Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology

Vitellogenin (vtg) was isolated from greenback flounder (Rhombosolea tapirina), rainbow trout, (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) plasma. The molecular weight of each native molecule, as determined by gel filtration, was 540, 383 and 557 kD respectively. With SDS-PAGE under reducing conditions, rainbow trout vtg dissociated into 1 major subunit (~154 kD), and Atlantic salmon and greenback flounder vtg dissociated into 3 major subunits (~ 159, 117, 86 kD and 155, 104, 79 kD respectively). Polyclonal antisera, produced against only the highest molecular weight subunit from each species following excision of these bands from reducing gels, were reactive with all subunits in Western blots. These antisera were found to be highly species-specific as determined by competition ELISA. No cross-reactivity was noted, even between the two salmonid species. These data suggest that excision of bands from gels is a simple procedure for the preparation of highly specific antisera, and that cross-species assays employing heterologous antisera are unlikely to be possible.