Download or read book The Alternative Sigma Factor B and Stress Response in Listeria Monocytogenes written by David Sue and published by . This book was released on 2004 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress Response Alternative Sigma Factor Sigma B and Virulence of Listeria Monocytogenes written by Celine Andree Nadon and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 2003 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Role of the Alternative Sigma Factor Sigma B in Stress Response and Regulation of Virulence in Listeria Monocytogenes written by Lynne A. Becker and published by . This book was released on 2002 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Role of the Alternative Sigma Factor superscript B in Osmotic Response and Regulation of Stress Response in Listeria Monocytogenes written by Mehmet Sevket Cetin and published by . This book was released on 2003 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Alternative Sigma Factors of Listeria Monocytogenes written by Sana Mujahid and published by . This book was released on 2013 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The foodborne pathogen Listeria monocytogenes is ubiquitous in the environment and can cause a life-threatening invasive infection in humans. L. monocytogenes has the ability to survive a wide range of environmental and physiological stress conditions through complex stress response and virulence mechanisms. Among the key mechanisms L. monocytogenes employs to respond to changing conditions, including those encountered during growth on food and in the infection process, is the regulation of gene, protein, and non-coding RNA (ncRNA) expression through the regulatory network of the alternative sigma factors, [sigma]B, [sigma]C, [sigma]H, and [sigma]L. In these studies we (i) explored [sigma]B-dependent regulation of the ncRNA SbrE, and (ii) determined [sigma]B, [sigma]C, [sigma]H, and [sigma]L regulons at the protein level using a quantitative proteomics approach. We demonstrated [sigma]B-dependent transcription of SbrE and identified putative targets of SbrE at the transcriptomic and proteomic level. We also found increased transcript levels of SbrE in stationary phase and after exposure of L. monocytogenes to oxidative stress. Our proteomic analysis of L. monocytogenes parent strain 10403S and a [DELTA]sigB mutant combined with a meta-analysis of published transcriptomic studies identified 149 genes and proteins as positively regulated by [sigma]B at either or both the transcript and protein level, and suggested contributions of [sigma]B to gene expression through direct regulation of gene transcription and through indirect mechanisms, including regulation of ncRNA. Finally, our comparison of the protein expression profiles of parent strain 10403S and a quadruple mutant [DELTA]sigBCHL, and comparisons of [DELTA]sigBCHL with triple mutants, [DELTA]sigBCH, [DELTA]sigBCL, and [DELTA]sigBHL, characterized the independent regulons of [sigma]L, [sigma]H, and [sigma]C at the protein level, as well as co-regulation and protein expression in the absence of all four alternative [sigma] factors. Co-regulated proteins identified included MptA, which has a potential role in regulation of PrfA, a transcriptional activator of L. monocytogenes virulence genes. These studies identify and characterize components of the complex regulatory network of L. monocytogenes alternative [sigma] factors and illustrate co-regulation of gene expression by multiple alternative [sigma] factors, which contributes to our understanding of the alternative [sigma] factor dependent stress response and virulence abilities of L. monocytogenes.

Download or read book RNA Polymerase Sigma Factor B written by Adriana de Oliveira Ferreira and published by . This book was released on 2002 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contributions of Sigma B and PrFa to Stress Response and Virulence Gene Expression in Listeria Monocytogenes written by Mark Joseph Kazmierczak and published by . This book was released on 2005 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The General Stress Responsive Sigma Factor B and Its Role in Intracellular Parasitism of Listeria Monocytogenes written by Hee-Sun Kim and published by . This book was released on 2004 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Listeria Monocytogenes written by Hassan Hachim and published by LAP Lambert Academic Publishing. This book was released on 2012-07 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Listeria monocytogenes is an important food-borne pathogen that has the capacity to cause severe infections, such as gastroenteritis, septicemia, abortion and meningitis in humans and animals. The alternative sigma factors ( B, C, H, & L) are responsible for regulating transcription of several Listeria monocytogenes virulence factors and stress response genes, including hemolysin gene (hly) that contribute to establishment of intracellular infection."

Download or read book Regulation of Transcription Factor Sigma B Activity in the Foodborne Pathogen Listeria Monocytogenes written by Soraya Chaturongakul and published by . This book was released on 2006 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alternative Transcription Factor Sigma B in Foodborne Bacteria written by Torey James Arvik and published by . This book was released on 2001 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Growth Temperature on the Regulation of Host Cell Invasion and Acid Stress Response in Listeria Monocytogenes written by Reid Aaron Ivy and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Listeria monocytogenes is a foodborne bacterial pathogen that has been isolated from various natural and urban environments during different seasons and has been shown to persist in food processing environments. L. monocytogenes has the ability to grow at refrigeration temperatures and is therefore a danger to makers and consumers of ready-to-eat (RTE) food products, as these foods are not subjected to a heating step prior to consumption. During transmission from the environment through foods to humans, L. monocytogenes must adapt to a range of environmental conditions including varying temperature, preservative stress, gastric stress, and host immunological defenses. Mechanisms of environmental adaptation in L. monocytogenes include two-component response regulators (RRs), alternative sigma factors, and other positive (e.g., PrfA) and negative (e.g., CtsR) transcriptional regulators. We characterized the effects of L. monocytogenes growth temperature on (i) the contributions to in vitro host cell invasion of 14 RRs, alternative sigma factor [sigma][EXP]B, virulence regulator PrfA and surface associated proteins InlA and FlaA and (ii) the response to sudden acid shock. Overall, invasion was higher for L. monocytogenes grown at 30[DEGREE]C compared to 37[DEGREE]C. RR mutants "cheY and "degU were invasiondeficient when grown at 30[DEGREE]C, but not 37[DEGREE]C. We observed 37[DEGREE]C-growth-dependent functional synergisms between !B and PrfA in contributing to host cell invasion and contributory synergisms between FlaA and InlA at both temperatures. Bacteria grown at 37[DEGREE]C were more resistant to HCl acid shock (pH 3.5) than cells grown at 7[DEGREE]C. For cells grown at 37[DEGREE]C, the transcriptional response to acid treatment involved the induction of genes with prior implication in acid response and intracellular survival, whereas the response of 7[DEGREE]C-grown cells involved the induction of two large operons of bacteriophage genes, which may explain the increased survival of 37[DEGREE]C grown cells. Our data show that growth temperature affects regulation of host cell invasion and the response to acid shock, which are both vital stages in L. monocytogenes transmission. Therefore, growth temperature should be considered an important variable in modeling L. monocytogenes stress survival and virulence.

Download or read book Novel Strategies for Characterizing and Controlling the Stress Response of Listeria Spp written by Daina Lydia Ringus and published by . This book was released on 2012 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The genus Listeria includes nine species, including the foodborne pathogen Listeria monocytogenes, which can cause serious illness in humans. Listeria spp. exist in urban and natural environments and are able to survive a diverse range of physiological conditions, to which the general stress response contributes. In Listeria spp. and other Gram-positive organisms, the general stress response is regulated by the alternative sigma factor sigma B (!B). In these studies, we explored several novel methods of controlling and characterizing Listeria spp. in areas relevant to food safety, ranging from inactivation technologies to newly identified compounds for controlling the bacterial stress response. Specifically, the work presented here investigated: i) the use of Pulsed Light (PL), a nonthermal method, to inactivate Listeria innocua (a surrogate organism for L. monocytogenes) on packaging materials, ii) the transcriptional responses to stress of persistent and non-persistent strains of L. monocytogenes isolated from food processing environments as a possible mechanism of persistence, and iii) a novel small molecule inhibitor of!B activity in L. monocytogenes and related Bacillus subtilis. We found that PL was able to achieve inactivation of L. innocua up to 7.2 log CFU on low density polyethylene, and that inactivation was associated with the reflectance properties of the packaging materials that we tested. We found that L. monocytogenes strains from food processing plants classified as persistent did not induce higher transcript levels of four stress genes regulated by the transcriptional factors CtsR and!B in response to salt stress compared to non-persistent strains. Finally, we determined that fluoro-phenyl-styrene-sulfonamide (FPSS), a novel inhibitor of!B activity, inhibits the activation of!B in response to environmental and energy stresses in B. subtilis, and we conclude FPSS does not exert its inhibitory effect by interactions with the phosphatases RsbP or RsbU, or the members of the RsbV/RsbW/!B partner switching model that is central to the regulation of!B. FPSS inhibits!B activity by a yet unknown mechanism, and determining its mechanism of action will further our understanding of the regulation of!B.

Download or read book Contribution of Sigma B to Stress Response and Virulence in Listeria Monocytogenes Lineages I Ii Iiia and Iiib written by Haley Ann Franks Oliver and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The widespread presence of Listeria monocytogenes in diverse environments, including those that are natural (i.e., non-agricultural), agricultural, and foodassociated, suggests that these environments may serve as sources or reservoirs of L. monocytogenes that can be transmitted to various hosts, including humans. The vast majority of human listeriosis infections are recognized to occur through consumption of contaminated foods. Phylogenetic analysis of L. monocytogenes strains has identified three distinct lineages. While lineages I and II are both common among human clinical and food isolates, lineage I strains are overrepresented among clinical isolates, and lineage II strains are overrepresented among food and environmental isolates. Lineage III, which includes subgroups IIIA and IIIB, is rare and predominantly associated with animal disease. [sigma]B, encoded by sigB, is a sigma factor previously demonstrated to critically contribute to stress response and virulence in lineage II strains. We used transcriptomic and phenotypic analyses to characterize the role of [sigma]B in L. monocytogenes strains representing lineages I, II, IIIA, and IIIB. Whole-genome expression microarrays, phenotypic assays, and the guinea pig gastrointestinal model for listeriosis were used to characterize the role of [sigma]B stationary phase wildtype and isogenic [DELTA]sigB mutants representing L. monocytogenes diversity. Our results indicate that the role of [sigma]B may differ among L. monocytogenes strains. The stationary phase transcriptome and [sigma]B regulon of L. monocytogenes 10403S was also defined using RNA sequencing (RNA-Seq) with the Illumina Genome Analyzer. We found that 83% of all genes were transcribed in stationary phase and a total of 96 genes had significantly higher transcript levels in 10403S than in [DELTA]sigB, indicating [sigma]Bdependent transcription of these genes. RNA-Seq analyses suggest that a total of 65 noncoding RNA molecules (ncRNAs) were transcribed in stationary phase. The RNA-Seq data also enabled annotation of putative operons and visualization of transcription start and stop sites. The results from these studies suggest that [sigma]B contributes to a complex network of transcriptional regulators which allows L. monocytogenes to survive stress and subsequently cause disease and RNA-Seq allows quantitative characterization of prokaryotic transcriptomes and is a new strategy for exploring transcriptional regulatory networks in bacteria.

Download or read book Putative Role of the Alternative Sigma Factor SigB in Survival of Listeria Monocytogenes 568 During Desiccation on Stainless Steel Surfaces written by Yannan Huang and published by . This book was released on 2011 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparative Evaluation of Sigma B dependent Stress Responses in Listeria Monocytogenes and Listeria Innocua written by Sarita Raengpradub and published by . This book was released on 2008 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whole genome microarray analyses identified (i) 168 genes to be positively regulated by sigmaB in L. monocytogenes, including 145 that appear to be directly sigmaB-regulated, (ii) 128 L. monocytogenes genes to be negatively regulated by sigmaB, (iii) 64 genes to be positively regulated by sigmaB in L. innocua, and (iv) 49 genes that appear to sigmaB-dependent in both L. monocytogenes and L. innocua, indicating a core group of genes that contribute to stress response in Listeria species. Transcription analysis of sigmaB-dependent genes and phenotypic characterization indicate species-specific differences between L. monocytogenes and L innocua, in particular sigmaB regulation of the internalins and sigma B contribution to stationary-phase acid resistance. sigma B appears to regulate genes encoding proteins with a wide range of functions, including stress response, transporters, carbohydrate metabolism, and transcriptional regulation, which suggests a role for sigmaB as a master regulator in the L. monocytogenes transcriptional regulatory network.

Download or read book Foodborne Microbial Pathogens written by Arun K. Bhunia and published by Springer. This book was released on 2018-05-21 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book primarily covers the general description of foodborne pathogens and their mechanisms of pathogenesis, control and prevention, and detection strategies, with easy-to-comprehend illustrations. The book is an essential resource for food microbiology graduate or undergraduate students, microbiology professionals, and academicians involved in food microbiology, food safety, and food defense-related research or teaching. This new edition covers the significant progress that has been made since 2008 in understanding the pathogenic mechanism of some common foodborne pathogens, and the host-pathogen interaction. Foodborne and food-associated zoonotic pathogens, responsible for high rates of mortality and morbidity, are discussed in detail. Chapters on foodborne viruses, parasites, molds and mycotoxins, and fish and shellfish are expanded. Additionally, chapters on opportunistic and emerging foodborne pathogens including Nipah virus, Ebola virus, Aeromonas hydrophila, Brucella abortus, Clostridium difficile, Cronobacter sakazakii, and Plesiomonas shigelloides have been added. The second edition contains more line drawings, color photographs, and hand-drawn illustrations.