Absence of Transient Elevated UV Resistance during Germination of 'Bacillus subtilis' Spores Lacking Small, Acid-Soluble Spore Proteins Alpha and Beta

摘要

Germinating spores of Bacillus subtilis mutants which lack small, acid-soluble spore proteins alpha and beta did not exhibit the transient elevated UV resistance seen during germination of wild-type spores. Dormant spores of various Bacillus species are much more resistant to UV irradiation than are the corresponding vegetative cells. This elevated spore UV resistance appears to have two causes. First, UV irradiation of spores does not produce the pyrimidine dimers formed in vegetative-cell DNA, but rather produces several other photoproducts, the most predominant of which is termed the spore photoproduct, a 5-thyminyl-5,6-dihydrothymine adduct (1, 10). Second, spores have at least two mechanisms which efficiently repair this spore photoproduct during spore germination, including one which monomerizes the adduct back to two thymines. Reprints. (mjm)