CORRELATION OF ENVIRONMENTAL AND BIOLOGICAL CHANGES OCCURRING IN A COMPLEX MEDIUM DURING GROWTH AND SPORULATION OF BACILLUS SPECIES

Abstract

Certain biological, physical and chemical changes which occur during the process of spore production in Bacillus anthracis and B. subtilis var. niger in liquid medium are reported. With chain-forming B. anthracis, viscosity and volume of sediment increase as chain length increases and then decrease as chains break up; with nonchain-forming B. subtilis var. nlger, these values increase directly with growth and do not decrease measurably after growth is complete. In both cases turbidity increases with growth and reaches a peak shortly after sporulation begins; a drop in turbidity is associated with autolysis of vegetative material. The pH of the growth medium of both organisms varies slightly from neutrality except during sporulation when it increases sharply to a pH greater than 8. Combined total solids of medium plus cells decrease sharply during vegetative growth and level off after sporulation has begun. No measurable changes in specific gravity of cultures occur. Rapid utilization of carbohydrate and nitrogen occurs during the vegetative phase and is essentially complete 2 to 4 hours before sporulation is apparent. Increase in extra-cellular nitrogen occurs during autolysis.