Persistence of plasmids, cholera toxin genes, and prophage DNA in classical Vibrio cholerae O1

Cook, W. L.; Wachsmuth, Kaye; Johnson, Steven Ross; Birkness, Kristin A.; Samadi, A R

doi:10.1128/iai.45.1.222-226.1984

Cited by 45 publications

(24 citation statements)

References 16 publications

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“…This element was designated the TLC (toxin-linked cryptic) element because it is adjacent to the CTX prophage on the V. cholerae chromosome. The size and low copy number of pTLC suggest that it is identical to the three megadalton plasmid identi®ed by Cook et al (1984) in many classical V. cholerae strains and the`small cryptic plasmid' identi-®ed by Bartowsky and Manning (1988) in classical strain V58.…”

Section: Discussionmentioning

confidence: 98%

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Replication and integration of a Vibrio cholerae cryptic plasmid linked to the CTX prophage

Rubín¹,

Lin²,

Mekalanos³

et al. 1998

Molecular Microbiology

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SummaryWe identi®ed a 4.7 kb cryptic plasmid in all ctxAB Vibrio cholerae strains we tested. An isolate of the V. cholerae classical biotype strain O395 that harbours the cryptic plasmid at high copy number was found. Hybridization analysis demonstrated that sequences highly related or identical to this plasmid exist in all toxigenic strains of V. cholerae but were notably absent in all non-toxigenic environmental isolates that lacked the genes for toxin-co-regulated pili and the ®lamen-tous CTX prophage. Accordingly, we have named the cryptic plasmid pTLC for toxin-linked cryptic. The complete nucleotide sequence of pTLC from the highcopy-number isolate was determined. The largest open reading frame in the plasmid is predicted to encode a protein similar to the replication initiation protein (pII) of Escherichia coli F-speci®c ®lamentous phages. The nucleotide sequence of pTLC also facilitated the structural characterization of the DNA homologous to pTLC in other strains of V. cholerae. pTLC-related DNA exists in these strains as both low-copy-number, covalently closed circular DNA and tandemly duplicated, chromosomally integrated DNA. Remarkably, the chromosomally integrated form of pTLC is adjacent to the CTX prophage. The strain distribution, chromosomal location and DNA sequence of pTLC suggests that it may be a genetic element that plays some role in the biology of CTXf, perhaps facilitating either its acquisition or its replication.

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Section: Discussionmentioning

confidence: 98%

“…Southern blot analysis demonstrates that integration occurs into the chromosomal copy of the TLC element (not shown). However, when p9A is introduced into a V. cholerae O1 strain that lacks any TLC-related sequences, strain 468±83 (Cook et al, 1984), all TLC hybridizing DNA is detected as plasmid (Fig. 3B).…”

Section: Ptlc Encodes Replication Functionsmentioning

confidence: 99%

Replication and integration of a Vibrio cholerae cryptic plasmid linked to the CTX prophage

Rubín¹,

Lin²,

Mekalanos³

et al. 1998

Molecular Microbiology

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“…DNA-DNA hybridization with V. cholerae prophages VcA-1 and VcA-2. V. cholerae is known to be lysogenized by at least three mutagenic prophages, VcA-1, VcA-2 (12), and VcA-3 (5). Since prophages are excised at a frequency very similar to the frequency with which the spontaneous nonmotile mutants were detected (ca.…”

Section: Resultsmentioning

confidence: 99%

High-frequency spontaneous mutation of classical Vibrio cholerae to a nonmotile phenotype

Mostow

Richardson

1990

Infect Immun

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The species Vibrio cholerae contains within it two biotypes, classical and El Tor, both of which are motile. Phenotypic expression of motility was unaffected by type of growth medium, salt concentration, pH, or temperature of incubation. However, seven strains of classical V. cholerae produced spontaneous nonmotile mutants at an unusually high frequency (ca. 10-4), while no mutants were detected for all three El Tor strains examined. No revertants of these nonmotile mutants were detected. Four independent mutants of classical strain 395 were isolated to characterize this phenomenon. By transmission electron microscopy, one of the nonmotile mutants was found to be flagellated, while the other three were found to be aflagellate. Chromosomal DNA from the mutants and parental wild-type strain 395 was exatnined by Southern blot analysis with, as probes, V. cholerae mutagenic prophages VcA-1 and VcA-2 and six cloned motility gene regions isolated from transposon insertion motility mutants of strains 395 and N16961 (El Tor, Inaba). The parental wild-type strain and all of the mutants exhibited the same pattern of bands when probed with VcA-1 and VcA-2 DNAs. Four of the cloned motility gene regions hybridized to the same fragments of DNA in both the wild-type and mutant isolates. However, two other probes detected a new fragment for a single aflagellate mutant. The observations that spontaneous nonmotile mutants occurred at a high frequency and that these mutants did not revert at a detectable frequency suggested that a genetic event is involved. The phenomenon appears to be limited to classical V. cholerae and may explain why classical V. cholerae is only sporadically associated with disease in the current pandemic.

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“…The arrangement of the CTX prophages with one CTX prophage in each of two replicons [2,5] is a constant pattern for the classical biotype strains unlike the El Tor O1 and O139 strains where diverse arrangements of the CTX prophages have been reported [18,19]. Even the classical O1 strains which reemerged in Bangladesh in 1979 had identical copy numbers and organization of the CTX prophages [20]. Analysis of the Southern blot of using ctx probe and enzymes HindIII, BglII and PstI showed heterogeneity among the V. cholerae strains.…”

Section: Rflp Of Ctx Genetic Elementmentioning

confidence: 98%

Diversity in the arrangement of the CTX prophages in classical strains of Vibrio cholerae O1

Basu

2000

FEMS Microbiology Letters

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This study reports the results of a molecular analysis of the CTX prophages in classical biotype strains of Vibrio cholerae O1 of clinical origin isolated between 1970 and 1979 in India. All strains were sensitive to group IV classical phage and polymyxin B but resistant to group 5 El Tor phage. These phenotypic traits are consistent to that exhibited by the classical biotype. PCR studies reconfirmed their biotype assignment and showed the presence of intact CTX prophages and the presence of the recently described toxin linked cryptic plasmid. Restriction fragment length polymorphism of rRNA genes and pulsed-field gel electrophoresis showed clonal diversity among the strains. The most notable observation was the finding that one strain (GP13) has three CTX prophages while another (GP147) has four CTX prophages. This is the first time heterogeneity is reported in the arrangement of the CTX prophages among classical strains of V. cholerae O1. ß

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Persistence of plasmids, cholera toxin genes, and prophage DNA in classical Vibrio cholerae O1

Cited by 45 publications

References 16 publications

Replication and integration of a Vibrio cholerae cryptic plasmid linked to the CTX prophage

Replication and integration of a Vibrio cholerae cryptic plasmid linked to the CTX prophage

High-frequency spontaneous mutation of classical Vibrio cholerae to a nonmotile phenotype

Diversity in the arrangement of the CTX prophages in classical strains of Vibrio cholerae O1

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