TISSUE-SPECIFICITY AND ONTOGENY OF LACTATE-DEHYDROGENASE IN SNOW CRAB, CHIONOECETES-OPILIO (BRACHYURA, MAJIDAE)

In the snow crab, Chionoecetes opilio (Brachyura: Majidae), LDH is pre sent in five isozymic forms, as revealed by the five coloration zones in zymograms. This is characteristic of a tetrameric LDH enzyme formed by the random association between two distinct sub-units. Isozymes of C. opilio LDH show tissue specificity. No LDH activity is detected in the hepatopancreas. The LDH-B locus is expressed in all other tissue s examined, except the eye, in which LDH-A is the only locus detected . Both loci are expressed in nervous, midgut and leg muscle tissues, t he last showing individual variability. At least among males, the LDH- B locus is expressed in leg muscle tissue at every developmental stag e, while LDH-A locus expression is initiated only in the VIIth post-l arval stage, just before the onset of gametogenesis. Results suggest t hat LDH sub-units in C. opilio have distinct physiological roles. This is very well known in vertebrates, but is virtually undocumented in i nvertebrates.