Rancinamycins I, II, III and IV are secondary metabolites produced by Streptomyces lincolnensis in a sulfur-depleted culture medium. Rancinamycins I and II, the main components of the mixture, show broad spectrum antibiotic activity in vitro. Subcutaneously injected or orally administered antibiotic afforded no protection for experimentally infected mice against lethal challenges of Staphylococcus aureus. Radioactive tracer studies failed to demonstrate that the rancinamycins were precursors in the biosynthesis of lincomycin.
Rancinamycins are secondary metabolites produced by Streptomyces lincolnensis in a sulfur-depleted culture medium. The structures (except stereochemistry) of the main components of the rancinamycin-complex were determined by the use of IR, UV, PMR and CMR spectra.
Two metabolites have been isolated from the fermentation broth of a new species of Kitasatoa, Kitasatoa griseophaeus. These alkaloids have been identified as quinoline-2- methanol and quinoline-2-methanol acetate. The former exhibits hypoglycemic activity in the rat.
A new antifungal antibiotic was isolated from the fermentation broth of Streptolnrces sp. 5140-A1. Degradation studies of the crystalline antibiotic, m.p. 186-188°C, C21H28O8N2, suggested its structure to be deisovaleryl-blastmycin. It exhibited antimicrobial activity against Piricularia oryzae and less toxicity against killifish than antimycin A-blastmycin antibiotics.
A new antibiotic, named 339-29, active against Gram-positive bacteria was isolated from a strain of Bacillus pumilus. The hydrochloride is soluble in water and aqueous alcohols. The antibiotic is a basic peptide containing valine (3), isoleucine (1), leucine (2), tyrosine(1), lysine (3) and a fatty acid.
A new peptide antibiotic complex, B-43, active against Gram-positive and Gram-negative bacteria, was isolated from a strain of Bacillus circulans. This antibiotic contains aspartic acid, valine, isoleucine, leucine, phenylalanine and 2, 4-diaminobutyric acid. It seems to be related to polypeptin and antibiotic complex 4205, but differs in that it contains aspartic acid residue.
Streptomyces sp. strain No. K-245 was found to transform maridomycin III into four derivatives (A1, A2, A3 and A4) in addition to the transformation products reported previously. Isolation of the main product A1 was carried out by column chromatography on silica gel developed with CHCl3-MeOH (19:1). From the partial investigation of the structure of A1 it proved to have a C 18-aldehyde group and C 4"-propionyl group but no antimicrobial activity. The relationships between A group's derivatives and known derivatives of maridomycin III are also discussed.
A radioimmunoassay (RIA) has been developed using 125I-amikacin. Amikacin was iodinated by a modified BOLTON and HUNTER method. Dextran-charcoal was used to separate bound from free drug. The standard curve was linear on a logit-log plot in the range of 0.5ng to 4ng amikacin per tube. There was no cross-reactivity of amikacin antisera to the aminoglycosides gentamicin, tobramycin, netilmicin, and sisomicin but a 70% cross-reaction was observed with kanamycin, the compound from which amikacin is synthetically derived. Correlation of the RIA with a microbioassay for the determination of serum amikacin levels in 18 patient samples was excellent (r=0.94). This new RIA technique is more sensitive, rapid, versatile, and less costly than the RIA using 3H-amikacin, and is far more sensitive and faster than microbioassay.
The nephrotoxicity of rats caused by dibekacin (3', 4'-dideoxykanamycin B) or kanamycin, with or without dextran was effectively reduced by D-glucaro-δ-Iactam potassium salt, as evidenced by lower levels of blood urea nitrogen and kidney edema rate, better excretion of antibiotics, and less morphological damage. Protection was dosage related, and potentiated with increasing doses, but only when the two drugs were given simultaneously. Among three alkali-metal salts examined, the potassium salt was almost equal to the lithium salt, but surpassed the sodium salt in effectiveness. Inorganic salts, in particular potassium chloride were found to be effective for the protection of normal rats, but their effect decreased for the dehydrated rats, especially in the presence of dextran.