Analysis of the envelope proteins of heat-shocked Vibrio parahaemolyticus cells by immunoblotting and biotin-labeling methods

Identification of outer membrane proteins of Yersinia pestis through biotinylation

The outer membrane of Gram-negative bacteria contains proteins that might be good targets for vaccines, antimicrobials or detection systems. The identification of surface located proteins using traditional methods is often difficult. Yersinia pestis, the causative agent of plague, was labelled with biotin. Tagged proteins were visualised through streptavidin probing of Western blots. Seven biotinylated proteins of Y. pestis were identified including two porins and the putative virulence factor catalase peroxidase.

Characterization of new O3:K6 strains and phylogenetically related strains of Vibrio parahaemolyticus isolated in Taiwan and other countries

AIMS

We analysed the genetic divergence in the pandemic new O3:K6 and phylogenetically related (new O3:K6-like) strains and compare these two groups in terms of virulence and other biological traits.

METHODS AND RESULTS

A total of 160 new O3:K6, new O3:K6-like and other strains of Vibrio parahaemolyticus isolated in Taiwan and other countries were collected and their clonal relationships analysed using SfiI-pulsed-field gel electrophoresis. All of the new O3:K6 and new O3:K6-like strains were grouped in cluster I with five new patterns identified. A O6:K18 strain was identified as a new member of the new O3:K6-like strains in addition to O4:K68, O1:KUT and O1:K25 strains. All of the lipopolysaccharide preparations of the selected strains exhibited closely spaced quadruplet banding patterns with similar mobility. The two groups of strains exhibited 100% sequence identity in the internal sequences of the toxR and laf genes, and also displayed similar virulence properties as determined with a suckling mouse model.

CONCLUSIONS

The new O3:K6 and new O3:K6-like strains were highly similar in virulence and in several other phenotypical and genotypical traits.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work demonstrated the spread and divergence of the pandemic and related clone of V. parahaemolyticus with similar virulence.