78 JOAN F. POWELL 



eluding it because, although its effect is striking, it appears that alanine in- 

 duction and alanine racemase are not common to all spores. For the moment, 

 it is not unreasonable to believe that alanine per se is peripheral and that 

 perhaps via pyruvic acid it, like adenosine and glucose, may well have to do 

 with the availability of energy at the zero focal point. 



If we visualize, provisionally, that the process is a kind of adaptive syn- 

 thesis (es), then we have to look for some kind of synthetic activity, it 

 possibly being the initial meaningful step in the metamorphosis of a spore 

 cell to a vegetative cell. There are some data that tend to argue against 

 this. One of the most imposing facts which might be hastily mustered against 

 this idea is the rapidity of germination under optimal conditions. But the 

 idea of synthesis being involved here should not be exempted, because no 

 matter how few minutes it takes to observe the gross changes we characterize 

 as germination, we know there must have taken place prior to that changes 

 undetected by techniques thus far employed. Certainly synthetic activity 

 could well be initiated within seconds or less of the triggering effect; and if 

 we judge from turnover numbers of known enzymes and from the fact that 

 the newly synthesized molecules need constitute but a minute portion of the 

 spore cell walls — and may be autocatalytically synthesized at that — I see 

 no reason why synthesis could not be the main theme commencing from 

 point zero. Induced synthesis can be very rapid. In our laboratory a 

 pseudomonad gave a definite response manometrically, indicative of synthesis 

 of an induced enzyme system, less than five minutes after addition of the 

 specific inducer. Needless to say, a lot of enzyme molecules must have been 

 synthesized prior to the time their activity could be detected manometrically. 

 One of the last experiments on germination in our laboratory was done over 

 five years ago by Dr. W. A. Hardwick. His preliminary experiment showed 

 the uptake and fixation of P'^-- or S^"''-methionine in spores of species of 

 Bacillus within a very minute of their being placed in a germination medium. 

 Of special interest is the fact that the fixation, indicative of an active metabo- 

 lism, was easily detected well before the great majority of spores had lost 

 their heat resistance and without the appearance of anything remotely re- 

 sembling vegetative cells. Unfortunately this experiment was not designed 

 to ascertain just how early in germination phosphate fixation could be 

 detected. 



Another experiment that Dr. Hardwick did in my laboratory also illustrates 

 a very early intraspore turnover well before germination, e.g. appearance 

 of vegetative cells. It supports the idea of very early synthesis by showing 

 how intracellular substances originate — in this case a pool of amino acids, 

 which presumably are precursors for de novo syntheses. S^^-labelled spores 

 of B. cereus were obtained by growth in a medium in which Na2S^'^04 was 



