1951 Volume 4 Issue 6 Pages 361-368
The author has investigated the relationship existing between nitrogen requirements and growth factors of bacteria. In the preceeding reports the author took the dynamic aspects of evolutional steps linking ammonia nitrogen requiring bacteria in amino nitrogen's bacterial group, mainly relating to nicotinic acid. It is the purpose of this paper to report the nitrogen regirements of bacteria in the group requiring amino nitrogen+growth factor, especially about the significance of essential amino acids.
It was shown that the essential amino acids depend partly on the kinds of carbon sources added in the medium. The experiments reported in this paper were designed to determine whether amino acids in the medium of Staphylococci mutually effect each other and also to examine the influence of the growth factor on these essential amino acids.
Strains examined were Staphylococcus aureus (Terashima, 209-P and Heatley) . As a starting medium to be examined the author selected one as similar as possible to that devised by Fildes et al. (Table 1 M-1) Each amino acid was omitted in turn from a mixture containing 11 amino acids and the effect on the growth was observed. Thus, the minimum nitrogen requirements and the mutual effect of those amino acids were investigated. Terashima, out of those three strains, was found most exacting, since the minimum requirements were found to depend on whether pyridoxine was present or absent. In view of the fact that Terashima requires pyridoxine depending on conditions and, therefore, has some relationship with transamination, the author isolated several free amino acids within the bacterial cell by paper chromatography.