%0 Journal Article %A Canosi, Umberto %A Ferrari, Franco A. %A Ferrari, Eugenio U. %A Mazza, Giorgio %A Siccardi, Antonio G. %T PBSX Induction in a Temperature-sensitive Mutant of Bacillus subtilis %D 1978 %J Journal of General Virology, %V 39 %N 1 %P 81-90 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-39-1-81 %I Microbiology Society, %X SUMMARY A temperature-sensitive mutant of Bacillus subtilis is described which produces PBSX phage at a non-permissive temperature (47 °C). The mutant is, in the properties tested, phenotypically identical to the mutant tsi23 reported by Siegel & Marmur (1969). Its mutation (tsi85) maps in the same chromosomal region (dal-purB) in which tsi23 is located; the two mutations are shown to be distinct but probably affect the same function. Double mutants carrying the mutations tsi and xin (which blocks the induction of PBSX by mitomycin C) do not produce PBSX at a non-permissive temperature but retain their thermosensitivity. Tsi mutants display a reduced rate of RNA synthesis at the non-permissive temperature. Such a phenotype is lost in tsi-xin double mutants, revealing that it is associated with PBSX induction. The nature of the primary lesion that leads to PBSX induction in tsi mutants remains to be ascertained. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-39-1-81