著者

Dhillon T.S. Dhillon Elvera K.S.

出版者

財団法人 学会誌刊行センター

雑誌

Japanese Journal of Microbiology (ISSN:00215139)

巻号頁・発行日

vol.20, no.5, pp.385-396, 1976

被引用文献数

20

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Wild type phage HK022 was mutagenized by N-methyl-N'-nitro-N-nitrosoguanidine to induce clear plaque mutants. A total of 225 clear plaque mutants were isolated and 198 of these were as-signable to one or the other of the two complementation groups of the corresponding cistrons which have been designated as cI and cII, respectively. Approximately 25% of the c mutants were found to be temperature-sensitive (cts); producing turbid plaques at 32 C and clear plaques at 38 C and above. From complementation tests involving cI and cII mutants, bacteria lysogenic for cII prophage were fre-quently obtained. Double lysogens harboring a cI and a cII prophage were infrequently found and single lysogens harboring only a cI prophage have not been recovered. Bacterial lysogens harboring a prophage carrying a cts mutation in the cI cistron were readily obtainable. However, such lysogens show a lethal phenotype at 40 C and above, although they appear to be fully viable at 32 C. It is shown that by incubation of lysogens harboring a cts mutant of the cI cistron at 42 C, it is possible to isolate cryptic lysogens which are non-immune but harbor at least one of the phage sus+ alleles. Genetic data involving cI, cII, and two complementing sus mutants of essential genes are presented. From these data the following vegetative map is deduced: sus4-cII-cI-sus3.