title: [DNA-dependent RNA polymerase activity of isolated zooflagellates (Crithidia oncopelti) nucleoli].
abstract: A fraction of nucleoli is isolated from zooflagellates (Crithidia oncopelti) nuclei, its DNA-dependent RNA polymerase activity is studied at different temperature, ionic strength and Mg2+, Mn2+ and antibiotic concentrations. The effect of some factors and alpha-amantine on RNA polymerase activity of exonucleolar chromatin was studied as a control. A comparison of heat denaturation of nucleoli and chromatin RNA polymerase activities within the temperature range 30--55 degrees C has revealed a higher thermosensitivity of nucleoli RNA polymerase. Substitution of Mg2+ with equivalent amount of Mn2+ results in a considerable decrease of rRNA synthesis in nucleoli. Nucleoli RNA polymerase activity in the presence of Mg2+ is sensitive to the elevation of ionic strength from 0.12 to 1.30 u; chromatin RNA polymerase activity in the presence of Mn2+ is maximal at high ionic strength (1.30 mu). alpha-Amantine and cycloheximide at high concentrations (10 and 200 mkg/ml) practically do not affect RNA polymerase activity of nucleoli. Nucleoli RNA polymerase of zooflagellates (Crithidia oncopelti) is similar to the A-form of the enzyme in higher eukaryotes.
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D002466:Cell Nucleolus / Q000201:enzymology; D002843:Chromatin / Q000201:enzymology; D003513:Cycloheximide / Q000494:pharmacology; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D056890:Eukaryota / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009994:Osmolar Concentration; D011489:Protein Denaturation; D012335:RNA, Ribosomal / Q000096:biosynthesis
chemical_list: D000546:Amanitins; D002843:Chromatin; D012335:RNA, Ribosomal; D008345:Manganese; D003513:Cycloheximide; D012321:DNA-Directed RNA Polymerases; D008274:Magnesium
vernacular_title: DNK-zavisimaia RNK-polimeraznaia aktivnost' izolirovannykh fadryshek zooflagelliat Crithidia oncopelti.