scholarly journals CTX Prophages in Classical Biotype Vibrio cholerae: Functional Phage Genes but Dysfunctional Phage Genomes

2000 ◽  
Vol 182 (24) ◽  
pp. 6992-6998 ◽  
Author(s):  
Brigid M. Davis ◽  
Kathryn E. Moyer ◽  
E. Fidelma Boyd ◽  
Matthew K. Waldor
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Virulence Factor ◽  
Experimental Results ◽  
Single Locus ◽  
Large Chromosome ◽  
Genetic Element ◽  
Functional Forms ◽  
Ctx Prophage ◽  
El Tor

ABSTRACT CTXφ is a filamentous, lysogenic bacteriophage whose genome encodes cholera toxin, the primary virulence factor produced byVibrio cholerae. CTX prophages in O1 El Tor and O139 strains of V. cholerae are found within arrays of genetically related elements integrated at a single locus within theV. cholerae large chromosome. The prophages of O1 El Tor and O139 strains generally yield infectious CTXφ. In contrast, O1 classical strains of V. cholerae do not produce CTXφ, although they produce cholera toxin and they contain CTX prophages integrated at two sites. We have identified the second site of CTX prophage integration in O1 classical strains and characterized the classical prophage arrays genetically and functionally. The genes of classical prophages encode functional forms of all of the proteins needed for production of CTXφ. Classical CTX prophages are present either as solitary prophages or as arrays of two truncated, fused prophages. RS1, a genetic element that is closely related to CTXφ and is often interspersed with CTX prophages in El Tor strains, was not detected in classical V. cholerae. Our model for CTXφ production predicts that the CTX prophage arrangements in classical strains will not yield extrachromosomal CTX DNA and thus will not yield virions, and our experimental results confirm this prediction. Thus, failure of O1 classical strains ofV. cholerae to produce CTXφ is due to overall deficiencies in the structures of the arrays of classical prophages, rather than to mutations affecting individual CTX prophage genes.

Classical RS1 and environmental RS1 elements in Vibrio cholerae O1 El Tor strains harbouring a tandem repeat of CTX prophage: revisiting Mozambique in 2005

2010 ◽  
Vol 59 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Seon Young Choi ◽  
Je Hee Lee ◽  
Eun Jin Kim ◽  
Hye Ri Lee ◽  
Yoon-Seong Jeon ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Tandem Repeat ◽  
Small Chromosome ◽  
Classical Type ◽  
Large Chromosome ◽  
New Type ◽  
Vibrio Cholerae O1 ◽  
Ctx Prophage ◽  
El Tor

Currently, Vibrio cholerae O1 serogroup biotype El Tor strains producing classical type cholera toxin (altered strains or El Tor variants) are prevalent in Asia and in Mozambique. Mozambican strains collected in 2004 contained a tandem repeat of CTX prophage on the small chromosome and each CTX prophage harboured the classical rstR and classical ctxB. We found that the majority of the strains collected in 2005 in Mozambique contained extra elements on the large chromosome in addition to the tandem repeat of CTX prophage on the small chromosome. New type RS1 elements RS1cla and RS1env, and a CTXenv with rstR env and the classical ctxB were identified on the large chromosome of the Mozambican isolates collected in 2005.

scholarly journals Multilocus variable-number tandem repeat analysis of Vibrio cholerae O1 El Tor strains harbouring classical toxin B

2010 ◽  
Vol 59 (7) ◽  
pp. 763-769 ◽  
Author(s):  
Seon Young Choi ◽  
Je Hee Lee ◽  
Yoon-Seong Jeon ◽  
Hye Ri Lee ◽  
Eun Jin Kim ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Group Iii ◽  
Repeat Analysis ◽  
Group I ◽  
Ctx Prophage ◽  
El Tor

Atypical Vibrio cholerae O1 strains – hybrid strains (strains that cannot be classified either as El Tor or classical biotype) and altered strains (El Tor biotype strains that produce classical cholera toxin) – are currently prevalent in Asia and Africa. A total of 74 hybrid and altered strains that harboured classical cholera toxin were investigated by multilocus variable-number tandem repeat analysis (MLVA). The results showed that the hybrid/altered strains could be categorized into three groups and that they were distant from the El Tor strain responsible for the seventh cholera pandemic. Hybrid/altered strains with a tandem repeat of the classical CTX prophage on the small chromosome were divided into two MLVA groups (group I: Mozambique/Bangladesh group; group III: Vietnam group), and altered strains with the RS1–CTX prophage containing the El Tor type rstR and classical ctxB on the large chromosome were placed in two MLVA groups (group II: India/Bangladesh group; group III: India/Vietnam group).

scholarly journals Genetic organization of pre-CTX and CTX prophages in the genome of an environmental Vibrio cholerae non-O1, non-O139 strain

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3633-3641 ◽  
Author(s):  
Diganta Maiti ◽  
Bhabatosh Das ◽  
Arjun Saha ◽  
Ranjan K. Nandy ◽  
G. Balakrish Nair ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genetic Locus ◽  
Single Copy ◽  
Small Chromosome ◽  
Large Chromosome ◽  
Critical Determinant ◽  
Multiple Copies ◽  
New Type ◽  
Ctx Prophage ◽  
El Tor

The cholera toxin (CT) is a critical determinant of the virulence of epidemic Vibrio cholerae strains. The ctxAB operon encoding CT is part of the genome of a filamentous bacteriophage CTXΦ, which may integrate as a single copy or as multiple copies in the genome of V. cholerae. The CTXΦ genome is composed of RS2 (2.4 kb) and core (4.5 kb) regions. In the present study extensive genetic mapping analyses indicated that two copies of tandemly arrayed CTX prophages are integrated in the small chromosome of an environmental V. cholerae strain, VCE232, belonging to serogroup O4. Further mapping revealed that the integration of prophages has occurred in the same genetic locus of the small chromosome of VCE232 as that of V. cholerae O1 biotype El Tor strains. Interestingly, a new type of RS2-like element 3.5 kb in size was found in the CTX prophage genome in the small chromosome of VCE232. Cloning followed by sequencing of the new RS2-like element of VCE232 revealed the presence of three ORFs, which probably encode highly divergent types of phage regulatory proteins. Furthermore, the strain VCE232 also harbours two copies of a tandemly arranged CTX prophage devoid of the ctxAB genes, called pre-CTX prophage, in its large chromosome. The presence of multiple copies of diverse CTX prophages in both the chromosomes of VCE232 suggests that toxigenic environmental V. cholerae non-O1, non-O139 strains could play a role in the emergence of new epidemic clones.

Molecular characterization of Vibrio cholerae O1 isolates obtained from outbreaks in the Philippines, 2015–2016

2021 ◽  
Vol 70 (11) ◽  
Author(s):  
Mark Philip Bugayong ◽  
Hidemasa Izumiya ◽  
Josie M. Bilar ◽  
Masatomo Morita ◽  
Eiji Arakawa ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
Variable Number Tandem Repeat ◽  
The Philippines ◽  
Large Chromosome ◽  
Content Type ◽  
Link Type ◽  
Mlva Type ◽  
El Tor

Introduction. The Philippines, comprising three island groups, namely, Luzon, Visayas and Mindanao, experienced an increase in cholera outbreaks in 2016. Previous studies have shown that Vibrio cholerae isolates obtained from the Philippines are novel hybrid El Tor strains that have evolved in the country and are clearly distinct from those found in Mozambique and Cameroon. Gap statement. The characterization of the strains isolated from outbreaks has been limited to phenotypic characteristics, such as biochemical and serological characteristics, in most previous studies. Aim. We performed multilocus variable-number tandem repeat (VNTR) analysis (MLVA) for V. cholerae isolates obtained from 2015 to 2016 to further characterize and understand the emergence and dissemination of the strains in the Philippines. Methodology. A total of 139 V . cholerae O1 Ogawa biotype El Tor isolates were obtained from the Philippines during diarrhoeal outbreaks in 18 provinces between 2015 and 2016. VNTR data were analysed to classify the MLVA profiles where the large-chromosome types (LCTs) were applied for grouping. Results. We identified 50 MLVA types among 139 isolates originating from 18 provinces, and 14 LCTs. The distribution of the LCTs was variable, and a few were located in specific areas or even in specific provinces. Based on eBURST analysis, 99 isolates with 7 LCTs and 32 MLVA types belonged to 1 group, suggesting that they were related to each other. LCT A was predominant (n=67) and was isolated from Luzon and Visayas. LCT A had 14 MLVA types; however, it mostly emerged during a single quarter of a year. Eight clusters were identified, each of which involved specific MLVA type(s). The largest cluster involved 23 isolates showing 3 MLVA types, 21 of which were MLVA type A-14 isolated from Negros Occidental during quarter 4 of 2016. Comparative analysis showed that almost all isolates from the Philippines were distinct from those in other countries. Conclusions. The genotypic relationship of the V. cholerae isolates obtained during outbreaks in the Philippines was studied, and their emergence and dissemination were elucidated. MLVA revealed the short-term dynamics of V. cholerae genotypes in the Philippines.

scholarly journals A Quinazoline-2,4-Diamino Analog Suppresses Vibrio cholerae Flagellar Motility by Interacting with Motor Protein PomB and Induces Envelope Stress

2013 ◽  
Vol 57 (8) ◽  
pp. 3950-3959 ◽  
Author(s):  
Hongxia Wang ◽  
Li Zhang ◽  
Anisia J. Silva ◽  
Jorge A. Benitez
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Motor Protein ◽  
Polar Flagellum ◽  
Flagellar Motility ◽  
Extracellular Rna ◽  
Content Type ◽  
Envelope Stress ◽  
Causative Agents ◽  
El Tor

ABSTRACTVibrio choleraestrains of serogroups O1 and O139, the causative agents of the diarrheal illness cholera, express a single polar flagellum powered by sodium motive force and require motility to colonize and spread along the small intestine. In a previous study, we described a high-throughput assay for screening for small molecules that selectively inhibit bacterial motility and identified a family of quinazoline-2,4-diamino analogs (Q24DAs) that (i) paralyzed the sodium-driven polar flagellum ofVibriosand (ii) diminished cholera toxin secreted by El Tor biotypeV. cholerae. In this study, we provide evidence that a Q24DA paralyzes the polar flagellum by interacting with the motor protein PomB. Inhibition of motility with the Q24DA enhanced the transcription of the cholera toxin genes in both biotypes. We also show that the Q24DA interacts with outer membrane protein OmpU and other porins to induce envelope stress and expression of the extracellular RNA polymerase sigma factor σE. We suggest that Q24DA-induced envelope stress could affect the correct folding, assembly, and secretion of pentameric cholera toxin in El Tor biotypeV. choleraeindependently of its effect on motility.

scholarly journals Vibrio cholerae LexA Coordinates CTX Prophage Gene Expression

2009 ◽  
Vol 191 (22) ◽  
pp. 6788-6795 ◽  
Author(s):  
Harvey H. Kimsey ◽  
Matthew K. Waldor
Keyword(s):  
Gene Expression ◽  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Single Site ◽  
Virion Production ◽  
Regulatory Circuit ◽  
Ctxφ Prophage ◽  
Gene Regulatory ◽  
Ctx Prophage ◽  
Operator Site

ABSTRACT The filamentous bacteriophage CTXΦ transmits the cholera toxin genes by infecting and lysogenizing its host, Vibrio cholerae. CTXΦ genes required for virion production initiate transcription from the strong P A promoter, which is dually repressed in lysogens by the phage-encoded repressor RstR and the host-encoded SOS repressor LexA. Here we identify the neighboring divergent rstR promoter, P R, and show that RstR both positively and negatively autoregulates its own expression from this promoter. LexA is absolutely required for RstR-mediated activation of P R transcription. RstR autoactivation occurs when RstR is bound to an operator site centered 60 bp upstream of the start of transcription, and the coactivator LexA is bound to a 16-bp SOS box centered at position −23.5, within the P R spacer region. Our results indicate that LexA, when bound to its single site in the CTXΦ prophage, both represses transcription from P A and coactivates transcription from the divergent P R. We propose that LexA coordinates P A and P R prophage transcription in a gene regulatory circuit. This circuit is predicted to display transient switch behavior upon induction of CTXΦ lysogens.

scholarly journals Expression of Cholera Toxin under Non-AKI Conditions in Vibrio cholerae El Tor Induced by Increasing the Exposed Surface of Cultures

2004 ◽  
Vol 186 (5) ◽  
pp. 1355-1361 ◽  
Author(s):  
Joaquín Sánchez ◽  
Gerardo Medina ◽  
Thomas Buhse ◽  
Jan Holmgren ◽  
Gloria Soberón-Chavez
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Expression Pattern ◽  
Phase 1 ◽  
Inert Atmosphere ◽  
Surface Area Ratio ◽  
Genes Encoding ◽  
El Tor

ABSTRACT The regulatory systems controlling expression of the ctxAB genes encoding cholera toxin (CT) in the classical and El Tor biotypes of pathogenic Vibrio cholerae have been characterized and found to be almost identical. Notwithstanding this, special in vitro conditions, called AKI conditions, are required for El Tor bacteria to produce CT. The AKI conditions involve biphasic cultures. In phase 1 the organism is grown in a still tube for 4 h. In phase 2 the medium is poured into a flask to continue growth with shaking. Virtually no expression of CT occurs if this protocol is not followed. Here we demonstrated that CT expression takes place in single-phase still cultures if the volume-to-surface-area ratio is decreased, both under air and under an inert atmosphere. The expression of key genes involved in the regulation of CT production was analyzed, and we found that the expression pattern closely resembles the in vivo expression pattern.

scholarly journals Resurgent Vibrio cholerae O139: Rearrangement of Cholera Toxin Genetic Elements and Amplification ofrrn Operon

1999 ◽  
Vol 67 (1) ◽  
pp. 148-154 ◽  
Author(s):  
Gopal Khetawat ◽  
Rupak K. Bhadra ◽  
Suvobroto Nandi ◽  
Jyotirmoy Das
Keyword(s):  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Indian Subcontinent ◽  
Antibiotic Sensitivity ◽  
Direct Repeat ◽  
Phenotypic Traits ◽  
Genetic Elements ◽  
Restriction Sites ◽  
Vibrio Cholerae O139 ◽  
El Tor

ABSTRACT The unprecedented genesis of a novel non-O1 Vibrio cholerae strain belonging to serogroup O139, which caused an epidemic in late 1992 in the Indian subcontinent, and its subsequent displacement by El Tor O1 vibrios after 18 months initiated a renewed investigation of the aspects of the organism that are related to pathogenesis. The reappearance of V. cholerae O139 with altered antibiotic sensitivity compared to O139 Bengal (O139B) in late 1996 has complicated the epidemiological scenario of V. cholerae and has necessitated an examination of possible rearrangements in the genome underlying such rapid changes in the phenotypic traits. With a view to investigating whether the phenotypic changes that have occurred are associated with alteration in the genome, the genome of the resurgent V. cholerae O139 (O139R) strains were examined. Pulsed-field gel electrophoresis analysis of NotI- and SfiI-digested genomic DNA of O139R isolates showed restriction fragment length polymorphism including in the cholera toxin (CTX) genetic element locus and with O139B isolates. Analyses of the organization of the CTX genetic elements in O139R strains showed that in contrast to two copies of the elements connected by two direct-repeat sequences (RS) in most of the genomes of O139B isolates, the genomes of all O139R strains examined, except strain AS192, have three such elements connected by a single RS. While the RS present in the upstream of the CTX genetic elements in the genome of O139R is of O139B origin, the RS connecting the cores of the elements has several new restriction sites and has lost theBglII site which is supposed to be conserved in all O1 strains and O139B. The endonuclease I-CeuI, which has sites only in the rrn operons in the genomes of all organisms examined so far, has 10 sites in the genomes of O139R strains, compared to 9 in the genomes of O139B strains. The recent isolates of V. cholerae O139 have thus gained one rrn operon. This variation in the number of rrn operons within a serogroup has not been reported for any other organism. The results presented in this report suggest that like the pathogenic El Tor O1 strains, the genomes of O139 strains are undergoing rapid alterations.

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