Effect of 2-deoxy-D-glucose on Herpetomonas samuelpessoai

Abstract

The effect of 2-deoxy-D-glucose (2-DG), a carbohydrate analogue, on growth, respiration and fine structure of Herpetomonas samuelpessoai is described. In a glucose-free medium, 2-DG inhibited growth down to 7% that of the control. In presence of equal concentrations of glucose, the inhibition by 2-DG was 55%. With 5 times as much 2-DG as glucose, the inhibition was 88%. Increase in 2-DG in relation to glucose resulted in a progressive inhibition of H. samuelpessoai. Only glucose, fructose of glycerol reversed the inhibition caused by 2-DG in H. samuelpessoai. Glucose was more active than glycerol and fructose. Protection against 2-DG toxicity was confirmed by respirometry experiments. Oxidation of glucose was less affected by 2-DG than that of fructose and glycerol. In presence of 2-DG the cells became round to oval and showed some granules in the cytoplasm. In control cells the mitochondrial cristae were short and straight while in cells treated with 2-DG they were longer and curved. Morphometric analysis of electron micrographs showed that the mitochondrial relative volume of normal cells was 0.084 +/- 0.018 while in treated cells were 0.166 +/- 0.030. Results are discussed in relation to the carbohydrate metabolism and the mode of action of 2-DG.

Biology and physiology of the lower Trypanosomatidae.

“…There have been few systematic studies of membrane transport in the lower trypanosomatids, although reports (23,96,226) concerned mainly with other aspects of the cell biology of these organisms have provided some insights into transport properties. Min (184,185) showed that both C. luciliae and Crithidia arili have specific, saturable transport of monosaccharides.…”

“…He did not attempt to isolate putative carrier molecules. Rembold et al (228) suggested that glucose and galactose share a common transport site in C. fasciculata, and Bunn et al (23) suggested that inhibition of membrane transport of fructose, glucose, and glycerol by 2-deoxyglucose is the basis for its inhibition of growth and respiration in H. samuelpessoai. Rembold and co-workers (227,228) reported that C. fasciculata has separate active transport systems for biopterin, folic acid, and riboflavin; they also reported that the system for biopterin is inhibited by cyanide and dinitrophenol and by increased concentrations of Na+, but is stimulated by increased K+.…”

Biological effects of lithium chloride on the insect trypanosomatidHerpetomonas samuelpessoai

“…The more differentiated opisthomastigote emerges at the stationary phase of growth and also when cell growth is inhibited (Roitman et al 1976;. In addition, this flagellate is able to oxidize carbohydrates and amino acids by an active aerobic metabolism (Bunn et al 1977).…”