The new antibiotic sarubicin A [red crystals, mp. 194 approximately 195 degrees C, C18H14N2O6 (I)] was isolated from fermentations of a Streptomyces strain. The compound is moderately active in vitro against Micrococcus luteus.

A new unsaturated glutamic acid analog, 4-amino-3-chloro-2-pentenedioic acid ( ACPA ) was isolated from a fermentation broth produced by a strain of Streptomyces. ACPA has a very narrow antibacterial spectrum, which is virtually limited to Micrococcus luteus.

Chartreusin was produced in the fermentation liquors of Streptomyces chartreusis at peak concentrations of 200 to 300 mug/ml. The titers could be increased by 200 to 300% or more by incorporating d-fucose, a part of the chartreusin molecule, into the fermentation media. A microbiological assay with Sarcina lutea could detect concentrations of the drug of 0.5 to 1.0 mug/ml.

DNA-based stable isotope probing (SIP) is a novel technique for the identification of organisms actively assimilating isotopically labeled compounds. Herein, we define the limitations to using 15N-labeled substrates for SIP and propose modifications to compensate for these shortcomings. Changes in DNA buoyant density (BD) resulting from 15N incorporation were determined using cultures of dispar...

Many commonly used pharmaceutical agents have been found to inhibit bacterial growth in vitro. Determinations of antimicrobial concentrations in sera of patients taking nonrecognized antibacterial agents could possibly be altered if bioassay systems are utilized for the determinations. We therefore attempted to determine the in vitro effect of commonly used drugs on bioassay indicator organisms...