Inhibition of messenger ribonucleic acid synthesis in Escherichia coli by thiolutin

Thiolutin, at concentrations of 5 to 40 mug/ml, inhibited the induced synthesis of beta-galactosidase in Escherichia coli CA8000. Thiolutin had no effect on the rate of in vitro hydrolysis of o-nitrophenyl-beta-d-galactoside by purified beta-galactosidase. Examination of the effects of thiolutin on the kinetics of appearance of beta-galactosidase in the presence and absence of rifampin in induced E. coli cells indicated that thiolutin interferes with the transcription process at the level of elongation of messenger ribonucleic acid (mRNA) chains. The data indicated that, in the presence of thiolutin, beta-galactosidase mRNA has a half-life of 1.6 min and that the first completed beta-galactosidase mRNA is produced about 1.5 min after induction. These data are consistent with estimates of transcription time and messenger half-life obtained by conventional means, and suggest that thiolutin does not affect translation of mRNA or its breakdown in vivo. After removal of thiolutin, cells fully regained the ability to be induced for synthesis of beta-galactosidase within 10 min, but mRNA which was incomplete at the time of thiolutin addition did not subsequently become functional

Transgenic plants and crops

xxii, 876 p. : ill. ; 26 cm

In Vivo Effect of Thiolutin on Cell Growth and Macromolecular Synthesis in Escherichia coli

Thiolutin reversibly inhibits growth and ribonucleic acid synthesis in Saccharomyces cerevisiae. It is now demonstrated that, at 5 μg/ml, thiolutin rapidly inhibits all incorporation of radioactive precursors into ribonucleic acid and protein in Escherichia coli, although the incorporation of deoxythymidine into deoxyribonucleic acid continues for some time. Concentrations of thiolutin of 5 μg/ml and above are bacteriostatic and do not lead to unbalanced growth, so that cell size remains constant. The antibiotic and its inhibitory effects are easily removed by washing, whereupon macromolecular synthesis and cell division resume unimpeded. These data are consistent with reversible inhibition of ribonucleic acid synthesis being the primary mode of action of thiolutin in E. coli, and suggest that thiolutin may be a useful tool for studies where such reversible inhibition is required