Physiological Studies on the Germination of Bacillus subtilis Spores

Abstract

Spores of two strains of Bacillus subtilis, Bac. subtilis PCI 219 (PCI 219) and Bac. subtilis TR 33 (TR 33, a laboratory strain) were studied on their heat resistance, release of dipicolinic acid and in creasein stainability caused by heating or germination. (1) TR 33 was much higher resistant to heat than PCI 219; three hours of heating at 100°C were required for TR 33 to reduce its germination rate to 17 per cent, while PCI 219 required only 20 minutes to fall to fall to the equall level. (2) Heat was more effective on PCI 219 than on TR 33 in order to induce release of dipicolinic acid and to increase stainability of the spores; by heating at 100°C for 20 minutes with PCI 219 and far 4 hours with TR 33, 90 per cent of dipicolinic acid was equally produced from each of the spores, and regarding increase in stainability up to 50 per cent, TR 33 required heating for more than 4 hrs. but PCI 219 heating only for 20 minutes. (3) Increase in total stainability caused both by heating and by germination of the heated spares appeared not to follow a pattern similar to that of the release of dipicolinic acid from the spores treated in the same way.