Microbiology Commons^™

Protection And Attachment Of Vibrio Cholerae Mediated By The Toxin-Coregulated Pilus In The Infant Mouse Model, Shelly J. Krebs, Ronald K. Taylor

Dartmouth Scholarship

Colonization of the human small intestine by Vibrio cholerae is an essential step in pathogenesis that requires the type IV toxin-coregulated pilus (TCP). To date, three functions of TCP have been characterized: it serves as the CTXΦ receptor, secretes the colonization factor TcpF, and functions in microcolony formation by mediating bacterium-bacterium interactions. Although type IV pili in other pathogenic bacteria have been characterized as playing a major role in attachment to epithelial cells, there are very few studies to suggest that TCP acts as an attachment factor. Taking this into consideration, we investigated the function of TCP in attachment to …

Expression And Function Of The Dna Damage Protein Umud Of Acinetobacter Baylyi, And Its Predicted Cleavage And Nucleophilic Activator Residue Mutants In Escherichia Coli, Sabal Adhikari

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science & Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Sabal Adhikari on July 28, 2011.

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …

Combating Bioterrorism: Purification And Structural Analysis Of The E3 Proteins Of The Venezuelan Equine Encephalitis Virus And The Chikungunya Virus, Tyshia Gwin

The Journal of Purdue Undergraduate Research

Outbreaks of the Venezuelan Equine Encephalitis Virus (VEEV) and the Chikungunya Virus (CHIKV) continue to emerge in Central and South America, Africa, and Asia, but there are currently no vaccines or anti-virals for these viruses. Given their ease of transmission, debilitating symptoms, and genetic alterability, VEEV and CHIKV have great potential for development into biological weapons. Therefore, there is an urgent need to determine possible methods of treatment or prevention. One possibility of prevention lies in determining the structure and biological function of the E3 protein that plays a key role in the infectivity of the viruses. In this research, …

Comparison Of Adenoviruses As Oncolytics And Cancer Vaccines In An Immunocompetent B Cell Lymphoma Model, Eric A. Weaver, Christopher Y. Chen, Shannon M. May, Mary E. Barry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

We have screened human adenoviruses (Ads) for oncolytic activity against a variety of mouse and hamster cell lines and have found a number that are susceptible to a variety of Ad serotypes. A20 lymphoma is derived from BALB/c mice and is susceptible to infection and killing by a variety of human Ads. A20 is also a suitable cancer vaccine model, because these cells express a unique immunoglobulin variable region that can be targeted by vaccination. To compare Ads as cancer vaccines versus Ads as oncolytics, A20 tumors were initiated in immunocompetent BALB/c mice. Mice immunized with first-generation Ad5 expressing the …

Systematic Analysis Of Diguanylate Cyclases That Promote Biofilm Formation By Pseudomonas Fluorescens Pf0-1, Peter D. Newell, Shiro Yoshioka, Kelli L. Hvorecny, Russell D. Monds, George A. O'Toole

Dartmouth Scholarship

Cyclic di-GMP (c-di-GMP) is a broadly conserved, intracellular second-messenger molecule that regulates biofilm formation by many bacteria. The synthesis of c-di-GMP is catalyzed by diguanylate cyclases (DGCs) containing the GGDEF domain, while its degradation is achieved through the phosphodiesterase activities of EAL and HD-GYP domains. c-di-GMP controls biofilm formation by Pseudomonas fluorescens Pf0-1 by promoting the cell surface localization of a large adhesive protein, LapA. LapA localization is regulated posttranslationally by a c-di-GMP effector system consisting of LapD and LapG, which senses cytoplasmic c-di-GMP and modifies the LapA protein in the outer membrane. Despite the apparent requirement for c-di-GMP for …

Emerging Dynamics Of Human Campylobacteriosis In Southern Ireland, Susan Bullman, Daniel Corcoran, James O'Leary, Derry O'Hare, Brigid Lucey, Roy D. Sleator

Department of Biological Sciences Publications

Infections with Campylobacter spp. pose a significant health burden worldwide. The significance of Campylobacter jejuni/Campylobacter coli infection is well appreciated but the contribution of non-C. jejuni/C. coli spp. to human gastroenteritis is largely unknown. In this study, we employed a two-tiered molecular study on 7194 patient faecal samples received by the Microbiology Department in Cork University Hospital during 2009. The first step, using EntericBio® (Serosep), a multiplex PCR system, detected Campylobacter to the genus level. The second step, utilizing Campylobacter species-specific PCR identified to the species level. A total of 340 samples were confirmed as Campylobacter genus positive, 329 of …

Generation Of A Kupffer Cell-Evading Adenovirus For Systemic And Liver-Directed Gene Transfer, Reeti Khare, Shannon M. May, Francesco Vetrini, Eric A. Weaver, Donna Palmer, Amanda Rosewell, Nathan Grove, Philip Ng, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

As much as 90% of an intravenously (i.v.) injected dose of adenovirus serotype 5 (Ad5) is absorbed and destroyed by liver Kupffer cells. Viruses that escape these cells can then transduce hepatocytes after binding factor X (FX). Given that interactions with FX and Kupffer cells are thought to occur on the Ad5 hexon protein, we replaced its exposed hypervariable regions (HVR) with those from Ad6. When tested in vivo in BALB/c mice and in hamsters, the Ad5/6 chimera mediated >10 times higher transduction in the liver. This effect was not due to changes in FX binding. Rather, Ad5/6 appeared to …

Mechanical Test Methods For Assessing Porcine Carotid And Uterine Artery Burst Pressure Following Ex Vivo Ultrasonic Ligature Seal And Transection, Carissa M. Krane, Margaret Pinnell, Courtney Gardner, Mercedes Thompson, James Coleman, Robert Wilkens

Biology Faculty Publications

A test method was developed to identify those variables important for assessing the performance of ultrasonic surgical devices in ex vivo ligature sealing of porcine carotid and uterine arteries. Ruggedness testing using a small sample size in pilot experiments was conducted using a newly developed test method in an effort to assess the usefulness of this methodology and to identify test variables that might warrant further testing. The development of this test method included the use of a custom-designed prototypic tension device for load-controlled ex vivo vessel stretching during saline perfusion and subsequent seal and transection of porcine arteries with …

In Situ Enrichment Of Ocean Crust Microbes On Igneous Minerals And Glasses Using An Osmotic Flow‐Through Device, Amy Renee Smith, Martin Fisk, Radu Popa, Mark Nielsen, C. Geoffrey Wheat, Hans W. Jannasch, Andrew T. Fisher, Keir Becker, Stefan M. Sievert, Gilberto Flores

Biology Faculty Publications and Presentations

The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long-term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbial colonization preferences for 12 minerals and glasses present in igneous rocks. Following recovery of the colonization systems, we measured cell density on the minerals and glasses by fluorescent staining and direct counting and found some significant differences between mineral samples. …

In Search Of An Uncultured Human-Associated Tm7 Bacterium In The Environment, Jorge Dinis, David Barton, Jamsheed Ghadiri, Deepa Surendar, Kavitha Reddy, Fernando Velasquez, Carol Chaffee, Mei-Chong Lee, Helen Gavrilova, Hazel Ozuna, Samuel Smits, Cleber Ouverney

Faculty Publications, Biological Sciences

We have identified an environmental bacterium in the Candidate Division TM7 with ≥98.5% 16S rDNA gene homology to a group of TM7 bacteria associated with the human oral cavity and skin. The environmental TM7 bacterium (referred to as TM7a-like) was readily detectable in wastewater with molecular techniques over two years of sampling. We present the first images of TM7a-like cells through FISH technique and the first images of any TM7 as viable cells through the STARFISH technique. In situ quantification showed TM7 concentration in wastewater up to five times greater than in human oral sites. We speculate that upon further …

Antioxidants In Cancer Research And Prevention: Assay Comparison, Structure-Function Analysis, And Food Product Analysis, Andrew Robert Garrett

Theses and Dissertations

Recent epidemiological studies have suggested that the development and progression of several chronic diseases may be initiated or augmented by oxidative stress. Reactive oxygen species and reactive nitrogen species react readily with and can damage nucleic acids, proteins, and lipids. While biological systems are equipped antioxidant defenses to cope with oxidative stress, oxidative damage may still occur when oxidative stress overwhelms antioxidant defenses. This damage, if left unchecked, may lead to a variety of degenerative diseases, including heart disease, Alzheimer's Disease, Parkinson's Disease and cancer. Several assays have been designed to describe the antioxidant activity of various phytochemicals, vitamins, and …

Growth Phase-Dependent Gene Regulation In Vivo In Sulfolobus Solfataricus, Melissa Deyoung, Michelle Thayer, John Van Der Oost, Kenneth M. Stedman

Biology Faculty Publications and Presentations

Ribosomal genes are strongly regulated dependent on growth phase in all organisms, but this regulation is poorly understood in Archaea. Moreover, very little is known about growth phase-dependent gene regulation in Archaea. SSV1- based lacS reporter gene constructs containing the Sulfolobus 16S/23S rRNA gene core promoter, the TF55a core promoter, or the native lacS promoter were tested in Sulfolobus solfataricus cells lacking the lacS gene. The 42-bp 16S/23S rRNA gene and 39-bp TF55a core promoters are sufficient for gene expression in S. solfataricus. However, only gene expression driven by the 16S/23S rRNA gene core promoter is dependent on …

Effects Of Canola And Corn Oil Mimetic On Jurkat Cells, Gabriela Ion, Kayla Fazio, Juliana A. Akinsete, W. Elaine Hardman

Biochemistry and Microbiology

BACKGROUND: The Western diet is high in omega-6 fatty acids and low in omega-3 fatty acids. Canola oil contains a healthier omega 3 to omega 6 ratio than corn oil. Jurkat T leukemia cells were treated with free fatty acids mixtures in ratios mimicking that found in commercially available canola oil (7% α-linolenic, 30% linoleic, 54% oleic) or corn oil (59% linoleic, 24% oleic) to determine the cell survival or cell death and changes in expression levels of inflammatory cytokines and receptors following oil treatment.

METHODS: Fatty acid uptake was assessed by gas chromatography. Cell survival and cell death were …

Molecular Analysis Reveals Unique Microbiome In Ileal Pouch During Pouchitis Compared To Healthy Pouches In Ulcerative Colitis And Familial Adenomatous Polyposis, Tiffany Wallingford Glavan

Master's Theses

In severe cases of ulcerative colitis (UC) unresponsive to current treatment options, patients require a complete proctocolectomy, or surgical removal of the colon. Ileal pouch anal anastomosis (IPAA) has become the preferred surgical technique for patients who require surgery, as this method restores rectal function. This procedure is also used to treat colorectal cancers such as adenocarcinoma and familial adenomatous polyposis (FAP). The surgery involves an abdominal colectomy with the construction of an ileal pouch created from folded tissue recovered from the ileal portion of the small intestine. Up to 50% of patients who require IPAA surgery experience an episode …

The Human Gut Microbiome: Ecology And Recent Evolutionary Changes, Jens Walter, Ruth Ley

Department of Food Science and Technology: Faculty Publications

The human gastrointestinal tract is divided into sections, allowing digestion and nutrient absorption in the proximal region to be separate from the vast microbial populations in the large intestine, thereby reducing conflict between host and microbes. In the distinct habitats of the gut, environmental filtering and competitive exclusion between microbes are the driving factors shaping microbial diversity, and stochastic factors during colonization history and in situ evolution are likely to introduce intersubject variability. Adaptive strategies of microbes with different niches are genomically encoded: Specialists have smaller genomes than generalists, and microbes with environmental reservoirs have large accessory genomes. A shift …

Characterization And Regulation Of The Icsp And Ospz Locus In Shigella Flexneri, Krystle Lashell Pew

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shigella flexneri is a gram negative, rod shaped bacterium that is the causative agent of bacillary dysentery, which is characterized by fever, abdominal pain, and bloody diarrhea. Genes essential to the pathogenicity of S. flexneri are encoded by a virulence plasmid. Shigella has evolved a complex regulatory system to regulate transcription of virulence genes. This involves two regulators, VirF and VirB, which allow the bacterium to respond to environmental stimuli and maximally exploit host niches. An additional factor impacting virulence gene regulation is H-NS, a histone nucleoid structuring protein that globally represses transcription. This work addresses the transcriptional regulation of …

Novel Model For Multispecies Biofilms That Uses Rigid Gas-Permeable Lenses, Rebecca Peyyala, Sreenatha S. Kirakodu, Jeffrey L. Ebersole, Karen F. Novak

Center for Oral Health Research Faculty Publications

Oral biofilms comprise complex multispecies consortia aided by specific inter- and intraspecies interactions occurring among commensals and pathogenic bacterial species. Oral biofilms are primary initiating factors of periodontal disease, although complex multifactorial biological influences, including host cell responses, contribute to the individual outcome of the disease. To provide a system to study initial stages of interaction between oral biofilms and the host cells that contribute to the disease process, we developed a novel in vitro model system to grow biofilms on rigid gas-permeable contact lenses (RGPLs), which enable oxygen to permeate through the lens material. Bacterial species belonging to early- …

Archaeoparasitology Of Chaco Canyon, Rachel Paseka

Department of Environmental Studies: Undergraduate Student Theses

Ancient cultures of the Colorado Plateau have been a focus of archaeoparasitology since its inception, and a vast parasitological history is recorded in coprolites preserved in this arid region. The inhabitants of Chaco Canyon dominated Ancestral Puebloan culture between 1050 and 1120 AD and were responsible for the construction of great towns, road systems, and early agriculture. Analysis of the parasites preserved in fecal remains contributes to an increased knowledge of ancient Chacoan health and culture. Nineteen coprolites from four sites in Chaco Canyon were rehydrated and analyzed microscopically for parasite remains. Rhabditiform and filariform nematode larvae were found from …

Microbiological Safety Of Organic Fertilizers Used For Produce Production, Cortney Miller

All Theses

Over the last few decades there has been an increase in the use of organic fertilizers due to the rise in popularity of organic food production. However, if the fertilizers are not adequately sanitized there is the possibility of contamination of agricultural crops by foodborne pathogens from the spreading of organic fertilizers onto the crops. This is especially important for animal waste-based fertilizers since animals frequently carry foodborne pathogens. Furthermore, antibiotic use in food animal production may induce antimicrobial resistance in gut bacteria which can be spread to crops and the environment through fertilizer use. The objectives of this study …