Di- and triacetyl derivatives of mycobacillin, a cyclic peptide, have been prepared. Acetylation lowers its antifungal activity, the inhibitory concentration (μg/ml) for the diand triacetyl derivatives being 35-40 and 40-45 respectively as against 15-20 for mycobacillin; but acetylation gives complete protection against serum inactivation of the antibiotic whose inhibitory concentration is increased tenfold in its presence.
A new antibiotic was isolated from the fermentation broth of an unclassified species of Streptomyces. The antibiotic activity against Serratia sp. and Bacillus subtilis, grown in a chemically defined minimal medium, was reversed by the addition of L-glutamine to the medium. Physical chemical characterization of the antibiotic and of the chemical and enzymatic degradation products revealed the structure to be L-(N5-phosphono)methionine-S-sulfoximinyl-L-alanyl-L-alanine.
Effects of bihoromycin on the respiration, protein and nucleic acid syntheses of Piricularia oryzae was investigated, and a marked inhibition of nucleic acid synthesis was observed. Further experiment using Bacillus subtilis revealed that DNA synthesis was more profoundly affected than RNA synthesis by the antibiotic. When leaves of pinto-bean and tobacco were treated with bihoromycin, it was found that the former plant was highly sensitive to the antibiotic.
The isolation and characterization of myomycin, a new broad spectrum antibiotic, are described. The isolation of myo-inositol, L-β-lysine and 3-amino-3-deoxy-D-mannose from hydrolyzates of myomycin established it to be an unusual member of the basic, water soluble family of cyclitol antibiotics.
A new crystalline amino acid was isolated from the fermentation broth of a Bacillus species and identified as N5-hydroxy-L-arginine. This compound possesses antimicrobial activity against several microorganisms, including Escherichia coli, which is reversed by L-arginine and related compounds.
D, L-3-Hydroxy-4-methylkynurenine was prepared from 3-methoxy-4-methylanthranilic acid and found to be a competitive precursor with L-tryptophan in the biosynthesis of actinomycin D by Streptomyces antibioticus (ATCC 14888).
BB-K8 (1) is a new semisynthetic derivative of kanamycin acylated with L(-)-Υ-ammo-α-hydroxybutyric acid (L-HABA) at the C-l amino group of the 2-deoxystreptamine moiety. The chemistry1) and antimicrobial activity1, 2)) of BB-K8 have been reported. The present paper describes the two configurational isomers of BB-K8, which bear the DL- and D-HABA residue at the C-l amino group of kanamycin A, as well as the three positional isomers of BB-K8, which are acylated with L-HABA at the C-3, C-6' and C-3" amino groups of kanamycin A.