Separation of Two Functional Roles of l -Alanine in the Initiation of Bacillus subtilis Spore Germination

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Abstract
Spores of the standard transformable Marburg strain of B. subtilis can be initiated to germinate by L-alanine alone. We isolated mutants which required for this process, in addition to L-alanine, the combination of D-glucose + D-fructose + K+ or NH4 + ions. In place of fructose, autoclaved or caramelized glucose can be used. Even the standard type strain required the addition of these three agents when D-alanine was present or when the temperature was raised. These findings show that L-alanine normally performs two functions during initiation, one of which is absent in the mutants or is blocked by D-alanine or elevated temperature. One of our mutants was not absolutely dependent on the addition of external L-alanine, be-cause it could be initiated at a reduced rate by the sole addition of glucose + K+ or NH4+. When K+ or NH4+ were replaced by Na+, the initiation rate was greatly reduced. The divalent metal ions Mg++, Mn++, and Ca++ could not satisfy the cation requirement.