Journal of General Microbiology (1974), 84,235-244 Printed in Great Britain The Outgrowth of Spores of Clostridium bifermentans

Germination and outgrowth of spores of Clostridium bifermentans occurred rapidly and synchronously in a medium containing casein hydrolysate, vitamins and metal salts. Germination began immediately after inoculation and within 10 min more than 90 % of the spores were phase dark. Swelling of the spores began immediately thereafter and by 25 min after inoculation more than 70 % of the spores were swollen. Elongation of the swollen spores was first detected at about 35 min; by 65 min 80 % of the spores had become cells, and by 90 min cell division had started. Increases in turbidity, RNA and protein were first detected during swelling and an increase in DNA was first observed at the beginning of elongation. By the time cell division began DNA had doubled. When spores were heated at 80 "C for 10 min, 20 % survived; the survivors germinated very much more slowly than unheated spores and only formed cells if anaerobic conditions were maintained. The increases in RNA, protein and DNA occurred much later during outgrowth than with unheated spores