Institute of Chemistry and Biology of the Marine Environment, 26111 Oldenburg, Germany.
In the marine polychaete, Platynereis dumerilii, the reproductive behaviour is synchronised by the consecutive release of male and female sex-specific pheromones. In the moment of the detection of a swarming female, males discharge a small cloud of sperm along with the egg release pheromone (ERP). The ERP stimulates the female to swim fast in narrow circles around the sperm cloud surrounded by attracted males. After a short period the female begins to spawn. Fertilisation is achieved by the attracted males circling around the eggs and discharging clouds of sperm.Here we describe the isolation and identification of the ERP, present in the coelomic fluid of sexually mature males. Isolation was obtained by ultrafiltration and reversed-phase high-performance liquid chromatography (RP-HPLC), identification was achieved by 1H-, 13C-, HMBC- and HMQC-NMR-experiments, ESI-MS and UV/VIS. Determination of the proposed structure was proved by comparing the spectroscopic data and behavioural response in bioassays of the natural compound with a synthetic sample. L-ovothiol A was identified as the ERP of Platynereis dumerilii, that is emitted by males with the release of sperm. Before these sulfur-containing amino acid was isolated only from the eggs of marine invertebrates and never found in male invertebrates.On account of the high sensitiveness against oxygen, substance-accumulation and structure- determination was obtained as the corresponded disulfide, that shows no behavioural effect on females. Treating the disulfide with sodiumborhydride recovered the highly active reduced form of the amino acid.