Formaldehyde kills spores of Bacillus subtilis by DNA damage and small, acid-soluble spore proteins of the alpha/beta-type protect spores against this DNA damage

Killing of wild-type spores of Bacillus subtilis with formaldehyde also cau sed significant: mutagenesis; spores (termed alpha(-)beta(-)) racking the t wo major alpha/beta-type small, acid-soluble spore proteins (SASP) were mor e sensitive to both formaldehyde killing and mutagenesis. A recA mutation s ensitized both wild-type and alpha(-)beta(-) spores to formaldehyde treatme nt, which caused significant expression of a recA-lacZ fusion when the trea ted spores germinated. Formaldehyde also caused protein-DNA cross-linking i n both wild-type and alpha(-)beta(-) spores. These results indicate that: ( i) formaldehyde kills B. subtilis spores at least in part: by DNA damage an d (b) alpha/beta-type SASP protect against spore killing by formaldehyde, p resumably by protecting spore DIVA.