Lactate dehydrogenase isozyme pattern of the mediterranean killifish aphanius fasciatus (Teleostei, Cyprinodontidae)

Abstract

Electrophoretic analyses of the tetrameric lactate dehydrogenase isozyme patterns of the endangered cyprinodontid fish Aphanius fasciatus were carried out. Organ and tissue samples of ten individuals of each sex were analysed by cellulose acetate elec-trophoresis and isoelectric focusing. Isozyme electrophoretic patterns indicated that three LDH loci (Ldh-A, Ldh-B and Ldh-C) were active and showed differential tissue expressions. No differences between sexes were observed. The Ldh-A and Ldh-B loci were expressed in all tissues analysed, and the A subunits possessed a net negative charge greater than B subunits. Heterote-tramers including subunit A were not observed, but a complex heterotetramer banding pattern of subunits B and C was detected. On the basis of the staining intensity of the electromorphs, Ldh-A predominated in all tissues analysed, with the exception of the liver, where Ldh-B predominated. Instead, Ldh-C was characterised by high relative anodal mobility and was expressed only in the eye. Furthermore, at this locus two alleles were observed in specimens analysed. The LDH banding pattern of A. fasciatus was consistent with that of advanced teleosts and it showed an inversion of the net negative charge of products of the Ldh-A and Ldh-B loci. © 1999 Taylor & Francis Group, LLC.