As reported before, washing of organisms results in the decrease of their respiration. The addition of mineral ions can restore that decrease, of which, however, the restorationis to a different extent according to the species of organisms and the sorts of substrates. This experiment is performed to study one aspect of the enzyme system of bacterial respiration, by observing the influence of inhibitors and antibiotics on this action of mineral ions. Organisms: Staphylococcus albus, Bacillus dysenteriae (Komagome B III) and Bacillus pyocyaneus. Substrates: Pyruvic acid, α-ketoglutaric acid, glutamic acid and α-glycerophosphoric acid. Mineral ions: Mg(++) and Fe(++) of four different concentrations. Inhibitors: KCN, D. N. P. and monoiodoacetic acid.
Antibiotics: aureomycin, chloramphenicol and penicillin. 1) KCN: The inhibitory action of this substance is antagonized by the mineral ions of high concentration, of which Fe(++) is much more antagonistic than Mg(++). 2) D. N. P.: The inhibitory action of this substance is increased in the case where the bacterial respiration is also increased by the mineral ions. 3) Monoiodoacetic acid: This shows more inhibitory action in the case where the mineral ions are in high concentration. 4) Aureomycin: The inhibitory action of this antibiotic is remarkably antagonized by the mineral ions of high concentration. At the point where Mg(++) is the most effective, however, this shows the most noticeable inhibitory action. 5) Chloramphenicol: This shows little inhibitory action against the respiration of organisms and also has no relation with mineral ions. 6) Penicillin: This is effective to promote the respiration of organisms. It is even more effective in the presence of Mg(++) except in the case of Bacillus dysenteriae. However, its promotive action disappears in the presence of Fe(++).