Search results for "vibrio cholerae"
showing 8 items of 28 documents
Cholesterol Specificity of Some Heptameric β-Barrel Pore-Forming Bacterial Toxins: Structural and Functional Aspects
2010
Apart from the thiol-specific/cholesterol-dependent cytolysin family of toxins (see Chapter 20) there are a number of other unrelated bacterial toxins that also have an affinity for plasma membrane cholesterol. Emphasis is given here on the Vibrio cholerae cytolysin (VCC) and the cytolysins from related Vibrio species. The inhibition of the cytolytic activity of these toxins by prior incubation with extracellular cholesterol or low density lipoprotein emerges as a unifying feature, as does plasma membrane cholesterol depletion. Incubation of VCC with cholesterol produces a heptameric oligomer, which is not equivalent to the pre-pore since it is unable to penetrate the plasma membrane. In st…
A cellular metalloproteinase activates Vibrio cholerae pro-cytolysin.
2004
Many strains of Vibrio cholerae produce a cytolysin (VCC) that forms oligomeric transmembrane pores in animal cells. The molecule is secreted as a procytolysin (pro-VCC) of 79 kDa that must be cleaved at the N terminus to generate the active 65-kDa toxin. Processing can occur in solution, and previous studies have described the action of mature VCC thus generated. However, little is known about the properties of pro-VCC itself. In this study, it is shown that pro-VCC exist as a monomer in solution and binds as a monomer to eukaryotic cells. Bound pro-VCC can then be activated either by exogenous, extracellular, or by endogenous, cell-bound proteases. In both cases, cleavage generates the 65…
Drought-related cholera outbreaks in Africa and the implications for climate change: a narrative review.
2021
ABSTRACT Africa has historically seen several periods of prolonged and extreme droughts across the continent, causing food insecurity, exacerbating social inequity and frequent mortality. A known consequence of droughts and their associated risk factors are infectious disease outbreaks, which are worsened by malnutrition, poor access to water, sanitation and hygiene and population displacement. Cholera is a potential causative agent of such outbreaks. Africa has the highest global cholera burden, several drought-prone regions and high levels of inequity. Despite this, research on cholera and drought in Africa is lacking. Here, we review available research on drought-related cholera outbreak…
Surface and virulence properties of environmental Vibrio cholerae non-O1 from Albufera Lake (Valencia, Spain).
1990
A total of 140 environmental Vibrio cholerae non-O1 isolates, together with several culture collection strains from both environmental and clinical sources, were studied in relation to hemagglutination, surface hydrophobicity, and the enzymatic, hemolytic, cytotoxic, and enterotoxic activities of their extracellular products. A total of 78 and 62% of the strains produced hemagglutinins and exohemagglutinins, respectively. Four different hemagglutinating and two exohemagglutinating activities were found by using eight sugars in the inhibition assays. Cell-bound mannose-sensitive hemagglutination was detected mainly in chicken blood, whereas fucose-sensitive hemagglutination was recorded only…
Iron-binding compounds and related outer membrane proteins in Vibrio cholerae non-O1 strains from aquatic environments
1990
A total of 156 strains of Vibrio cholerae non-O1 from aquatic origins were examined for the presence of iron uptake mechanisms and compared with O1 strains and other Vibrio species. All non-O1 strains were able to grow in iron-limiting conditions, with MICs of ethylenediaminedi (O-hydroxyphenylacetic acid) ranging from 20 microM to 2 mM. The production of siderophores was demonstrated by growth in chrome azurol S agar and cross-feeding assays. All strains produced phenolate-type compounds, as assessed by the chemical tests and by bioassays with Salmonella typhimurium enb-7. Some of the strains also promoted the growth of S. typhimurium enb-1 (which can use only enterobactin as a siderophore…
Core and Accessory Genome Analysis of Vibrio mimicus
2021
© 2021 by the authors.
Identification of the membrane penetrating domain of Vibrio cholerae cytolysin as a β-barrel structure
2005
Summary Vibrio cholerae cytolysin (VCC) is an oligomerizing pore-forming toxin that is related to cytolysins of many other Gram-negative organisms. VCC contains six cysteine residues, of which two were found to be present in free sulphydryl form. The positions of two intramolecular disulphide bonds were mapped, and one was shown to be essential for correct folding of protoxin. Mutations were created in which the two free cysteines were deleted, so that single cysteine substitution mutants could be generated for site-specific labelling. Employment of polarity-sensitive fluorophores identified amino acid side-chains that formed part of the pore-forming domain of VCC. The sequence commenced at…
Genetic relationship between clinical and environmental Vibrio cholerae isolates in Tanzania: A comparison using repetitive extragenic palindromic (R…
2015
The bacterium causing cholera, Vibrio cholerae, is a marine organism and coastal waters are important reservoirs of the organism. There are more than 200 serogroups of V. cholerae, of which serogroups O1 and O139 are known to be the causative agent of the cholera. The main virulent factor in V. cholerae is cholera toxin gene (ctx) that is found from the epidemic O1 and O139 strains, but may also be found in some strains other than O1 and O139 (non-O1 and non-O139). In this study, 48 V. cholerae strains isolated from three estuaries of Tanzania and 20 stool isolates were characterized in terms of their serogroups and possession of ctx gene and then compared using two PCR based fingerprinting…