RT Journal Article SR Electronic(1) A1 FRANGOU-LAZARIDIS, MARIA A1 SEDDON, BARRIEYR 1985 T1 Effect of Gramicidin S on the Transcription System of the Producer Bacillus brevis Nagano JF Microbiology, VO 131 IS 3 SP 437 OP 449 DO https://doi.org/10.1099/00221287-131-3-437 PB Microbiology Society, SN 1465-2080, AB The effect of the peptide antibiotic gramicidin S, produced by Bacillus brevis Nagano, was tested on the transcription system of the producer by using in vivo, semi in vitro and in vitro systems for studies of RNA synthesis. The effects of other peptide antibiotics (linear gramicidin, tyrocidine and tyrothricin) were also tested for comparison. It was found that (a) RNA polymerase isolated from either gramicidin S-producing or non-producing strains had a similar structure and requirements and that (b) the presence of gramicidin S caused a very strong inhibition of the in vitro transcription system. We present evidence that this inhibition is most probably through formation of a complex between the antibiotic and the DNA. In vivo studies indicate that transcription during growth and sporulatio is not affected by gramicidin S and the implication is made that gramicidin S inhibits transcription during germination and outgrowth., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-131-3-437