Circular DNA and cardiolipin in hydrogenosomes, microbody-like organelles of trichomonads.

Circular molecules of DNA approximately 3 mum in length were revealed by electron microscopy in deproteinized extracts prepared from purified hydrogenosomal fraction of a protozoan Tritrichomonae foetus. This fraction contained also cardiolipin amounting to approximately 14.4% of its total phospholipids, as detected by thin-layer chromatography and quantitative phosphorus measurement. These characteristics extend a number of biochemical properties of hydrogenosome shared also by mitochondria and by prokaryotic cells.