Carbohydrate metabolism in Onchocerca gutturosa and Onchocerca lienalis (Nematoda:Filarioidea)

Abstract

Dunn T. S., Raines P. S., Barrett J. and Butterworth P. E. 1988. Carbohydrate metabolism in Onchocerca gutturosa and Onchocerca lienalis (Nematoda:Filarioidea). International Journal for Parasitology 18: 21–26. Adult O. gutturosa and O. lienalis have a complete sequence of glycolytic and tricarboxylic acid cycle enzymes. The relative activities of the glycolytic enzymes are similar to those found in other glycolytic tissues. A comparison of the mass action ratios of the glycolytic enzymes with their apparent equilibrium constants indicates that phosphorylase, hexokinase, phosphofructokinase and pyruvate kinase are non-equilibrium regulatory enzymes. There is also some evidence that aldolase may be pseudo-regulatory under conditions of high flux. Both O. gutturosa and O. lienalis have measureable amounts of fumarate reductase activity as well as phosphoenolpyruvate carboxykinase and NADP-linked malic enzyme. The two filariids appear to be essentially homolactic fermentors, the only other end-product being traces of alanine and occasionally succinate. The rate of lactate production was unaffected by the presence or absence of oxygen or by the presence or absence of exogenous glucose. Similarly, oxygen uptake by the two worms was unaffected by the presence or absence of exogenous glucose.