engleski

Activation of carbonic anhydrase in branchial cavity tissue of lobster (Homarus gammarus) by dilute seawater exposure

Activitiy of carbonic anhydrase and its distribution in the branchial cavity tissues were studied in European lobster Homarus gammarus from ambient seawater (salinity = 38 ppt, 1126 mosmol/l ) and acclimated to dilute seawater (salinity=20 ppt ; 548 mOsmol/l). Acetazolamide inhibited dose dependently the activity of carbonic anhydrase in homogenates of epipodites, where the inhibition constant (IC50=0.12 microM) did not differ significantly from that of membrane vesicles and cytosolic fraction. In subcellular fraction from DSW -acclimated lobsters, the main proportion of 75.8% (epipodite), 61.0% (branchiostegite) of total carbonic anhydrase in each of these tissues remained in cytosol portion. Partially purified membranes contained 6.8% (epipodite) and 16.2% (branchiostegite) and the remainder of 15% (epipodite) and 27% (branchiostegite) was found in mitochondrial and nuclear fractions. In gills, 49.2% and 9% of total gill carbonic anhydrase activity was found respectively in cytosol and partially purified vesicles and the rest in mitochondrial and nuclear fractions.

Carbonic anhydrase; Dilute seawater; Branchial cavity tissues; lobster; Homarus gammarus

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