The occurrence of lichenase in the digestive tract of invertebrates

Abstract

A reducing sugar identified as glucose by the formation of the characteristic osazone was produced from lichenin (purified carbohydrate and crude extract of Iceland moss) by the action of extracts of the hepatopancreas or alimentary canal of twenty species of invertebrates, representing the following phyla; Porifera, Annelida, Echinodermata, Mollusca, Arthropoda, and Tunicata. No evidence of a lichenin-splitting enzyme was observed in twelve species of vertebrates, embracing the following classes: Pisces, Amphibia, Reptilia, Aves, and Mammalia. The activity of the preparations tested was in every case controlled by tests for an amylase, which was invariably found to be present. Extracts of muscle tissue of the crustaceans could not split lichenin. The constant occurrence of lichenase in the digestive tract of the invertebrates studied, suggests that the ability to hydrolyze lichenin may be a characteristic of invertebrates as contrasted with vertebrates. The presence of an inulase or raffinase in the species studied was not constant. Lichenase to judge from the present series of experiments is not invariably associated with inulase as has been suggested (existence of an inulo-lichenase). The following species were studied; sponge, earthworm, leech, starfish (2 species), sea urchin, chiton (2), mussel (s), snail (2), crab (2), shrimp, grasshopper, tunicate, gold fish, frog (adult and tadpole stages), horned toad, garter snake, terrapin (2), domestic fowl, wild rabbit, pig, sheep, dog, and man (saliva). The strongest reactions were obtained with the star fish (Asterias ochracea), snail (Planorbis trivolvunt), and grasshopper (Melano#lus diflerentialis).