Characterization of the Yersinia Autotransporter Proteins (yaps) and Their Roles in the Pathogenesis of Y. Pestis PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Characterization of the Yersinia Autotransporter Proteins (yaps) and Their Roles in the Pathogenesis of Y. Pestis PDF full book. Access full book title Characterization of the Yersinia Autotransporter Proteins (yaps) and Their Roles in the Pathogenesis of Y. Pestis by Jonathan David Lenz. Download full books in PDF and EPUB format.
Author: Jonathan David Lenz
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 219
Get Book Here
Book Description
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: Jonathan David Lenz
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 219
Get Book Here
Book Description
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:
Publisher:
ISBN:
Category :
Languages : en
Pages : 35
Get Book Here
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.
Author: Hanni Lee-Lewis
Publisher:
ISBN:
Category : Electronic Dissertations
Languages : en
Pages : 174
Get Book Here
Book Description
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: Anna Maria Kolodziejek
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 354
Get Book Here
Book Description
Yersinia pestis is the causative agent of plague. Multiple virulence determinants contribute to its highly efficient transmission and pathogenicity. These include factors inherited from its enteric predecessors; Y. entrocolitica and Y. pseudotuberculosis, as well as phenotypes that were acquired or lost during Y. pestis evolution. Representatives of a large Enterobacteriaceae Ail/Lom family of outer membrane proteins (Omp) are found in the genomes of all pathogenic Yersiniae . They promote adherence and internalization to epithelial cells, resistance to complement, and survival in macrophages. Even though well studied in enteric Yersiniae, their role in Y. pestis pathogenesis is unknown. To investigate the role of Y. pestis OmpX protein, an Ail homologue, in adherence and internalization to epithelial cells, resistance to complement, and virulence, we generated site-directed mutations in ompX and tested them for loss of any of these phenotypes. Our results demonstrated that OmpX was required for adherence and internalization to epithelial cells, and serum resistance. Infection studies revealed that loss of OmpX delayed the time-to-death in the mouse infection model of pneumonic plague. Because murine serum was not bactericidal for the ompX mutant, the mechanism underlying the delay in time-to-death in mice may be attributed to loss of adhesion/internalization properties, but not serum resistance. When OmpX virulence was assessed in the rat model complete attenuation of virulence was observed. This highlighted the critical role of serum resistance in primary pneumonic plague and showed its relevance for human disease. To resolve conflicting evidence for Y. pestis LPS and OmpX contributions to serum resistance, we expressed the protein in E. coli and its isogenic derivatives with progressively truncated LPS core saccharides. Our results showed that OmpX-mediated serum resistance, adhesiveness, and invasiveness were dependent on LPS core length, but recombinant OmpX displayed these functions in E. coli, independently of other Yersinia proteins and/or LPS. Also, our results showed that OmpX-mediated autoaggregation was required for efficient adhesiveness and internalization but not for serum resistance. Overall, our data present an important contribution to understanding mechanisms of Y. pestis pathogenesis and their significance to human species.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The aim of these studies continues to be the investigation into the molecular mechanisms that underlie the virulence process in Yersinia pestis. In particular, the focus of this work centers on the identification of novel genes and pathways responsible for the pathogenic properties of this organism. In spite of more than four decades of intense investigation in this field, the dilemma as to what makes Y. pestis such a virulent and lethal pathogen remains unanswered. The method being employed makes use microarray technology (DNA chip) that enables the examination of the global activities of the whole complement of genes in this pathogen. Two primary resources available to the investigators (one directly obtained from a separate CBNP-funded project) make these studies possible: (1) Whole genome comparisons of the genes in Y. pestis and its near neighbors with attenuated or non pathogenic characteristics, and (2) the ability to duplicate in vitro, conditions that mimic the infection process of this pathogen. This year we have extended our studies from the original work of characterizing the global transcriptional regulation in Y. pestis triggered during temperature transition from 26 C to 37 C (roughly conditions found in the flea vector and the mammalian host, respectively) to studies of regulation encountered during shift between growth from conditions of neutral pH to acidic pH (the latter conditions, those mimic the environment found inside macrophages, a likely environment found by these cells during infection.). For this work, DNA arrays containing some 5,000 genes (the entire genome of Y. pestis plus those genes found uniquely in the enteropathogen, and near neighbor, Y. pseudotuberculosis) are used to monitor the simultaneous expression levels of each gene of known and unknown function in Y. pestis. Those genes that are up-regulate under the experimental conditions represent genes potentially involved in the pathogenic process. The ultimate role in pathogenicity of those candidate genes uncovered from these studies will be further ascertained by direct knock outs (gene inactivation) and by in vivo studies using an animal model. Discovery of new virulence factors in Y. pestis will directly impact the development of new signatures for detection and geo-location since it will help us to understand and identify those genes that are essential in making the organism pathogenic. These are genes that cannot be altered or removed from the pathogen and as such constitute the best type of signature that we can utilize in their detection and identification. Applications such as this will also enable the utilization of similar technologies to study other pathogens such as Francisella and Brucella, for which we know substantially less in terms of their modality of virulence.
Author: Elisabeth Carniel
Publisher: Caister Academic Press Limited
ISBN: 9781908230058
Category : Science
Languages : en
Pages : 0
Get Book Here
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:
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
Get Book Here
Book Description
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: Aarthi Karkal
Publisher:
ISBN:
Category : Gram-negative bacteria
Languages : en
Pages : 200
Get Book Here
Book Description
Author:
Publisher: ScholarlyEditions
ISBN: 1481684485
Category : Medical
Languages : en
Pages : 83
Get Book Here
Book Description
Advances in Yersinia Research and Treatment: 2013 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about Yersinia pestis in a concise format. The editors have built Advances in Yersinia Research and Treatment: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Yersinia pestis in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Yersinia Research and Treatment: 2013 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/.
Author: Klaudia Brix
Publisher: Springer Science & Business Media
ISBN: 3709108853
Category : Science
Languages : en
Pages : 568
Get Book Here
Book Description
Proteolysis is an irreversible posttranslational modification affecting each and every protein from its biosynthesis to its degradation. Limited proteolysis regulates targeting and activity throughout the lifetime of proteins. Balancing proteolysis is therefore crucial for physiological homeostasis. Control mechanisms include proteolytic maturation of zymogens resulting in active proteases and the shut down of proteolysis by counteracting endogenous protease inhibitors. Beyond the protein level, proteolytic enzymes are involved in key decisions during development that determine life and death – from single cells to adult individuals. In particular, we are becoming aware of the subtle role that proteases play in signaling events within proteolysis networks, in which the enzymes act synergistically and form alliances in a web-like fashion. Proteases come in different flavors. At least five families of mechanistically distinct enzymes and even more inhibitor families are known to date, many family members are still to be studied in detail. We have learned a lot about the diversity of the about 600 proteases in the human genome and begin to understand their physiological roles in the degradome. However, there are still many open questions regarding their actions in pathophysiology. It is in this area where the development of small molecule inhibitors as therapeutic agents is extremely promising. Approaching proteolysis as the most important, irreversible post-translational protein modification essentially requires an integrated effort of complementary research disciplines. In fact, proteolytic enzymes seem as diverse as the scientists working with these intriguing proteins. This book reflects the efforts of many in this exciting field of research where team and network formations are essential to move ahead.
