Enzymes Dormant in the Intact Spore 



G. G. Krishna Murty 



Department of Bacteriology, University of Illinois, Urbana, Illinois 



IN CONFORMITY with the views expressed eailier by Mr. Nakata and others, 

 I shall restrict my discussion to enzyme systems which are dormant in 

 the intact resting spore but which can be activated without disturbing in 

 any way the gross morphology of the spore or stimulating germination. In 

 other words, I shall discuss only those enzymes whose activity can be mea- 

 sured in the intact spore in the absence of germination, the ways of activa- 

 tion of these enzymes, the changes occurring during the process of activation, 

 and the probable mechanism of their dormancy and stability to heat while 

 dormant in the intact spore. 



To my knowledge the only enzymes meeting the above criteria are the 

 oxidative enzymes. Working with spores of a strain of Bacillus subtilis which 

 specifically required L-alanine, Murrell (1955) found that when a suspension 

 of the spores was incubated with L-alanine, the decrease in the viable count 

 of heat-stable spores was inversely proportional to the strength of the spore 

 suspension. When dense suspensions were incubated with glucose alone, oxy- 

 gen uptake could barely be measured, but on addition of L-alanine to the sys- 

 tems, there was a marked increase in the oxygen uptake in the absence of any 

 detectable germination of the spores. Spencer and Powell (1952) observed 

 a similar synergism between oxidation of glucose and L-alanine. D-alanine, 

 added before or at the same time as the L-isomer, inhibited the action of 

 L-alanine. Adenosine and tyrosine had no such stimulatory action. Murrell 

 further observed that the time and order of addition of the substrates had 

 a profound effect on the oxidation of glucose. 



When L-alanine was added first and glucose added as the second substrate, 

 the rate of oxidation of glucose decreased with increasing time of incubation 

 of the spores with L-alanine alone. When glucose was added first and 

 L-alanine added as the second substrate, the rate of oxidation was stimulated 

 to the same extent each time alanine was added. The effect of pretreatment 

 of the spores was more complex. 



When the spores were treated with alanine, washed and tested with glucose 

 alone, the rale of oxidation was the same as with untreated spores. Tested 

 with glucose and L-alanine the rate of oxidation was considerably less than 

 with, untreated spores. 



Spores treated with L-alanine and glucose and washed. Tested with glucose 

 alone the rate of oxidation was the same as with untreated spores except for a 



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