期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：1
页码：151-155
DOI：10.1073/pnas.79.1.151
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Phenotypically nontoxinogenic mutants of Vibrio cholerae were isolated after infection with either of two mutagenic vibriophages, VcAI and VcA2ctsl. DNA isolated from these mutants was analyzed for toxin gene sequences by the Southern blotting method with 32P-labeled probes derived from the cloned A and B subunit genes for the heat-labile enterotoxin of Escherichia coli, designated LT. Several of the mutant isolates were shown by this method to have lost all sequences hybridizing to the LT probes, indicating that these clones contain deletion mutations that removed the structural gene(s) for cholera toxin. The mutants were prototrophic and grew normally, in vitro, demonstrating that the toxin is not essential for the growth and viability of V. cholerae. Moreover, the toxin gene deletion mutants multiplied well in vivo in ligated rabbit intestine. Because of these growth properties and the stability of deletion mutations, these strains are promising candidates for testing as live oral vaccine strains for protection against cholera.
