Different patterns of two carbonic anhydrase types in green crab gills when exposed to low salt levels

The cytoplasmic isoform of carbonic anhydrase increases 100-fold in abundance in green crab gills when acclimated to low salinity.

• The membrane-associated isoform of carbonic anhydrase shows a 3-fold increase initially in low salinity before stabilizing.
• A 20-fold increase in carbonic anhydrase protein-specific activity is linked to the rapid rise in cytoplasmic isoform mRNA during low salinity acclimation.
• Maximal levels of cytoplasmic isoform mRNA expression occur by 24 hours, aligning with the stabilization of hemolymph osmotic and ionic levels.
• Changes in the expression of the membrane-associated isoform are associated with alterations in the population of branchial chloride cells.
• Expressions of other genes, such as the alpha-subunit of the Na(+)/K(+)-ATPase, show smaller changes compared to the cytoplasmic isoform, but with a similar timing.

Simplified