Purification and properties of nucleic acids from an unusual cytoplasmic organelle in the flagellate protozoan Crithidia oncopelti.

A simple, rapid method for preparing bipolar bodies from sonicated (rithidia oncopelti cells, with a yield of 2-5%, is described. Apart from 2-4% contamination with unbroken cells the fraction was considered pure with respect to contamination by other nucleic acid-containing organelles, as judged by light and electron microscopy. A light satellite DNA, f bouyant density 1.695 g/ml in neutral CsCl, and derived from the bipolar body, had a Tm of 81.6 degrees C in0.15 M NaCl/0.015 M sodium citrate (pH 7.0) and a kinetic complexity of 2.7 with 109. The bipolar body fraction also contained ribonucleoprotein particles with and s20,w of 67 S, in contrast to cytoplasmic ribosomes (87 S). Bipolar body ribosomes contained rRNA components which migraged coincidentally with Escherichia coli rRNA (molecular weights 1.07 with 10-6 and 0.56 with 10-6) on polyacrylamide gel electrophoresis. Cytoplasmic ribosomes contained rRNAs of molecular weights 1.30 with 10-6 and 0.83 with 10-6. Bipolar body rRNA accounted for up to 10% of the rRNA extracted from cells. The properties of these bipolar body nucleic acids provide good evidence for the bacterial nature of this subcellular component.