Complementation of an Escherichia coli glycolysis mutant by Giardia lamblia triosephosphate isomerase.

The Giardia lamblia triosephosphate isomerase (TIM) gene was cloned using a probe generated by a polymerase chain reaction that employed primers complementary to highly conserved regions of TIM. The nucleotide sequence predicts a protein that is 38 and 47% identical to TIM from prokaryotic and eukaryotic sources, respectively. Like all other Giardia protein-coding genes studied thus far, the TIM gene lacks introns and is transcribed to yield a polyadenylated mRNA with an extremely short 5' untranslated region.

Purification and biochemical properties of calmodulin in Entamoeba histolytica and its distribution during secretion of electron-dense granules.

1. Calmodulin (CaM) was detected during secretion of electron-dense granules by Entamoeba histolytica trophozoites with immunofluorescence. 2.

Binding of tricyclic antidepressant drugs to trophozoites of Giardia lamblia.

1. Parameters affecting the binding of the tricyclic drugs imipramine and 3-chloroimipramine to Giardia lamblia trophozoites were studied. 2.

The activity of tricyclic antidepressant drugs against Trypanosoma cruzi.

Imipramine and related derivatives were tested as possible chemotherapeutic agents against Trypanosoma cruzi parasites in vitro. The IC50 values and the lethal concentrations for two cloned stocks of the parasite were determined. 2-Nitrodesmethylimipramine was the most effective compound tested (IC50 = 4-7 microM).

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.

Effects of succinylacetone on growth and respiration of L1210 leukemia cells.

4,6-Dioxoheptanoic acid (succinylacetone, SA), a potent inhibitor of heme biosynthesis, suppressed growth and decreased respiration of L1210 leukemia cells in vitro. Growth of cells incubated in the presence of 2--4 mM SA for the first 2 days declined, and after 3 days virtually ceased. L1210 cells in the logarithmic growth phase exhibited active respiration (40 +/- 9.

Antidepressant drugs suppress growth of the human pathogenic protozoan Giardia lamblia.

The tricyclic antidepressant drug chlorimipramine, some of its congeners, and its mammalian metabolites inhibited the growth in vitro of the human intestinal pathogen Giardia lamblia. The inhibitory action may reside in their ability to inhibit the membrane-associated ATPase characteristic of eukaryotes. Synthesis of other compounds of the tricyclic class may produce drugs of potential therapeutic use in the treatment of giardiasis and possibly other protozoal diseases.

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.

Mechanism of L-serine oxidation in Entamoeba histolytica.

1. The enzymatic mechanism of oxygen uptake elicited by L-serine in axenically cultivated trophozoites of Entamoeba histolytica was investigated. 2.

Incorporation of calcium into the soft tissues and calcareous corpuscles of larval Taenia taeniaeformis.

Larval Taenia taeniaeformis in vivo accumulates 45Ca2+ in soft tissues and calcareous corpuscles. Radioactivity was demonstrable in the corpuscles six months after a single dose of 45Ca2+ was administered to the host by means of a stomach tube. Ca2+ also was taken up by isolated larvae.

Oxygen consumption of human blood platelets. II. Effect of inhibitors on thrombin-induced oxygen burst.

The effect of selected inhibitors on the thrombin-stimulated burst and the basal oxygen consumption of washed human platelets were investigated and compared with inhibition of the release reaction. Cyanide (0.2 mM) caused complete inhibition of the basal respiration, but only 15% inhibition of the thrombin-stimulated burst of oxygen consumption.

Oxygen consumption of human blood platelets. I. Effect of thrombin.

The effect of thrombin on the oxygen consumption of washed human platelets was measured polarographically with the Clark oxygen electrode. The average basal respiratory rate was 18 plus or minus 1.6 (mean plus or minus S.