Regulation of oxygen consumption and cytochrome oxidase activity after artificial increase of mitochondrial content in fish embryos
Abramova, N.B.; Korzh, V.P.; Neifakh, A.A.
Biokhimiia 45(6): 1124-1132
1980
ISSN/ISBN: 0320-9725 PMID: 6260239 Document Number: 165386
The amount of mitochondria in loach embryos (M. fossilis) was artificially increased by microinjecting isolated mitochondria into the eggs and mitochondrial concentration, by centrifuging the eggs or translocation of the mitochondria from the egg yolk to the blastodisc during egg centrifugation. Cytochrome oxidase activity of such embryos was 1.5-2 times higher than control. After mitochondrial injection into the oocytes of loach and amphibia their increased cytochrome oxidase activity remained unchanged for > 72 h. In the developing embryos the increased cytochrome oxidase activity gradually returned to normal; upon injection of isolated mitochondria, after 12-16 h; upon injection of a layer of concentrated mitochondria, after 22-24 h; upon translocation of yolk mitochondria into the embryo, after 30-40 h. The synthesis of mitochondrial proteins in the embryos with increased mitochondrial content was decreased 2-fold, which can be due to a compensatory mechanism controlling the mitochondrial content. The respiration of intact eggs and isolated embryos with the increased mitochondrial content attained the control level; when calculated per unit of the cytochrome oxidase activity, it was 5 times lower than control. The respiration rate of the embryos is subjected to regulation and within certain limits, is independent of the amount of mitochondria. Apparently, mechanism controls the amount of mitochondria.