ULTRASTRUCTURAL CHARACTERISTICS OF MITOCHONDRIA DURING CELL ADAPTATION TO ROTENONE
ACTION
E. N. Bufetov,1 O. O. Polygalova, A. A. Ponomareva
Institute of Biochemistry and Biophysics, Kazan' Scientific Centre RAS, Kazan', Russia;
1 e-mail: ponomareva@mail.knc.ru
A study was made of respiration, heat production, K+ output and ultrastructure of wheat root cells treated for 6 h with rotenone (10 mM), an inhibitor
of HADH-ubiquinone oxidoreductase (Complex I). Besides, the involvement of alter native pathways for adaptation to this inhibitor was studied. After 20 min of treatment, a
brightened mitochondrial matrix and mitochondria with torus shapes were observed. We propose that the outer area of mitochondria increases due to their torus shapes,
and this can point to the activating of extremal NAD(P)H-dehydrogenase, which uses enternal NAD(P)H. Further on the normal ultrastructure of mitochondria was observed,
which may result from activation of succinate dehydrogenase and rotenone resistant NAD(P)H-dehydrogenase. After 1 h of treatment, a decrease in respiration, heat production,
K+ output and pH increase of incubation medi-um were obs srved. Starting from 2 h of incubation and up to the end of the experiment, an increase of respiration
and heat pro luction was observed, pointing to the activation of oxidative phosphorilation. Besides, re-entry of K+ and pH decrease in the incubation medium were
observed. We conclude that these findings may indicate to a possible adaptation of root cells to this inhibitor. We propose that the torus shape of mitochondria may be associated
with function of external NAD(P)H-dehydrogenase.
Key words: respiration chain, rotenone, torus shape of mitochondria
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