. The actinomycetes. Actinomycetales. 100 NATURE, FORMATION, AND ACTIVITIES. 0 12 5 HOURS Figure 7. Effect of novol)iocin (1 mg ])er ml) on turbidity and vial)le count of growing cells of E. coli; = viable count; = turbidity. (Reproduced from Brock, T. D. and Brock, M. L. Arch. Biochem. Biophys. 85: 176-185, 1959.) Actinomyciyi Actinomycin is a bacteriostatic agent, active primarily upon gram-positive bac- teria and to a lesser degree upon gram-nega- tive bacteria. It is also active upon certain neoplasms. It is extremely toxic to animals, a factor which limits its utilization in the therapy o
. The actinomycetes. Actinomycetales. 100 NATURE, FORMATION, AND ACTIVITIES. 0 12 5 HOURS Figure 7. Effect of novol)iocin (1 mg ])er ml) on turbidity and vial)le count of growing cells of E. coli; = viable count; = turbidity. (Reproduced from Brock, T. D. and Brock, M. L. Arch. Biochem. Biophys. 85: 176-185, 1959.) Actinomyciyi Actinomycin is a bacteriostatic agent, active primarily upon gram-positive bac- teria and to a lesser degree upon gram-nega- tive bacteria. It is also active upon certain neoplasms. It is extremely toxic to animals, a factor which limits its utilization in the therapy of infectious diseases and certain forms of cancer. One milligram of actinomy- cin given to mice, rats, or rabl:)its intra- venously, intraperitoneally, subcutaneously, or orally is lethal for 1 kg weight of the animals. Doses as small as 50 /xg per kg injected intraperitoneally daily for 6 days cause death accompanied by severe gross pathological changes, a marked shrinkage of the spleen. Actinomycin is rapidly excreted from the body. Kawamata and Imanishi (1960) suggested that the carcinogenic effect of actinomycin may be due to its interaction with deoxyri- bonucleic acid. Foley (1955) found that the action of ac- tinomycin D upon bacteria consists in inter- ference with pantothenate utilization. This phenomenon could not be confirmed by Slotnick (1957) for B. subtilis. Slotnick (1960) demonstrated that actinomycin D suppresses the assimilation of ammonia by B. suhtilis and inhibits completely the for- mation of certain inducible enzymes. He concluded that this antibiotic interferes in some reactions leading to protein synthesis. Kirk (1960) studied the metabolic reac- tion between actinomycin D and DXA and found that the antibiotic has no significant inhibitory effect on the polynucleotide phos- phorylase of Staph, aureus, that it inhibits the incorporation of radioactivity into the HC104-insolul)le fraction when P^^Q^y- adenosine triphosphate is incubated with a
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