scholarly journals Distinct Sensory Pathways in Vibrio cholerae El Tor and Classical Biotypes Modulate Cyclic Dimeric GMP Levels To Control Biofilm Formation

2008 ◽  
Vol 191 (1) ◽  
pp. 169-177 ◽  
Author(s):  
Brian K. Hammer ◽  
Bonnie L. Bassler
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Target Genes ◽  
Cell Communication ◽  
Luciferase Expression ◽  
Signal Molecules ◽  
Exopolysaccharide Production ◽  
Sensory Pathways ◽  
Pandemic Strains ◽  
El Tor

ABSTRACT Quorum sensing (QS), or cell-cell communication in bacteria, is achieved through the production and subsequent response to the accumulation of extracellular signal molecules called autoinducers (AIs). To identify AI-regulated target genes in Vibrio cholerae El Tor (V. cholerae El), the strain responsible for the current cholera pandemic, luciferase expression was assayed in an AI− strain carrying a random lux transcriptional reporter library in the presence and absence of exogenously added AIs. Twenty-three genes were identified and shown to require the QS transcription factor, HapR, for their regulation. Several of the QS-dependent target genes, annotated as encoding hypothetical proteins, in fact encode HD-GYP proteins, phosphodiesterases that degrade the intracellular second messenger cyclic dimeric GMP (c-di-GMP), which is important for controlling biofilm formation. Indeed, overexpression of a representative QS-activated HD-GYP protein in V. cholerae El reduced the intracellular concentration of c-di-GMP, which in turn decreased exopolysaccharide production and biofilm formation. The V. cholerae classical biotype (V. cholerae Cl), which caused previous cholera pandemics and is HapR−, controls c-di-GMP levels and biofilm formation by the VieA signaling pathway. We show that the VieA pathway is dispensable for biofilm formation in V. cholerae El but that restoring HapR in V. cholerae Cl reestablishes QS-dependent repression of exopolysaccharide production. Thus, different pandemic strains of V. cholerae modulate c-di-GMP levels and control biofilm formation in response to distinct sensory pathways.

scholarly journals Quorum sensing controls Vibrio cholerae multicellular aggregate formation

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Matthew Jemielita ◽  
Ned S Wingreen ◽  
Bonnie L Bassler
Keyword(s):  
Quorum Sensing ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Aggregate Size ◽  
Extracellular Dna ◽  
Signal Molecules ◽  
Aggregate Formation ◽  
Multicellular Aggregate ◽  
Canonical Surface ◽  
Pandemic Strains

Bacteria communicate and collectively regulate gene expression using a process called quorum sensing (QS). QS relies on group-wide responses to signal molecules called autoinducers. Here, we show that QS activates a new program of multicellularity in Vibrio cholerae. This program, which we term aggregation, is distinct from the canonical surface-biofilm formation program, which QS represses. Aggregation is induced by autoinducers, occurs rapidly in cell suspensions, and does not require cell division, features strikingly dissimilar from those characteristic of V. cholerae biofilm formation. Extracellular DNA limits aggregate size, but is not sufficient to drive aggregation. A mutagenesis screen identifies genes required for aggregate formation, revealing proteins involved in V. cholerae intestinal colonization, stress response, and a protein that distinguishes the current V. cholerae pandemic strain from earlier pandemic strains. We suggest that QS-controlled aggregate formation is important for V. cholerae to successfully transit between the marine niche and the human host.

scholarly journals High-Frequency Rugose Exopolysaccharide Production by Vibrio cholerae

2002 ◽  
Vol 68 (11) ◽  
pp. 5773-5778 ◽  
Author(s):  
Afsar Ali ◽  
Mohammed H. Rashid ◽  
David K. R. Karaolis
Keyword(s):  
Vibrio Cholerae ◽  
High Frequency ◽  
Biofilm Formation ◽  
Colony Morphology ◽  
Exopolysaccharide Production ◽  
Clinical Strains ◽  
Environmental Survival ◽  
El Tor

ABSTRACT Vibrio cholerae can shift to a “rugose” phenotype, thereby producing copious exopolysaccharide (EPS), which promotes its environmental survival and persistence. We report conditions that promote high-frequency rugose EPS production (HFRP), whereby cells switch at high frequency (up to 80%) to rugose EPS production. HFRP appeared to be more common in clinical strains, as HFRP was found in 6 of 19 clinical strains (32%) (including classical, El Tor, and non-O1 strains) but in only 1 of 16 environmental strains (6%). Differences were found between strains in rugose colony morphology, conditions promoting HFRP, the frequency of rugose-to-smooth (R-S) cell reversion, and biofilm formation. We propose that rugose EPS and HFRP provide an evolutionary and adaptive advantage to specific epidemic V. cholerae strains for increased persistence in the environment.

scholarly journals THE INFLUENCE OF SOME FACTORS ON THE FORMATION OF BIOFILM BY TOXIGENIC AND NON-TOXIGENIC VIBRIO CHOLERAE EL TOR STRAINS

2012 ◽  
Vol 17 (5) ◽  
pp. 36-40
Author(s):  
O. A. Tatarenko ◽  
L. P. Alekseeva ◽  
N. R. Telesmanich ◽  
I. S. Shestialtynova ◽  
O. C. Chemisova ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Culture Medium ◽  
Microtiter Plate ◽  
Medium Composition ◽  
Medium Temperature ◽  
Exopolysaccharide Production ◽  
Medium Interface ◽  
Toxigenic Strains ◽  
El Tor

The early stages of biofilm formation on polystyrene surface were studied in 14 Vibrio cholerae El Tor strains, all of which carried genes of vps cluster, mshA, and hapR genes. 13 Vibrio cholerae El Tor strains were shown to be capable of adsorption on the walls of microtiter plate wells and of ring formation at the "polystyrene-medium" interface. One of the Vibrio cholerae El Tor strains tested was defective in this ability. The use of different media - modified M1 medium and 1 per cent peptone - failed to reveal sufficient influence of culture medium composition on the ability of Vibrio cholerae to form multilayer biofilm at the phase boundary "polystyrene-medium". Temperature reduction from 37°C to 25°C also didn t result in statistically significant enhancement of monolayer formation in both media. Quantitative evaluation of biofilm formation showed that this ability was clearly marked only in two toxigenic and two non-toxigenic strains of Vibrio cholerae El Tor. Monolayer comparison in ELISA demonstrated that only two toxigenic and two non-toxigenic strains possessed the ability for exopolysaccharide production.

scholarly journals Comparison of Vibrio choleraePathogenicity Islands in Sixth and Seventh Pandemic Strains

2001 ◽  
Vol 69 (3) ◽  
pp. 1947-1952 ◽  
Author(s):  
David K. R. Karaolis ◽  
Ruiting Lan ◽  
James B. Kaper ◽  
Peter R. Reeves
Keyword(s):  
Amino Acid ◽  
Vibrio Cholerae ◽  
Virulence Factor ◽  
Virulence Genes ◽  
Preliminary Evidence ◽  
Colonization Factor ◽  
Type Iv ◽  
Factor Expression ◽  
Pandemic Strains ◽  
El Tor

ABSTRACT Epidemic Vibrio cholerae strains possess a large cluster of essential virulence genes on the chromosome called theVibrio pathogenicity island (VPI). The VPI contains thetcp gene cluster encoding the type IV pilus toxin-coregulated pilus colonization factor which can act as the cholera toxin bacteriophage (CTXΦ) receptor. The VPI also contains genes that regulate virulence factor expression. We have fully sequenced and compared the VPI of the seventh-pandemic (El Tor biotype) strain N16961 and the sixth-pandemic (classical biotype) strain 395 and found that the N16961 VPI is 41,272 bp and encodes 29 predicted proteins, whereas the 395 VPI is 41,290 bp. In addition to various nucleotide and amino acid polymorphisms, there were several proteins whose predicted size differed greatly between the strains as a result of frameshift mutations. We hypothesize that these VPI sequence differences provide preliminary evidence to help explain the differences in virulence factor expression between epidemic strains (i.e., the biotypes) of V. cholerae.

scholarly journals Multilocus genetic analysis reveals that the Australian strains of Vibrio cholerae O1 are similar to the pre-seventh pandemic strains of the El Tor biotype

2009 ◽  
Vol 58 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Ashrafus Safa ◽  
Nurul A. Bhuiyan ◽  
Denise Murphy ◽  
John Bates ◽  
Suraia Nusrin ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Genetic Screening ◽  
Phenotypic Traits ◽  
Pfge Analysis ◽  
Genotype 2 ◽  
Environmental Reservoir ◽  
Vibrio Cholerae O1 ◽  
Pandemic Strains ◽  
Genomic Regions ◽  
El Tor

Episodes of cholera stemming from indigenous Vibrio cholerae strains in Australia are mainly associated with environmental sources. In the present study, 10 V. cholerae O1 strains of Australian origin were characterized. All of the strains were serogroup O1 and their conventional phenotypic traits categorized them as belonging to the El Tor biotype. Genetic screening of 12 genomic regions that are associated with virulence in V. cholerae showed variable results. Analysis of the ctxAB gene showed that the Australian environmental reservoir contains both toxigenic and non-toxigenic V. cholerae strains. DNA sequencing revealed that all of the toxigenic V. cholerae strains examined were of ctxB genotype 2. Whole genome PFGE analysis revealed that the environmental toxigenic V. cholerae O1 strains were more diverse than the non-toxigenic environmental O1 strains, and the absence of genes that make up the Vibrio seventh pandemic island-I and -II in all of the strains indicates their pre-seventh pandemic ancestry.

scholarly journals VpsR, a Member of the Response Regulators of the Two-Component Regulatory Systems, Is Required for Expression ofvps Biosynthesis Genes and EPSETr-Associated Phenotypes in Vibrio cholerae O1 El Tor

2001 ◽  
Vol 183 (5) ◽  
pp. 1716-1726 ◽  
Author(s):  
Fitnat H. Yildiz ◽  
Nadia A. Dolganov ◽  
Gary K. Schoolnik
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Genetic Background ◽  
Bactericidal Action ◽  
Response Regulators ◽  
Targeted Disruption ◽  
Regulatory Systems ◽  
Two Component ◽  
Vibrio Cholerae O1 ◽  
El Tor

ABSTRACT The rugose colonial variant of Vibrio cholerae O1 El Tor produces an exopolysaccharide (EPSETr) that enables the organism to form a biofilm and to resist oxidative stress and the bactericidal action of chlorine. Transposon mutagenesis of the rugose variant led to the identification of vpsR, which codes for a homologue of the NtrC subclass of response regulators. Targeted disruption of vpsR in the rugose colony genetic background yielded a nonreverting smooth-colony morphotype that produced no detectable EPSETr and did not form an architecturally mature biofilm. Analysis of two genes, vpsA andvpsL, within the vps cluster of EPSETr biosynthesis genes revealed that their expression is induced above basal levels in the rugose variant, compared to the smooth colonial variant, and requires vpsR. These results show that VpsR functions as a positive regulator of vpsAand vpsL and thus acts to positively regulate EPSETr production and biofilm formation.

scholarly journals A Role for the Mannose-Sensitive Hemagglutinin in Biofilm Formation by Vibrio cholerae El Tor

1999 ◽  
Vol 181 (11) ◽  
pp. 3606-3609 ◽  
Author(s):  
Paula I. Watnick ◽  
Karla Jean Fullner ◽  
Roberto Kolter
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Molecular Basis ◽  
Genetic Basis ◽  
Survival Strategy ◽  
Host Pathogen Interactions ◽  
Abiotic Surfaces ◽  
Host Pathogen ◽  
Toxin Coregulated Pilus ◽  
El Tor

ABSTRACT While much has been learned regarding the genetic basis of host-pathogen interactions, less is known about the molecular basis of a pathogen’s survival in the environment. Biofilm formation on abiotic surfaces represents a survival strategy utilized by many microbes. Here it is shown that Vibrio cholerae El Tor does not use the virulence-associated toxin-coregulated pilus to form biofilms on borosilicate but rather uses the mannose-sensitive hemagglutinin (MSHA) pilus, which plays no role in pathogenicity. In contrast, attachment ofV. cholerae to chitin is shown to be independent of the MSHA pilus, suggesting divergent pathways for biofilm formation on nutritive and nonnutritive abiotic surfaces.

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