76 H. HALVORSON et al. 



SIGNIFICANCE OF THE ENZYMIC ACTIVITIES OF DORMANT SPORES 



It is easy to imagine that the establishing of a metaboHcally 

 inert dormant state can be of selective advantage to an organ- 

 ism. However, one would also expect that selective pressures 

 would be operative in favor of those which can survive dormancy 

 and rapidly revert to vegetative forms in which the full comple- 

 ment of metabolic activity is unmasked and active. The micro- 

 biological literature, especially the applied aspects, are rich in 

 examples of delayed dormancy. For example, McCoy and 

 Hastings^'^, employing single-cell technique, found that in 

 Clostridium acetobutylicurn the germination of 5 % of the freshly 

 harvested spores was delayed from 11 to 117 days and one 

 spore, isolated from a year-old culture, required 222 days to 

 germinate. The question is raised in these examples of the 

 physiological defect in these spores displaying delayed dor- 

 mancy. 



A priori one can visualize two types of metabolic activity 

 which can be recognized in spores: 



(1) The maintenance of a low level of metabolism for 

 maintenance of the dormant state; 



(2) The maintenance of enzymes essential for the triggering 

 of germination of activated spores and unmasking of 

 overall metabolism. 



The question of whether or not metabolism is required, or 

 even present, in dormant spores has unfortunately not been 

 sufficiently considered. This problem should be subject to test in 

 either dormant or delayed dormant spores. Germinated or even 

 activated spores differ sufficiently in density that it is possible to 

 separate clean dormant spores by density gradient sedimenta- 

 tion as material for examination. If there were any appreciable 

 metabolic activity present in these spores one should be able, 

 for example, to demonstrate the incorporation of ^^P phosphate 

 into ATP. Employing carrier-free 32PO4, and carrier isolation, 

 the sensitivity of the respiratory activity should be amplified by 



