Pathogenic Microbiology Commons^™

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an …

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 …

Campylobacter Ureolyticus: An Emerging Gastrointestinal Pathogen?, Susan Bullman, Daniel Corcoran, James O'Leary, Brigid Lucey, Deirdre Byrne, Roy D. Sleator

Department of Biological Sciences Publications

A total of 7194 faecal samples collected over a 1-year period from patients presenting with diarrhoea were screened for Campylobacter spp. using EntericBios, a multiplex-PCR system. Of 349 Campylobacter-positive samples, 23.8% were shown to be Campylobacter ureolyticus, using a combination of 16S rRNA gene analysis and highly specific primers targeting the HSP60 gene of this organism. This is, to the best of our knowledge, the first report of C. ureolyticus in the faeces of patients presenting with gastroenteritis and may suggest a role for this organism as an emerging enteric pathogen.

Analysis Of The Clear Plaque Phenotype Of The Bacteriophage Hk75, Phani Chandrika Kunapuli

Masters Theses & Specialist Projects

The growth of bacteriophage HK75 is inhibited by specific mutations in the zinc binding domain of the host RNA polymerase beta prime subunit. It shares this rare property with bacteriophage HK022 and other phages that use RNA mediated antitermination to promote early gene expression. Recent genomic analysis of HK75 and HK022 has confirmed the relatedness of these two phages and place HK75 in the lambdoid family of bacteriophages. Lambdoid phages are temperate and can adopt a lytic or lysogenic lifestyle upon infection of a suitable host. However, HK75 only forms clear plaques and thus appears to be defective in its …

Characterization Of The Agrobacterium Tumefaciens Virb2 Pilin Of The Virb/D4 Type Iv Secretion System, Jennifer Kerr

Dissertations and Theses (Open Access)

The Agrobacterium tumefaciens VirB/D4 type IV secretion system (T4SS) delivers oncogenic T-DNA and effector proteins to susceptible plant cells. This leads to the formation of tumors termed Crown Galls. The VirB/D4 T4SS is comprised of 12 subunits (VirB1 to VirB11 and VirD4), which assemble to form two structures, a secretion channel spanning the cell envelope and a T-pilus extending from the cell surface. In A. tumefaciens, the VirB2 pilin subunit is required for assembly of the secretion channel and is the main subunit of the T-pilus. The focus of this thesis is to define key reactions associated with the T4SS …

Enterobacterial Repetitive Intergenic Consensus-Pcr (Eric-Pcr) Analysis Among Raw Vegetables Isolates Of Campylobacter Jejuni., Tuan Suraya Tuan Soh

Student Works (2010-2019)

A total of 20 (n=20) raw vegetable isolates of Campylobacter jejuni were examined for the presence of virulence genes and genetic diversity using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) analysis. All C. jejuni isolates were obtained from the laboratory of Food Science and Biotechnology, University Putra Malaysia, Serdang, Selangor. When specific PCR amplification were determined, all raw vegetables isolates of Campylobacter jejuni contained cadF and ceuE genes. Whereas, 12 (12/20) isolates were positive cdtB and 6 (6/20) were positive cdtC. None of the C. jejuni isolates was cdtA positive. Using ERIC-PCR analysis, all 20 isolates of C. jejuni were …

Cloning And Expression Of A Putative Exported Protein Coding Gene Sas1089 From An Invasive Community Associated Staphylococcus Aureus Strain Mssa476, Nailah Alzaki

All-Inclusive List of Electronic Theses and Dissertations

Originally, methicillin resistant Staphylococcus aureus (MRSA) occurred primarily in the hospital setting and was designated hospital- associated MRSA (HA-MRSA). In recent years, isolates of Staphylococcus aureus from the community (CA-MRSA), found to be methicillin resistant, are not as resistant tooth~ antibiotics as HA-MRSA. However, community strains are noted for their invasiveness causing soft tissue infections with propensity for invasion to deeper sites.

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Development Of Pcr Assays To Detect And Characterise Salmonella Isolates From Cheese And Meat Products By Utilizing An Integrated Genomics Approach, Noelle Geraldine Mccarthy

Theses

Salmonella is an extremely important foodborne pathogen which is responsible for millions of cases of gastroenteritis annually. Salmonella outbreaks have been associated with numerous common food stuffs such as meat, dairy and seafood. Traditional culture based methods for the detection Salmonella are labourious and costly. Rapid detection and serovar identification would dramatically decrease the time required to identify Salmonella outbreaks and potential health risks.

In the US 99% of all Salmonella infections are caused by members of Salmonella enterica subspecies 1. Serovars within subspecies 1 can vary due to host specificity and pathogenicity. DNA sequencing projects have provided valuable genomic …

The Regulation Of The Icsp Promoter Of Shigella Flexneri By The Virulence Factor Virb, Maria Castellanos, Dustin Harrison, Helen Wing

Undergraduate Research Opportunities Program (UROP)

Shigella flexneri is a pathogenic bacterium that causes severe dysentery in humans commonly known as shigellosis. Shigella encodes an outer membrane protease called IcsP. The regulation of icsP expression is under direct control of a transcriptional factor called VirB, which controls the expression of many virulence genes in Shigella. Previous work has shown through deletion analysis of the icsP promoter region that sequences as far as 1368 base pairs upstream of the transcription starting site are important for the regulation of the icsP gene by VirB. However, it is still unclear whether VirB activation requires sequences within the icsP promoter …

Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom

Dartmouth Scholarship

Candida albicans is an opportunistic human fungal pathogen that causes systemic candidiasis as well as superficial mucosal candidiasis. In response to the host environment, C. albicans transitions between yeast and hyphal forms. In particular, hyphal growth is important in facilitating adhesion and invasion of host tissues, concomitant with the expression of various hypha-specific virulence factors. In previous work, we showed that the cyclic AMP (cAMP) signaling pathway plays a crucial role in morphogenic transitions and virulence of C. albicans by studying genes encoding adenylate cyclase-associated protein (CAP1) and high-affinity phosphodiesterase (PDE2) (Y. S. Bahn, J. Staab, and P. Sundstrom, Mol. …

Mechanisms Of Virulence Regulation In Porphyromonas Gingivalis W83, Elaine Ann-Marie Vanterpool

Loma Linda University Electronic Theses, Dissertations & Projects

The expression of extracellular proteolytic activities is highly regulated in both prokaryotic and eukaryotic systems. This regulation can occur at multiple levels including expression of the protease genes, secretion, processing of an inactive secreted precursor to its active form and/or the posttranslational glycosylation of the proteins. These regulatory mechanisms are vital to ensure that expression is tightly controlled. Porphyromonas gingivalis has been associated with adult periodontitis and in the development of many systematic diseases. The major virulence factors of P. gingivalis, the gingipains, are responsible for pathogenesis including degradation of complement and immunoglobulin, inactivation of cytokines and their receptors, …

Pcr And 16s Rdna Sequencing For Identifying And Comparing Gram-Negative Bacteria, Molly Truax

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Caenorhabditis Elegans: A Look At Koch's Postulates And Host-Pathogen Interactions, Nicole Helmrichs

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Genetic And Structural Analyses Of Cytoplasmic Filaments Of Wild-Type Treponema Phagedenis And A Flagellar Filament-Deficient Mutant, Jacques Izard, William A. Samsonoff, Mary Beth Kinoshita, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpA, was identified in various treponemal species. Treponema phagedenis cfpA was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from T. denticola, T. vincentii, and T. pallidum subsp. pertenue. Wild-type T. phagedenis and a …

Insertional Inactivation Of Treponema Denticola Tap1 Results In A Nonmotile Mutant With Elongated Flagellar Hooks, Ronald J. Limberger, Linda L. Slivienski, Jacques Izard, William A. Samsonoff

Department of Food Science and Technology: Faculty Publications

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription …