[Lactate dehydrogenase isoenzymes in loach (Misgurnus fossilis) development]

Isoenzyme patterns of lactatedehydrogenase (LDH, EC 1.1.1.27) were determined in the loach (Misgurnus fossilis) oocytes, unfertilized eggs, developing embryos and larvae, and the sensitivity of the isoenzymes to the effect of AgNO3, p-chlormercurybenzoate and high temperature were investigated. The presence of 4 phenotypes of LDH patterns which differed in the isozymes number, in their relative activity, in electrophoretic mobility in the polyacrylamide gel columnes and in the frequency of occurence in different populations of the investigated species is demonstrated. Before the hatching stage there appeared a new isozyme which was completely inhibited by AgNO3 and had the same electrophoretic mobility in all LDH phenotypes. During the larvae development the content of this LDH isozyme increased. Some isozymes, especially those which had low anodic mobility and decreased in their relative quantity, disappeared during the development of embryos and larvae, p-Chlormercurybenzoate in the concentration 1 mM and heating at 70 degrees C during 20 minutes did not significantly affect LDH activities in the loach eggs, embryos and larvae.