MIRACIL D - EFFECTS ON NUCLEIC ACID SYNTHESIS PROTEIN SYNTHESIS AND ENZYME INDUCTION IN ESCHERICHIA COLI

When added to a culture of intact E. coli, Miracil D inhibits growth, causes virtually complete inhibition of total cellular RNA synthesis and partial inhibition of DNA and protein synthesis, and blocks the induction of [beta]-galactosidase. All of these toxic effects are prevented by simultaneous addition to the culture of spermine. Evidence is presented that spermine acts by blocking cellular uptake of Miracil D. An additional effect of spermine on the formation of the Miracil D-DNA complex is suggested. Miracil D also inhibits DNA-directed RNA synthesis with purified E. coli RNA polymerase but in the usual assay system it does not inhibit subcellular amino acid incorporation. Miracil D inhibits bacterial growth mainly by complexing with DNA, thereby blocking cellular RNA synthesis. The drug provides an interesting comparison to actinomycin D in terms of specificity and mode of action.[long dash]Authors.