THE ROLE OF TREHALOSE IN THE PHYSIOLOGY OF NEMATODES

The sugar trehalose, an alpha-1-linked non-reducing disaccharide of gl ucose, is important in the physiology of many micro-organisms as well as in some groups of metazoan organisms, including insects and nematod es. Trehalose is a stress protectant in biological systems as it inter acts with and directly protects lipid membranes and proteins from the damage caused by environmental stresses such as desiccation and freezi ng. Trehalose is present in many nematode species where its concentrat ion often exceeds that of glucose but is usually lower than that of gl ycogen. In Ascaris suum it is found in all tissues, with highest conce ntrations in muscle, haemolymph and the female and male reproductive o rgans. Trehalose acts as an energy reserve in some nematodes and their eggs, and may be important in uptake of glucose; it appears to functi on as the major circulating blood sugar. Trehalose accumulates in nema todes that can withstand dehydration and may be important in supercool ing of nematodes or eggs that can withstand freezing. In many nematode s trehalose is also important in the process of egg hatching. The comb ined action of 2 enzymes, trehalose 6-phosphate (T6P) synthase and T6P phosphatase, catalyses the synthesis of trehalose in most organisms. Hydrolysis of trehalose to glucose is catalysed by trehalase. These en zymes have been detected in nematodes but the processes regulating the ir activity are unknown. Trehalose metabolism may provide new molecula r targets for attack in nematodes parasitic in mammals. (C) 1997 Austr alian Society for Parasitology. Published by Elsevier Science Ltd.