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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 410

Kim, J.V., Kudzina, L.J., Zinchenko, V.P., and Evtodienko, J.V.; Ca2+ transport in mitochondria of the ciliate protozoan Tetrahymena pyriformis. Cell Calcium 5:29-41, 1984

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Mitochondria isolated from the late-exponential non-shaken culture of the ciliate protozoan Tetrahymena pyriformis GL was investigated. The presence of energy-dependent Ca2+ transport system was shown. In the main the properties of this system have been essentially the same as in mitochondria of vertebrate organisms. The isolated mitochondria contained 23+/-5 ng-ion Ca2+ per mg of protein. The intramitochondrial free concentration of Ca2+ was measured in the presence of uncoupler FCCP with the use of fluorescent Ca2+ chelator chlortetracycline and null point titration method. In the absence of phosphate, free [Ca2+] varied from 1 to 2.5 mM depending on the internal Ca2+ content. In the presence of 2 mM phosphate, free [Ca2+] ion has not exceeded 0.1-0.3 mM. It was shown that ruthenium red and Mg2+ in different manner have an inhibitory effect on Ca2+ transport. Besides this, Mg2+ also has a stabilizing effect on mitochondria, possibly, by preventing passive ions leaks across the membrane.