title: Production of types A and B spores of Clostridium botulinum by the biphasic method: effect on spore population, radiation resistance, and toxigenicity.
abstract: Spores of three strains each of type A and type B Clostridium botulinum were produced both by a biphasic (solid medium overlaid with an aqueous phase) and by a "conventional" (deep broth culture) procedure. Sporogenesis by the biphasic system was more rapid, convenient, and economical, and yielded as many or more heat-resistant (80 C, 10 min) spores per milliliter as by the conventional technique. Of several aqueous phases [thiamine-hydrochloride, yeast extract, (NH(4))(2)SO(4)] tested with strain 62A, the highest spore colony counts were obtained with 2.0% (NH(4))(2)SO(4). The six strains formed maximum spore numbers in 5 to 6 days of incubation. Spores produced by the two methods had essentially equal radiation resistances (D and lag values), and their subcultures gave similar toxin titers (LD(50) values).
mesh_terms: D000645:Ammonium Sulfate; D000818:Animals; D001431:Bacteriological Techniques; D003014:Clostridium botulinum / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D003036:Cobalt Isotopes; D003470:Culture Media; D005069:Evaluation Studies as Topic; D006358:Hot Temperature; D007928:Lethal Dose 50; D051379:Mice; D008858:Microscopy, Phase-Contrast; D010936:Plant Extracts; D011830:Radiation Effects; D012440:Saccharomyces; D012703:Serotyping; D013170:Spores / Q000254:growth & development*; D013171:Spores, Bacterial / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D013194:Staining and Labeling; D013831:Thiamine; D014118:Toxins, Biological / Q000096:biosynthesis
chemical_list: D003036:Cobalt Isotopes; D003470:Culture Media; D010936:Plant Extracts; D014118:Toxins, Biological; D000645:Ammonium Sulfate; D013831:Thiamine