Pigments ofChaetopterus variopedatus(polychaeta)

Abstract

A chemical and histological study has been made of the pigments of the polychaete worm Chaetopterus variopedatus. The conspicuous green color 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 phaeophorbides a and b, the former predominating. Other pigments found in the gut-wall of the middle region of the worm include the chlorophyll derivatives iso-phaeophorbide d, dioxymesophyllochlorin, copper phaeophorbide chelation compounds, and possible rhodoporphyrin g7 carboxylic acid; coproporphyrin HI; bile pigment-type compounds turbo-glaucobilin and helioporobilin, and the carotenoids [beta]-carotene and traces of a xanthophyll. The body wall contains [beta]-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 and [beta]-carotene. The phaeophorbides a and b are derived from chlorophylls a and b in the animal''s food (detritus). The green spherules in vivo are not 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.