title: Effect of radioprotective agents in sporulation medium on Bacillus subtilis spore resistance to hydrogen peroxide, wet heat and germicidal and environmentally relevant UV radiation.
abstract: OBJECTIVE
  To determine the effects of cysteine, cystine, proline and thioproline as sporulation medium supplements on Bacillus subtilis spore resistance to hydrogen peroxide (H(2)O(2)), wet heat, and germicidal 254 nm and simulated environmental UV radiation.
  
  
  RESULTS
  Bacillus subtilis spores were prepared in a chemically defined liquid medium, with and without supplementation of cysteine, cystine, proline or thioproline. Spores produced with thioproline, cysteine or cystine were more resistant to environmentally relevant UV radiation at 280-400 and 320-400 nm, while proline supplementation had no effect. Spores prepared with cysteine, cystine or thioproline were also more resistant to H(2)O(2) but not to wet heat or 254-nm UV radiation. The increases in spore resistance attributed to the sporulation supplements were eliminated if spores were chemically decoated.
  
  
  CONCLUSIONS
  Supplementation of sporulation medium with cysteine, cystine or thioproline increases spore resistance to solar UV radiation reaching the Earth's surface and to H(2)O(2). These effects were eliminated if the spores were decoated, indicating that alterations in coat proteins by different sporulation conditions can affect spore resistance to some agents.
  
  
  CONCLUSIONS
  This study provides further evidence that the composition of the sporulation medium can have significant effects on B. subtilis spore resistance to UV radiation and H(2)O(2). This knowledge provides further insight into factors influencing spore resistance and inactivation.
authors.affiliation: German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Cologne, Germany. ralf.moeller@dlr.de
authors.forename: R
authors.initials: R
authors.lastname: Moeller
authors.forename: M
authors.initials: M
authors.lastname: Wassmann
authors.forename: G
authors.initials: G
authors.lastname: Reitz
authors.forename: P
authors.initials: P
authors.lastname: Setlow
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects / Q000528:radiation effects*; D003470:Culture Media / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry; D003553:Cystine / Q000737:chemistry; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D011392:Proline / Q000737:chemistry; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects / Q000528:radiation effects; D053778:Thiazolidines / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D011837:Radiation-Protective Agents; D053778:Thiazolidines; D003553:Cystine; D011392:Proline; D006861:Hydrogen Peroxide; C003438:thiazolidine-4-carboxylic acid; D003545:Cysteine