Microbiology Commons^™

Toll-Like Receptor 9-Mediated Inflammation Triggers Alveolar Bone Loss In Experimental Murine Periodontitis, Paul D. Kim, Xia Xia-Juan, Katie E. Crump, Toshiharu Abe, George Hajishengallis, Sinem E. Sahingur

Biology Faculty Articles

Chronic periodontitis is a local inflammatory disease induced by a dysbiotic microbiota and leading to destruction of the tooth-supporting structures. Microbial nucleic acids are abundantly present in the periodontium, derived through release after phagocytic uptake of microbes and/or from biofilm-associated extracellular DNA. Binding of microbial DNA to its cognate receptors, such as Toll-like receptor 9 (TLR9), can trigger inflammation. In this study, we utilized TLR9 knockout (TLR9^−/−) mice and wild-type (WT) controls in a murine model of Porphyromonas gingivalis-induced periodontitis and report the first in vivo evidence that TLR9 signaling mediates the induction of periodontal bone loss.P. gingivalis-infected …

Aspergillus Fumigatus Spinal Abscess In An Immunocompetent Child, Mohammad Faizan Zahid, Joveria Farooqi

Department of Pathology and Laboratory Medicine

No abstract provided.

Iron Chelation In Patients With Transfusion Dependent Thalassemia: An Insight On Response To Deferasirox, Muhammad Shariq Shaikh, Salman Naseem Adil

Department of Pathology and Laboratory Medicine

No abstract provided.

Determining The Prevalence And Distribution Of Tick-Borne Pathogens In Southeastern Virginia And Exploring The Transmission Dynamics Of Rickettsia Parkeri In Amblyomma Maculatum, Chelsea L. Wright Thompson

Biological Sciences Theses & Dissertations

Tick-borne pathogens are an increasing threat to human and animal health worldwide. In the United States, cases of Lyme disease, spotted fever rickettsioses, ehrlichiosis and anaplasmosis are on the rise. Factors related to emergence include appearance of a new pathogen, recognition of an existing pathogen and environmental changes that result in new exposure events. Despite the rise in tick-borne disease incidence within many states, including Virginia, there is a paucity of data related to the prevalence and distribution of ticks and tick-borne pathogens.

The first aim of this dissertation research was to determine the tick-borne pathogen composition within tick populations …

Inhibition Of Cell Differentiation In Bacillus Subtilis By Pseudomonas Protegens, Matthew J. Powers, Edgardo Sanabria-Valentín, Albert A. Bowers, Elizabeth A. Shanka

Publications and Research

Interspecies interactions have been described for numerous bacterial systems, leading to the identification of chemical compounds that impact bacterial physiology and differentiation for processes such as biofilm formation. Here, we identified soil microbes that inhibit biofilm formation and sporulation in the common soil bacterium Bacillus subtilis. We did so by creating a reporter strain that fluoresces when the transcription of a biofilm-specific gene is repressed. Using this reporter in a coculture screen, we identified Pseudomonas putida and Pseudomonas protegens as bacteria that secrete compounds that inhibit biofilm gene expression in B. subtilis. The active compound produced by P. protegens was …

Deletion Of Nfnab In Thermoanaerobacterium Saccharolyticum And Its Effect On Metabolism, Jonathan Lo, Tianyong Zheng, Daniel G. Olson, Natalie Ruppertsberger, Shital Tripathi, Adam Guss, Lee Lynd

Dartmouth Scholarship

NfnAB catalyzes the reversible transfer of electrons from reduced ferredoxin and NADH to 2 NADP⁺. The NfnAB complex has been hypothesized to be the main enzyme for ferredoxin oxidization in strains of Thermoanaerobacterium saccharolyticum engineered for increased ethanol production. NfnAB complex activity was detectable in crude cell extracts of T. saccharolyticum. Activity was also detected using activity staining of native PAGE gels. The nfnAB gene was deleted in different strains of T. saccharolyticum to determine its effect on end product formation. In wild-type T. saccharolyticum, deletion of nfnAB resulted in a 46% increase in H₂ formation but …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Genomic Signatures Of Cooperation And Conflict In The Social Amoeba, Elizabeth A. Ostrowski, Yufeng Shen, Xiangjun Tian, Richard Sucgang, Huaiyang Jiang, Jiaxin Qu, Mariko Katoh-Kurasawa, Debra A. Brock, Christopher Dinh, Fremiet Lara-Garduno, Sandra L. Lee, Christie L. Kovar, Huyen H. Dinh, Viktoriya Korchina, Laronda Jackson, Shobha Patil, Yi Han, Lesley Chaboub, Gad Shaulsky, Donna M. Muzny, Kim C. Worley, Richard A. Gibbs, Stephen Richards, Adam Kuspa, Joan E. Strassmann, David C. Queller

Biology Faculty Research

• Molecular evolution analyses reveal the history of social conflict
• Genes that mediate social conflict show signatures of frequency-dependent selection
• Balanced polymorphisms suggest that cheating may be stable and endemic

Cooperative systems are susceptible to invasion by selfish individuals that profit from receiving the social benefits but fail to contribute. These so-called "cheaters" can have a fitness advantage in the laboratory, but it is unclear whether cheating provides an important selective advantage in nature. We used a population genomic approach to examine the history of genes involved in cheating behaviors in the social amoeba Dictyostelium discoideum, testing whether these genes experience …

Vibrio Cholera: Detection And Destruction, Amber Brown, Dr. Julianne Grose

Journal of Undergraduate Research

Cholera, the Disease: Cholera is a disease that affects three to five million people each year with approximately 100,000 deaths. Transmitted mainly by the drinking-­‐water supply, it causes an infection in the small intestine leading to severe diarrhea and vomiting. If left untreated, it can cause death within hours. The disease is caused by the bacterium Vibrio cholerae which was first isolated by Filippo Pacini in 1854. Vibrio cholerae is gram negative, comma shaped, and flagellated. It is easily treated with modern water purification techniques, and as such it is most prevalent in developing countries that lack this infrastructure. Countries …

Biofilm Binding Capabilities Of Yersinia Pseudotuberculosis Mutants, Bailey Benson, Dr. David Erickson

Journal of Undergraduate Research

Yersinia pestis — the causative agent of the deadly bubonic plague, which killed over one-third of Europe in the 14th century – spreads quickly from person to person due to its ability to create a biofilm, characterized by bacterial adhesion to themselves and surfaces. The bacteria infects fleas and forms a biofilm in their midgut, which causes the flea to both feed more often and cough up bacteria biofim into each new host. In this way, the formation of a strong biofilm is essential for the rapid spread of the bubonic plague. In my experiment, I analyzed which genes would …

Understanding The Role Of Estrogen In The Mucosal Immune Response, Youna Choi, Dr. Eric Wilson

Journal of Undergraduate Research

Most antigens (foreign substances) enter an organism via mucosal surfaces. Thus, understanding the mechanisms involved in immune protection at these surfaces is of paramount importance. Immune responses are highly dependent on homing mechanisms responsible for directing lymphocyte (white blood cell) migration and accumulation at target tissues. Estrogen control of lymphocyte homing within the uterus has recently been established (2).

Virulence Gene Expression Of Vibrio Parahaemolyticus In The Viable But Nonculturable State, Tiffany Pui-Yun Tse

Master's Theses

Vibrio parahaemolyticus is a food-borne pathogen commonly associated with the consumption of raw or undercooked seafood resulting in primary infections of the human gastrointestinal tract. It is estimated to cause about 4500 illnesses each year in the United States. However, infection from this food-borne pathogen can be avoided if this organism is detected in the implicated food, prior to consumption. Current standard methods of detecting this organism are dependent on the culturability of the bacteria. Detection based on an organism’s culturability may be problematic as V. parahaemolyticus has been known to exist in a viable but nonculturable (VBNC) state. Bacteria …

High Salinity Stabilizes Bacterial Community Composition And Activity Through Time, Tylan Wayne Magnusson

Theses and Dissertations

Dormancy is a plausible strategy for bacteria to overcome the effects of temporal fluctuations in resources or stresses and await more “optimal” conditions to resume metabolic activity and growth. Seasonal changes in environmental conditions force microbes to adjust their metabolic activity accordingly, and community composition drastically shifts. In extreme environments, however, the overriding effects of a constant stress may constrain the need or benefit of bacteria entering dormancy. In hypersaline lakes, high metabolic activity is required to maintain adaptations that permit survival. Sampling from six lakes on a salinity gradient (0.05% – 30.3%), we measured seasonal fluctuations in bacterial dormancy …

The Antioxidant And Dna Repair Capacities Of Resveratrol, Piceatannol, And Pterostilbene, Justin Ryan Livingston

Theses and Dissertations

Lifestyle diseases represent a large burden on developed societies and account for much morbidity worldwide. Research has shown that eating a diet rich in fruit and vegetables helps to ameliorate and prevent some of these diseases. Antioxidants found in fruits and vegetables may provide a substantial benefit in reducing disease incidence. This thesis examines the antioxidant properties of resveratrol, piceatannol, and pterostilbene, and the ability of Burkitt's Lymphoma (Raji) cells to uptake these three antioxidants. It also studies the effect of the antioxidants in protecting against DNA damage and their role in DNA repair following oxygen radical exposure in Raji …

Identifying And Characterizing Yeast Pas Kinase 1 Substrates Reveals Regulation Of Mitochondrial And Cell Growth Pathways, Desiree Demille

Theses and Dissertations

Glucose allocation is an important cellular process that is misregulated in the interrelated diseases obesity, diabetes and cancer. Cells have evolved critical mechanisms for regulating glucose allocation, one of which is sensory protein kinases. PAS kinase is a key sensory protein kinase that regulates glucose allocation in yeast, mice and man; and is a novel therapeutic target for the treatment of metabolic diseases such as obesity, diabetes and cancer. Despite its importance, the molecular mechanisms of PAS kinase function are largely unknown. Through large-scale protein-interaction studies, we have identified 93 novel binding partners for PAS kinase which help to expand …

Genetic Changes To A Transcriptional Silencer Element Confers Phenotypic Diversity Within And Between Drosophila Species, Winslow C. Johnson, Alison J. Ordway, Masayoshi Watada, Jonathan N. Pruitt, Thomas M. Williams, Mark Rebeiz

Biology Faculty Publications

The modification of transcriptional regulation has become increasingly appreciated as a major contributor to morphological evolution. However, the role of negative-acting control elements (e.g. silencers) in generating morphological diversity has been generally overlooked relative to positive-acting “enhancer” elements. The highly variable body coloration patterns among Drosophilid insects represents a powerful model system in which the molecular alterations that underlie phenotypic diversity can be defined. In a survey of pigment phenotypes among geographically disparate Japanese populations of Drosophila auraria, we discovered a remarkable degree of variation in male-specific abdominal coloration. In testing the expression patterns of the major pigment-producing enzymes, …

Advancing Phage Genomics And Honeybee Health Through Discovery And Characterization Of Paenibacillaceae Bacteriophages, Bryan Douglas Merrill

Theses and Dissertations

The Paenibacillaceae family of bacteria includes two species known to infect the hives of honeybees, Paenibacillus larvae and Brevibacillus laterosporus. P. larvae, the causative agent of American Foulbrood (AFB) causes a lethal infection of honeybee larvae, while B. laterosporus is a secondary invader following European Foulbrood (EFB) infection. Increasing antibiotic resistance of P. larvae bacteria has prompted a search for alternative treatment methods for this disease. Bacteriophages are the most diverse life forms on earth and can provide important insights about the bacterial hosts they infect. However, few Paenibacillaceae phages have been isolated or characterized. In this study, the first …

The Biological Consequences Of Kaolin Geophagia, Deloris Alexander, Desire Richardson, Lakisha Odom, Kara Cromwell, Dejuana Grant, Micoya Myers, Eddy Cadet, Hamid Mahama, Vijaya Rangari, Ralphenia Pace, Ramble Ankumah, Kokoasse Kpomblekou-A, Curtis Fluker

Professional Agricultural Workers Journal

Abstract

Kaolin geophagia is associated with the relief of gastrointestinal distress, but it may also cause adverse health effects on the body. This study was designed to: assess kaolin composition; test if 129SvEv mice would consume kaolin and determine the consequences of consumption; and assess rotational stress modulation of consumption. Thirteen kaolin samples were purchased from Alabama and Georgia stores. Chemical and physical properties were characterized for each sample using a Munsell chart, pH meter, Energy Dispersive Spectroscopy, Transmission Electron Microscopy, Visible Near-InfraRed Spectra, and Inductively Coupled Plasma-Optical Emission Spectrometry. Kaolin was then given to mice as food supplements and …

Isolation And Host Range Of Staphylococcus Aureus Bacteriophages And Use For Decontamination Of Fomites, Kyle C. Jensen

Theses and Dissertations

Staphylococcus aureus is a common bacterium found on the skin and mucosal membranes of about 20% of the population. S. aureus growth on the skin is harmless, but if it bypasses the skin it can causes life-threatening diseases such as pneumonia, meningitis, bacteremia, and sepsis. Antibiotic-resistant strains of S. aureus, called Methicillin Resistant S. aureus (MRSA), are resistant to most antibiotics except vancomycin. However, vancomycin resistant strains of MRSA are becoming more common. In this study, 12 phages were isolated capable of infecting human S. aureus and/or MRSA strains. Five phages were discovered through mitomycin C induction of prophages and …

Fungi Inhabiting The Healthy Human Gastrointestinal Tract: A Diverse And Dynamic Community, Heather E. Hallen-Adams, Stephen D. Kachman, Jaehyoung Kim, Ryan Legge, Inés Martínez

Department of Food Science and Technology: Faculty Publications

Fungal DNA was selectively amplified, and the ITS region sequenced, from fecal samples taken from 45 healthy human volunteers at one (21 volunteers) or two (24 volunteers) time points. Seventy-two operational taxonomic units, representing two phyla and ten classes of fungi, were recovered. Candida yeasts, notably C. tropicalis (present in 51 samples), and yeasts in the Dipodascaceae (39 samples), dominated, while 38 OTUs were detected in a single sample each. Fungi included known human symbionts (Candida, Cryptococcus, Malassezia and Trichosporon spp.), common airborne fungi (Cladosporium sp.) and fungi known to be associated with food ( …