Studies on the Synthetic Media for culture of some Bacteria Part Ⅰ Some findings about the growth of bacteria on nitrogen source added plate media

In order to study the effect on growth of bacteria of some compounds served as nitrogen source, the author observed the effects of addition of these compounds by paper disc method on the synthetic agar media containing 0.1% glucose and 0.04% peptone. The species of bacteria used were Staph. aureus, Staph. albus, Sal. enteritidis, Sal. typhi 57 S and R, Sal. paratyphi A, Sal. paratyphi B, Sal. paratyphy C, Sal. typhi murium, Shigella sonnei and Shigella flexneri 2 a, which were stock-cultured in the author's laboratory. And the results were as follows. 1) The paper disc method, the author adopted, showed the advantages, in that the method could detect the effect of several nitrogen sources very easily and simultaneously. 2) In this examinations, it was beneficial for reading the effect to prepare the basal nutrient media to each species tested, so as to grow the bacteria merely around the paper disc. 3) Nicotinic acid exerted the marked effect of growth stimulation on Staphylococcus and Shigella. And cystine showed some effect of stimulation on almost all species.