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Biomedical subjects

Q J Ma

Publications and source records attributed to Q J Ma.

24 records · Page 2Linked to original sources
PubMed1991

B subunit of cholera toxin produced in Escherichia coli.

An engineered E. coli strain containing high expression level of CT-B subunits has been obtained by the application of recombinant DNA techniques. The B subunit can be secreted into the medium and reaches 20-40 micrograms/ml when this strain is incubated in a 50 l fermentation tank. The CT-B subunit purified with affinity chromatography in E. coli has the same characters as the natural CT-B subunit in molecular weight, N terminal amino acid analysis and antigenicity. The CT-B subunit has good immunogenicity and can be used as a preparation for protecting against diarrhea caused by V. cholera and enterotoxigenic E. coli. It can also be used as a vector for hepatins.

Animals↗
PubMed1990

Construction of a bivalent oral vaccine for prevention of typhoid fever and cholera diarrhea.

A recombinant plasmid pMM-CTB containing the gene for production of the nontoxic B subunit of Vibrio cholera was transferred into a safe, effective and attenuated oral vaccine Ty21a strain of Salmonella typhi. The resulting Ty21a (pMM-CTB) could steadily produce CT-B subunit that was secreted extracellularly and had the same antigenicity as CT-B produced by V. cholera. Furthermore, the characteristics of the antigenicity, the persistance in mice and the galactose sensitivity possessed in the strain of Ty21a were also retained in Ty21a (pMM-CTB). A bivalent vaccine containing Ty21a (pMM-CTB) and the killed whole cell of V. cholera was then constructed which had good immunogenecity for typhoid fever and cholera diarrhea.

Animals↗
PubMed1989

The expression of enterotoxin A-B+ gene of V. cholerae in E. coli.

The cloning in E. coli of a cholerae toxin gene that is A-B+ has been successfully constructed by using DNA recombinant techniques. E. coli cells carrying the recombinant plasmid pMM-CTB have been shown to produce a large amount of CTB subunits which are secreted as extracellular proteins.

Animals↗