Bottromycin A2 inhibits polylysine synthesis with poly A at low concentrations of E. coli ribosomes. Peptide release by puromycin from ribosomes was significantly inhibited by blasticidin S, chloramphenicol and thiophenicol, but not by bottromycin A2 in the absence of GTP and G factor. Puromycindependent release of peptide from ribosomes was stimulated by the presence of GTPand G factor; it was inhibited by bottromycin A2. The results indicate that bottromycin A2 inhibits translocation of peptidyl-tRNA on the ribosomes, but does not affect peptide bond synthesis.
Streptomycin was inactivated in the presence of ATP and magnesium ion by an enzyme preparation made from E. coli K 12 ML 1629 which is resistant to streptomycin. The structure of the inactivated streptomycin was determined, and it was found that the hydroxy group on C-3 of the N-methyl-L-glucosamine moiety of streptomycin is adenylylated.
The biosynthesis of 3-amino-3-deoxy-D-glucose by Bacillus aminoglucosidicus was studied. Incorporation of C-1-, C-2-, C-6- and C-U-labeled glucoses into the aminosugar was proved. The aminosugar was synthesized in a cellfree system by a route which involved UDP-D-glucose. It was synthesized from enzyme solution, UDP-D-glucose, DPN and glutamine or ammonia.
Polyoxin inhibited the growth of a number of fungi with Pellicularia sasakii and Rhizoctonia solani being the most sensitive. The growth of P. sasakii in shake culture was inhibited completely at all growth stages by the antibiotic. P. sasakii which had been treated with polyoxin resumed growing when transferred to fresh CZAPEK-Dox medium. The inhibitory action of polyoxin was prevented by the addition of certain nitrogen compounds to the media. Dipeptides were the most effective, while a number of amino acids and bases had no effect. Although the ultraviolet absorption spectrum of polyoxin was modified by the addition of many nitrogen compounds, there was no relationship between the shift in the ultraviolet spectrum and the antagonistic effect.
Data are presented on the antiworm activity of 74 natural and synthetic isothiocyanates. They were characterized by the values of ED100i. e. molar concentrations of the compounds in culture medium causing irreversible arrest of the motility of Turbatrix aceti at the end of 20 hours' action. Some data are discussed with respect to the relationships between the structure and the biological activity of isothiocyanates. Benzyl-, arylalkyl-, benzohydryl-, cinamoyl-, diphenyl-, derivatives of isothiocyanates and of polycondensed aromatic isothiocyanates were studied. Most of the described isothiocyanates were new compounds synthesized for the first time.
Data are presented on the antiworm activity against Turbatrix aceti of 66 isothiocyanates derived from stilbene, azobenzene, arylalkylsulphides, diarylsulphides, arylalkylsulphones, diarylsulphones, as well as 4-terphenyl isothiocyanates, 4-phenoxyphenyl, diphenylmethane, and diphenylamine derivatives of isothiocyanates. A noteworthy activity against T. aceti has been found for 4-substituted phenoxyphenylisothiocyanates, 4-methylsulphidphenylisothiocyanates, 4-methylsulphonephenylisothiocyanates, and 4-benzylsulphidphenylisothiocyanate.