Muscle parvalbumin isoforms of Clarias gariepinus, Heterobranchus longifilis and Chrysichthys auratus:: isolation, characterization and expression during development

The white-muscle parvalbumin isoforms of Clarias gariepinus, Heterobranchus longifilis and Chrysichthys auratus were purified and their physicochemical parameters determined. The three catfish isoforms are distinct but those of C. gariepinus and H. longifilis are more similar. In the course of development, the successive appearance of larval and adult parvalbumins was observed, Larval isoforms (PA I, PA IIa, PA IIb) displayed a lower isoelectric point (pl) and molecular mass than adult ones (PA IIc, PA IIIa, PA IIIb, PA III, PA IV). The PA IIa isoform appeared as an omnipresent typical larval isoform. PA IIb appeared mostly larval, being insignificant in adult specimens; its physicochemical features were the same in the three catfish species. In Chrysichthys auratus, there were three PA II isoforms, one appearing as an adult isoform (PA IIc). The Fact that the two types of pan albumin isoforms appear at different times should reflect specific physiological needs (mobility, feeding) of different developmental stages. (C) 1999 The Fisheries Society of the British Isles.