Nilemycin, an intercalating agent for deoxyribonucleic acid.

1. Nilemycin (NM) is found to exert an inhibitory effect on the mouse tumor Sarcoma 180 near toxic doses but not with Leukemia 1210. 2.

Isolation of cairomycins A and C.

Cairomycin B in the fermentation broths of Streptomyces sp. strain AS-C-19 accompanied cairomycin A and cairomycin C. The cairomycins are peptides with potent activity against gram-positive bacteria.

The mechanism of action of polychlorosubtilin.

Polychlorosubtilin (PCS) inhibits the growth of Escherichia coli. The antibiotic affected neither respiration nor glycolysis while the synthesis of nucleic acids and proteins were feebly hindered. Formation of aminoacyl-tRNA, peptide bonds and translocation from A to P sites of ribosomes were insignificantly influenced by the drug.

Staphcoccomycin, a new basic macrolide antibiotic.

Staphcoccomycin (SCM) is a new member of the basic macrolide family of antibiotics which was isolated from the fermentation broth of Streptomyces sp. AS-NG 16. The production, purification and determination of physical and chemical properties of this novel metabolite have been completed.

Kuwaitimycin, effect on synthesis of lipids in Bacillus subtillis cells.

The effects exerted by kuwaitimycin on synthesis of lipids as well as some metabolic activities of Bacillus subtilis were studied. The antibiotic not only arrested the inocrporation of 14C-acetate into the microbial lipids but also altered the fatty acids pattern, contents of i-C 15, a-C 15, i-C 17 and a-C 17 WERE MARKEDLY REDUCED, CONCOMITANT WITH AN INCREASE IN THE CONtents of i-C 14 AND N-C 14. Moreover, the rates of synthesis of phospholipids were decreased by the drug, especially that of phosphatidyl ethanolamine.

Cairomycin B, a new antibiotic.

Cairomycin B is a new cyclic peptide antibiotic that was isolated from Streptomyces As-C-19 obtained from the soil of Cairo. The antibiotic had the following empirical formula: C(10)H(15)N(3)O(3); on acid hydrolysis, it yielded aspartic acid and lysine. Spectral analysis and its chemical characteristics indicated that it was a cyclic peptide.

4,4'-isopropylidine-bis(2-isopropyl)phenol, a new inhibitor for cell wall formation of Bacillus subtilis.

4,4'-Isopropylidine-bis[2-isopropyl]phenol was found to possess antimicrobial activity against gram-positive bacteria and some fungi, whereas it had no effect on gram-negative organisms. The drug has a potent inhibitory action on the synthesis of cell wall mucopeptides of Bacillus subtilis by inhibiting the enzyme d-glutamate ligase, which is responsible for the incorporation of d-glutamic acid into uridine 5'-diphosphate-muramyl-l-alanine. The drug had a weak lytic effect on protoplasts and inhibited protein synthesis, whereas no significant effect on the synthesis of deoxyribonucleic acid and ribonucleic acid was found.

The mode of action of ASK-753 on Bacillus subtilis.

The mode of action of ASK-753 on Bacillus subtilis was examined. Unlike proper sideromycin antibiotics ferrioxamine B failed to antagonize the antimicrobial effects of ASK-753. The antibiotic could inhibit the biosynthesis of nucleic acids; effect on the RNA was more pronounced.

On the effect of N-methyl-bis (3-mesyloxypropyl) amine hydroxychloride on Bacillus subtilis cells.

N-Methyl-bis (3-mesyloxypropyl)amine hydrochloride is now in use as an antitumer drug. In view of its activity against some bacteria the present work was conducted to study its mode of action of Bacillus subtilis. The compound was found to induce irreversible damage to bacterial DNA whereas its effect on RNA was temporary and depending on maintenance of effective concentrations of the compound.