Many crabs are able to survive in environments where salinity fluctuates widely, although this ability varies substantially even within a given genus. Osmoregulation, maintaining a constant internal salinity when external salinity fluctuates, requires transport of salt into or out of the body. Salt transport occurs across specialized cell layers and is mediated by salt transport proteins.
This work will focus on development of an antibody against invertebrate salt (Na-K-Cl) cotransporters and will demonstrate the ability to detect Na-K-Cl cotransporters in fiddler crabs. Developing species-specific antibodies against fiddler crab cotransporters will require cloning transporters from each species. The full-length sequence of the blue crab Na-K-Cl cotransporter is now in the sequence database. This sequence from a related organism will facilitate the cloning efforts. Preliminary evidence will be collected to demonstrate that invertebrate cation-chloride cotransporters can be successfully expressed and characterized using the Sf9 cell expression system. Data will be accumulated to show that there are changing expression patterns in gill proteins after salinity stress. In particular, these analyses will focus on demonstrating differences between anterior and posterior gills.