Gene Analysis of <i>Vibrio cholerae</i> NAGV14 Pilus and Its Distribution

Kuroki, Hiromi; Toma, Claudia; Nakasone, Noboru; Yamashiro, Tetsu; Iwanaga, Masaaki

doi:10.1111/j.1348-0421.2001.tb02640.x

Cited by 6 publications

(17 citation statements)

References 49 publications

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“…2) and low overall similarity, as is typical in comparisons of type IV-A pili (37). The closest known relatives to PilA are VcfA (20) and MshA (19,26) from V. cholerae. PilA and MshA were 33% identical and 52% similar over 56 N-terminal residues.…”

Section: Resultsmentioning

confidence: 99%

“…We have cloned a gene, designated pilA, from V. fischeri that encodes an ORF resembling type IV-A pili, the nearest known relatives of which are the mannosesensitive pilins VcfA (20) and MshA (19,26) of V. cholerae. Because previous studies (16,27) suggested a role of mannoserecognizing adhesins in the establishment of this symbiosis, we assessed the symbiotic competence of pilA mutants.…”

Section: Discussionmentioning

confidence: 99%

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Contribution of pilA to Competitive Colonization of the Squid Euprymna scolopes by Vibrio fischeri

Stabb

Ruby

2003

Appl Environ Microbiol

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Vibrio fischeri colonizes the squid Euprymna scolopes in a mutualistic symbiosis. Hatchling squid lack these bacterial symbionts, and V. fischeri strains must compete to occupy this privileged niche. We cloned a V. fischeri gene, designated pilA, that contributes to colonization competitiveness and encodes a protein similar to type IV-A pilins. Unlike its closest known relatives, Vibrio cholerae mshA and vcfA, pilA is monocistronic and not clustered with genes associated with pilin export or assembly. Using wild-type strain ES114 as the parent, we generated an in-frame pilA deletion mutant, as well as pilA mutants marked with a kanamycin resistance gene. In mixed inocula, marked mutants were repeatedly outcompeted by ES114 (P < 0.05) but not by an unmarked pilA mutant, for squid colonization. In contrast, the ratio of mutant to ES114 CFUs did not change during 70 generations of coculturing. The competitive defect of pilA mutants ranged from 1.7-to 10-fold and was more pronounced when inocula were within the range estimated for V. fischeri populations in Hawaiian seawater (200 to 2,000 cells/ml) than when higher densities were used. ES114 also outcompeted a pilA mutant by an average of twofold at lower inoculum densities, when only a fraction of the squid became infected, most by only one strain. V. fischeri strain ET101, which was isolated from Euprymna tasmanica and is outcompeted by ES114, lacks pilA; however, 11 other diverse V. fischeri isolates apparently possess pilA. The competitive defect of pilA mutants suggests that cell surface molecules may play important roles in the initiation of beneficial symbioses in which animals must acquire symbionts from a mixed community of environmental bacteria.All animals and plants are hosts to a native microbiota. These microbial symbionts often contribute to the normal health and development of their respective hosts in exchange for a relatively privileged niche. Many plant and animal symbionts are transmitted horizontally, through the environment after embryogenesis, and are not directly inherited through germplasm from the previous generation. Therefore, with each host generation, environmental bacteria must compete to colonize the empty niches within new host individuals. In perhaps the best-studied example of such competition, mixed communities of rhizobia compete for access to the roots and nodules of leguminous plants. Many complex traits, including antibiotic production, motility, and specific cell surface attributes contribute to the nodulation competitiveness of rhizobial strains (3,9,41,46). Less is known about the competition between environmental bacteria for colonization of animal hosts, especially the natural modes of infection by the native, nonpathogenic microbiota.The light organ symbiosis between the luminescent bacterium Vibrio fischeri and the nocturnal Hawaiian squid Euprymna scolopes serves as a model chronic, mutualistic association between extracellular bacteria and animal epithelia (32,43). At the time of hatching, the light organs of juvenile...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Contribution of pilA to Competitive Colonization of the Squid Euprymna scolopes by Vibrio fischeri

Stabb

Ruby

2003

Appl Environ Microbiol

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“…In a previous study, we analyzed the nucleotide sequence of the major pilin subunit of NAGV14 pilus (VcfA) and studied the distribution of NAGV14 vcfA among V. cholerae strains by PCR. Only 4% of the V. cholerae non‐O1, non‐O139 strains tested were positive, while all V. cholerae O1 and all O139 strains were negative [15]. This result suggested that other pilin subunit(s) might be responsible for the cross‐reactivity observed previously in the whole cell lysates of V. cholerae O1 strains [14].…”

Section: Introductionmentioning

confidence: 79%

“…Escherichia coli XL‐1 Blue and M15[pREP4] were used as recombinant host strains. V. cholerae O34 strain 88UDT119, which also possesses NAGV14 pili [15], was used as a host strain for construction of a hyperpiliated strain. Other strains stocked in our laboratory were used for PCR analysis.…”

Section: Methodsmentioning

confidence: 99%

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Minor pilin subunits are conserved inVibrio choleraetype IV pili

Toma¹,

Kuroki²,

Nakasone³

et al. 2002

FEMS Immunology &Amp; Medical Microbiology

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The nucleotide sequences of five open reading frames within the Vibrio cholerae NAGV14 type IV pilus gene cluster were determined. The genes showed high homology to the mannose-sensitive hemagglutinin (MSHA) pilus genes mshB, mshC, mshD, mshO and mshP. PCR analysis showed that a MSHA-like gene cluster is highly conserved among different V. cholerae strains, with the exception of the previously reported major pilin subunit. Recombinant MshB and MshO proteins were purified and specific antiserum was raised to each of them. Western blotting analyses showed that these antisera reacted with purified NAGV14 and MSHA pili. The results suggested that MshB and MshO are minor components of the pilus fiber. Although there was no cross-reaction between the major pilin subunits of NAGV14 and MSHA pili, minor components seemed to be highly homologous and immunologically cross-reactive.

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