Activators and Inhibitors of Germination 



Clarence F. Schmidt 



Continental Can Company, Chicago 20, Illinois 



Introduction 



THIS aspect of spore germination has received a great amount of atten- 

 tion in the last ten years. Mr. Titus and I estimate that during this 

 period of time there have been well over one hundred papers published 

 containing sound and relevant information. Since it is obviously impossible 

 to review adequately and correlate the pubhshed work during the allotted 

 period of time, we decided that I would present some original data on 

 activation and inhibition of spore germination, and that Mr. Titus would 

 then present some comments and relevant references to the literature. 



As was quite apparent in an earlier session, there is still some disagreement 

 as to the definition of spore germination and as to the criteria to be used in 

 determining that it has taken place. For the present we must admit that 

 different criteria have been used in different laboratories and for different 

 purposes and hope we may correlate the results satisfactorily until stronger 

 definitions and criteria may be agreed upon. 



In the work to be presented, the criterion of germination of a spore was the 

 appearance of a colony on a plating medium, since this work was conducted 

 in relation to spore counting and spore recovery techniques. 



Procedure 



Two suspensions were used in this work, 5230-5 and 5230-24. Culture 

 5230, a strain of Bacillus subtilis, was received in 1952 from Dr. H. R. 

 Curran as #15u. Suspension 5230-5 was produced from growth on nutrient 

 agar with 1 ppm manganese. Suspension 5230-24 was produced on the syn- 

 thetic medium 5504. These suspensions did not contain more than 0.1% 

 vegetative cells. 



For plating two media have been used: Difco dextrose tryptone agar plus 

 0.5% Difco soluble starch, hereafter referred to as DT + ST, and medium 

 5504. The second medium was composed of 0.2% L-asparagine, 0.5% dex- 

 trose, the usual salts A and B, and 1.5% Difco agar. The medium was pre- 

 pared and sterilized without the dextrose, which was added in the form of 

 a concentrated, separately sterilized solution to the melted basal medium just 

 prior to pouring plates. All other additives to either medium Avere also pre- 

 pared in separately sterilized solutions and added to the melted media just 

 prior to pouring plates. 



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