title: Mitochondrial flocculent densities in ischemia. Digestion experiments.
abstract: Flocculent densities appear in the mitochondrial matrix during ischemic damage. These densities were examined in kidneys after 2 hours of autolysis. The samples were embedded in water-miscible glycol methacrylate (GMA). Ultrathin sections on copper grids were digested with pronase, trypsin, ribonuclease T1, various phospholipases (A2, C, D), lipase, and desoxyribonuclease I. For statistical analysis the mean number (+/- SD) of densities per mitochondrion was determined in tubular epithelial cells. A statistically significant (p less than 0.001) decrease in the number of densities was apparent after treatment with pronase (75.5%) of the densities digested completely) and with trypsin (43.3% of the densities digested completely). Digestion with other enzymes did not significantly decrease the number of densities. This study provides quantitative support for the hypothesis that flocculent densities are composed of proteins, most probably mitochondrial membrane proteins or matrix proteins. The results do not support the hypothesis that RNA, neutral lipids, phospholipids or DNA are major constituents of these structures.
mesh_terms: D000818:Animals; D004798:Enzymes; D005427:Flocculation; D007511:Ischemia / Q000473:pathology*; D007668:Kidney / Q000098:blood supply / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000032:analysis*; D011506:Proteins / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D004798:Enzymes; D011506:Proteins