Download or read book Transcription Regulation of Virulence Gene Expression in Francisella Tularensis written by James Carl Charity and published by . This book was released on 2010 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: F. tularensis also contains two additional critical regulators of virulence gene expression: ppGpp (a small molecule that signals nutrient stress) and PigR (a putative DNA-binding protein). Genome-wide transcription analyses indicated that MglA, SspA, PigR, and ppGpp regulate the same set of genes. Bacterial two-hybrid assays showed that MglA, SspA, and PigR form a three-protein complex, and in vivo crosslinking experiments showed that ppGpp facilitates the interaction between PigR and the MglA-SspA complex. These findings provide a framework for understanding the mechanistic basis for virulence gene control in F. tularensis and uncover a novel mechanism by which ppGpp influences gene expression--by modulating the interaction between a transcription activator and the RNAP-associated MglA-SspA complex.
Download or read book Coordinate Control of Virulence Gene Expression in Francisella Tularensis written by Amy Elizabeth Rohlfing and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The small molecule ppGpp has previously been shown to promote the interaction between the MglA-SspA complex and PigR in F. tularensis. It is unknown if ppGpp directly or indirectly promotes this interaction. We determined that ppGpp is required to detect an interaction between the MglA-SspA complex and PigR in the E. coli bridge-hybrid assay, indicating that ppGpp is either directly involved in promoting this interaction or works through an indirect mechanism that is conserved between F. tularensis and E. coli. One potential conserved mechanism through which ppGpp may be influencing the interaction between the MglA-SspA complex and PigR is through regulation of the levels of the molecule polyphosphate. However, we determined that polyphosphate is not required in order for the MglA-SspA complex and PigR to detectably interact with one another in the E. coli bridge-hybrid assay. Furthermore, analysis of the role of polyphosphate in gene expression in F. tularensis revealed that polyphosphate is a negative regulator of virulence gene expression.
Download or read book Regulation of Virulence Gene Transcripts by the Francisella Orphan Response Regulator PmrA written by Brian Len Bell and published by . This book was released on 2009 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Francisella tularensis subspecies tularensis is the etiologic agent of tularemia and has been designated a category A biothreat agent by the CDC. Tularemia is characterized by replication and dissemination within host phagocytes. Intramacrophage growth is dependent upon the regulation of Francisella Pathogenicity Island (FPI) virulence genes, which is poorly understood. Two-component regulatory systems (TCS) are widely employed by Gram negative bacteria to monitor and respond to environmental signals. Virulent strains of F. tularensis are devoid of classical, tandemnly arranged TCS, but orphaned members, such as the response regulator PmrA, have been identified. In the F. novicida model system, previous work has shown that a pmrA mutant is deficient for intramacrophage growth and is avirulent in the mouse model. Here we determine that phosphorylation aids PmrA binding to regulated promoters pmrA and the FPI encoded pdpD, and KdpD is the histidine kinase primarily responsible for phosphorylation of PmrA at the aspartic acid at position 51 (D51). A strain expressing PmrA D51A retains some DNA binding but exhibits reduced expression of the PmrA-regulon, is deficient for intramacrophage replication and is attenuated in the mouse model. PmrA co-precipitates with the FPI transcription factors MglA and SspA, which bind RNA polymerase. Together this data suggests a model of Francisella gene regulation that includes a TCS consisting of KdpD and PmrA. Once phosphorylated, PmrA binds to regulated gene promoters recruiting free or RNA polymerase bound MglA and SspA to initiate FPI gene transcription.
Download or read book Francisella Tularensis Insertion Sequence Elements Contribute to Differential Gene Expression written by Amanda Marie Bartling and published by . This book was released on 2018 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Francisella tularensis is the causative agent of the disease tularemia and a select agent. The genome of this pathogen contains many insertion sequence (IS) elements with ISFtu1 being the most abundant. ISFtu1 expression and the contribution of this IS element to differential gene expression in the F. tularensis subpopulations was evaluated. Full-length and truncated ISFtu1 sense and antisense transcriptional expression was detected. The prototype A.I strain (Schu S4) had considerably higher expression levels of ISFtu1 and the adjacent genes than the wild type A.I strain (NE061598). The A.II strains (WY96-3418 and WY-00W4114) had similar expression levels for ISFtu1 and the adjacent genes. In the highly virulent A.I strains, a bicistronic transcript encoding the universal stress protein (Usp) and a downstream ISFtu1 was highly expressed during early and mid log growth phase when provisions were plentiful, and was induced 2-fold by nitric oxide and a polyamine. During late log growth and stationary phase, only monocistronic transcripts for usp and ISFtu1 were being moderately expressed. Intrinsic transcription termination sequences were not apparent between usp and ISFtu1. Secondary RNA structure models indicated that the bicistronic transcript will form more readily than the monocistronic usp transcript. The co-expression of ISFtu1 and the adjacent gene(s) may provide a fitness advantage by regulating expression and/or transcript stability of the co-transcribed gene(s). Additional study will provide a better understanding of the contribution of IS elements to the differential gene expression and virulence observed for the various F. tularensis clades.
Download or read book Analysis of Francisella Tularensis Mutants Defective in Intracellular Survival written by Frances Valencia and published by . This book was released on 2007 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Francisella tularensis is a gram-negative bacterium categorized as a category A agent of biological warfare that causes the disease known as tularemia. To identify virulence factors of the F. tularensis type A strain Schu S4 a transposon-insertion library as generated and screened for mutant strains defective in intracellular survival. We focused in particular on two mutant strains, BJM1005 and BJM1026. BJM1005 has a transposon insertion in the dsbB gene, that encodes a protein that is required for disulfide bond formation. DsbB appear to be part of an operon with two genes FTT1016c and FTT105c, that potentially encode a multidrug efflux pump. We hypothesize that the dsbB null mutation prevented expression of the downstream FTT1016c and FTT105c genes. Therefore, we attempted to determine if dsbB and the downstream genes FTT0106c and FTT0105c are cotranscribed on a polycistronic mRNA. Oligonucleotide primer pairs for reverse-transcription PCR (RT-PCR) were designed to test this hypothesis. The preliminary results do not confirm cotranscription because we were unable to detect gene expression above background. BJM1026 has a transposon in FTT1236 (hypothetical protein) that is potentially cotranscribed with FTT1237, a putative glycosyl transferase. We hypothesized that the mutation of FTT1236 in Francisella tularensis has a polar effect on the putative glycosyl transferase, causing a defect in lipopolysaccharide (LPS) synthesis. To investigate this we performed a western blot with primary rabbit anti-LVS, antibodies that are able to detect F. tularensis LPS. Our results demonstrated a defect in the O-antigen of the LPS which both supports our hypothesis and suggests that LPS synthesis and its role in F. tularensis virulence needs to be investigated further.
Download or read book Francisella tularensis and tularemia written by Anders Sjöstedt and published by Frontiers E-books. This book was released on 2011-06-11 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: The bacterium today known as Francisella tularensis was first identified 99 years ago and, since then, much research has been devoted to study it and the resulting disease, tularemia. F. tularensis became the focus of an intense research effort during the first half of the 20th century, in particularly in the United States and Soviet Union, since the disease was fairly common. Due to its high infectivity, ease of spread, and severity of the resulting disease, it was one of the agents given the highest priority in the biological weapon programs of the United States and Soviet Union. After termination of these programs in the 1960s, the interest in F. tularensis diminished significantly, but after several decades of little attention, the last decade has led to resurgence in the research on F. tularensis. In 2003, the Science magazine phrased it as follows: “an obscure weapon of the cold war edges into the limelight”. There were multiple reasons for this resurgence, one of which was an increase in the number of tularemia cases in several European countries and, moreover, the intense research effort on potential bioterrorist agents in the US post 9/11. Thereby, the number of annual publications on F. tularensis has tripled in 10 years, and many new research groups, in particular American, have entered the field. This has led to very rapid development of state-of-the-art research tools, and fast progress in the understanding of F. tularensis. A proof of the rapid progress was the publication of a comprehensive volume on Francisella and tularemia in 2007. Although only four years ago, the rapid pace of the research has led to many new discoveries since then and, to this end, we now present a collection of articles from leading scientists on the up-to-date knowledge regarding F. tularensis. The articles cover important areas such as molecular research tools, experimental models, genomics, virulence mechanisms, manipulation and subversion of host responses, host immune responses, and the ecology of F. tularensis.
Download or read book Bacterial Pathogens and Their Virulence Factors written by Douglas I. Johnson and published by Springer. This book was released on 2017-11-23 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bacterial Pathogens and their Virulence Factors contains a detailed description of 32 major bacterial pathogens that affect human health and their associated virulence determinants. Chapter 1 gives an overview of the different types and classes of general virulence factors involved in host cell adherence and invasion, dissemination within the host, host cell damage, and evasion of host defense systems, as well as mechanisms by which these virulence factors are regulated. Chapters 2 through 33 give concise descriptions of the disease states associated with the 32 bacterial genera and their major pathogenic species, along with an in-depth description of the individual virulence factors that have been found to be functionally involved in pathogenicity. A detailed bibliography derived from primary literature and review articles accompanies each of these chapters, allowing the reader to delve more deeply into individual pathogens and their virulence determinants. Chapter 34 discusses the exciting possibilities and initial successes of using detailed information on a pathogen’s virulence toolkit to design new therapeutics aimed at specific virulence traits.
Download or read book Role of the Francisella Tularensis Antioxidant Transcriptional Regulator OxyR in Oxidative Stress Resistance written by Vincenzo Russo and published by . This book was released on 2016 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Francisella tularensis is a highly virulent human pathogen. The ability of F. tularensis to cause a fulminate infection is due in part to its ability to survive and replicate in phagocytic cells involved in host's innate immune defense. In order to establish an intracellular niche, F. tularensis has to overcome oxidative stress posed by reactive oxygen species. The genome sequence analysis reveals the presence of oxyR, while both soxR/soxS regulons are absent in F. tularensis. The presence of OxyR as the only oxidant stress regulator indicates that regulation of oxidative stress response genes in Francisella are unique. However, nothing is known about the wider regulatory role of OxyR during Francisella infection. This study investigated the role of OxyR of F. tularensis in tularemia pathogenesis and regulation of genes involved in oxidative stress response. We generated a deletion mutant (oxyR) and a transcomplemented strain of oxyR gene of F. tularensis LVS. The oxyR mutant was characterized for its sensitivity towards oxidants and antibiotics. To investigate the regulatory role of OxyR, we performed iTRAQ analysis, chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays (EMSA). To assess the role of OxyR in pathogenesis, we tested the capacity of the oxyR mutant to survive in macrophages, its virulence in mice and its impact on host cell defenses. We demonstrate that OxyR of F. tularensis is required for resistance to oxidants, survival in macrophages and virulence in mice, yet not for inflammasome activation. Proteomic analysis revealed differential expression of multiple proteins associated with oxidative stress resistance and cellular functions in the oxyR mutant as compared to the wild-type F. tularensis LVS, indicating that OxyR serves as a global regulator of oxidant stress response. Most importantly, OxyR regulates transcription of primary antioxidant enzyme genes ahpC, katG and sodB by binding directly to their upstream promoter regions. These results highlight that OxyR is an important regulator of oxidative stress response and renders F. tularensis a pathoadaptive advantage to establish an intracellular niche. An understanding of these unique pathogenic mechanisms is essential for the development of effective therapeutics and prophylactics against this important biothreat agent.
Download or read book Regulation of Bacterial Virulence written by Michael L. Vasil and published by American Society for Microbiology Press. This book was released on 2012-12-05 with total page 1189 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive compendium of scholarly contributions relating to bacterial virulence gene regulation. • Provides insights into global control and the switch between distinct infectious states (e.g., acute vs. chronic). • Considers key issues about the mechanisms of gene regulation relating to: surface factors, exported toxins and export mechanisms. • Reflects on how the regulation of intracellular lifestyles and the response to stress can ultimately have an impact on the outcome of an infection. • Highlights and examines some emerging regulatory mechanisms of special significance. • Serves as an ideal compendium of valuable topics for students, researchers and faculty with interests in how the mechanisms of gene regulation ultimately affect the outcome of an array of bacterial infectious diseases.
Download or read book Francisella Tularensis written by Yousef Abu Kwaik and published by Wiley-Blackwell. This book was released on 2007-07-23 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book on tularemia. With the biodefense initiative, there has been a major boost by the NIH to fund studies on bioterrorism agents, including Francisella, which is classified as a class A bioterrorism agent. With the major interest in biodefense and the major threats of bioterrorism, Francisella tularensis has become a major interest for microbiologists, cell biologists, immunologists, and infectious disease experts. The volume explores the mechanisms of pathogenesis, genetics and genetic manipulations, genomics and metagenomics, identification of vaccine candidates, animal models to study the disease process, mechanisms of protective immunity, pathophysiology, vaccine development, genetic susceptibility, more effective therapies, clinical diagnosis, and routine and rapid microbiological diagnostic tools. NOTE: Annals volumes are available for sale as individual books or as a journal. For information on institutional journal subscriptions, please visit www.blackwellpublishing.com/nyas. ACADEMY MEMBERS: Please contact the New York Academy of Sciences directly to place your order (www.nyas.org). Members of the New York Academy of Science receive full-text access to the Annals online and discounts on print volumes. Please visit www.nyas.org/membership/main.asp for more information about becoming a member.
Download or read book The Prokaryotes written by Edward F. DeLong and published by Springer. This book was released on 2014-10-02 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Prokaryotes is a comprehensive, multi-authored, peer reviewed reference work on Bacteria and Achaea. This fourth edition of The Prokaryotes is organized to cover all taxonomic diversity, using the family level to delineate chapters. Different from other resources, this new Springer product includes not only taxonomy, but also prokaryotic biology and technology of taxa in a broad context. Technological aspects highlight the usefulness of prokaryotes in processes and products, including biocontrol agents and as genetics tools. The content of the expanded fourth edition is divided into two parts: Part 1 contains review chapters dealing with the most important general concepts in molecular, applied and general prokaryote biology; Part 2 describes the known properties of specific taxonomic groups. Two completely new sections have been added to Part 1: bacterial communities and human bacteriology. The bacterial communities section reflects the growing realization that studies on pure cultures of bacteria have led to an incomplete picture of the microbial world for two fundamental reasons: the vast majority of bacteria in soil, water and associated with biological tissues are currently not culturable, and that an understanding of microbial ecology requires knowledge on how different bacterial species interact with each other in their natural environment. The new section on human microbiology deals with bacteria associated with healthy humans and bacterial pathogenesis. Each of the major human diseases caused by bacteria is reviewed, from identifying the pathogens by classical clinical and non-culturing techniques to the biochemical mechanisms of the disease process. The 4th edition of The Prokaryotes is the most complete resource on the biology of prokaryotes. The following volumes are published consecutively within the 4th Edition: Prokaryotic Biology and Symbiotic Associations Prokaryotic Communities and Ecophysiology Prokaryotic Physiology and Biochemistry Applied Bacteriology and Biotechnology Human Microbiology Actinobacteria Firmicutes Alphaproteobacteria and Betaproteobacteria Gammaproteobacteria Deltaproteobacteria and Epsilonproteobacteria Other Major Lineages of Bacteria and the Archaea
Download or read book p ppGpp and Its Homologs Enzymatic and Mechanistic Diversity Among the Microbes written by Katarzyna Potrykus and published by Frontiers Media SA. This book was released on 2021-07-01 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stress Response in Pathogenic Bacteria written by Stephen P. Kidd and published by CABI. This book was released on 2011-03 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of pathogenic bacteria to adapt to various chemical, biochemical and physical conditions within the human host and their ability to respond to stresses generated in these environments is a central feature of infectious diseases and the outcome of bacterial infection. This book covers the key aspects of this rapidly developing field, including the generation of stresses by the host immune system, bacterial response to reactive chemicals, and adaptation to environmental conditions of anatomical niches such as the gut, mouth and urogenital tract. It also addresses the increasing impor.
Download or read book Microbial Endocrinology written by Mark Lyte and published by Springer Science & Business Media. This book was released on 2010-04-06 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial endocrinology represents a newly emerging interdisciplinary field that is formed by the intersection of the fields of neurobiology and microbiology. This book will introduce a new perspective to the current understanding not only of the factors that mediate the ability of microbes to cause disease, but also to the mechanisms that maintain normal homeostasis. The discovery that microbes can directly respond to neuroendocrine hormones, as evidenced by increased growth and production of virulence-associated factors, provides for a new framework with which to investigate how microorganisms interface not only with vertebrates, but also with invertebrates and even plants. The reader will learn that the neuroendocrine hormones that one most commonly associates with mammals are actually found throughout the plant, insect and microbial communities to an extent that will undoubtedly surprise many, and most importantly, how interactions between microbes and neuroendocrine hormones can influence the pathophysiology of infectious disease.
Download or read book Microbial Forensics written by Bruce Budowle and published by Academic Press. This book was released on 2010-10-27 with total page 753 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial Forensics is a rapidly evolving scientific discipline. In the last decade, and particularly due to the anthrax letter attacks in the United States, microbial forensics has become more formalized and has played an increasingly greater role in crime investigations. This has brought renewed interest, development and application of new technologies, and new rules of forensic and policy engagement. It has many applications ranging from biodefense, criminal investigations, providing intelligence information, making society more secure, and helping protect precious resources, particularly human life. A combination of diverse areas is investigated, including the major disciplines of biology, microbiology, medicine, chemistry, physics, statistics, population genetics, and computer science. Microbial Forensics, Second Edition is fully revised and updated and serves as a complete reference of the discipline. It describes the advances, as well as the challenges and opportunities ahead, and will be integral in applying science to help solve future biocrimes. - A collection of microbiology, virology, toxicology and mycology as it relates to forensics, in one reference - New and expanded content to include statistical analysis of forensic data and legal admissibility and the standards of evidence, to name a few - Includes research information and application of that research to crime scene analysis, which will allow practitioners to understand and apply the knowledge to their practice with ease
Download or read book Issues in Immunology Research 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 1988 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Immunology Research / 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Immunology Research. The editors have built Issues in Immunology Research: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Immunology Research in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Immunology Research: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Regulating with RNA in Bacteria and Archaea written by Gisela Storz and published by John Wiley & Sons. This book was released on 2020-07-10 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Revealing the many roles of RNA in regulating gene expression For decades after the discoveries of messenger RNA, transfer RNA, and ribosomal RNA, it was largely assumed that the role of RNA in the cell was limited to shuttling the genomic message, chaperoning amino acids, and toiling in the ribosomes. Eventually, hints that RNA molecules might have regulatory roles began to appear. With the advent of genomics and bioinformatics, it became evident that numerous other RNA forms exist and have specific functions, including small RNAs (sRNA), RNA thermometers, and riboswitches to regulate core metabolic pathways, bacterial pathogenesis, iron homeostasis, quorum sensing, and biofilm formation. All of these functions, and more, are presented in Regulating with RNA in Bacteria and Archaea, written by RNA biologists from around the globe. Divided into eight sections-RNases and Helicases, Cis-Acting RNAs, Cis Encoded Base Pairing RNAs, Trans-Encoded Base Pairing RNAs, Protein Titration and Scaffolding, General Considerations, Emerging Topics, and Resources-this book serves as an excellent resource for established RNA biologists and for the many scientists who are studying regulated cellular systems. It is no longer a fair assumption that gene expression regulation is the provenance of proteins only or that control is exerted primarily at the level of transcription. This book makes clear that regulatory RNAs are key partners along with proteins in controlling the complex interactions and pathways found within prokaryotes.
