Purification of the helical filaments appearing in mitochondria

Abstract

Helical filaments with characteristic morphology have been found exclusively in the outer compartment of mitochondria in the epithelial cells of renal proximal tubules of patients, and in the brain astrocytes, the ameloblasts and the epithelial cells of renal medullary tubules of the normal rats, and in the liver parenchymal cells of the rats with and without ethanol ingestion. Recently, the filaments with same helical structure found in the mitochondria of the certain parasite. Thus, the intramitochondrial helical filaments appeared widely in biological fields. However, the nature, origin and physiological significance of the helical filament are at present unknown. In the present study, to clarify the molecular arrangement of the helical filament, the filaments were purified from the mitochondriaof the liver of ethanol ingested rats in which have been confirmed to appear large amount of the helical filaments in mitochondria.Male S-D strain rats (6-week old) were used in the present study. Rat were given 30% ethanol for 90 days with oral administration. With conventional TEM observations, the helical filaments were frequently found in mitochondria of liver cells of the rat with ethanol ingestion (Fig. 1). For purification of the helical filaments, the mitochondria were isolated from ethanol ingested rats liver cells by slightly modified Bustamante et al. method. The isolated mitochondria were ruptured by osmotic breakage.