Studies on the chemistry of the octopus renal system and an observation on the symbiotic relationship of the dicyemid mesozoa

Abstract

1. A partial characterization of the dialyzable solutes in the renal system of Octopus vulgaris was conducted with a view towards examining the relationship between the octopus and the endoparasitic dicyemid mesozoans. 2. The urine contains 3·25% salts, 0·08% high molecular weight material, and 0·21% small organic solutes. The totality of the organic solutes is composed of the following: kynurenic acid, 76%; hypoxanthine. 12%; N-methyl picolinic acid (homarine), 7·1%; guanine, 1·4%; taurine, 1·3%; xanthine, 1·0%; lysine, 0·4%; others, 0·8%. 3. The renal appendage contains, relative to the dry weight of dialyzable organic material, hypoxanthine, 7·5%; N-methyl picolinic acid, 3·6%; taurine, 3·4%; tryptophan, 1·9%; adenosine monophosphate, 0·9%; inosine monophosphate, 0·8%. 4. Kynurenic acid in the renal fluid probably derives from the branchial heart appendage, which produces the aqueous vehicle for the urine, suggesting that the processes of filtration and secretion are not completely separate in Octopus. 5. The environment of the mesozoans is an interface between the renal fluid and the renal appendage surface. 6. The mesozoans facilitate host excretion of NH 3 by contributing to the acidification of the urine and are therefore symbionts.