STUDIES ON THE GERMINATION OF SPORES OF 

 BACILLUS LICHENIFORMIS 



A. KEYNAN AND M. HALMANN 



Israe institute for Biological Research, Ness-Ziona (Israel) 



Many of us will agree with Orin Halvorson's statement in a 

 recent review that the 'trigger mechanism for germination is one 

 of the most interesting and unique mechanisms found in 

 nature'^. Although much research and speculation has been 

 devoted recently to this process and akhough a picture is 

 beginning to emerge of the events leading to the germination of 

 bacterial spores, the exact mechanism of the latter has not yet 

 been elucidated. Many of the facts connected with the 'trigger 

 reaction' leading to germination have been described in the 

 preceding lectures. I will, therefore, repeat only briefly some of 

 those on which our conception of the nature of induction of 

 germination is based. 



It is well known that freshly grown bacterial spores of many 

 species will not germinate readily after harvesting. In order to 

 induce germination in these spores they have to be 'aged' or 

 'heat activated'. There is much evidence today that during 

 'aging' or 'heat treatment' some dormant enzyme system is 

 activated. Adopting Harlyn Halvorson's conception, one might 

 say, that the 'heat treatment' breaks down a mechanism which 

 controls dormancy. 



'Aged' or 'heat-treated' spores may be triggered readily and 

 converted into heat-sensitive germinated cells by the action of a 

 number of substances, among which L-alanine is the most 

 common. The mechanism of the action of alanine in this 

 process is not known, but both substrate and catalytic activity 

 have been suggested-. O'Connor and Halvorson^ have shown 

 that germination is attended by deamination of both endogenous 

 and exogenous alanine by an L-alanine dehydrogenase to yield 

 pyruvate. Much evidence has accumulated that metabolism of 

 pyruvate is involved in germination. Inhibitors of pyruvate 



