Oxidative Enzymes of Bacterial Spore Extracts 



Harlyn Halvorson 



Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 



UNTIL recent years we were faced with a contradiction in attempting 

 to understand the biochemical basis of dormancy and the breaking 

 of dormancy in bacterial spores which were believed to be nearly 

 devoid of enzymatic activity. Previous papers given at this symposium have 

 presented increasing evidence for an extended constitutive enzyme pattern 

 of the bacterial spore. However, our evidence is still too meager to afford 

 a biochemical explanation of the various cytological and physiological 

 changes occuring during germination. One approach to the problem is to 

 compare the enzyme paKerns of vegetative cells, dormant spores, and spores 

 in different stages of germination. We have heard here of dormant or in- 

 active enzymes. Do, for example, changes in enzymatic activities following 

 heat activation and germination activate these dormant enzymes, or does the 

 appearance of new activities represent a limited protein synthesis? It is 

 clear in certain cases, as outlined by Dr. Murty and Dr. Church, that activa- 

 tion of enzymes occurs. However, what is the extent to which quantitative 

 (constitutive) and qualitative (induced) protein synthesis takes place? In 

 both cases, we would expect energy yielding reactions and carbohydrate 

 metabolism to provide the carbon skeletons for amino acid synthesis. An 

 examination of the oxidative metabolism in spore extracts provides an ex- 

 cellent starting point for such a study. 



Carbohydrate oxidation 



Claims for respiratory activity of bacterial spores have been advanced 

 by a number of different investigators (Brody, 1955; Keilin and Hartree. 

 1947; Tarr, 1933) ; however, failure to check the possibility that this me- 

 tabolic activity was due to contaminating vegetative enzvmes or germinated 

 spores makes one question these claims. Employing well cleaned spores and 

 micro respirometer techniques, Crook (1952) was barely able to detect res 

 piration either with or without glucose. Crook's failure to observe the dor 

 mant glucose-oxidizing system in resting spores was probably due to insuf 

 licient activation. When aged spores are sufficientlv activated by heat shock 

 adenosine (Church and Halvorson, 1956). or heat shock and L-alanine (Mur 

 rell, 1955; Murty and Halvorson, 1956), an active glucose oxidation can be 

 demonstrated in the absence of detectable loss of heat resistance. 



The activation of glucose oxidation by heat in clean spores of Bacillus 



144 



