The toxin-coregulated pilus (TCP) of Vibrio cholerae: molecular cloning of genes involved in pilus biosynthesis and evaluation of TCP as a protective antigen in the infant mouse model

1989 ◽  
Vol 7 (6) ◽  
pp. 437-448 ◽  
Author(s):  
Dharam P. Sharma ◽  
Uwe H. Stroeher ◽  
Connor J. Thomas ◽  
Paul A. Manning ◽  
Stephen R. Attridge
Microbiology ◽  
2021 ◽  
Vol 167 (10) ◽  
Author(s):  
Mengting Shi ◽  
Yue Zheng ◽  
Xianghong Wang ◽  
Zhengjia Wang ◽  
Menghua Yang

Vibrio cholerae the causative agent of cholera, uses a large number of coordinated transcriptional regulatory events to transition from its environmental reservoir to the host intestine, which is its preferred colonization site. Transcription of the mannose-sensitive haemagglutinin pilus (MSHA), which aids the persistence of V. cholerae in aquatic environments, but causes its clearance by host immune defenses, was found to be regulated by a yet unknown mechanism during the infection cycle of V. cholerae . In this study, genomic expression library screening revealed that two regulators, VC1371 and VcRfaH, are able to positively activate the transcription of MSHA operon. VC1371 is localized and active in the cell membrane. Deletion of vc1371 or VcrfaH genes in V. cholerae resulted in less MshA protein production and less efficiency of biofilm formation compared to that in the wild-type strain. An adult mouse model showed that the mutants with vc1371 or VcrfaH deletion colonized less efficiently than the wild-type; the VcrfaH deletion mutant showed less colonization efficiency in the infant mouse model. The findings strongly suggested that the two regulators, namely VC1371 and VcRfaH, which are involved in the regulation of MSHA expression, play an important role in V. cholerae biofilm formation and colonization in mice.


2005 ◽  
Vol 73 (8) ◽  
pp. 4461-4470 ◽  
Author(s):  
Thomas J. Kirn ◽  
Ronald K. Taylor

ABSTRACT Vibrio cholerae causes diarrhea by colonizing the human small bowel and intoxicating epithelial cells. Colonization is a required step in pathogenesis, and strains defective for colonization are significantly attenuated. The best-characterized V. cholerae colonization factor is the toxin-coregulated pilus (TCP). It has been demonstrated that TCP is required for V. cholerae colonization in both humans and mice. TCP enhances bacterial interactions that allow microcolony formation and thereby promotes survival in the intestine. We have recently discovered that the TCP biogenesis apparatus also serves as a secretion system, mediating the terminal step in the extracellular secretion pathway of TcpF. TcpF was identified in classical isolates of V. cholerae O1 as a soluble factor essential for colonization in the infant mouse cholera model. In the present study, we expanded our analysis of TcpF to include the O1 El Tor and O139 serogroups and investigated how TCP and TcpF act together to mediate colonization. Additionally, we demonstrated that antibodies generated against TcpF are protective against experimental V. cholerae infection in the infant mouse cholera model. This observation, coupled with the fact that TcpF is a potent mediator of colonization, suggests that TcpF should be considered as a component of a polyvalent cholera vaccine formulation.


2004 ◽  
Vol 72 (10) ◽  
pp. 6050-6060 ◽  
Author(s):  
Ronald K. Taylor ◽  
Thomas J. Kirn ◽  
Michael D. Meeks ◽  
Terri K. Wade ◽  
William F. Wade

ABSTRACT Vibrio cholerae is a gram-negative bacterium that has been associated with cholera pandemics since the early 1800s. Whole-cell, killed, and live-attenuated oral cholera vaccines are in use. We and others have focused on the development of a subunit cholera vaccine that features standardized epitopes from various V. cholerae macromolecules that are known to induce protective antibody responses. TcpA protein is assembled into toxin-coregulated pilus (TCP), a type IVb pilus required for V. cholerae colonization, and thus is a strong candidate for a cholera subunit vaccine. Polypeptides (24 to 26 amino acids) in TcpA that can induce protective antibody responses have been reported, but further characterization of their amino acid targets relative to tertiary or quaternary TCP structures has not been done. We report a refinement of the TcpA sequences that can induce protective antibody. One sequence, TcpA 15 (residues 170 to 183), induces antibodies that bind linear TcpA in a Western blot as well as weakly bind soluble TcpA in solution. These antibodies bind assembled pili at high density and provide 80 to 100% protection in the infant mouse protection assay. This is in sharp contrast to other anti-TcpA peptide sera (TcpA 11, TcpA 13, and TcpA 17) that bind very strongly in Western blot and solution assays yet do not provide protection or effectively bind TCP, as evidenced by immunoelectron microscopy. The sequences of TcpA 15 that induce protective antibody were localized on a model of assembled TCP. These sequences are centered on a site that is predicted to be important for TCP structure.


2005 ◽  
Vol 73 (10) ◽  
pp. 6674-6679 ◽  
Author(s):  
Ashfaqul Alam ◽  
Regina C. LaRocque ◽  
Jason B. Harris ◽  
Cecily Vanderspurt ◽  
Edward T. Ryan ◽  
...  

ABSTRACT It has previously been shown that passage of Vibrio cholerae through the human intestine imparts a transient hyperinfectious phenotype that may contribute to the epidemic spread of cholera. The mechanism underlying this human-passaged hyperinfectivity is incompletely understood, in part due to inherent difficulties in recovering and studying organisms that are freshly passed in human stool. Here, we demonstrate that passage of V. cholerae through the infant mouse intestine leads to an equivalent degree of hyperinfectivity as passage through the human host. We have used this infant mouse model of host-passaged hyperinfectivity to characterize the timing and the anatomic location of the competitive advantage of mouse-passaged V. cholerae as well as the contribution of three type IV pili to the phenotype.


2004 ◽  
Vol 186 (15) ◽  
pp. 5167-5171 ◽  
Author(s):  
Carlos G. Osorio ◽  
Hector Martinez-Wilson ◽  
Andrew Camilli

ABSTRACT We made single and combined mutations in ompU, ompT, and the two putative porin genes vca1008 and vc0972. The fitness of the strains was tested in vitro and in the infant mouse model of intestinal infection. We also studied the transcriptional induction of vca1008 in vitro and during mouse infection. We show that vca1008 is induced during infection and is necessary and sufficient (in the absence of ompU, ompT, and vc0972) for infection.


mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Alexandra R. Mey ◽  
Heidi A. Butz ◽  
Shelley M. Payne

ABSTRACTToxR is a major virulence gene regulator inVibrio cholerae. Although constitutively expressed under many laboratory conditions, our previous work demonstrated that the level of ToxR increases significantly when cells are grown in the presence of the 4 amino acids asparagine, arginine, glutamate, and serine (NRES). We show here that the increase in ToxR production in response to NRES requires the Var/Csr global regulatory circuit. The VarS/VarA two-component system controls the amount of active CsrA, a small RNA-binding protein involved in the regulation of a wide range of cellular processes. Our data show that avarAmutant, which is expected to overproduce active CsrA, had elevated levels of ToxR in the absence of the NRES stimulus. Conversely, specific amino acid substitutions in CsrA were associated with defects in ToxR production in response to NRES. These data indicate that CsrA is a positive regulator of ToxR levels. Unlike previously described effects of CsrA on virulence gene regulation, the effects of CsrA on ToxR were not mediated through quorum sensing and HapR. CsrA is likely essential inV. cholerae, since a complete deletion ofcsrAwas not possible; however, point mutations in CsrA were tolerated well. The CsrA Arg6His mutant had wild-type growthin vitrobut was severely attenuated in the infant mouse model ofV. choleraeinfection, showing that CsrA is critical for pathogenesis. This study has broad implications for our understanding of howV. choleraeintegrates its response to environmental cues with the regulation of important virulence genes.IMPORTANCEIn order to colonize the human host,Vibrio choleraemust sense and respond to environmental signals to ensure appropriate expression of genes required for pathogenesis. Uncovering howV. choleraesenses its environment and activates its virulence gene repertoire is critical for our understanding of howV. choleraetransitions from its natural aquatic habitat to the human host. Here we demonstrate a previously unknown link between the global regulator CsrA and the majorV. choleraevirulence gene regulator ToxR. The role of CsrA in the cell is to receive input from the environment and coordinate an appropriate cellular response. By linking environmental sensing to the ToxR regulon, CsrA effectively acts as a switch that controls pathogenesis in response to specific signals. We demonstrate that CsrA is critical for virulence in the infant mouse model ofV. choleraeinfection, consistent with its role as anin vivoregulator of virulence gene expression.


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