The haemolysin of a Kanagawa-phenomenon-positive Vibrio parahaemolyticus strain was purified to apparent homogeneity by acid precipitation, DEAE-Trisacryl, hydroxyapatite and FPLC (Mono-Q) columns: 1.4 micrograms of protein gave a single band on conventional SDS-PAGE with silver staining. The haemolysin was not inactivated by heating for 10 min at 100 degrees C. It was a monomeric protein with a molecular weight estimated to be 29 kDa by PAGE under denaturing and non-denaturing conditions. The haemolysin caused fluid accumulation in the ligated mouse ileum, was cytolytic against cultured mammalian cells and also lysed erythrocytes of various animal species (equine erythrocytes being the most resistant).

Chromatography, DEAE-Cellulose↗

PubMedDate not supplied

Genetic basis of trimethoprim and O/129 resistance in Vibrio cholerae.

Because of its important consequences on prophylaxis and therapy of cholera and on bacterial identification, we have studied the genetic basis of cross-resistance to trimethoprim and O/129 of strains of Vibrio cholerae O1 independently isolated in Africa. Two classes of bacteria were found. In the first class, the strains were also resistant to ampicillin and kanamycin and to high levels of streptomycin by synthesis of a 3"- or 6-aminoglycoside phosphotransferase. The strains hybridized weakly with a Tn7 probe and all the resistance characters were transferable en bloc to Escherichia coli. The second class included strains which, in addition to trimethoprim and O/129, were resistant to moderate levels of streptomycin and spectinomycin by production of a 3",9-aminoglycoside-aminocyclitol adenylyltransferase. The resistance characters were not self-transferable to E. coli and the host strain hybridized strongly with Tn7. It therefore appears, that both plasmids and transposons are responsible for the dissemination of resistance to trimethoprim and O/129 in Vibrio.

Anti-Bacterial Agents↗

PubMedDate not supplied

Study of the haemolytic process and receptors of thermostable direct haemolysin from Vibrio parahaemolyticus.

The haemolytic action of 125I-labelled thermostable direct haemolysin from Vibrio parahaemolyticus was studied on human and equine erythrocytes. In the first step, the haemolysin bound to the membranes of both erythrocyte species. This binding seemed temperature-independent. Then, for human erythrocytes, haemolysin produced cell disruption, and haemoglobin was released. Following this step, haemolysin was also released in a temperature-dependent manner. In contrast, equine erythrocytes were not disrupted, and no release of haemolysin occurred. The receptors of labelled haemolysin were analysed by assaying the lipid/toxin interaction on a nylon membrane and by binding on thin-layer chromatograms. the ganglioside asialo-GM2 was found to be the most potent receptor, but asialo-GM1 and lactocerebroside may also have been involved.

Animals↗

PubMedDate not supplied

[A comparison of the serological effects of classical cholera vaccine and of purified fraction vaccine, with or without simultaneous yellow fever vaccine (author's transl)].

In order to test whether simultaneously administered cholera vaccine has a depressive effect on yellow fever vaccine, a controlled trial was undertaken on school-age children in the South-Central Province of Cameroun. In addition to this principle objective, the study also permitted a comparison of the serological response in subjects vaccinated with classical cholera vaccine and in those vaccinated with a purified fraction vaccine, either with or without simultaneous yellow fever vaccine. The evaluation was measured by changes in vibriocidal antibodies and cholera agglutinins 30 days after vaccination. Only subjects without cholera antibodies prior to the study, were included. 1) Results obtained by assay of vibriocidal antibodies. It was confirmed that, no matter which cholera vaccine was used, the simultaneous administration of yellow fever vaccine had no influence on the percentage of subjects showing a significant rise in vibriocidal antibodies (4-fold increase in titre) following vaccination. In addition, in this study the purified fraction vaccine resulted in a significantly higher rate of seroconversion than did the classical vaccine. However, in comparison to other studies using classical cholera vaccine, our figures for seroconversion after purified fraction vaccine show very little, if any, differences. 2) Results obtained by assay of agglutinating antibodies. When measured by this method, there was a high frequency of non-reactors to the vaccines. This may be attributed to the date of the post vaccination blood speciment (30th day after vaccination). It has been shown that agglutinins decay rapidly after the 15th day following clinical cholera. Thus, the late date of the second speciment after vaccination could explain why we were unable to show any difference in the level of agglutinin after either classical or purified cholera vaccination. The simultaneous administration of the yellow fever vaccine did not influence the titre of agglutinins induced by the classic cholera vaccine. On the other hand, using the association, the seroconversion rate as observed on the 30th day post vaccination was significantly higher than that observed when the fraction was administered alone. If one accepts the generally admitted specificity of the agglutination reaction after clinical disease, two hypotheses can be considered: a) the yellow fever vaccine has an adjuvant effect for the production of antibodies induced by the purified fraction vaccine, or b) the addition of yellow fever vaccine has a retarding effect on the elimination of the agglutinins which, in the natural disease, are rapidly eliminated. Further studies to verify these hypothesis should be undertaken.

Adolescent↗

PubMedDate not supplied

[Antirabies vaccinations in France in 1974. I. Antirabies vaccinations at the Pasteur Institute of Paris].

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Humans↗