Microcalorimetric studies of the effect of cerium (Ш) on isolated rice mitochondria fed by pyruvate

Mitochondria were isolated from the hybrid rice Xiangzaoxian 31, then the effects of low and high concentrations of Ce (Ш) on metabolism of mitochondria fed by pyruvate were investigated respectively, by microcalorimetry and oxygen electrode method The thermogenic curve of mitochondria without Ce (Ш) could be divided into three parts: activity recovery phase, stationary phase and decline phase. And the thermokinetic parameters have been calculated through the metabolic thermogenic curves. With addition of different concentrations of Ce (Ш), the results demonstrated that low levels of cerium ion stimulated the metabolic activity of energized mitochondria and the inhibition was discovered with high concentrations of Ce (Ш). At the same time, it is shown that the effect in respiration correspond to the effect on mitochondrial metabolism on addition of different concentrations of Ce (Ш). Moreover, the addition of low and high concentrations of Ce (Ш) had no obvious effect on the total heat output (Q). The concentration-dependent effect of Ce (Ш) on metabolism of mitochondria is similar to plant growth response to rare earth elements (Hormesis effect).

► We obtain the thermogenic curves of energized mitochondria with Ce (Ш) incubation.
► The metabolism of mitochondria is stimulated by low concentrations of Ce (Ш).
► Rice mitochondrial metabolism is inhibited by high concentrations of Ce (Ш).
► Metabolism of rice mitochondrial is a character of hormesis with Ce (Ш) treatment.
► The addition of Ce (Ш) have little effect on total heat in mitochondrial metabolism.