Under electron microscope, the matrix of sectioned mitochondria exhibits ribosomes and an oval, electron-transparent zone which is devoid of ribosomes and is named chondriolite. Fine fibers or clumps of an electron-dense material appeared in this zone after several fixation and contrasting steps and were identified with mitochondrial DNA by cytologists. To verify this assumption, we labeled DNA by a monoclonal antibody and a secondary antibody coupled to immunogold. The label was observed in the nucleus and in the chondriolite zone of sectioned mitochondria. Because the ultrastructure of chondriolites resembles that of nucleoids of prokaryotes, we suggest the term mitochondrial nucleoid for the zone of mitochondrial matrix devoid of ribosomes and containing DNA.

• MeSH
• Aspartate Carbamoyltransferase analysis   MeSH
• DNA, Fungal analysis   MeSH
• Microscopy, Immunoelectron methods   MeSH
• Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) analysis   MeSH
• DNA, Mitochondrial analysis   MeSH
• Mitochondria chemistry   ultrastructure   MeSH
• Multienzyme Complexes analysis   MeSH
• Saccharomyces cerevisiae Proteins * MeSH
• Saccharomyces cerevisiae chemistry   genetics   ultrastructure   MeSH
• Submitochondrial Particles chemistry   ultrastructure   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Aspartate Carbamoyltransferase MeSH
• DNA, Fungal MeSH
• Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) MeSH
• DNA, Mitochondrial MeSH
• Multienzyme Complexes MeSH
• Saccharomyces cerevisiae Proteins * MeSH
• URA2 protein, S cerevisiae MeSH Browser