Estimation of the in vivo rate of tissue uptake for the organic osmolyte trimethylamine oxide in the winter skate ( <i>Leucoraja ocellata</i> )
Bibliographic record
Abstract
Elasmobranch fishes rely on nitrogenous organic osmolytes to maintain body fluids slightly hyperosmotic to the surrounding seawater. Methylamines are an important part of this osmoregulatory strategy with trimethylamine oxide (TMAO) being a significant osmolyte. The skate ( Leucoraja ocellata ) lacks significant TMAO synthesis, relying on low whole animal losses (≤ 1.2 % day −1 ) to maintain TMAO during periods of food deprivation [Treberg and Driedzic, 2006, AJP 291: R1790‐R1798]. TMAO is accumulated intracellularly, creating a substantial concentration gradient (> 50 mM). Herein we revisit TMAO handling in skates and provide the first quantitative estimates of TMAO uptake in tissues based on the exchange of radiolabeled tracer between the plasma and tissue compartments. Muscle TMAO uptake is very low (0.6 μmol g −1 day −1 ), indicating a long residency time once compartmentalized within muscle cells. The uptake of TMAO differs greatly amongst tissues; visceral tissues (liver and intestine) having rates an order of magnitude greater than muscle. Assuming sodium‐dependent concentrating mechanism, similar to other osmolyte systems, accumulation of TMAO is likely a small fraction of overall metabolic rate, but could constitute a significant part of the osmoregulatory energetic demand in skates. Presentation funded by NSERC and CIHR.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".