CHANGES IN THERMORESISTANCE OF CLOSTRIDIUM ROSEUM AS RELATED TO THE INTRACELLULAR CONTENT OF CALCIUM AND DIPICOLINIC ACID

Abstract
The cellular content of calcium and dipicolinic acid was determined quantitatively throughout the sporulation and germination processes of Clostridium, roseum. Cell counts were made throughout both processes to relate the changes in the thermoresistant population with the changes in cellular calcium and DPA. Calcium accumulation and DPA biosynthesis occurred early in sporogenesis and preceded the transition of the vegetative cells to thermoresistant spores. Calcium accumulation preceded both DPA biosynthesis and thermoresistance. During germination 80% of the cells became thermosensitive within 15 minutes after heat shock; however, the loss of calcium and DPA from the cells proceeded at a much slower rate. Approximately 2 hours of incubation were required for completion of the germination transition and the onset of cell division.