title: Occurrence of free D-aspartic acid in the circumsoesophageal ganglia of Aplysia fasciata.
abstract: This study reports the presence of high concentrations of free D-aspartic acid (D-Asp) in the circumoesophageal ganglia of the opisthobranch mollusc Aplysia fasciata. D-Asp was discovered using specific methods that employ Octopus D-aspartate oxidase and hog kidney D-amino acid oxidase to measure D-Asp levels. The concentration of D-Asp was 0.281 mumol/g wet tissue weight, which was 8.3% of the total free aspartic acid (D and L forms) present. No other free D-amino acids that were oxidised by D-amino acid oxidase were detected. To our knowledge the only molluscs that have previously been shown to have D-Asp within their nervous tissue are the cephalopods Octopus vulgaris, Loligo vulgaris and Sepia officinalis. In these, as in A. fasciata, no other D-amino acids were detected within the nervous tissue. The fact that free D-Asp occurs specifically in the nervous tissue of the above molluscs suggests that it may have a neurological function that is yet to be described.
authors.affiliation: Department of Biochemistry, Stazione Zoologica A. Dohrn, Napoli, Italy.
authors.forename: A
authors.initials: A
authors.lastname: D'Aniello
authors.forename: G
authors.initials: G
authors.lastname: Nardi
authors.forename: A
authors.initials: A
authors.lastname: Vetere
authors.forename: G P
authors.initials: GP
authors.lastname: Ferguson
mesh_terms: D000818:Animals; D001048:Aplysia; D001224:Aspartic Acid / Q000378:metabolism*; D004947:Esophagus / Q000294:innervation; D005724:Ganglia / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D001224:Aspartic Acid