title: Roles of DacB and spm proteins in clostridium perfringens spore resistance to moist heat, chemicals, and UV radiation.
abstract: Clostridium perfringens food poisoning is caused mainly by enterotoxigenic type A isolates that typically possess high spore heat resistance. Previous studies have shown that alpha/beta-type small, acid-soluble proteins (SASP) play a major role in the resistance of Bacillus subtilis and C. perfringens spores to moist heat, UV radiation, and some chemicals. Additional major factors in B. subtilis spore resistance are the spore's core water content and cortex peptidoglycan (PG) structure, with the latter properties modulated by the spm and dacB gene products and the sporulation temperature. In the current work, we have shown that the spm and dacB genes are expressed only during C. perfringens sporulation and have examined the effects of spm and dacB mutations and sporulation temperature on spore core water content and spore resistance to moist heat, UV radiation, and a number of chemicals. The results of these analyses indicate that for C. perfringens SM101 (i) core water content and, probably, cortex PG structure have little if any role in spore resistance to UV and formaldehyde, presumably because these spores' DNA is saturated with alpha/beta-type SASP; (ii) spore resistance to moist heat and nitrous acid is determined to a large extent by core water content and, probably, cortex structure; (iii) core water content and cortex PG cross-linking play little or no role in spore resistance to hydrogen peroxide; (iv) spore core water content decreases with higher sporulation temperatures, resulting in spores that are more resistant to moist heat; and (v) factors in addition to SpmAB, DacB, and sporulation temperature play roles in determining spore core water content and thus, spore resistance to moist heat.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 216 Dryden Hall, Corvallis, OR 97331, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Paredes-Sabja
authors.forename: Nahid
authors.initials: N
authors.lastname: Sarker
authors.forename: Barbara
authors.initials: B
authors.lastname: Setlow
authors.forename: Peter
authors.initials: P
authors.lastname: Setlow
authors.forename: Mahfuzur R
authors.initials: MR
authors.lastname: Sarker
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D003016:Clostridium perfringens / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D005557:Formaldehyde / Q000494:pharmacology; D017353:Gene Deletion; D020869:Gene Expression Profiling; D023061:Gene Order; D005816:Genetic Complementation Test; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D050296:Microbial Viability; D009608:Nitrous Acid / Q000494:pharmacology; D013171:Spores, Bacterial / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays; D014867:Water / Q000032:analysis
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D014867:Water; D005557:Formaldehyde; D006861:Hydrogen Peroxide; D009608:Nitrous Acid