Pigments ofChaetopterus variopedatus(polychaeta)

Abstract

A chemical and histological study has been made of the pigments of the polychaete wormChaetopterus variopedatus. The conspicuous green colour of the gut in the middle and posterior regions is due to a green pigment hitherto known as ‘chaetopterin’, which is localized in small green spherules in the gut epithelial cells. ‘Chaetopterin’ is a mixture of phaeophorbidesaandb, the former predominating. Other pigments found in the gut-wall of the middle region of the worm include the chlorophyll derivativesiso-phaeophorbided, dioxymesophyllochlorin, copper phaeophorbide chelation compounds, and possibly rhodoporphyring7carboxylic acid; coproporphyrin III; bile pigment-type compounds turbo-glaucobilin and helioporobilin, and the carotenoidsβ-carotene and traces of a xanthophyll. The body wall containsβ-carotene. A black melanin is present in the black chaetae of setigerous segment IV, and a reddish melanoid pigment in a red stripe at the anterior margin of the head. Pigments present in the faeces include phaeophorbides andβ-carotene. The phaeophorbidesaandbare derived from chlorophyllsaandbin the animal’s food (detritus). The green spherulesin vivoare not fluorescent, suggesting that fluorescent, suggesting that the pigment is adsorbed on to some large molecule, possibly a mucopolysaccharide. No evidence was found that the green spherules are symbionts. Since they are such a constant feature of the animals, even during prolonged starvation, they would appear to play some essential biochemical role.