9808141 Claiborne The fish gill is a multi-purpose organ. Analogous to the lungs in land-dwelling animals, the gills allow the fish to breathe oxygen and excrete carbon-dioxide. Further, the gills perform functions of the kidneys as they eliminate toxic metabolic acid from the animal. Dr. Claiborne has hypothesized that saltwater fish may excrete acid using a family of sodium hydrogen exchanger proteins (NHE) within the gills. These proteins were first discovered in mammals but our preliminary data indicate that they are also present in more primitive animals like fish. The PI will investigate the genetic regulation and protein expression of the NHEs in the gills of two different marine species - the sculpin and the killifish. This should provide new insight into the physiology of gill acid-base and ion regulation and shed new light on evolutionary relationships between the vertebrates. Further, since it is known that the cellular mechanisms within the gills are similar to those currently being studied in the mammalian kidney, a new understanding of the physiology of the kidney and other organs may also be achieved.
