The cockroach integument: PAS-positive granules and their possible relationship with phenol storage

Abstract

Biochemical studies on the epidermal cell extracts of Periplaneta americana (L.) in various stages of the moult have shown the occasional presence of the diphenol, N-acetyl dopamine. Ultrastructural examination of the integument shows the localization of a PAS-positive material in granules even after the deletion of glycogen. In view of these data it has been postulated that diphenols are stored in the epidermal cells after hydrolysis of the old cuticle. The rôle of these probable deposits is discussed in relation to the moulting process.