Branchial Ionoregulatory Mechanisms of Sodium Regulation in Freshwater Salmonids with Conservational Implications for Arctic Grayling (Thymallus arcticus)
Bibliographic record
Abstract
This thesis on fish osmoregulation focuses particularly on the mechanisms utilized by freshwater salmonids to absorb Na+ ions from dilute hypotonic environments and at the same time, their capacity to make necessary changes in order to tolerate higher saline environments. In this thesis, I present data that indicate rainbow trout embryos/larvae reared in low Na+ soft water maintain homeostasis by way of an EIPA-sensitive Na+ uptake pathway. In addition rainbow trout showed significantly increased nhe3b expression at the embryo/larvae and juvenile life stages and overall, these data support a primary role for nhe3b at these life stages. Three nhe isoforms: nhe2, nhe3a, and nhe3b were cloned, from trout gill (2 and 3b) and kidney (3a), into pDisplay expression vectors for transfection into the AP – 1 cell line in an attempt to further characterize the pharmacological properties of these transporters. However, at this time stable transfections have not resulted in successful Nhe protein expression. From a conservation physiology perspective I have shown that the Arctic grayling (a threatened native salmonid) demonstrates a reduced salinity tolerance and develops a novel associated interlamellar cell mass, in response to hypersaline waters, which has strong implications for hypersaline spills from hydraulic fracturing and other oil and gas operations. I presented data indicating this interlamellar cell mass and osmotic stress can be reversed if the salinity exposure lasts 48 hrs or less and recovery in freshwater is achievable. In iii addition to salinity tolerance data and in order to have a comprehensive management plan for Arctic grayling, thermal tolerance data were collected indicating CTmax of 26.9°C and 27.8°C when acclimated to 13°C and 17°C water temperatures (see Appendix A). This work provides evidence of three nhe isoform expression patterns during development in rainbow trout despite thermodynamic constraints, demonstrates reduced salinity tolerance of a threatened native salmonid in Alberta, provides the first reported instance of a salinity-induced ILCM in salmonids, and provides necessary physiological data for conservation management strategies for Arctic grayling.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".