Abstract
The more the ratio of 2-methyl-4-amino-5-hydroxymethylpyrimidine (OMP) to pyridoxal (PAL) up to about 5,000,the more the growth inhibitory effect of OMP on Leuc. mesenteroides P-60 increased, then the growth of the bacteria started to resume. When ratio of OMP to PAL reached to 10,000-20,000,the growth of the bacteria was again restricted. The strange phenomenon could only be observed when DL-alanine or both of L-alanine and D-alanine were present in the medium of Leuc. mesenteroides regardless of vitamin B_6 existence. The characteristic phenomenon appeared also when 2-methyl-4-methylamino-5-hydroxymethylpyrimidine or isonicotinic hydrazide was added to the medium as vitamin B_6 antagonist. The above phenomenon did not occured when Streptococcus faecalis R was cultured.
