SPORE GERMINATION OF B. Hchefuformis 67 



vorson'^, who demonstrated the existence of a time interval 

 between a very short exposure to L-alanine and the subsequent 

 manifestation of germination, and also by Woese^, who showed 

 the existence of a time interval between alanine activation and 

 the subsequent release of dipicolinic acid. 



All the evidence that may be derived from our experiment of 

 'double temperature' exposure shows that whatever occurs at 

 temperatures below 20° depends entirely on preincubation at 

 the higher temperature. As already stated, extent of germina- 

 tion, as measured by total drop in optical density at 15° or 18°, 

 depends on duration and temperature of preincubation at 37°. 

 The temperature dependence is demonstrated in Table I, which 



TABLE I 



INFLUENCE OF TEMPERATURE OF PREINCUBATION ON THE EXTENT OF GERMI- 

 NATION AT 18° OF SPORE SUSPENSIONS OF B. Ucheuifonms 

 (Conditions as in experiment presented in Fig. 1 ) 



Temperature of Per cent of decrease in optical Final drop in optical 

 preincubation density after 6 niin of density after transfer to 



for 6 min preincubation-' ^^ ** (%) 



24° 5 



29° 2 20 



36° 19 38 



* Per cent of decrease in optical density expressed as: 



initial optical density — final optical density 



■■■,.,, ^x 100. 



initial optical density 



** The drop in optical density was considered as final when no measurable 

 change occurred during 1 hour. 



gives data of an experiment in which spore suspensions were 

 exposed for 6 min to different temperatures above 20° and then 

 transferred to 18°. 



If we suppose that this procedure separates events occurring 

 during germination, we have to conclude that whatever occurs 

 at the lower temperature is an outcome, but not a part of the 



References p. 70 



