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West Nile Virus Seroreversion And The Influence Of Herd Immunity On Disease Risk In A Long-Term Study Of Free-Ranging Birds, Eileen M. Mckee

All Student Theses and Dissertations

The transmission and amplification of West Nile virus (WNV) is driven by the number of susceptible avian hosts. The quantity of susceptible hosts is determined by 1) recruitment of juvenile birds during the breeding season, 2) adult birds previously unexposed to WNV, and 3) adult birds with waning antibody titers. Although rarely tested, avian herd immunity and seroreversion could have a direct impact on Culex infection rate, a proxy for the reproductive number of WNV. In this study, we utilized data from a seven year study investigating WNV transmission ecology in suburban Chicago, Illinois. We tested the hypothesis that herd …

Spatial And Temporal Immune Response In House Flies In Response To Ingestion Of Bacillus Cereus And Eschericha Coli 0157-H7, Adam Fleming

College of Graduate Studies: Theses & Dissertations

House flies (Musca domestica L.) feed and breed on septic substrates, putting them in direct contact with a multitude of disease causing agents and can act as a bridge for those agents to humans. The house fly has previously been shown to carry many different species of bacteria that are pathogenic. Escherichia coli O157:H7 is a pathogenic enterohemorrhagic serotype of E. coli that can be vectored by the house fly. Bacillus cereus is a foodborne pathogen that has also been isolated from the house fly in previous studies. To examine vector potential for these pathogens, house flies were fed green …

Small Molecule Inhibitors Of Bacillus Anthracis Protective Antigen Proteolytic Activation And Oligomerization, Alexander N. Wein, Brian N. Williams, Shihui Liu, Boris Ermolinsky, Daniele Provenzano, Ruben Abagyan, Andrew Orry, Stephen H. Leppla, Michael Peredelchuk

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

Protective antigen (PA), lethal factor, and edema factor, the protein toxins of Bacillus anthracis, are among its most important virulence factors and play a key role in infection. We performed a virtual ligand screen of a library of 10000 members to identify compounds predicted to bind to PA and prevent its oligomerization. Four of these compounds slowed PA association in a FRET-based oligomerization assay, and two of those protected cells from intoxication at concentrations of 1-10 μM. Exploration of the protective mechanism by Western blot showed decreased SDS-resistant PA oligomer on cells and, surprisingly, decreased amounts of activated PA. In …

High Prevalence Of The Amphibian Chytrid Fungus (Batrachochytrium Dendrobatidis) Across Multiple Taxa And Localities In The Highlands Of Ethiopia, David J. Gower, Thomas M. Doherty-Bone, Roman K. Aberra, Abebe Mengistu, Silvia Schwaller, Michele Menegon, Rafael O. De Sá, Samy A. Saber, Andrew A. Cunningham, Simon P. Loader

Biology Faculty Publications

Surveys of the potentially lethal amphibian chytrid fungus (Batrachochytrium dendrobatidis - Bd) in Africa are patchy, especially in some regions of high species endemicity. We present results of the first Bd surveys of wild amphibians in Ethiopia, for two upland regions on either side of the Rift Valley: the Bale Mountains and the Kaffa region. Surveys were opportunistic so that robust interpretation of the data is limited. Utilizing diagnostic qPCR assays, 51 out of 120 frogs (14 species in 10 genera) tested positive for Bd at altitudes of 1,620–3,225 m, across all genera and species, and all but …

Competitive Abilities In Experimental Microcosms Are Accurately Predicted By A Demographic Index For R*, Ebony G. Murrell, Steven A. Juliano

Faculty Publications – Biological Sciences

Resource competition theory predicts that R*, the equilibrium resource amount yielding zero growth of a consumer population, should predict species' competitive abilities for that resource. This concept has been supported for unicellular organisms, but has not been well-tested for metazoans, probably due to the difficulty of raising experimental populations to equilibrium and measuring population growth rates for species with long or complex life cycles. We developed an index (R-index) of R* based on demography of one insect cohort, growing from egg to adult in a non-equilibrium setting, and tested whether R-index yielded accurate predictions of competitive abilities using mosquitoes as …

Antony Van Leeuwenhoek: Creation “Magnified” Through His Magnificent Microscopes, Alan L. Gillen, Douglas Oliver

Faculty Publications and Presentations

Although van Leeuwenhoek was not the inventor of the microscope, he advanced it more than anyone else for seeing living things.

Antony van Leeuwenhoek1 (Fig. 1) found great joy in God’s smallest creatures. He first discovered protozoans in his youth. The Dutch haberdasher retained a child-like joy of discovery from his youth until his death at age 90. He lived to see tiny microbes though his homemade microscopes. He loved to grind and focus a new lens in order to see the unseen world. Leeuwenhoek spent countless hours grinding tiny lenses and looking through them. This Christian lay biologist …

Transient Expression Of Ova Antigen: Rtb Fusions In Plants For Production Of Improved Subunit Vaccines, Lana Elkins

Student Theses and Dissertations

Plant-based production systems may provide a solution to the safety, cost, and scalability limitations of traditional vaccine production. While subunit vaccines offer several advantages, challenges of low immunogenicity need to be addressed. The nontoxic B subunit of ricin (RTB) may provide a novel platform for effective delivery and immune presentation for subunit vaccines. The RTB lectin binds sugars on the surface of mammalian cells to facilitate uptake/transport of fused antigen. The natural cell trafficking of RTB may allow differential presentation to the two major arms of the animal immune system, antibody- and cell-mediated using an RTB and RTBKDEL fusion vaccine …

Microbial Degradation Of 2,4-Dichlorophenoxyacetic Acid On The Greenland Ice Sheet, Marek Stibal, Jacob Baelum, William E. Holben, Sebastian R. Sørensen, Anders Jensen, Carsten S. Jacobsen

Biological Sciences Faculty Publications

The Greenland ice sheet (GrIS) receives organic carbon (OC) of anthropogenic origin, including pesticides, from the atmosphere and/or local sources, and the fate of these compounds in the ice is currently unknown. The ability of supraglacial heterotrophic microbes to mineralize different types of OC is likely a significant factor determining the fate of anthropogenic OC on the ice sheet. Here we determine the potential of the microbial community from the surface of the GrIS to mineralize the widely used herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Surface ice cores were collected and incubated for up to 529 days in microcosms simulating in situ …

Predicting Occupancy Of Wintering Migratory Birds: Is Microhabitat Information Necessary?, Christopher J. W. Mcclure, Brian W. Rolek, Geoffrey E. Hill

Biology Faculty Publications and Presentations

Information regarding microhabitat, here defined as small-scale vegetation structure, is often useful in predicting use of habitat by birds. Quantifying microhabitat, however, is expensive and labor intensive compared to assessment of habitat at a larger scale, possibly from remotely sensed imagery. To assess the importance of microhabitat information in constructing predictive models of habitat occupancy, we compared occupancy models built on the basis of macro- and microhabitat together and separately. We based our models on counts of wintering migratory bird species and vegetation surveys within Tuskegee National Forest, Alabama, completed during winter 2009. Models built from macrohabitat data only outperformed …

Regulation Of To Xin Synthesis By Clostridium Difficile, Charles Darkoh

Dissertations and Theses (Open Access)

Clostridium difficile is the leading definable cause of nosocomial diarrhea worldwide due to its virulence, multi-drug resistance, spore-forming ability, and environmental persistence. The incidence of C. difficile infection (CDI) has been increasing exponentially in the last decade. Virulent strains of C. difficile produce either toxin A and/or toxin B, which are essential for the pathogenesis of this bacterium. Current methods for diagnosing CDI are mostly qualitative tests that detect the bacterium, the toxins, or the toxin genes. These methods do not differentiate virulent C. difficile strains that produce active toxins from non-virulent strains that do not produce toxins or produce …

Continual Passage Of Staphylococcus Epidermidis In Subinhibitory Levels Of The Biocide Triclosan Results In A Marked Increase In The Minimum Inhibitory Concentration, Antibiotic Resistance, And Ethidium Bromide Resistance, William T. Moore

Master's Theses or Doctor of Nursing Practice

Triclosan is a multi-purpose biocide that is used in many personal care products, including antibacterial hand soaps and toothpastes. The wide usage of triclosan fosters its dispersal into the enviro11l11ent, which might contribute to the ability of microorganisms to become resistant to triclosan in addition to certain other biocides and clinical antibiotics. The aim of this study was to evaluate whether long-term exposure of two strains of Staphylococcal epide]'midis to subinhibitory concentrations of triclosan would select for resistant mutants, and whether their ability to form polysaccharide biofilms lends to this resistance. This study also aimed to determine whether a mutation …

Wing Shape As An Indicator Of Larval Rearing Conditions For Aedes Albopictus And Aedes Aegypti (Diptera: Culicidae), C R. Stephens, Steven A. Juliano

Faculty Publications – Biological Sciences

Estimating a mosquito's vector competence, or likelihood of transmitting disease, if it takes an infectious bloodmeal, is an important aspect of predicting when and where outbreaks of infectious diseases will occur. Vector competence can be affected by rearing temperature and inter- and intraspecific competition experienced by the individual mosquito during its larval development. This research investigates whether a new morphological indicator of larval rearing conditions, wing shape, can be used to distinguish reliably temperature and competitive conditions experienced during larval stages. Aedes albopictus (Skuse) and Aedes aegypti (L.) (Diptera: Culicidae) larvae were reared in low intraspecific, high intraspecific, or high …

Human Breast Milk And Antiretrovirals Dramatically Reduce Oral Hiv-1 Transmission In Blt Humanized Mice, Angela Wahl, Michael D. Swanson, Tomonori Nochi, Rikke Olesen, Paul W. Denton, Morgan Chateau, J. Victor Garcia

Biology Faculty Publications

Currently, over 15% of new HIV infections occur in children. Breastfeeding is a major contributor to HIV infections in infants. This represents a major paradox in the field because in vitro, breast milk has been shown to have a strong inhibitory effect on HIV infectivity. However, this inhibitory effect has never been demonstrated in vivo. Here, we address this important paradox using the first humanized mouse model of oral HIV transmission. We established that reconstitution of the oral cavity and upper gastrointestinal (GI) tract of humanized bone marrow/liver/thymus (BLT) mice with human leukocytes, including the human cell types important for …

Modeling The Effect Of Environmental Factors On The Spread Of Bacterial Disease In An Economically Structured Population, Ram Naresh, Surabhi Pandey

Applications and Applied Mathematics: An International Journal (AAM)

We have proposed and analyzed a nonlinear mathematical model for the spread of bacterial disease in an economically structured population (rich and poor) including the role of vaccination. It is assumed that rich susceptible get infected through direct contact with infectives in the same class and with infectives from the poor class who work as service providers in the houses of rich people, living in much cleaner environment. The susceptible in the poor class are assumed to become infected through direct contact with infectives in the same class as well as by bacteria present in their own environment, degraded due …

A Mathematical Study On The Dynamics Of An Eco-Epidemiological Model In The Presence Of Delay, T. K. Kar, Prasanta K. Mondal

Applications and Applied Mathematics: An International Journal (AAM)

In the present work a mathematical model of the prey-predator system with disease in the prey is proposed. The basic model is then modified by the introduction of time delay. The stability of the boundary and endemic equilibria are discussed. The stability and bifurcation analysis of the resulting delay differential equation model is studied and ranges of the delay inducing stability as well as the instability for the system are found. Using the normal form theory and center manifold argument, we derive the methodical formulae for determining the bifurcation direction and the stability of the bifurcating periodic solution. Some numerical …

Dissection Of The Role Of The Stable Signal Peptide Of The Arenavirus Envelope Glycoprotein In Membrane Fusion, Emily L. Messina, Joanne York, Jack H. Nunberg

Biological Sciences Faculty Publications

The arenavirus envelope glycoprotein (GPC) retains a stable signal peptide (SSP) as an essential subunit in the mature complex. The 58-amino-acid residue SSP comprises two membrane-spanning hydrophobic regions separated by a short ectodomain loop that interacts with the G2 fusion subunit to promote pH-dependent membrane fusion. Small-molecule compounds that target this unique SSP-G2 interaction prevent arenavirus entry and infection. The interaction between SSP and G2 is sensitive to the phylogenetic distance between New World (Junin) and Old World (Lassa) arenaviruses. For example, heterotypic GPC complexes are unable to support virion entry. In this report, we demonstrate that the hybrid GPC …

Host-Parasite Interactions In Galapagos Seabirds, Iris Ilena Levin

Dissertations

Parasites exhibit a wide range of life history strategies that contribute to different dispersal abilities, host specialization, transmission modes, life-cycle complexity and population structure. Understanding dispersal rates in hosts and parasites is instrumental in defining the scale at which coevolution may be occurring. In order to better understand how and when parasites move between different hosts, I studied a seabird – Hippoboscid fly ectoparasite (and vector) – Haemosporidian parasite system in the Galapagos Islands. I began by describing the Haemosporidian parasites of Galapagos seabirds, discovering a Plasmodium species parasite in Galapagos Penguins (Sphensicus mendiculus), and a new clade of Hippoboscid-vectored …

Pathogen Response Genes Mediate Caenorhabditis Elegans Innate Immunity, Hannah L. Anthony

Celebration

Innate immunity is crucial in the response and defense against pathogens for invertebrates and vertebrates alike. The soil nematode Caenorhabditis elegans is a useful model to study the eukaryotic innate immune response to microbial pathogenesis. Prior research indicates that the protein receptor FSHR-1 plays an important role in the innate recognition of intestinal infection due to pathogen consumption. Determining what genes are controlled by FSHR-1 may uncover an unknown pathway that could increase not only the comprehension of the C. elegans immune system but also innate immunity generally. To characterize the function of FSHR-1, four candidate pathogen response genes that …

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 …

The Prevalence Of Essential Hypertension In Kasigau, Kenya, Lindsay Williams

Mahurin Honors College Capstone Experience/Thesis Projects

Hypertension is the leading cause of cardiovascular disease worldwide. Cardiovascular disease (CVD) is a widespread chronic non-communicable disease (NCD) which is on the rise in developing countries. Evidence based on extensive research studies on risk factors for NCDs suggests that they could be easily significantly decreased by simply controlling their risk factors. Although high blood pressure has been recognized as a leading risk factor for CVD, little research has been done to document the prevalence and incidence of essential hypertension (EH) in lower socioeconomic developing countries. One such country is Kenya. It was found in our research study that Kasigau …

Host Specificity Of Ecuadorian Bat Flies (Diptera: Streblidae), Eric Stamper

Mahurin Honors College Capstone Experience/Thesis Projects

Diptera: Streblidae are ectoparasites of bat populations found in many locations throughout the world. These ectoparasites are generally known as bat flies. They attach themselves to the wing membranes and bodies of bats to bite and feed on their blood. Using a large sample consisting of over 2,000 bats and 6,000 bat flies, I have conducted a study of the degree of host specificity of these ectoparasites. Host specificity is a measurement of the degree to which a particular parasite is restricted to its host or hosts. Here I find evidence to support more recent findings that bat flies are …

Variation And Organization In Social Behavior: Infectious Disease And Human Intergroup Conflict And Warfare; And The Organization Of Foraging Behavior In Harvester Ants, Kenneth Letendre

Biology ETDs

Social behavior is an important contributor to the success of widely distributed animal taxa, including such distantly related taxa as humans and ants. There is variation in the features and organization of social systems based on ecological constraints and goals, as these alter the costs and benefits of social behaviors, and select for different optimal behaviors for social groups in different environments. I present two bodies of research: an effort to explain geographic variation in the frequency and intensity of human civil conflict; and an effort to describe and model the foraging behavior of colonies of harvester ants of the …

The Antiviral Activity Of Curcumin On Herpes Simplex Virus-1, Susan A. Pungitore

Theses, Dissertations and Culminating Projects

Herpes simplex virus 1 is a common human pathogen that causes an initial productive infection followed by a lifelong latent infection of sensory neurons. Although the active infection is self-limiting in healthy populations, HSV can pose serious health risks to immunocompromised individuals. Furthermore, drug-resistant strains of HSV-1 have emerged in the human immunodeficiency virus (HIV) afflicted populations, necessitating the development of efficacious treatment options to combat HSV-1 infections. In recent years, plant derived products have gained popularity as promising antiviral agents. Studies of plant-derived compounds, including polysaccharide extracts from algae and hydrolyzable tannins, indicated that antiviral activity may be contributed …

Signaling Pathways And Genetic Interactions That Lead To Metastatic Cancer In Drosophila Melanogaster, Amanda Cole

Renée Crown University Honors Thesis Projects - All

Cancer is a complex and multigenic disease, which is typically initiated by genetic mutations in tumor suppressor genes that regulate homeostatic mechanisms within cells. Oncogenic promoter mutations, like those involved in signal transduction pathways, also have the potential to induce cancer in an otherwise healthy organism. Transformation is highly dependent upon mutations to both tumor suppressor and oncogenes, as neither mutation is exclusive in its ability to generate malignant tumors. In the model organism, Drosophila melanogaster, I have generated metastatic cancer through the genetic effect of overactive Raf signaling, in conjugation with silencing selected tumor suppressor genes using RNA …

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 …

Assessing The Genotoxicity Of Triclosan In Tadpoles Of The American Bullfrog, Lithobates Catesbeianus., David Emery

Theses and Dissertations

Amphibians are particularly sensitive to environmental degradation and, therefore, serve as effective environmental quality indicators. Research has suggested that amphibian declines are exacerbated by manmade environmental toxicants, especially those found in high concentrations in urban areas. The NIH has pinpointed genotoxicity as a major route of cancer causation, and has since developed stringent testing procedures for potentially hazardous chemicals. One such method, recognized for its simplicity and economy, is the micronucleus assay. A study was conducted assessing the genotoxicity of the widely used antimicrobial agent Triclosan to American Bullfrog tadpoles. Lithobates catesbeianus tadpoles were reared in glass aquaria containing ultra-high …

Polyglutamine Toxicity Is Controlled By Prion Composition And Gene Dosage In Yeast, He Gong, Nina V. Romanova, Kim D. Allen, Pavithra Chandramowlishwaran, Kavita Gokhale, Gary P. Newnam, Piotr Miceczkowski, Michael Y. Sherman, Yury O. Chernoff

Publications and Research

Polyglutamine expansion causes diseases in humans and other mammals. One example is Huntington’s disease. Fragments of human huntingtin protein having an expanded polyglutamine stretch form aggregates and cause cytotoxicity in yeast cells bearing endogenous QN-rich proteins in the aggregated (prion) form. Attachment of the proline(P)-rich region targets polyglutamines to the large perinuclear deposit (aggresome). Aggresome formation ameliorates polyglutamine cytotoxicity in cells containing only the prion form of Rnq1 protein. Here we show that expanded polyglutamines both with (poly-QP) or without (poly-Q) a P-rich stretch remain toxic in the presence of the prion form of translation termination (release) factor Sup35 (eRF3). …

Human-Wildlife Interaction In Serengeti And Ngorongoro Districts Of Tanzania: A Case Study On Small Mammals, Fj Magige

Tanzania Journal of Science

In the Serengeti and Ngorongoro Districts, small mammals are said to provide protein and income to the local people. However, they are simultaneously reported to conflict with farming activities. These conflicting aspects have not been investigated there. The present article considers humansmall mammal interactions in six villages adjacent to the protected areas. Data were obtained through questionnaire administration to the local people in the districts. Small mammals were hunted in the two districts for food purposes and some villagers declared that they were earning income from selling small mammals products. Seventy percent of the respondents in Serengeti District claimed that …

Dengue Virus Infection Perturbs Lipid Homeostasis In Infected Mosquito Cells., Rushika Perera, Catherine Riley, Giorgis Isaac, Amber S. Hopf-Jannasch, Ronald J. Moore, Karl W. Weitz, Ljiljana Pasa-Tolic, Thomas O. Metz, Jiri Adamec, Richard J. Kuhn

Department of Biological Sciences Faculty Publications

Dengue virus causes ~50–100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex …

Variable Effect Of Co-Infection On The Hiv Infectivity: Within-Host Dynamics And Epidemiological Significance, Diego F. Cuadros, Gisela García-Ramos

Biology Faculty Publications

BACKGROUND: Recent studies have implicated viral characteristics in accounting for the variation in the HIV set-point viral load (spVL) observed among individuals. These studies have suggested that the spVL might be a heritable factor. The spVL, however, is not in an absolute equilibrium state; it is frequently perturbed by immune activations generated by co-infections, resulting in a significant amplification of the HIV viral load (VL). Here, we postulated that if the HIV replication capacity were an important determinant of the spVL, it would also determine the effect of co-infection on the VL. Then, we hypothesized that viral factors contribute to …