THE MINERAL REQUIREMENTS FOR SPORULATION 9 



excess of manganese he got about as many spores as he did using both man- 

 ganese and calcium, but they were smaller, less refractile and considerably 

 less heat resistant. 



Powell: We have made some studies in our laboratories on the sporu- 

 lation of laboratory strains of Bacillus cereus, B. suhtilis and B. megather- 

 ium.^ The effect of glucose (,10-M) and manganese (lO^M) addition on 

 sporulation in shaken tryptic meat digest medium ( 100 mg. nitrogen/100 ml.) 

 was tested. All the above organisms grew well but showed no signs of spor- 

 ulation in the test medium with no additions or with added glucose. 



Manganese addition stimulated almost complete sporulation of B. cereus 

 in the presence but not in the absence of glucose, of B. suhtilis in the ab- 

 sence but not in the presence of glucose, and of B. megatherium both in the 

 presence and absence of glucose. These results were not always repeatable 

 with different batches of meat digest medium prepared in an identical man- 

 ner and of equivalent nitrogen content. For example, in four other batches 

 of medium, only in one batch was sporulation of B. cereus stimulated by 

 addition of manganese and glucose. In all the batches of medium tested, B. 

 sphaericus sporulated well in the absence of any additions. 



Roth: We have studied the sporulation of Bacillus anthracis in a casein 

 hydrolysate medium to which we added calcium, magnesium and manga- 

 nese. When we used tap water with these minerals, we obtained very good 

 sporulation, 5 x 10^ spores per ml, but when we used deionized water with 

 the same minerals, we obtained very few spores. This indicates that there 

 are other trace mineral requirements for sporulation besides calcium, mag- 

 nesium and manganese. 



Ordal: I want to comment on the requirement of manganese for proper 

 cell division. We found that B. coagulans, in a manganese deficient medium, 

 at 55° grows reasonably well, but produces only filaments, whereas in a 

 culture containing small quantities of manganese, it produces typical short 

 rods. 



Sussman: I was struck by the fact that two effects of manganese are 

 mentioned in the literature and I am wondering if these have been noted 

 on the same organism? I refer to the effect that Dr. Curran has mentioned, 

 namely, its ability to induce sporulation, and secondly to bring about ger- 

 mination. Have any experiments been done to determine the amount of 

 manganese needed to induce sporulation as compared to the amount re- 

 quired for subsequent activation of the spores? 



Curran: As far as I know, there are no quantitative data available on 

 this point. 



1 Powell, J. F., Unpublished results. 



