ACTIVITY AND ORIGIN OF DIGESTIVE ENZYMES IN GUT OF THE TROPICAL EARTHWORM PONTOSCOLEX-CORETHRURUS

Activities of glucidic digestive enzymes in the gut (content plus wall s) of a tropical endogeic earthworm, Pontoscolex corethrurus, have bee n assayed. In order to determine the origin of the enzymes found in th e gut, the wall tissues were cultured in vitro, and enzymatic activiti es were measured both in the cultured tissues and in the culture mediu m. The earthworm possesses a weak but quite complete enzyme system. In the gut, the enzymes were capable of degrading the following substrat es: heteroside (N-acetylglucosamine), oligosaccharides (maltose, lamin aribiose) and polysaccharides (starch, laminaran, pullulan, microcryst alline cellulose, carboxymethylcellulose, mannan, glucomannan and caro ub galactomannan, lichenin). The strongest enzymatic activities were l ocated in the foregut and midgut. Among the main enzymes found in the gut, cellulase and mannanase were neither detected, in the cultured ti ssues nor in the culture medium, which indicates that these two enzyme s were produced by micro-organisms ingested with the soil. The oligosa ccharidase and heterosidase activities were higher in the cultured tis sues than in the medium, which was not the case for the polysaccharida ses.