ACTIVATORS AND INHIBITORS OF GKRMINATION 65 



ill the presence of L-alanine alone. These spores were less than six months 

 old. had been stored at refrigerator temperatures, had never been subjected 

 to heating of any kind, and were regarded as free of vegetative cells. 



Although it seems that spores of some aerobic strains have no heat re- 

 quirement for germination, it is quite obvious that heat plays a vital role 

 in the germination of many, if not the majority of aerobic spores. I heartily 

 agree with Dr. Schmidt that spore suspensions should be subjected to heat 

 only where it is a known and controllable variable. 



A specific germination requirement for L-alanine is even more prevalent 

 among the aerobic spore formers than is the requirement for heat activation, 

 although several exceptions have been recorded. Knaysi (1945) reported that 

 spores of B. mycoides germinated in the presence of glucose and acetate, 

 although germination was apparently relatively low and inconsistent. Pulver- 

 taft and Haynes < 1951) found that spores of Bacillus cereiis and B. subtilis 

 germinated in the presence of adenosine alone. These determinations were 

 apparently made in the presence of autolyzed vegetative cells, however, and 

 the possible presence of L-alanine and/or other stimulants cannot be dis- 

 counted. Heiligman et al (1956a) and Hachisuka and coworkers (1955a) 

 also reported germination of aerobic spores in the absence of L-alanine. 



A requirement for the presence of adenosine for optimum germination has 

 been reported in several instances, although this requirement does not appear 

 to be as specific or as widespread as does the requirement for L-alanine. 

 Other ribosides seem to be able to replace adenosine, and Powell and Hunter 

 (1955) reported that inosine provided better germination than did adenosine. 



Several workers have reported that glucose, either alone or in combination 

 with other compounds, stimulates germination of some aerobic spores. Heilig- 

 man et al (1956a) found that spores of Bacillus coagulans. Bacillus globigii, 

 and the anaerobic spore former, PA 3679, required only glucose or another 

 energy yielding organic carbon source for germination. Hachisuka et al 

 (1955a, 1955b) reported that glucose and L-asparagine or DL-isoleucine were 

 sufficient for complete germination of B. subtilis spores, but only after the 

 glucose (or other sugar) had been caramelized to a yellowish brown color. 



The requirements for optimum germination of the anaerobic spore formers 

 has not been investigated as thoroughly as has been the case with the aerobes. 

 Wynne (1956) found that glucose autoclaved at a pH above 5.0 caused 

 germination of spores of several Clostridia strains. As mentioned earlier. 

 Heiligman et al (1956a) found that PA 3679 required only glucose for 

 germination. Hitzman, Zoha, and Halvorson (1955) reported that L-phenyl- 

 alaninfe, L-arginine, and L-alanine were required for optimum germination 

 of heated spores of Clostridium botulinum type B and Clostridium roseum. 

 Brown (1956) found that spores of two strains of PA 3679 germinated com- 



