EFFECT OF ORGANIC-ACIDS ON THE SWELLING OF BACILLUS-SUBTILIS SPORES DURING GERMINATION

The effect of organic acids on swelling of Bacillus subtilis during germination was followed by measuring changes in the cell volume by means of the Coulter Counter method. There was a direct correlation between the chain length of organic acids and the extent of inhibition of swelling of spores. Propanoic acid, butanoic acid, and 3-methyl-butanoic acid are more inhibitory than formic acid and acetic acid. The former may not be able to penetrate the spore coat and cortex layer of spores or neutralize electronegative groups which maintain high hydrostatic pressure in the spore cortex and inhibit germinants such as L-alanine from permeating or binding to specific triggering sites on the core membrane.