Calcium transport and catabolism of adenosine triphosphate in the protozoan parasite Giardia lamblia.

1. Calcium uptake by washed trophozoites of Giardia lamblia was dependent on inorganic orthophosphate and stimulated by glucose. Uptake was both rapid and substantial: 224 +/- 73 nmoles Ca2+/mg protein/min.

Giardia lamblia: detection and characterization of calmodulin.

Calmodulin was detected in Giardia lamblia by radioimmunoassay and cyclic AMP phosphodiesterase activation. This protein was purified to apparent homogeneity by fast protein liquid chromatography with a yield of 260 ng of calmodulin/mg of protozoan protein. Purity was established by gel electrophoresis, gel filtration, and ion exchange chromatography.

Effects of tricyclic antidepressant drugs on energy-linked reactions in mitochondria.

The effects of impramine and chlorimipramine on energy-linked reactions in mitochondria were characterized. Both compounds exhibited some characteristics of classical uncouplers of oxidative phosphorylation, i.e.

Reserpine as an uncoupler of oxidative phosphorylation and the relevance to its psychoactive properties.

Many drugs differing widely in chemical structure uncouple mitochondrial oxidative phosphorylation in vitro. This observation has led to the hypothesis that in vivo uncoupling is the basis of their pharmacological activity. Serpasil, a parenteral preparation of reserpine, recently has been shown to uncouple oxidative phosphorylation in vervet monkey kidney mitochondria.