[DNA-dependent RNA-polymerase activity of isolated kinetoplasts of crithidia oncopelti].

DNA-dependent RNA-polymerase activity was found in the kinetoplasts of Crithidia oncopelti. Kinetic patterns of 14C-UTP incorporation into the acid-insoluble fraction of isolated kinetoplasts at 25 degrees, 30 degrees and 35 degrees C were estimated. The effects of different antibiotics and intercalating agents on RNA synthesis in kinetoplasts were studied. alpha-amanitin, a specific inhibitor of the nuclear enzyme, does not affect the RNA-polymerase activity of the kinetoplasts. Streptolidigin and rifampicin, inhibitors of bacterial RNA-polymerase, have little effect on RNA synthesis in the kinetoplasts even at high concentrations. Kinetoplasts preincubation in the phosphate buffer increases the permeability of their membranes for rifampicin. Intercalating agents, acriflavin and ethidium bromide, strongly inhibit the kinetoplast RNA synthesis. Similar specific effects of some antibiotics and intercalating agents on RNA synthesis in kinetoplasts and typical mitochondria may be indicative of similarity of functional properties of RNA-polymerases in those organelles.