Influence of Exchangeable Ions on Germinability of Bacterial Spores

Abstract

Native spores of Bacillus megaterium Texas, and H-spores produced by titration of native spores to pH 4 with mineral acid, did not germinate in a solution of alanine and inosine unless a strong electrolyte was present. Ca-spores prepared from either H-spores or native spores did germinate efficiently in the same solution without a strong electrolyte. Of several other bivalent cations tested, only strontium and barium could substitute for calcium in conditioning spores for subsequent germination in the absence of an electrolyte. Variable responses were obtained with different metal ion forms of 62 unidentified soil isolates and several stock species of Bacillus. Although the pattern of response was not uniform in all organisms, ions played a crucial role in the germinability of the great majority of strains tested.

Germination of the Decoated Spores of Bacillus megaterium

“…It has been reported for many strains that partial replacement of spore metals with hydrogen ion or various divalent cations influences germination properties of the spores, e.g. the requirement for electrolytes, with a suggestion that the exchangeable cations would be located in the spore coat ( 1,2,13,14,(18)(19)(20). With regard to the spores of B. megaterium ATCC 12872, which was used in this study, treatment with thioglycolic acid at pH 2.6 allowed the spores to be germinated by glucose in the presence of electrolytes but not in their absense (20).…”

“…These results suggest that binding of calcium to a "special site" is temperature dependent and important for the initiation of germination, and also, they indicate that the "site" is not present in the outer and inner coat. However the suggestion that the spore coat is the site for exchangeable cations (1,2,13,14,(18)(19)(20) cannot be neglected, because the amount of calcium detected in the decoated Ca-spores, as shown in Table 2, was much lower than that in Caspores prepared from the wild type spores (14,19) and also the release of calcium from untreated spores by acid treatment was much less than the increase in calcium caused by calcium treatment of H-spores in the coat-carrying spores (13,14,18,19).…”

Effect of Trichloroacetic Acid Treatment on Certain Properties of Spores of Bacillus cereus T

“…Exposure of spores to an acid environment resulted in a loss of ions essential for dormancy (16), for resistance to heat (1,22), and for germinability (19,22). In this regard, although it has not investigated it is likely that removal of certain ions by treatment of spores with TCA increases their heat-sensitivity.…”

“…In this regard, although it has not investigated it is likely that removal of certain ions by treatment of spores with TCA increases their heat-sensitivity. With the reduction in the germinability of spores treated with TCA, however, this assumption is not applicable because spores exposed to an acid environment retained their ability to germinate in a phosphate buffer (pH 8.0) containing L-alanine and inosine (19).…”

“…Keynan et al (13) found that exposure of spores to extreme pH values activated dormant spores, and Brown and Melling (5) demonstrated that similar treatment released dipicolinic acid (DPA) from spores and affected the dormancy of the spores. There are several reports that exposure of spores to an acid environment with (22) or without (1,16,19) a reducing agent resulted in loss of ions essential for dormancy (16), for resistance to heat (1,22), and for germinability (19,22).…”