This dissertation investigated the cellular and molecular basis of osmoregulation in developing and adult Gulf killifish, Fundulus grandis, acclimated to salinities ranging from fresh water to sea water. In chapter 2, F. grandis embryos were reared in 0.1, 5, and 32 ppt water from 2 days (d) post fertilization until late embryogenesis. There were no discernable differences among salinities in the morphology of osmoregulatory organs, including the pharyngeal arches, digestive tract, or kidney. The localization and abundance of Na+/K+ ATPase (NKA), Na+/K+/2Cl- cotransporter (NKCC), and the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) on the external surfaces of these tissues support a role in osmoregulatory as early as prior to hatch. In addition, F. grandis larvae were exposed from hatch to 0.1, 5, and 32 ppt water until 6 weeks post hatch (wph). Differential localization of NKCC and CFTR during osmotic challenges indicated putative altered functions of the intestine and gills, but not of the kidney in larval F. grandis. In Chapter 3, adult F. grandis were acutely transferred from 5 ppt water to 0.1, 1, and 5 ppt water for 7 d, or were acclimated to 0.1 ppt water then acutely transferred to 0.1 and 32 ppt water for 7 d. The mRNA and protein levels of NKA, NKCC, and CFTR in the intestine were differentially affected by the hypo- or hyperosmotic challenges. Localization of transport proteins suggested differences in intestine function associated with salinity acclimation. The anterior and posterior intestine may function in HCO3- or Cl- secretion during exposure to 0.1 ppt water; the anterior intestine from 32 ppt acclimated fish may facilitate both Cl- and water absorption; and the posterior intestine during exposure to 32 ppt water may facilitate HCO3- or Cl- secretion. In chapter 4, the roles of these proteins in the anterior intestine of F. grandis were assessed using an electrophysiological approach coupled with pharmacological inhibition of transporters. A high apical CFTR activity in the anterior intestine during acclimation in fresh water was observed. In conclusion, salinity acclimation affected the possible functions of osmoregulatory tissues of larval F. grandis, as well as the putative functions in ion/water regulation in the intestine of adult F. grandis.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-01212014-155100 |
| Date | 27 January 2014 |
| Creators | Meng, Yanling |
| Contributors | Galvez, Fernando, Siebenaller, Joseph, Lynn, John, Green, Christopher, Gilman, Doug |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-01212014-155100/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0015 seconds