Abstract
Pluramycin A, an antitumor and antibacterial antibiotic produced by Streptomyces pluricolorescens, inhibits protein and nucleic acid syntheses by intact cells of E. coli B at the concentration innocuous to energy generation. Synthesis of DNA was most profoundly and that of RNA significantly inhibited by this antibiotic. When total RNA was separated into sRNA, 16S RNA, 23S RNA and mRNA by MAK column or sucrose density gradient centrifugation, all species of RNA were shown to be inhibited at the same level. The results were in accordance with those of shift up and shift down experiments. The inhibition of protein synthesis was chiefly attributed to the secondary effect produced by insufficient supplement of mRNA. The same tendency of inhibition by pluramycin A of DNA, RNA and protein syntheses was observed with HeLa cells in tissue cultures.
