[Repair of mitochondrial DNA after x-ray irradiation of teleost fish loach Misgurnus fossillis eggs].

: X-ray irradiation of loach Misgurnus fossilis mature eggs induces breaks in mtDNA molecules with efficiency about 100 ev per break. The yield of damaged molecules of mtDNA reduces after fertilization or activation of irradiated eggs and subsequent incubation. Two-fold reduction in the relative amount of broken DNA molecules in mitochondria is observed after an 6-7 hour incubation. X-ray irradiation largely accelerates mtDNA synthesis in eggs. Activation of mtDNA synthesis is observed in whole irradiated eggs and in mitochondria isolated from them as well. Appearance of nascent DNA in the broken mtDNA molecules indicates the repair nature of mtDNA synthesis induced by X-irradiation.