosmutant for gyc76C or its downsteam effector protein kinase G (PKG) 1, tracheal lumena are disconnected. Dorsal trunk (DT) cells of gyc76C mutant embryos migrate to contact each other and complete the …

Aspects Of Host Usage Of The Chestnut Lamprey (Ichthyomyzon Castaneus) In Arkansas, Jeremiah Max Salinger

Student Theses and Dissertations

Most native North American lamprey species are imperiled in some manner, but are curiously understudied. The research described in this thesis addresses the adult feeding biology of the Chestnut Lamprey (Ichthyomyzon castaneus), a freshwater parasitic lamprey native to the southeastern United States. This thesis addresses Chestnut Lamprey attachment site selection and size-selective parasitism of Rainbow Trout (Oncorhynchus mykiss) in an outdoor laboratory setting, as well as Chestnut Lamprey host usage and distribution in Arkansas. Approximately 75% of the 80 wounded Rainbow Trout studied were attacked in their dorsal mid-section. Chestnut Lampreys were found to select shorter hosts, with no mass …

Review Of Experimental Compounds Demonstrating Anti-Toxoplasma Activity, Madalyn M. Mcfarland, Sydney J. Zach, Xiaofang Wang, Lakshmi-Prasad Potluri, Andrew J. Neville, Jonathan L. Vennerstrom, Paul H. Davis

Biology Faculty Publications

Toxoplasma gondii is a ubiquitous apicomplexan parasite capable of infecting humans and other animals. Current treatment options for T. gondii infection are limited and most have drawbacks, including high toxicity and low tolerability. Additionally, no FDA-approved treatments are available for pregnant women, a high-risk population due to transplacental infection. Therefore, the development of novel treatment options is needed. To aid this effort, this review highlights experimental compounds that, at a minimum, demonstrate inhibition of in vitro growth of T. gondii. When available, host cell toxicity and in vivo data are also discussed. The purpose of this review is to facilitate …

An Ultrasensitive Electrogenerated Chemiluminescence-Based Immunoassay For Specific Detection Of Zika Virus, Dhiraj Acharya, Pradip Bastola, Linda Le, Amber M. Paul, Estefania Fernandez, Michael S. Diamond, Wujian Miao, Fengwei Bai

Faculty Publications

Zika virus (ZIKV) is a globally emerging mosquito-transmitted flavivirus that can cause severe fetal abnormalities, including microcephaly. As such, highly sensitive, specific, and cost-effective diagnostic methods are urgently needed. Here, we report a novel electrogenerated chemiluminescence (ECL)-based immunoassay for ultrasensitive and specific detection of ZIKV in human biological fluids. We loaded polystyrene beads (PSB) with a large number of ECL labels and conjugated them with anti-ZIKV monoclonal antibodies to generate anti-ZIKV-PSBs. These anti-ZIKV-PSBs efficiently captured ZIKV in solution forming ZIKV-anti-ZIKV-PSB complexes, which were subjected to measurement of ECL intensity after further magnetic beads separation. Our results show that the anti-ZIKV-PSBs …

The Effects Of Ivermectin On Brugia Malayi Females In Vitro: A Transcriptomic Approach, Cristina Ballesteros, Lucienne Tritten, Maeghan O'Neill, Erica Burkman, Weam I. Zaky, Jianguo Xia, Andrew Moorhead, Steven A. Williams, Timothy G. Geary

Biological Sciences: Faculty Publications

Lymphatic filariasis and onchocerciasis are tropical diseases caused by infections with parasitic nematodes. Resulting chronic diseases can be strongly blinding and disfiguring, and contribute to an entrenched cycle of poverty in affected populations. Ivermectin is one of the pivotal drugs used to control these infections. The mechanism of antifilarial action of the drug is incompletely resolved. It kills circulating larval stages (microfilariae), but only reversibly sterilizes adult worms without killing them. Our limited understanding of the involved mechanisms hampers treatment optimization and sustainability of the efficacy of the drug, and investigations into its pharmacology are of paramount importance. Working with …

Utilization Of Cholera Toxin B As An Adjuvant For The Subunit Pspa Vaccine, Provides Effective Protection Against Streptococcus Pneumoniae Challenge, Daniel R. Pinho

Seton Hall University Dissertations and Theses (ETDs)

Streptococcus pneumoniae is a prevalent human pathogen associated with pneumonia. It is estimated that approximately 1 million people around the world die each year, specifically with young children and the elderly comprising a significant portion. Currently, antibiotics can treat the infection but individuals such as the young or elderly are more susceptible to bodily damage from symptoms, such as pneumonia, meningitis, and sepsis, thus require more preventive measures. As a result, vaccinations are a key solution to providing effective protection against infectious pathogens. Presently, two vaccinations exist in the market: PPSV₂₃ and PCV₁₃, which only protect against …

Functions For Murine Norovirus Protein Ns1/2 In Mice And Cells, Broc Taylor Mccune

Arts & Sciences Graduate Student Theses and Dissertations

Noroviruses are a leading cause of epidemic gastroenteritis and a major health burden worldwide. One source for outbreaks is individuals who shed virus asymptomatically and persistently. Viral persistence is a successful strategy for viruses to spread, but the mechanisms and consequences of norovirus persistent infection are unknown. In this dissertation, we sought to determine the norovirus determinant(s) of persistence and explore the functions of the associated viral molecules.To determine the viral determinants of persistent infection and tropism, we used the murine norovirus model system in mice. Using plasmid infectious clones for persistent strain CR6 and non-persistent strain CW3, we mapped …

Guideline For Stakeholder Engagement On Aquatic Resource Management-Related Processes, Department Of Fisheries

Fisheries Occasional Publications

No abstract provided.