Umezawa et al.¹⁾ have screened soil actinomycetes for the production of watersoluble, basic antibiotics and discovered a new one which was named kanamycin. This antibiotic is produced by Streptomyces kanamyceticus and extracted by a cation exchange resin process. Maeda, et al.²⁾ purified this antibiotic as the crystalline monosulfate. Degradation studies made by four groups, Maeda, et al.³⁾, Cron, et al.^4),5), Ogawa, et al.⁶⁾ and S. Umezawa, et al.¹⁾ have cleared that kanamycin (C₁₈H₃₆O₁₁N₄) is a glycoside constituting from 2-deoxystreptamine, 6-amino-6-deoxy-D-glucose and another amino hexose named kanosamine (C₆H₁₃O₅N). Kanamycin does not reduce Fehling solution.

As described by Takeuchi, et al.⁸⁾, kanamycin inhibits the growth of Gram negative and positive bacteria including mycobacteria, and its antibacterial spectrum resembles that of streptomycin or fradiomycin (neomycin). The latter is related to kanamycin also in the point that it contains 2-deoxystreptamine, though they are different in the other parts of the molecules. As described by Takeuchi, et al.^8),9), however, there is a marked difference between toxicity of kanamycin and that of fradiomycin. LD₅₀ of kanamycin to mice is about 350mg/kg by the intravenous injection and about 1,600mg/kg by the subcutaneous injection. Dogs tolerated the daily intramuscular injections of 150mg/kg. It is also reported by Takeuchi, et al.⁹⁾ that kanamycin is less in toxicity to the vestibular system of dogs and cats than streptomycin and less in ototoxicity to rats than dihydrostreptomycin.

As it can be expected from the bacteriostatic effect in vitro and the low toxicity, protective or therapeutic effects of this antibiotic have been confirmed on miscellaneous bacterial infections in mice by Takeuchi, et al.⁸⁾ and Robinson, et al.¹⁰⁾ Yanagisawa, et al.^11),12) have confirmed the therapeutic effect on experimental tuberculosis in mice and guinea pigs. These results indicate that this antibiotic is effective in vivo as well as in vitro. Ichikawa, et al.¹³⁾ and Donomae, et al.¹⁴⁾ reported the clinical effects which could be expected from the bacteriostatic effects in vitro. In these circumstances, the antibacterial spectrum in detail is helpful to see effective clinical fields of this antibiotic.

This paper describes the detailed antibacterial spectrum and one-way cross resistance with streptomycin which was observed in E. coli.

In the previous paper¹⁾ the detailed antibacterial spectrum of kanamycin was described. Gram positive and negative bacteria including mycobacteria except streptococci, pseudomonas and clostridia were sensitive to this antibiotic. This bacteriostatic effect shown in vitro has been confirmed to be exhibited also in vivo by Takeuchi, et al.²⁾, Gourevitch, et al.³⁾, and Robinson, et al.⁴⁾. These authors have reported protective or therapeutic effects of this antibiotic on miscellaneous bacterial infections in mice. Yanagisawa⁶⁾ confirmed therapeutic effects of kanamycin on experimental tuberculosis in mice and guinea pigs. These studies suggest that the bacteriostatic effect of kanamycin is not influenced by serum or other body fluids. Actually, as shown by Takeuchi, et al.²⁾ , Gourevithch, et al.³⁾ and Dickinson, et al.⁷⁾, serum did not reduce the bacteriostatic effect, and this antibiotic showed a high blood level after the intramuscular injection.

However, Yanagisawa and Satō⁸⁾ observed that the bacteriostatic effect of this antibiotic was much weaker on egg media than in Kirchner medium. Their observation suggested an existence of a certain substance in an egg inhibiting the bacteriostatic effect of kanamycin. The present studies were made for the purpose to clear the mechanism of this inhibition by an egg.

Kanamycin is a glycoside being constituted from 2-deoxystreptamine, 6-amino-6-deoxy-n-glucose and another hexosamine, and kanosamine (C₆H₁₃O₅N), as reported by Cron, et al.⁹⁾ From this structure a competitive inhibition with some aminosaccharides could be expected. Therefore, milks, which have been known, as shown in papers of Kuhn¹⁰⁾, to contain aminosaccharides, were also included in the present studies.

As described in this paper, the active factor inhibiting the bactericidal effect of kanamycin in an egg exists in an water-insoluble part of the yolk obtained after treated with ether and acetone, and the mechanism of this inhibition was confirmed to be the adsorption of kanamycin on the active factor.

Griseoflavin reported in 1951^1,2) is an antibiotic produced by a streptomyces strain No. 160. This antibiotic is interesting in its acidic nature²⁾ and low toxicity, but on account of its low yield, investigation has been greatly hindered.

In 1955, novobiocin was discovered independently in separate 3 laboratories⁴⁾. When we compare griseoflavin with novobiocin, a remarkable resemblance can be noticed between them in their antibacterial spectrum, toxicity and papergrams. Recently a sample of novobiocin monosodium salt was made available to us, so we carried out a comparison on the biological and physicochemical properties.

Kanamycin is an antibiotic of Streptomyces discovered by Umezawa and others¹⁾, and was purified as its sulfate, C₁₈H₃₆O₁₁N₄•H₂S0₄•H₂O²⁾. The potency of this antibiotic was decided to be expressed by the weight of its base .

Takeuchi and others³⁾ studied the toxicity of this antibiotic and reported that it was low in acute toxicity to mice, rats and rabbits, and in chronic toxicity to mice and dogs. This antibiotic is water-soluble and basic, therefore, further detailed studies on chronic toxicity, especially to nervous system, were required before the clinical studies. The present paper describes studies on chronic toxicity to dogs and cats and on ototoxicity to rats.

Sarkomycin is an antitumor substance produced by Streptomyces erythrochromogenes¹⁾, and the structure, 2-methylene-3-oxo-cyclopentanecarboxylic acid, has been determined by Hooper and others²⁾. Maeda and Kondō³⁾ studied the inactivation course of sarkomycin and determined the structure of inactivated products of sarkomycin. The anti tumor effects of sarkomycin have been described by Takeuchi and others⁴⁾.

Hara and others⁵⁾ studied the reaction of sarkomycin with isonicotinic acid hydrazide, and they found that a product constituting from two moles of sarkomycin and one mole of INH had both antitumor and antimicrobial activity. This active compound was named sarkomycin-INH. According to thes.e authors, the purified sarkomycin-INH, when compared with the standard sarkomycin, has the potency of 3mg units/mg.

In the point of its stable character, sarkomycin-INH is an interesting derivative. The present authors studied antitumor effects of this substance against Ehrlich carcinoma of mice and Yoshida rat sarcoma and also the anti-HeLa cell effect. These two experimental animal tumors and HeLa cell were sensitive to this substance and sarkomycin-INH exhibited a stronger antitumor activity against Yoshida rat sarcoma than sarkomycin.

In the preceding paper^1,2) of this series, it was demonstrated that various compounds related to the Krebs tricarboxylic acid cycle were oxidized by the starved cell suspension of S. griseus grown on the casein medium. Among the amino acids used, only glutamic acid was oxidized markedly by the starved cells. When glucose was used as the substrate, glutamate, aspartate, and lysine were formed by S. griseus.

In this paper, some results of study on the oxidation of amino acids with special reference to glutamic acid by the freeze-dried mycelium powder of S. griseus grown on the casein medium will be reported.

In the preceding paper¹⁾ of this series, it was reported that various amino acids especially glutamic acid were oxidized by the freeze-dried powder of S. griseus grown on the casein medium. But, the freeze-dried powder itself suspended in the phosphate buffer did not oxidized them. The activity of the amino acid oxidation occurred by the incubation for a long time. But, the enzyme solution employed there was a complex system. Recently, the author obtained the mycelium suspension from Dulaney’s synthetic medium supplemented with glutamate, which oxidizes glutamic acid without particular procedures. The extraction of glutamic dehydrogenase from the mass cultured mycelium by grinding was unsuccessful, because the homcgenate contained the excess amount of the mucilage.

In the present study, some results on L-glutamate oxidation by the intact mycelium of S. griseus grown on Dulaney’s medium supplemented with glutamate will be reported.