Incorporation and Metabolism of Cysteine in the Haemolymph and Saliva of A Plant Bug

Abstract

When injected into the haemolymph of a pentatomid plant bug, cysteine labelled with 35S was transferred to the salivary glands and was there incorporated as cysteine-cystine into the precursors of the salivary "stylet sheath". Cysteine did not appear to be converted into methionine either in the haemolymph or in the salivary glands. Some of the injected cysteine was incorporated into soluble protein or peptide in the haemolymph and salivary secretions, some was excreted as cysteine and cystine, and some was deaminated in the haemolymph and was also found in this form in the salivary glands and excreta.