Microbiology Commons^™

Freshwater Metaviromics And Bacteriophages: A Current Assessment Of The State Of The Art In Relation To Bioinformatic Challenges, Katherine Bruder, Kema Malki, Alexandria Cooper, Emily Sible, Jason W. Shapiro, Siobhan C. Watkins, Catherine Putonti

Bioinformatics Faculty Publications

Advances in bioinformatics and sequencing technologies have allowed for the analysis of complex microbial communities at an unprecedented rate. While much focus is often placed on the cellular members of these communities, viruses play a pivotal role, particularly bacteria-infecting viruses (bacteriophages); phages mediate global biogeochemical processes and drive microbial evolution through bacterial grazing and horizontal gene transfer. Despite their importance and ubiquity in nature, very little is known about the diversity and structure of viral communities. Though the need for culture-based methods for viral identification has been somewhat circumvented through metagenomic techniques, the analysis of metaviromic data is marred with …

Synthesis And Biological Activity Of Novel Quorum Sensing Compounds, Joseph Nicholas Capilato

Theses and Dissertations

Bacteria communicate with chemical signals in a process known as quorum sensing. This population density-dependent process involves the bacterial production, release and detection of structurally specific small molecules and enables the bacterial pathogen to regulate its virulence on a population-wide level. Using a variety of chemical and biological techniques, I have studied various quorum sensing systems in several bacteria, including Vibrio cholera and Pseudomonas aeruginosa. A key principle of this research involves the design, synthesis and testing of novel compounds for their biological activity. These molecules are typically based off of an initial lead target, which is often identified …

Antiviral Rna Silencing Suppression Activity Of Tomato Spotted Wilt Virus Nss Protein, Tania Ocampo Ocampo, Sergio M. Gabriel Peralta, Nicole Bacheller, Stella Uiterwaal, Aaron Knapp, Alanna Hennen, Daniel Leobardo Ochoa-Martínez, Hernan Garcia-Ruiz

Department of Plant Pathology: Faculty Publications

In addition to regulating gene expression, RNA silencing is an essential antiviral defense system in plants. Triggered by double-stranded RNA, silencing results in degradation or translational repression of target transcripts. Viruses are inducers and targets of RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressors that interfere with this process, such as the Tomato spotted wilt virus (TSWV) NSs protein. The mechanism by which NSs suppresses RNA silencing and its role in viral infection and movement remain to be determined. We cloned NSs from the Hawaii isolate of TSWV and using two independent assays show for the first …

Population Dynamics And Community Composition Of Ammonia Oxidizers In Salt Marshes After The Deepwater Horizon Oil Spill, Anne E. Bernhard, Roberta Sheffer, Anne E. Giblin, John M. Marton, Brian J. Roberts

Biology Faculty Publications

The recent oil spill in the Gulf of Mexico had significant effects on microbial communities in the Gulf, but impacts on nitrifying communities in adjacent salt marshes have not been investigated. We studied persistent effects of oil on ammonia-oxidizing archaeal (AOA) and bacterial (AOB) communities and their relationship to nitrification rates and soil properties in Louisiana marshes impacted by the Deepwater Horizon oil spill. Soils were collected at oiled and unoiled sites from Louisiana coastal marshes in July 2012, 2 years after the spill, and analyzed for community differences based on ammonia monooxygenase genes (amoA). Terminal Restriction Fragment …

Effect Of A Ropy Exopolysaccharide-Producing Bifidobacterium Animalis Subsp. Lactis Strain Orally Administered On Dss-Induced Colitis Mice Model, Claudio Hidalgo-Cantabrana, Francesca Algieri, Alba Rodriguez-Nogales, Teresa Vezza, Pablo Martínez-Camblor

Dartmouth Scholarship

Exopolysaccharide (EPS)-producing bifidobacteria, particularly Bifidobacterium animalis subsp. lactis strains, are used in the functional food industry as promising probiotics with purported beneficial effects. We used three isogenic strains of B. animalis subsp. lactis, with different EPS producing phenotypes (mucoid-ropy and non-ropy), in order to determine their capability to survive the murine gastrointestinal tract transit, as well as to evaluate their role in improving clinical outcomes in a chemically-induced colitis model. The three strains were able to survive in the intestinal tract of C57BL/6J mice during the course of the intervention study. Furthermore, the disease activity index (DAI) of the animal …

Identification, Characterization, And Life Cycle Of Intein-Associated Homing Endonucleases, Joshua J. Skydel

Honors Scholar Theses

Inteins are molecular parasites that have been identified in unicellular organisms from the three domains of life. The intein self-excises following translation of the host gene, and therefore incurs a fitness cost for its carrier. The symbiotic state of the intein to its host is dependent on the presence or absence of a homing endonuclease domain, which facilitates horizontal transfer of the molecule. Identification of this domain provides information on the evolutionary history of the intein, as well as patterns of horizontal gene transfer in microbial communities. I have therefore developed Hidden Markov Models (HMMs) to identify homing endonuclease domains …

The Pseudomonas Aeruginosa Efflux Pump Mexghi-Opmd Transports A Natural Phenazine That Controls Gene Expression And Biofilm Development, Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K. Morales, Blanche Fields, Alexa Price-Whelan, Deborah Hogan

Dartmouth Scholarship

Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We …

Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas

Dissertations, Theses, and Capstone Projects

Mycobacterial species include a variety of obligate and opportunistic pathogens that cause several important diseases affecting mankind such as tuberculosis and leprosy. The most unique feature of these bacteria is their intricate cell wall that poses a permeability barrier to antibiotics and contributes to their pathogenicity and persistence within the host. The cell wall hosts several complex lipids such as dimycocerosate esters (DIMs), which are found in many clinically relevant pathogenic species of mycobacteria. DIMs have been implicated in the virulence of mycobacteria and play a major role in helping the bacteria evade host immune responses. It is therefore crucial …

Is Aerosalization A Problem With Carbapenem-Resistant Acinetobacter Baumannii In Thailand Hospital?, Anucha Apisarnthanarak, Ploenpit Tantajina, Pornpimol Laovachirasuwan, David J. Weber, Nalini Singh

Pediatrics Faculty Publications

We evaluated the presence of air contamination with carbapenem-resistant Acinetobacter baumannii (CRAB) in medical units where patients with CRAB pneumonia were hospitalized, and in Obstetrics and Gynecology units with open-air ventilation in-patient settings. There was no evidence of CRAB contamination in either of the units.

Household Clustering Of Escherichia Coli Sequence Type 131 Clinical And Fecal Isolates According To Whole Genome Sequence Analysis, James R. Johnson, Gregg Davis, Connie Clabots, Brian D. Johnston, Stephen Porter, Lance B. Price, +10 Additional Authors

Environmental and Occupational Health Faculty Publications

Background. Within-household sharing of strains from the resistance-associated H30R1 and H30Rx subclones of Escherichia coli sequence type 131 (ST131) has been inferred based on conventional typing data, but has been assessed minimally using whole genome sequence (WGS) analysis.

Methods. Thirty-three clinical and fecal isolates of ST131-H30R1 and ST131-H30Rx, from 20 humans and pets in six households, underwent WGS analysis for comparison with 52 published ST131 genomes. Phylogenetic relationships were inferred using a bootstrapped maximum likelihood tree based on core genome sequence polymorphisms. Accessory traits were compared between phylogenetically similar isolates.

Results. In the WGS-based …

A Pan-Dengue Virus Reverse Transcription-Insulated Isothermal Pcr Assay Intended For Point-Of-Need Diagnosis Of Dengue Virus Infection By Use Of The Pockit Nucleic Acid Analyzer, Yun Young Go, R. P. V. Jayanthe Rajapakse, Senanayake A. M. Kularatne, Pei-Yu Alison Lee, Keun Bon Ku, Sangwoo Nam, Pin-Hsing Chou, Yun-Long Tsai, Yu-Lun Liu, Hsiao-Fen Grace Chang, Hwa-Tang Thomas Wang, Udeni B. R. Balasuriya

Maxwell H. Gluck Equine Research Center Faculty Publications

Dengue virus (DENV) infection is considered a major public health problem in developing tropical countries where the virus is endemic and continues to cause major disease outbreaks every year. Here, we describe the development of a novel, inexpensive, and user-friendly diagnostic assay based on a reverse transcription-insulated isothermal PCR (RT-iiPCR) method for the detection of all four serotypes of DENV in clinical samples. The diagnostic performance of the newly established pan-DENV RT-iiPCR assay targeting a conserved 3′ untranslated region of the viral genome was evaluated. The limit of detection with a 95% confidence was estimated to be 10 copies of …

The Pmrhfijklm Operon In Yersinia Pseudotuberculosis Enhances Resistance To Ccl28 And Promotes Phagocytic Engulfment By Neutrophils, Lauren Elizabeth Johnson

Theses and Dissertations

Yersinia pseudotuberculosis is a foodborne pathogen that is the ancestral strain to Yersinia pestis, the causative agent of Plague. Y. pseudotuberculosis invades a host through the intestinal epithelium. The bacteria resist mucosal innate immune defenses including antimicrobial chemokines and phagocytic cells, and replicate in local lymph nodes. They cause Tuberculosis-like symptoms, including necrosis of local tissue and granuloma formation. Like all bacteria, Y. pseudotuberculosis has a net negative charge, which contributes to its susceptibility to some cationic antimicrobial peptides. Y. pseudotuberculosis is able to reduce this negative charge by adding 4-amino-4-deoxy-L-arabinose (L-Ara4N) to the lipid A portion of lipopolysaccharide. The …

The Influence Of Juncus-Rhizosphere Dissolved Organic Matter On Coastal Plankton Communities, Brittany Zepernick, Robert Michael Mckay, George S. Bullerjahn, Jeffrey W. Krause, Behzad Mortazavi

Honors Projects

Many aquatic plants produce copious amounts of dissolved organic matter (DOM) which enters surrounding waters and potentially stimulates planktonic activity. In the northern Gulf of Mexico, Juncus roemarianus (i.e. black needlerush) is a dominant marsh grass species residing in coastal zones and barrier islands. The below-ground biomass i.e. rhizosphere, can be consistently submerged, serving as a potential source of DOM to the surrounding waters. The lability and possible stimulatory effect of J. roemarianus DOM was examined for three plankton communities collected within the discharge region of Mobile Bay and adjacent waters of Gulf Shores, Alabama (less affected by Mobile Bay). …

Characterization Of Influenza Nucleoprotein Body Domain As Antiviral Target, Alicia Morgan Davis

Electronic Theses, Projects, and Dissertations

Influenza is a segmented negative strand RNA virus. Each RNA segment is encapsulated by viral nucleoprotein (NP) and bound by the viral RNA dependent RNA polymerase (RdRP) to form viral ribonucleoproteins (vRNPs) responsible for RNA synthesis. NP is a structural component of the vRNP but also interacts with both viral and host factors to regulate viral RNA expression. NP is conserved among influenza A isolates, making NP interactions compelling antiviral targets. Here I characterize mutations within 5 amino acids of NP that comprise an accessible region of the NP body domain, as determined by NP crystal structure. This region was …

Characterization Of Five Brevibacillus Bacteriophages And Their Genomes, Michael Allen Sheflo

Theses and Dissertations

Brevibacillus laterosporus (B. laterosporus) is a pathogen difficult to distinguish from Paenibacillus larvae (P. larvae), and contributes to Colony Collapse Disorder (CCD) of honeybees. To develop a biocontrol agent to limit its presence, bacteriophages were isolated from Utah County soil samples and used to infect B. laterosporus isolated from Utah County honey and larvae samples. Since CCD is prevalent in Utah beehives, bacteriophage that infect and lyse B. laterosporus may be isolated and characterized. Pathogens were isolated from soil samples, and 16S rRNA gene tests initially identified the strains as P. larvae. Bacteriophages were isolated, purified, and amplified sufficiently to …

Comparative Studies Of Tslp And Il-7 In Normal Early Human Neonatal And Adult B Cell Development, Terry-Ann Milford

Loma Linda University Electronic Theses, Dissertations & Projects

Defining the role of cytokines in promoting human B cell development is important for understanding B cell leukemia and for developing strategies to restore B cell production that is lost during some therapies. The purpose of this study was to investigate the roles of the IL-7R ligands, thymic stromal lymphopoietin (TSLP) and IL- 7, in the early stages of normal postnatal and adult human B cell development. Using novel in vitro and in vivo model systems, we show that TSLP and IL-7 are able to expand B cell precursors individually and in combination from CB hematopoietic stem cells. In this …

The Effects Of Quorum Sensing And Temperature On The Soluble Proteome Of Vibrio Salmonicida, Christopher L. Massey

Master's Theses

Vibrio salmonicida causes cold-water vibriosis in salmon populations around the world and causes financial damage to fisheries designed to farm these salmon. Very little is known about the physiology of how V. salmonicida causes disease and measures to contain vibriosis are restricted to either vaccinating individual fish against disease or administering antibiotics when an outbreak is detected. These procedures are costly and increase the risk for selection of antibiotic-resistant V. salmonicida strains. A recent reoccurrence of outbreaks in Norwegian fisheries provided incentive to better understand the virulence mechanisms of V. salmonicida. In this thesis, a proteomic approach was used to …

Glomus Tumor Of Trachea In An Adult Male, Sidra Arshad, Zubair Ahmad, Nasir Ud Din

Department of Pathology and Laboratory Medicine

Glomus tumors most commonly occur in distal extremities, particularly in the subungual region. The origin of these tumors is modified smooth muscle cells of glomus bodies. Trachea is one of the rare sites where normal glomus bodies may be sparse or absent, so occurrence of glomus tumor in trachea is very rare. Only 30 cases have been reported in the literature so far. In this case report, the authors describe a very rare and in fact first case of glomus tumor of trachea in a 45-year male Pakistani patient.

The Role Of The Transcriptional Antiterminator Rfah In Lipopolysaccharide Synthesis, Resistance To Antimicrobial Peptides, And Virulence Of Yersinia Pseudotuberculosis And Yersinia Pestis, Jared Michael Hoffman

Theses and Dissertations

RfaH is a unique bacterial protein that enhances transcription of a select group of long operons in many Gram-negative bacteria. Operons regulated by RfaH possess an upstream operon polarity suppressor sequence, which recruits the RfaH protein to the RNA polymerase during transcription of genes, most of which are involved in the synthesis of cell-surface features. These include synthesis of the lipopolysaccharide (LPS) core and O-antigen in Salmonella and Escherichia coli, as well as F-plasmid conjugation pilus and capsule in E. coli. LPS is an important virulence factor in many Gram-negative bacteria, and protects Y. pseudotuberculosis against host antimicrobial …

Human Herpesvirus 6a Infection And Immunopathogenesis In Humanized Rag2-/-Γc-/- Mice And Relevance To Hiv/Aids And Autoimmunity, Anne Tanner

Theses and Dissertations

Human herpesvirus 6A (HHV-6A) has yet to be definitively linked to a specific disease. This is due in part to the ubiquitous nature of the virus. Humanized Rag2^-/-γc-/- (Rag-hu) mice were tested to determine if these were a suitable animal model to study the virus. Both cell-free and cell-associated virus was used for infection and both were found to be efficient at infecting the mice. Viral DNA was found in the plasma and cellular blood fractions, bone marrow, lymph node, and thymus, indicating successful infection and propagation of the virus in vivo. The CD3+CD4- population was depleted, while the …