THE BACTERIAL ENDOSPORE 



43 



acetic 

 acid 







4 6 8 



Time in hours 



Fig. 4. Pyruvic and acetic acid 

 production vs. time. 



Sum of pyruvic 

 and acetic 

 cids 



400 



300 — 



3 



200 



100 

 



4J 



4 6 8 



Time in hours 



Fig. 5. pH and sum of pyruvic and 

 acetic acid vs. time. 



culture just preceding sporulation. During the growth of the 

 vegetative cells, the glucose is broken down to acids, but the 

 acids are not utilized. When the glucose is completely gone, an 

 adaptive enzyme apparently forms for the utilization of the 

 acids. This accounts for the rise of the pH curve. One may also 

 assume that the oxidation of these acids is supplying the energy 

 needed for the synthesis of the spore material. 



These observations led us to investigate a variety of inhibitors 

 to see if compounds which would inhibit the utilization of inter- 

 mediates might also interfere with sporulation. The first one we 

 studied was a-picolinic acid"^"^. It is obvious why we selected this 

 one. We beHeved it might serve as an analogue for dipicolinic 

 acid and might interfere with its synthesis and thus interfere 

 with the production of the spores. The results obtained with 

 this inhibitor were quite surprising and are shown in Fig. 6. An 

 examination of this figure will show that a-picolinic acid, when 

 added to the culture while the pH is still dropping, interferes 



References p. 59 



