GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    The YsrS Paralog DygS Has the Capacity To Activate Expression of the Yersinia enterocolitica Ysa Type III Secretion System
    American Society for Microbiology ; 2016
    In:  Journal of Bacteriology Vol. 198, No. 12 ( 2016-06-15), p. 1725-1734
    Details
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 198, No. 12 ( 2016-06-15), p. 1725-1734
    Abstract: The Yersinia enterocolitica Ysa type III secretion system (T3SS) is associated with intracellular survival, and, like other characterized T3SSs, it is tightly controlled. Expression of the ysa genes is only detected following growth at low temperatures (26°C) and in high concentrations of sodium chloride (290 mM) in the medium. The YsrSTR phosphorelay (PR) system is required for ysa expression and likely responds to NaCl. During our investigations into the Ysr PR system, we discovered that genes YE3578 and YE3579 are remarkably similar to ysrR and ysrS , respectively, and are probably a consequence of a gene duplication event. The amino acid differences between YE3578 and ysrR are primarily clustered into two short regions. The differences between YE3579 and ysrS are nearly all located in the periplasmic sensing domain; the cytoplasmic domains are 98% identical. We investigated whether these paralogs were capable of activating ysa gene expression. We found that the sensor paralog, named DygS, is capable of compensating for loss of ysrS , but the response regulator paralog, DygR, cannot complement a ysrR gene deletion. In addition, YsrR, but not DygR, interacts with the histidine phosphorelay protein YsrT. Thus, DygS likely activates ysa gene expression in response to a signal other than NaCl and provides an example of a phosphorelay system in which two sensor kinases feed into the same regulatory pathway. IMPORTANCE All organisms need mechanisms to promote survival in changing environments. Prokaryotic phosphorelay systems are minimally comprised of a histidine kinase (HK) that senses an extracellular stimulus and a response regulator (RR) but can contain three or more proteins. Through gene duplication, a unique hybrid HK was created. We show that, while the hybrid appears to retain all of the phosphorelay functions, it responds to a different signal than the original. Both HKs transmit the signal to the same RR, which activates a promoter that transcribes a set of genes encoding a type III secretion system (T3SS) whose function is not yet evident. The significance of this work lies in finding that two HKs regulate this T3SS, highlighting its importance.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    URL: Article
    DOI: 10.1128/JB.00240-16
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2016
    detail.hit.zdb_id: 1481988-0
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Evolution and Virulence Contributions of the Autotransporter Proteins YapJ and YapK of Yersinia pestis CO92 and Their Homologs in Y. pseudotuberculosis IP32953
    American Society for Microbiology ; 2012
    In:  Infection and Immunity Vol. 80, No. 10 ( 2012-10), p. 3693-3705
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 80, No. 10 ( 2012-10), p. 3693-3705
    Abstract: Yersinia pestis , the causative agent of plague, evolved from the gastrointestinal pathogen Yersinia pseudotuberculosis . Both species have numerous type Va autotransporters, most of which appear to be highly conserved. In Y. pestis CO92, the autotransporter genes yapK and yapJ share a high level of sequence identity. By comparing yapK and yapJ to three homologous genes in Y. pseudotuberculosis IP32953 (YPTB0365, YPTB3285, and YPTB3286), we show that yapK is conserved in Y. pseudotuberculosis , while yapJ is unique to Y. pestis . All of these autotransporters exhibit 〉 96% identity in the C terminus of the protein and identities ranging from 58 to 72% in their N termini. By extending this analysis to include homologous sequences from numerous Y. pestis and Y. pseudotuberculosis strains, we determined that these autotransporters cluster into a YapK (YPTB3285) class and a YapJ (YPTB3286) class. The YPTB3286-like gene of most Y. pestis strains appears to be inactivated, perhaps in favor of maintaining yapJ . Since autotransporters are important for virulence in many bacterial pathogens, including Y. pestis , any change in autotransporter content should be considered for its impact on virulence. Using established mouse models of Y. pestis infection, we demonstrated that despite the high level of sequence identity, yapK is distinct from yapJ in its contribution to disseminated Y. pestis infection. In addition, a mutant lacking both of these genes exhibits an additive attenuation, suggesting nonredundant roles for yapJ and yapK in systemic Y. pestis infection. However, the deletion of the homologous genes in Y. pseudotuberculosis does not seem to impact the virulence of this organism in orogastric or systemic infection models.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.00529-12
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2012
    detail.hit.zdb_id: 1483247-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    A Klebsiella pneumoniae Regulatory Mutant Has Reduced Capsule Expression but Retains Hypermucoviscosity
    American Society for Microbiology ; 2019
    In:  mBio Vol. 10, No. 2 ( 2019-04-30)
    Details
    In: mBio, American Society for Microbiology, Vol. 10, No. 2 ( 2019-04-30)
    Abstract: The polysaccharide capsule is an essential virulence factor for Klebsiella pneumoniae in both community-acquired hypervirulent strains as well as health care-associated classical strains that are posing significant challenges due to multidrug resistance. Capsule production is known to be transcriptionally regulated by a number of proteins, but very little is known about how these proteins collectively control capsule production. RmpA and RcsB are two known regulators of capsule gene expression, and RmpA is required for the hypermucoviscous (HMV) phenotype in hypervirulent K. pneumoniae strains. In this report, we confirmed that these regulators performed their anticipated functions in the ATCC 43816 derivative, KPPR1S: rcsB and rmpA mutants are HMV negative and have reduced capsule gene expression. We also identified a novel transcriptional regulator, RmpC, encoded by a gene near rmpA . The Δ rmpC strain has reduced capsule gene expression but retains the HMV phenotype. We further showed that a regulatory cascade exists in which KvrA and KvrB, the recently characterized MarR-like regulators, and RcsB contribute to capsule regulation through regulation of the rmpA promoter and through additional mechanisms. In a murine pneumonia model, the regulator mutants have a range of colonization defects, suggesting that they regulate virulence factors in addition to capsule. Further testing of the rmpC and rmpA mutants revealed that they have distinct and overlapping functions and provide evidence that HMV is not dependent on overproduction of capsule. This distinction will facilitate a better understanding of HMV and how it contributes to enhanced virulence of hypervirulent strains. IMPORTANCE Klebsiella pneumoniae continues to be a substantial public health threat due to its ability to cause health care-associated and community-acquired infections combined with its ability to acquire antibiotic resistance. Novel therapeutics are needed to combat this pathogen, and a greater understanding of its virulence factors is required for the development of new drugs. A key virulence factor for K. pneumoniae is the capsule, and community-acquired hypervirulent strains produce a capsule that causes hypermucoidy. We report here a novel capsule regulator, RmpC, and provide evidence that capsule production and the hypermucoviscosity phenotype are distinct processes. Infection studies showing that this and other capsule regulator mutants have a range of phenotypes indicate that additional virulence factors are in their regulons. These results shed new light on the mechanisms controlling capsule production and introduce targets that may prove useful for the development of novel therapeutics for the treatment of this increasingly problematic pathogen.
    Type of Medium: Online Resource
    ISSN: 2161-2129 , 2150-7511
    URL: Article
    DOI: 10.1128/mBio.00089-19
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2019
    detail.hit.zdb_id: 2557172-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Identification of Two Regulators of Virulence That Are Conserved in Klebsiella pneumoniae Classical and Hypervirulent Strains
    American Society for Microbiology ; 2018
    In:  mBio Vol. 9, No. 4 ( 2018-09-05)
    Details
    In: mBio, American Society for Microbiology, Vol. 9, No. 4 ( 2018-09-05)
    Abstract: In addition to having a reputation as the causative agent for hospital-acquired infections as well as community-acquired invasive infections, Klebsiella pneumoniae has gained widespread attention as a pathogen with a propensity for acquiring antibiotic resistance. Due to the rapid emergence of carbapenem resistance among K. pneumoniae strains, a better understanding of virulence mechanisms and identification of new potential drug targets are needed. This study identified two novel regulators (KvrA and KvrB) of virulence in K. pneumoniae and demonstrated that their effect on virulence in invasive strains is likely due in part to effects on capsule production (a major virulence determinant) and hypermucoviscosity. KvrA also impacts the virulence of classical strains but does not appear to affect capsule gene expression in this strain. KvrA and KvrB are conserved among K. pneumoniae strains and thus could regulate capsule expression and virulence in diverse strains regardless of capsule type.
    Type of Medium: Online Resource
    ISSN: 2161-2129 , 2150-7511
    URL: Article
    DOI: 10.1128/mBio.01443-18
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2018
    detail.hit.zdb_id: 2557172-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Hypermucoviscosity Regulator RmpD Interacts with Wzc and Controls Capsular Polysaccharide Chain Length
    American Society for Microbiology ; 2023
    In:  mBio Vol. 14, No. 3 ( 2023-06-27)
    Details
    In: mBio, American Society for Microbiology, Vol. 14, No. 3 ( 2023-06-27)
    Abstract: Klebsiella pneumoniae is a leading cause of nosocomial infections, including pneumonia, bacteremia, and urinary tract infections. Treatment options are increasingly restricted by the high prevalence of resistance to frontline antibiotics, including carbapenems, and the recently identified plasmid-conferred colistin resistance. The classical pathotype (cKp) is responsible for most of the nosocomial infections observed globally, and these isolates are often multidrug resistant. The hypervirulent pathotype (hvKp) is a primary pathogen capable of causing community-acquired infections in immunocompetent hosts. The hypermucoviscosity (HMV) phenotype is strongly associated with the increased virulence of hvKp isolates. Recent studies demonstrated that HMV requires capsule (CPS) synthesis and the small protein RmpD but is not dependent on the increased amount of capsule associated with hvKp. Here, we identified the structure of the capsular and extracellular polysaccharide isolated from hvKp strain KPPR1S (serotype K2) with and without RmpD. We found that the polymer repeat unit structure is the same in both strains and that it is identical to the K2 capsule. However, the chain length of CPS produced by strains expressing rmpD demonstrates more uniform length. This property was reconstituted in CPS from Escherichia coli isolates that possess the same CPS biosynthesis pathway as K. pneumoniae but naturally lack rmpD. Furthermore, we demonstrate that RmpD binds Wzc, a conserved capsule biosynthesis protein required for CPS polymerization and export. Based on these observations, we present a model for how the interaction of RmpD with Wzc could impact CPS chain length and HMV. IMPORTANCE Infections caused by Klebsiella pneumoniae continue to be a global public health threat; the treatment of these infections is complicated by the high frequency of multidrug resistance. K. pneumoniae produces a polysaccharide capsule required for virulence. Hypervirulent isolates also have a hypermucoviscous (HMV) phenotype that increases virulence, and we recently demonstrated that a horizontally acquired gene, rmpD , is required for HMV and hypervirulence but that the identity of the polymeric product(s) in HMV isolates is uncertain. Here, we demonstrate that RmpD regulates capsule chain length and interacts with Wzc, a part of the capsule polymerization and export machinery shared by many pathogens. We further show that RmpD confers HMV and regulates capsule chain length in a heterologous host ( E. coli ). As Wzc is a conserved protein found in many pathogens, it is possible that RmpD-mediated HMV and increased virulence may not be restricted to K. pneumoniae .
    Type of Medium: Online Resource
    ISSN: 2150-7511
    URL: Article
    DOI: 10.1128/mbio.00800-23
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2023
    detail.hit.zdb_id: 2557172-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...