128 MOLECULES, VmUSES, AND BACTERL^ 



permit the synthesis of the spore structure but not the synthesis of 

 DPA and thus would prevent the production of a heat-resistant spore. 

 B. D. Church and Harlyn Halvorson ( 1959 ) were able to do this with 

 phenylalanine. We have succeeded in obtaining this result with two in- 

 hibitors—ethyl oxamate and diethyl pimelate. 



To pursue this study one needs some mechanism to difiFerentiate 

 between heat-sensitive spores, vegetative cells, and germinated spores. 

 It cannot be done by heating, but octyl alcohol proved to be a suitable 

 agent. This alcohol is very toxic to vegetative cells, killing them almost 

 instantly, and it will also destroy germinated spores almost equally fast. 

 Spores are extremely resistant to this chemical, and, as will be shown 

 later, the heat-sensitive spores also are resistant. Table VI shows the 

 effect of octyl alcohol upon germinated spores and vegetative cells of 



TABLE VI 



Effect of Octyl Alcohol on the Viability of Spores, 

 Germinated Spores, and Vegetative Cells of Bacillus Cereus T. 



B. cereus. Table VII shows the effect of ethyl oxamate upon the pro- 

 duction of heat-resistant spores of B. cereus. It is to be noted from this 

 that ethyl oxamate interferes with the formation of heat-resistant spores 

 whether it is added in the beginning or before or after the pH has 

 started to rise. If one waits, however, until the pH has gone up to 7.1 

 or higher, it has no effect. Apparently by this time the synthesis of 



TABLE VII 



Effect of Time of Addition of Ethyl Oxamate ( lO-^M) 

 on the Production of Heat-Stable Spores 



Type of Culture Used 



Spore Inoculum 

 Active Culture at O Time 

 Active Culture pH 5.2 (falling) 

 Active Culture pH 5.8 (rising) 

 Active Culture pH 7.1 (rising) 

 Active Culture pH 7.9 (rising) 



