title: Decay of ribonucleic acid synthesis in amino acid-starved Escherichia coli after rifampin treatment.
abstract: The concentration of rifampin necessary to affect the initiation of ribonucleic acid (RNA) synthesis quickly in Escherichia coli strains K-12 and 15TAU was about 200 mug/ml, as determined by extrapolation of the effect of the drug on the induction of beta-galactosidase synthesis. A lag in the action of rifampin of about 10 s was confirmed. Rifampin was then used as a probe to compare RNA synthesis in growing and amino acid-starved E. coli. Restoring arginine to arginine-starved strain 15TAU immediately after rifampin inhibition did not detectably restore the rate of uracil uptake to that of uninhibited cells. The residual rate of RNA synthesis (corrected for acid-soluble triphosphate specific activities) after rifampin treatment of both growing and isoleucine-starved (valine-inhibited) cultures of strain K-12 showed similar decay kinetics. These findings support the notion that amino acid starvation blocks the initiation of some RNA transcription units, but do not rule out other possibilities.
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D001120:Arginine / Q000378:metabolism; D002250:Carbon Radioisotopes; D003470:Culture Media; D012321:DNA-Directed RNA Polymerases / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D004926:Escherichia coli / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D005696:Galactosidases / Q000096:biosynthesis; D007532:Isoleucine / Q000378:metabolism; D009154:Mutation; D010761:Phosphorus Radioisotopes; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012293:Rifampin / Q000494:pharmacology*; D013053:Spectrophotometry; D013997:Time Factors; D014158:Transcription, Genetic; D014316:Tritium; D014498:Uracil / Q000378:metabolism
chemical_list: D000596:Amino Acids; D002250:Carbon Radioisotopes; D003470:Culture Media; D010761:Phosphorus Radioisotopes; D012329:RNA, Bacterial; D007532:Isoleucine; D014316:Tritium; D014498:Uracil; D001120:Arginine; D012321:DNA-Directed RNA Polymerases; D005696:Galactosidases; D000241:Adenosine; D012293:Rifampin