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 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 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 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 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 Understanding the Roles of Transcriptional Regulators for the Development of Natural and Novel Inhibitors of Listeria Monocytogenes written by Mary Elizabeth Palmer 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 pathogenic intracellular foodborne bacterium that causes listeriosis, a rare, but serious disease in humans. Despite the use of antibiotics, the mortality rate remains at 20-30%. The ability of L. monocytogenes to survive transmission through food systems and to cause disease is attributed in part to the regulatory networks that control environmental stress adaptation and virulence functions. Therefore, a comprehensive understanding of the factors that are important to virulence, stress response and antimicrobial resistance will help us better develop novel inhibitors for therapeutics. With the information garnered from select regulators, it is possible to identify new drug targets and new drugs for treatment alternatives. The purpose of this research in L. monocytogenes is to (i) determine the contributions of select transcriptional regulators to virulence functions, (ii) assess the contributions of two regulators to antimicrobial peptides response, and (iii) identify novel small molecule inhibitors of the regulator [sigma]B. In summary, we found that of central transcriptional regulators, [sigma]B, PrfA, HrcA, CtsR, [sigma]L, [sigma]H, and [sigma]C, [sigma]B contributes to invasion, PrfA contributes to cell-to-cell growth and CtsR, in addition to PrfA and [sigma]B, contributes to virulence in a guinea pig model of listeriosis. We determined that [sigma]B and [sigma]L are important to controlling expression of genes needed for resistance to the select antimicrobial peptides SdpC and Nisin, thus indicating that [sigma]B has a role in virulence and stress survival as well as antimicrobial resistance. Therefore, we focused on [sigma]B as a promising novel drug target for the treatment of listeriosis. From a library of 57,000 small molecules, we identified a novel compound, sigmastatin, which inhibits the activity of [sigma]B and its regulon, inhibits Bacillus subtilis [sigma]B and severely impedes L. monocytogenes enterocyte invasion. With a solid understanding of the contributions and roles of various regulators in L. monocytogenes, novel inhibitors can be used to target those regulators, like [sigma]B, which are associated with survival, pathogenesis, and resistance. These novel agents can be used to treat listeriosis, extrapolated for use against other similar clinically relevant diseases, or used to gain insight into physiology of pathogenic bacteria and related gene regulation.

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 Pathogenesis and Host Response written by Howard Goldfine and published by Springer Science & Business Media. This book was released on 2007-06-24 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past twenty years Listeria monocytogenes has emerged as one of the most intensely studied bacterial pathogens. New windows are constantly being opened into the complexity of host cell biology and the interplay of the signals connecting the various cells and organs involved in the host response. This volume includes research from studies at the molecular level on the pathogenesis of Listeria monocytogenes and the response of the host to its infections.

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 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 The SigmaB PrfA Co regulon in the Foodborne Pathogen Listeria Monocytogenes written by Juliane Ollinger and published by . This book was released on 2008 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overall the results presented here show that sigmaB and PrfA function in a coordinated transcriptional regulatory network in response to environmental conditions. Fine-tuning of virulence gene transcription appears to critically contribute to optimal intracellular survival of L. monocytogenes . The results presented here also showed that neither wild type PrfA nor PrfA* negatively affect gene transcription in L. monocytogenes, establishing an exclusive activator function for PrfA.

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 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 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.

Download or read book The New Microbiology written by Pascale Cossart and published by John Wiley & Sons. This book was released on 2020-07-10 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbiology has undergone radical changes over the past few decades, ushering in an exciting new era in science. In The New Microbiology, Pascale Cossart tells a splendid story about the revolution in microbiology, especially in bacteriology. This story has wide-ranging implications for human health and medicine, agriculture, environmental science, and our understanding of evolution. The revolution results from the powerful tools of molecular and cellular biology, genomics, and bioinformatics, which have yielded amazing discoveries, from entire genome sequences to video of bacteria invading host cells. This book is for both scientists and especially nonscientists who would like to learn more about the extraordinary world of bacteria. Dr. Cossart's overview of the field of microbiology research, from infectious disease history to the ongoing scientific revolution resulting from CRISPR technologies, is presented in four parts. New concepts in microbiology introduces the world of bacteria and some recent discoveries about how they live, such as the role of regulatory RNAs including riboswitches, the CRISPR defense system, and resistance to antibiotics. Sociomicrobiology: the social lives of bacteria helps us see the new paradigm by which scientists view bacteria as highly social creatures that communicate in many ways, for example in the assemblies that reside in our intestine or in the environment. The biology of infections reviews some of history's worst epidemics and describes current and emerging infectious diseases, the organisms that cause them, and how they produce an infection. Bacteria as tools introduces us to molecules derived from microbes that scientists have harnessed in the service of research and medicine, including the CRISPR/Cas9 genome-editing technology. The New Microbiology takes us on a journey through a remarkable revolution in science that is occurring here and now.

Download or read book Gram positive Pathogens written by Vincent A. Fischetti and published by . This book was released on 2000 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the only single volume to deal with all aspects of gram–positive pathogens. It addresses the mechanisms of gram–positive bacterial pathogenicity, including the current knowledge on gram–positive structure and mechanisms of antibiotic resistance. Emphasizing streptococci, staphylococci, listeria, and spore–forming pathogens, Gram–Positive Pathogens includes chapters written by many of the leading researchers in these areas. The chapters systematically dissect these organisms biologically, genetically, and immunologically in an attempt to understand the strategies used by these bacteria to cause human disease.

Download or read book Handbook of Listeria Monocytogenes written by Dongyou Liu and published by CRC Press. This book was released on 2008-04-21 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once feared as a deadly intracellular bacterium with the extraordinary capacity to survive a wide array of arduous external stressors, Listeria monocytogenes is increasingly recognized as a preferred vector for delivering anti-infective and anti-cancer vaccine molecules. A reliable, single-source reference on the fundamental aspects of