24 Z. JOHN ORDAL 



Table II 



Eflfect of folic acid and related metabolites on 



sporulation of Bacillus coagulans [43-P] 



Percent sporulation 



1. Complete medium 75 - 90 



2. [1] minus folic acid 5 - 10 



3. [2] plus PABA 75-90 



4. [2] plus adenosine 25 - 50 



5. [2] plus adenine 20-30 



Inosine, guanine, uracil, and thymine no effect at 10 /xg/ml. 



the same paper referred to earlier. In their hands, sporulation was reduced 

 when para-aminobenzoic acid was omitted from the medium. While they 

 do not present specific data on the effect of the omission of this compound 

 on the amount of growth, their discussion of the general results imply some 

 reduction in the amount of growth. 



We have obtained some evidence that B. coagulans requires more folic 

 acid (or PABA) for sporulation than it does for growth. Typical data are 

 presented in Table II. The complete medium is the synthetic medium con- 

 taining agar which supports a high degree of sporulation as indicated by 

 the first line. The omission of folic acid markedly reduces the percentage 

 sporulation. The requirement for folic acid is fulfilled by PABA (line 3). 

 As folic acid is considered to function in the synthesis of purines and pyri- 

 midines, we have attempted to compensate for this function by the addition 

 of various purine and pyrimidine bases in place of the folic acid or PABA. 

 The addtion of adenosine or adenine produces a partial stimulation, but 

 inosine, guanine, uracil, or thymine failed to exert a demonstrable effect. 

 High concentrations (100 /Ag/ml) of guanine or uracil completely suppressed 

 the growth of this organism in this medium. 



(d) Other factors. There have been reports on other substances which 

 do not readily fall into either of the above three categories, but which have 

 stimulated sporulation under the conditions in which they were used. I 

 have chosen to "lump" a few of these together. 



Powell (1951) reported that oxalate (10 niM) stimulated spore forma- 

 tion by B. megaterium when added to a complex medium. Subsequently 

 Powell and Hunter (1955) reported that on the same medium sporulation 

 by B. sphaericus was stimulated by the addition of bicarbonate or oc-keto- 

 glutarate. They concluded that the higher COo concentration furnished by 

 these compounds was the stimulating factor. They also postulated that the 



