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Author: Juan-Luis Ramos Publisher: Springer Science & Business Media ISBN: 9780306483769 Category : Science Languages : en Pages : 584
Book Description
Pseudomonas comprises three volumes covering the biology of pseudomonads in a wide context, including the niches they inhabit, the taxonomic relations among members of this group, the molecular biology of gene expression in different niches and under different environmental conditions, the analysis of virulence traits in plants, animals and human pathogens as well as the determinants that make some strains useful for biotechnological applications and promotion of plant growth. There has been growing interest in pseudomonads and a particular urge to understand the biology underlying the complex metabolism of these ubiquitous microbes. These bacteria are capable of colonizing a wide range of niches, including the soil, the plant rhizosphere and phylosphere, and animal tissues; more recently they have attracted attention because of their capacity to form biofilms, a characteristic with potentially important medical and environmental implications. The three volumes cover the following topics: - Taxonomy, - Genomics, - Life styles, - Cell Architecture, - Virulence, - Regulation, - Macromolecules, - Alternative Respiratory Substrates, - Catabolism and Biotransformations. Pseudomonas will be of use to all researchers working on these bacteria, particularly those studying microbiology, plant crops, pathogenesis, and chemical engineering. Advanced students in biology, medicine and agronomy will also find these three volumes a valuable reference during their studies.
Author: Juan-Luis Ramos Publisher: Springer Science & Business Media ISBN: 9780306483769 Category : Science Languages : en Pages : 584
Book Description
Pseudomonas comprises three volumes covering the biology of pseudomonads in a wide context, including the niches they inhabit, the taxonomic relations among members of this group, the molecular biology of gene expression in different niches and under different environmental conditions, the analysis of virulence traits in plants, animals and human pathogens as well as the determinants that make some strains useful for biotechnological applications and promotion of plant growth. There has been growing interest in pseudomonads and a particular urge to understand the biology underlying the complex metabolism of these ubiquitous microbes. These bacteria are capable of colonizing a wide range of niches, including the soil, the plant rhizosphere and phylosphere, and animal tissues; more recently they have attracted attention because of their capacity to form biofilms, a characteristic with potentially important medical and environmental implications. The three volumes cover the following topics: - Taxonomy, - Genomics, - Life styles, - Cell Architecture, - Virulence, - Regulation, - Macromolecules, - Alternative Respiratory Substrates, - Catabolism and Biotransformations. Pseudomonas will be of use to all researchers working on these bacteria, particularly those studying microbiology, plant crops, pathogenesis, and chemical engineering. Advanced students in biology, medicine and agronomy will also find these three volumes a valuable reference during their studies.
Author: Michael L. Vasil Publisher: American Society for Microbiology Press ISBN: 1555816762 Category : Science Languages : en Pages : 1189
Book Description
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.
Author: Frans J. de Bruijn Publisher: John Wiley & Sons ISBN: 1119004896 Category : Science Languages : en Pages : 1472
Book Description
Bacteria in various habitats are subject to continuously changing environmental conditions, such as nutrient deprivation, heat and cold stress, UV radiation, oxidative stress, dessication, acid stress, nitrosative stress, cell envelope stress, heavy metal exposure, osmotic stress, and others. In order to survive, they have to respond to these conditions by adapting their physiology through sometimes drastic changes in gene expression. In addition they may adapt by changing their morphology, forming biofilms, fruiting bodies or spores, filaments, Viable But Not Culturable (VBNC) cells or moving away from stress compounds via chemotaxis. Changes in gene expression constitute the main component of the bacterial response to stress and environmental changes, and involve a myriad of different mechanisms, including (alternative) sigma factors, bi- or tri-component regulatory systems, small non-coding RNA’s, chaperones, CHRIS-Cas systems, DNA repair, toxin-antitoxin systems, the stringent response, efflux pumps, alarmones, and modulation of the cell envelope or membranes, to name a few. Many regulatory elements are conserved in different bacteria; however there are endless variations on the theme and novel elements of gene regulation in bacteria inhabiting particular environments are constantly being discovered. Especially in (pathogenic) bacteria colonizing the human body a plethora of bacterial responses to innate stresses such as pH, reactive nitrogen and oxygen species and antibiotic stress are being described. An attempt is made to not only cover model systems but give a broad overview of the stress-responsive regulatory systems in a variety of bacteria, including medically important bacteria, where elucidation of certain aspects of these systems could lead to treatment strategies of the pathogens. Many of the regulatory systems being uncovered are specific, but there is also considerable “cross-talk” between different circuits. Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria is a comprehensive two-volume work bringing together both review and original research articles on key topics in stress and environmental control of gene expression in bacteria. Volume One contains key overview chapters, as well as content on one/two/three component regulatory systems and stress responses, sigma factors and stress responses, small non-coding RNAs and stress responses, toxin-antitoxin systems and stress responses, stringent response to stress, responses to UV irradiation, SOS and double stranded systems repair systems and stress, adaptation to both oxidative and osmotic stress, and desiccation tolerance and drought stress. Volume Two covers heat shock responses, chaperonins and stress, cold shock responses, adaptation to acid stress, nitrosative stress, and envelope stress, as well as iron homeostasis, metal resistance, quorum sensing, chemotaxis and biofilm formation, and viable but not culturable (VBNC) cells. Covering the full breadth of current stress and environmental control of gene expression studies and expanding it towards future advances in the field, these two volumes are a one-stop reference for (non) medical molecular geneticists interested in gene regulation under stress.
Author: Shiny Martis Badiadka Publisher: ISBN: Category : Languages : en Pages : 181
Book Description
Plant pathogens are a major threat to food security all around the world. Virulence genes enable the pathogens to disease the host and pose threats. We study and computationally model the expression of virulence in pathogens. The pel genes, a major virulence factor in pectinolytic bacteria which infect plants and cause soft rot disease. The Pel enzymes released by the pathogen result in the maceration of tissue in crops and facilitate pathogenesis. We model the pel genes in our model organism Dickeya dadantii. We study pelD/E genes which encode proteins with similar enzymatic activities, but also share the same set of transcriptional regulators, thus raising the question of the benefit of this duplication and the specific role of these two genes. We model their expression with respect to the KdgR repressor and CRP activator. We develop a quantitative dynamic kinetic model of this process that reproduces the observed behavior of the two genes and explains their specific role in the infection. The regulatory part of the model is based on experimental values, and fitted kinetic parameters are subjected to systematic evaluation. The model is robust and has multiple applications for studying the pathogenesis of pectinolytic bacteria. In addition, we explore the instance of carbon catabolite repression observed during the regulation of virulence genes Dickeya dadantii. The novel antibiotic seconeolitsin is characterized in the gram negative model organism Dickeya dadantii. Growth kinetics and MIC studies are carried out. The variations in the level of supercoiling in the presence of seconeolitsin and novobiocin are quantified and analyzed. The effect of supercoiling on the expression of genes, especially the pelE gene is studied using the novel antibiotic seconeolitsin. The study explores the role of supercoiling as a gene regulator.
Author: Theresa Koehler Publisher: Springer Science & Business Media ISBN: 9783540434979 Category : Medical Languages : en Pages : 190
Book Description
Bacillus anthracis causes anthrax in all mammals, including humans. Depending upon the route of entry of B. anthracis spores, infection can result in cutaneous lesions, which are readily treatable with antibiotics, or systemic lethal disease, which is nearly always fatal. The continuing worldwide incidence of anthrax in animal populations, the risk of human infection associated with animal outbreaks, and the threat of use of B. anthracis as a biological weapon warrant continued investigation of this organisms and its virulence mechanims. Furthermore, B. anthracis is an excellent model system for inverstigation of virulence gene expression by bacteria.
Author: Matthew Leon Faron Publisher: ISBN: Category : Alveolitis Languages : en Pages : 121
Book Description
Francisella tularensis is a facultative intracellular pathogen and is the etiological agent of tularemia. One key aspect to the success of Francisella as a pathogen is ability of the organism to establish infection with a low inoculum, as few as 10 colony forming units (cfu). Essential to this process is the Francisella pathogenicity island (FPI). Several studies have been performed to understand how the FPI is regulated; however, the working model is not complete, as the signals important for regulation are unknown. Additionally, the mechanisms of the proteins MigR, TrmE, and CphA, which are important for activation of the FPI, are unknown. I initiated the study of this regulatory system by measuring the ability of various cellular stresses to activate an iglA-lacZ reporter. I identified that amino acid starvation and growth in basic pH activated expression of the reporter in both LVS and Schu S4. By combining these two stresses I was able to induce iglA-lacZ reporter expression in an additive manner. As it was previously demonstrated that ppGpp is important for stabilization of the regulatory complex that transcribes FPI genes, I demonstrated by TLC that both amino acid starvation and basic pH effected iglA-lacZ expression by increasing ppGpp. Due to the importance of ppGpp in FPI expression and because MigR, TrmE, and CphA each appear to be involved in a metabolic process: fatty acid metabolism (migR) t-RNA modification (trmE) and amino acid storage (cphA), I had hypothesized that the effect on these mutations were due to decreased levels of the small alarmone ppGpp. I compared ppGpp accumulation of LVS mutants in migR, trmE, and cphA to the parent strain and observed that loss of these genes resulted in reduced ppGpp. To better understand the importance of ppGpp synthesis in F. tularensis pathogenesis, I compared the phenotypes of these strains in primary human macrophages and two immortalized epithelial cell lines. These experiments demonstrated that although each of these strains had reduced ppGpp, there were cell line specific growth phenotypes. Mice infected with these strains survived suggesting tight regulation of the FPI is required for virulence. When similar mutations were characterized in the Schu S4 background these mutations retained their regulatory role; however, mutation of migR did not significantly decrease virulence in mice. As my data demonstrated that there are different challenges that Francisella must overcome to successfully replicate within cells, I developed an in vitro model to study the interactions of F. tularensis with human alveolar type II cells (AT-II). Interestingly, Schu S4 internalizes and replicates in these recently immortalized human AT-II cells whereas, LVS internalizes, but replicates poorly within these cells. Finally, to better understand the role of AT-II cells in vivo, I performed Transmission Electron Microscopy (TEM) of infected mice. These data confirmed that Schu S4 infected both alveolar macrophages and AT-II cells. Together, this work contributes to the understanding of how Francisella adapts to various environments by modulating virulence gene expression and highlights differences between virulent Schu S4 and LVS, which may partially contribute to virulence differences observed between strains.
Author: Juan-Luis Ramos
Author: Juan-Luis Ramos
Author: Michael L. Vasil
Author: Juan-Luis Ramos
Author: Richard P. Novick
Author: Frans J. de Bruijn
Author: Shiny Martis Badiadka
Author: Jeremy M. Yarwood
Author: Theresa Koehler
Author: Matthew Leon Faron
Author: Rosa Rong-Ying Yu