NUTRITIONAL AND ENVIKONMKNTAL CONDITIONS 31 



cursors, specificall) hibeled pools can be prepared. A study of sporulation 

 employing these controlled pools can provide valuable information not only 

 to the nutritional requirements of spore formation but also to the extent to 

 which vegetative macromolecules existing prior to the commitment to spor- 

 ulation are incorporated into the spore. 



Campbell: Dr. Ordal, in connection with the effect of folic and para- 

 amino benzoic acids on spore formation, have vou tried replacing either 

 one of these with Vitamin B-12? 



Ordal: Yes, but we found that B-12 cannot replace the folic acid re- 

 quirement. 



Campbell: In connection Avith your findings that sulfate can replace 

 methionine, it is of interest to note what we have found in the vegetative 

 growth of B. coagulans. We thought we also had a methionine-requiring 

 strain and tried to replace these sulphur amino acids with sulphate. This 

 did not work unless we had B-12 present in the medium. With this organism 

 we can leave out the methionine or other sulphur amino acids and give 

 them sulphate plus B-12 and get good growth. 



Pow^ELL: We have not made any thorough study of the requirements 

 of sporulation, but there are one or two things we have come up against 

 that you may be able to explain to us. We find that all the strains of B. 

 megatherium, B. cereus and B. subtilis we have looked at do not sporulate 

 in tryptic broth, but three strains of B. sphericus and B. fusiformis sporu- 

 late with no trouble at all. The medium contains 500 milligrams of nitro- 

 gen per 100 ml so the growth of B. sphericus is not enough to exhaust the 

 medium; nevertheless this organism has no trouble whatsoever in sporulat- 

 ing in tryptic digest broth. We made another interesting observation when 

 we diluted the tryptic broth and added glucose and manganese. In this 

 diluted digest broth we got very strong stimulation or sporulation of B. 

 cereus provided glucose was present. We got very strong stimulation of B. 

 megatherium in the presence and absence of glucose. We got stimulation of 

 sporulation by manganese in the absence of glucose for B. subtilis. When 

 we changed our batch of medium we couldn't repeat those results. 



Church: I would like to ask the people studying sporulation if the con- 

 ditions under which the spores have grown affect their properties, in par- 

 ticular as regards their germination requirements? 



Mandels: I want to comment on the question raised by Dr. Church. We 

 have done some work with fungus spores indicating that the nature of the 

 medium upon which they are grown has a really terrific effect upon the 

 viability of the spores produced. The spores grown on a sugar yeast ex- 

 tract medium, for example, lose their viability within a week when left in 



