生理的食塩水浮游液中におけるブドウ球菌の死滅について (その二)

抄録

In the previous paper, the death phenomenon of staphylococci in saline solution was described and the results of the studies on the biological nature of this phenomenon were reported.
This phenomenon is not only interesting in its biological nature but also seems to have some important significances because saline suspensions of staphylococci are usually employed as the control sample in various kinds of biological reactions. In these reaction, the control sample of bacterial suspensions should be in the resting condition under which the bacterial cells would not be killed and at the same time not proliferate.
From this point of view, experiments were carried out to study on the inhibitors for the above mentioned death of staphylococcus in saline solution and to devise the idealistic medium for the suspension of staphylococcus composing of minimum set of amino acids.
Results are as follows:
(1) The death rate of staphylococcus in saline suspension can be slightly decreased if glucose is added to the saline medium.
(2) If the staphylococci are suspended in simple casamino acid medium at 37°C and shaking-incubated, there occurs neither death nor growth of cocci even after overnight incubation.
(3) Of the eight kinds of amino acids which are known to be required as the essential nutrient for the propagation of the St. aureus, three amino acids namely 1-tryptophane, glutamic acid, and hystidine which have been reported to promote the propagation of the staphylococci but are not indispensable, are proven to be unable to inhibite the death of staphylococci even when all of them are added into the saline medium.
(4) Subsequently four amino acids; 1-arginine, 1-cystine, 1-glycine and 1-proline, which are known to be indispensable for the propagation of the staphylococci, were examined for their ability to inhibit the death of staphylococci when they were added to saline medium. The former three were proven to give a considerable suppressing effect to this phenomenon, and among them, the effect of cystine was the strongest. But the latter one could not show any effect.
(5) Although the above mentioned suppressing effects of these three amino acids are less than that of casamino acid, they could show a remarkable effect as much as equivalent to that of the casamino acid when all these three amino acids were added together.
(6) Consequently the mixture of the above mentioned 3 amino acids and glucose could be recommended as the most suitable medium for staphylococcus suspension.