Biochemical studies on Brachionus plicatilis: hydrolytic enzymes, integument proteins and composition of trophi

Abstract

An overview is provided of the results of biochemical investigations performed on the rotifer Brachionus plicatilis. Hydrolytic enzymes (mostly glycosidases and proteinases) from Brachionus plicatilis were examined in total homogenates and in fractions obtained by differential and by density gradient centrifugations. By this means (1) soluble, (2) membrane associated and (3) lysosomal enzymes could be distinguished. The first two classes are presumed to be involved in extracellular digestion processes. Integument material from Brachionus was prepared by dissolving the rotifer tissues with strong protein denaturants which leave the material of the intrasyncytial dense lamina, or lorica, intact. The lorica material was then dissolved by treatment with denaturants plus disulphide breaking agents, and characterized by electrophoretic methods, by its sensitivity to proteinases and by its cross-reactivity with keratine-antibodies. Application of these methods to other rotifer species has revealed that at least two types of integument-material with differing chemical properties occur in rotifers. Using similar methods trophi-material of the mastax was prepared for morphological as well as chemical examination. These investigations showed that the trophi contain chitin.