Abstract

There are at least two different strategies of pH regulation among fish. The first is coupled pH regulation (CPR), where regulation of blood pH facilitates tissue pH regulation; and the second is preferential intracellular pH (pHi) regulation (PPR), where tissue pH remains tightly regulated despite a sustained reduction in blood pH. The cellular and molecular mechanisms underlying the differences in pHi regulation are currently unknown. I investigated the mechanisms of pH regulation in fishes using Rainbow Trout (Oncorhynchus mykiss) and Channel Catfish (Ictalurus punctatus) which use CPR and PPR, respectively. Fish were exposed to elevated CO2 for either 3 or 24 h, then blood and tissues were collected and examined for molecular responses. Real Time-quantitative Polymerase Chain Reaction (Rt-qPCR) showed upregulation of slc4a4a, slc4a5 and slc4a7 by 24 h in heart and gill tissue of the catfish. Where the same isoforms had no significant changes in regulation within the trout heart but were down regulated in gill tissue. No significant changes were seen in expression of these three genes in catfish liver or muscle from the same tissue for trout. Expression time and localization of NBCe1 (slc4a4’s protein) was consistent with the mRNA expression in catfish tissue. This demonstrates that sodium-bicarbonate transporters may be important for PPR at the tissue level but may not have the same importance for fish using CPR.

Date of publication

Summer 8-13-2024

Document Type

Thesis

Language

english

Persistent identifier

http://hdl.handle.net/10950/4757

Committee members

Ryan B. Shartau, Brent Bill, Ali Azghani

Degree

Masters in Biology

Additional Files
Thesis Final Approval D.Flowers.pdf (100 kB)
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