Proteomic Characterization of Yersinia Pestis Virulence PDF Download
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Languages : en
Pages : 35
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Yersinia pestis, the etiological agent of plague, functions via the Type III secretion mechanism whereby virulence factors are induced upon interactions with a mammalian host. Here, the Y. pestis proteome was studied by two-dimensional differential gel electrophoresis (2-D DIGE) under physiologically relevant growth conditions mimicking the calcium concentrations and temperatures that the pathogen would encounter in the flea vector and upon interaction with the mammalian host. Over 4100 individual protein spots were detected of which hundreds were differentially expressed in the entire comparative experiment. A total of 43 proteins that were differentially expressed between the vector and host growth conditions were identified by mass spectrometry. Expected differences in expression were observed for several known virulence factors including catalase-peroxidase (KatY), murine toxin (Ymt), plasminogen activator (Pla), and F1 capsule antigen (Caf1), as well as putative virulence factors. Chaperone proteins and signaling molecules hypothesized to be involved in virulence due to their role in Type III secretion were also identified. Other differentially expressed proteins not previously reported to contribute to virulence are candidates for more detailed mechanistic studies, representing potential new virulence determinants. For example, several sugar metabolism proteins were differentially regulated in response to lower calcium and higher temperature, suggesting these proteins, while not directly connected to virulence, either represent a metabolic switch for survival in the host environment or may facilitate production of virulence factors. Results presented here contribute to a more thorough understanding of the virulence mechanism of Y. pestis through proteomic characterization of the pathogen under induced virulence.
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Publisher:
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Category :
Languages : en
Pages : 35
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Book Description
Yersinia pestis, the etiological agent of plague, functions via the Type III secretion mechanism whereby virulence factors are induced upon interactions with a mammalian host. Here, the Y. pestis proteome was studied by two-dimensional differential gel electrophoresis (2-D DIGE) under physiologically relevant growth conditions mimicking the calcium concentrations and temperatures that the pathogen would encounter in the flea vector and upon interaction with the mammalian host. Over 4100 individual protein spots were detected of which hundreds were differentially expressed in the entire comparative experiment. A total of 43 proteins that were differentially expressed between the vector and host growth conditions were identified by mass spectrometry. Expected differences in expression were observed for several known virulence factors including catalase-peroxidase (KatY), murine toxin (Ymt), plasminogen activator (Pla), and F1 capsule antigen (Caf1), as well as putative virulence factors. Chaperone proteins and signaling molecules hypothesized to be involved in virulence due to their role in Type III secretion were also identified. Other differentially expressed proteins not previously reported to contribute to virulence are candidates for more detailed mechanistic studies, representing potential new virulence determinants. For example, several sugar metabolism proteins were differentially regulated in response to lower calcium and higher temperature, suggesting these proteins, while not directly connected to virulence, either represent a metabolic switch for survival in the host environment or may facilitate production of virulence factors. Results presented here contribute to a more thorough understanding of the virulence mechanism of Y. pestis through proteomic characterization of the pathogen under induced virulence.
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Languages : en
Pages : 20
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Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Y. pseudotuberculosis and Y. enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague.
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Languages : en
Pages : 22
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A real-time reporter system was developed to monitor the thermal induction of virulence factors in Yersinia pestis. The reporter system consists of a plasmid in Y. pestis in which the expression of green fluorescent protein (GFP) is under the control of the promoters for six virulence factors, yopE, sycE, yopK, yopT, yscN, and lcrE/yopN, which are all components of the Type III secretion virulence mechanism of Y. pestis. Induction of the expression of these genes in vivo was determined by the increase in fluorescence intensity of GFP in real time. Basal expression levels observed for the Y. pestis promoters, expressed as percentages of the positive control with GFP under the control of the lac promoter, were: yopE (15%), sycE (15%), yopK (13%), yopT (4%), lcrE (3.3%) and yscN (0.8%). The yopE reporter showed the strongest gene induction following temperature transition from 26 C to 37 C. The induction levels of the other virulence factors, expressed as percentages of yopE induction, were: yopK (57%), sycE (9%), yscN (3%), lcrE (3%), and yopT (2%). The thermal induction of each of these promoter fusions was repressed by calcium, and the ratios of the initial rates of thermal induction without calcium supplementation compared to the rate with calcium supplementation were: yopE (11 fold), yscN (7 fold), yopK (6 fold), lcrE (3 fold), yopT (2 fold), and sycE (2 fold). This work demonstrates a novel approach to quantify gene induction and provides a method to rapidly determine the effects of external stimuli on expression of Y. pestis virulence factors in real time, in living cells.
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Category :
Languages : en
Pages : 48
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Yersinia pestis, the etiological agent of plague, is of concern to human health both from an infectious disease and a civilian biodefense perspective. While Y. pestis and Y. pseudotuberculosis share more than 90% DNA homology, they have significantly different clinical manifestations. Plague is often fatal if untreated, yet Y. pseudotuberculosis causes severe intestinal distress and is rarely fatal. A better understanding of host response to these closely related pathogens may help explain the different mechanisms of virulence and pathogenesis that result in such different clinical outcomes. The aim of this study was to characterize host protein expression changes in human monocyte-like U937 cells after exposure to Y. pestis and Y. pseudotuberculosis. In order to gain global proteomic coverage of host response, proteins from cytoplasmic, nuclear and membrane fractions of host cells were studied by 2-dimensional differential gel electrophoresis (2-D DIGE) and relative protein expression differences were quantitated. Differentially expressed proteins, with at least 1.5 fold expression changes and p values of 0.01 or less, were identified by MALDI-MS or LC/MS/MS. With these criteria, differential expression was detected in 16 human proteins after Y. pestis exposure and 13 human proteins after Y. pseudotuberculosis exposure, of which only two of the differentially expressed proteins identified were shared between the two exposures. Proteins identified in this study are reported to be involved in a wide spectrum of cellular functions and host defense mechanisms including apoptosis, cytoskeletal rearrangement, protein synthesis and degradation, DNA replication and transcription, metabolism, protein folding, and cell signaling. Notably, the differential expression patterns observed can distinguish the two pathogen exposures from each other and from unexposed host cells. The functions of the differentially expressed proteins identified provide insight on the different virulence and pathogenic mechanisms of Y. pestis and Y. pseudotuberculosis.
Author: Jonathan David Lenz
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 219
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Yersinia pestis CO92 has 12 open reading frames encoding putative conventional autotransporters (yaps), nine of which appear to produce functional proteins. This work provides evidence supporting the annotation of these genes as autotransporters by demonstrating that the Yaps localize to the cell surface in both E. coli and Y. pestis, and that a subset is processed by bacterial omptin proteases and released into the supernatant. Using mouse models of plague, we determined that all nine yap genes are transcribed in the lymph nodes during bubonic infection and in the lungs during pneumonic infection, suggesting a role for the Yaps during infection. Autotransporters have been implicated in the pathogenesis of numerous Gram-negative bacteria. We therefore evaluated the contribution of several yaps to the virulence of Y. pestis in mouse models of plague and found three that are important for Y. pestis virulence. The yapE gene is unique in that it is found not only in Y. pestis, but also in the related gastrointestinal pathogens Y. pseudotuberculosis and Y. enterocolitica. Deletion of yapE from Y. pestis results in decreased efficiency in lymph node colonization and disseminated spread during bubonic infection. YapE appears to function as an adhesin, as it facilitates adhesion to eukaryotic cells and bacterial auto-aggregation. yapK and yapJ are found in Y. pestis and share high sequence identity, but only yapK is found in Y. pseudotuberculosis, along with two homologs not found in Y. pestis (YPTB3285 and YPTB3286). Phylogenetic analysis indicates that members of this family cluster as either YapK-like (YapK, YPTB0365, YPTB3285) or YapJ-like (YapJ, YPTB3286), while sharing>96% amino acid identity in their C-termini and 58-72% in their N-termini. Deletion of all yapJ/yapK homologous in Y. pseudotuberculosis does not seem to impact virulence in orogastric or systemic infection models, but yapK and yapJ make non-redundant contributions to systemic Y. pestis infection. Further work aims to elucidate the specific functions of the Yaps and clarify the contributions of these proteins to Y. pestis pathogenesis.
Author: Elisabeth Carniel
Publisher: Caister Academic Press Limited
ISBN: 9781908230058
Category : Science
Languages : en
Pages : 0
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Book Description
Three members of the genus Yersinia are important human pathogens, causing diseases ranging from the deadly Plague (Yersinia pestis) to a relatively mild gastroenteritis (Y. enterocolitica and Y. pseudotuberculosis). Plague, a re-emerging disease, is endemic in many parts of the world. The extraordinary pathogenicity of Y. pestis makes it a potential bioterrorist weapon. On the other hand, the two enteropathogenic Yersinia species represent the third most common bacterial cause of gastroenteritis in Europe and probably elsewhere, although their prevalence is largely underestimated. This, and the emergence of antibiotic resistant Y. pestis in recent years, highlights the urgency to understand the mechanisms of pathogenicity and the need to devise new strategies for the prevention and control of human pathogenic Yersinia. In this book, leading Yersinia researchers review the hot topics in the systems biology and the control of these important bacteria. Topics include: transcriptome analysis of the bacterial response to the host, and of the host response, to a Yersinia infection * proteome analysis of the bacterial and host responses * treatment and antibiotic resistance * vaccines * surveillance * control. The book will be essential reading for everyone working on Yersinia and related organisms. It is recommended reading for researchers interested in biodefense, microbial genomics, and the evolution of microbial virulence.
Author: Hanni Lee-Lewis
Publisher:
ISBN:
Category : Electronic Dissertations
Languages : en
Pages : 174
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The extreme virulence of Yersinia pestis in all three forms of plague disease is attributed to its multiple virulence factors. Y. pestis pathogenesis research often focuses on characterization of these factors to better understand their regulation and mechanisms, in hopes of identifying potential targets useful for development of therapeutic and preventative options. Concern regarding a potential outbreak of Y. pestis disease in the form of pneumonic plague has led to heightened focus on elucidating the pathogenesis of this specific form of disease. In the studies presented here, we describe our discovery of the pigmentation (pgm) locus as containing one or multiple virulence factors necessary for the development of pneumonic plague. Pgm-deficient strains are commonly used for plague pathogenesis research due to its exclusion from select agent restrictions. However, our results have demonstrated its inapplicability as a model for pneumonic plague research as pgm-deficient strains are unable to cause respiratory disease. Further characterization of the siderophore-producing yersiniabactin (Ybt) system located in the pgm locus identified the Ybt siderophore as playing an essential role in bacterial growth within the lungs as well as potential immunomodulation of the host response. Additional studies to better understand the exact mechanism behind the effects of Ybt are needed to determine whether knowledge of this virulence factor can be used to our advantage in treatment and prevention.
Author: Matthew S. Francis
Publisher: Frontiers E-books
ISBN: 288919258X
Category : Infectious and parasitic diseases
Languages : en
Pages : 200
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From early studies of the plague causing agent through to comparatively more recent research defining aspects of the type III secretion mechanism, pathogenic Yersinia have served as an inventive model organism for researchers seeking to understand the complexities of bacteria-host cell interactions. In fact, seminal studies on Yersinia virulence mechanisms contributed to the emergence and recognition of the research field – cellular microbiology. Researching Yersinia infection biology continues to bring to light novel discoveries. Assortments of Yersinia whole genome sequencing projects are providing unparalleled insight into bacterial pathogen evolution and environmental adaptation. This is enabling researchers to identify and define more fascinating virulence and/or survival mechanisms that advance and expand existing perceptions of bacterial-host encounters. Current research is also beginning to bring to light how the pathogenic Yersiniae respond to physicochemical environmental cues to spatially and temporally control their armoury of customized virulence/survival factors. This Research Topic is therefore focused on presenting and summarizing new developments in Yersinia pathogenicity through highlighting cutting-edge studies on the Yersinia-host cell interaction and the network of regulatory control mechanisms that define this outcome. It will also endeavour to address how such findings might influence selection of potential targets for the design and development of anti-Yersinia therapeutic drugs and vaccines, as well as identify translational studies that involve unique and rewarding cooperation between diverse disciplines
Author: Haroun N. Shah
Publisher: John Wiley & Sons
ISBN: 1118960238
Category : Science
Languages : en
Pages : 850
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This book highlights the triumph of MALDI-TOF mass spectrometry over the past decade and provides insight into new and expanding technologies through a comprehensive range of short chapters that enable the reader to gauge their current status and how they may progress over the next decade. This book serves as a platform to consolidate current strengths of the technology and highlight new frontiers in tandem MS/MS that are likely to eventually supersede MALDI-TOF MS. Chapters discuss: Challenges of Identifying Mycobacterium to the Species level Identification of Bacteroides and Other Clinically Relevant Anaerobes Identification of Species in Mixed Microbial Populations Detection of Resistance Mechanisms Proteomics as a biomarker discovery and validation platform Determination of Antimicrobial Resistance using Tandem Mass Spectrometry
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ISBN:
Category :
Languages : en
Pages : 463
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