Membranes as possible pacemaker of metabolism in cypriniform fish: does phylogeny matter?
Bibliographic record
Abstract
The 'membrane pacemaker theory of metabolism' proposes that membranes set metabolic rate by modulating protein activity, and thus purports to explain membrane fatty acid allometry. This relationship has never been tested across species in ectotherms. After accounting for phylogeny, recent analyses have failed to support this theory based on correlations between muscle membrane composition and body mass across mammals. Therefore, the goal of this study was to seek phylogenetically corrected correlations between membrane composition, body mass and calcium-ATPase activity, using 12 species of closely related cypriniform fish (4-5500 g) covering a much narrower genetic scale than in previous tests. The results show that fish membrane unsaturation decreases with mass, but through different mechanisms from those in endotherms: 16:0 replacing 22:6 in muscle and 18:0 replacing 16:1, 18:1 and 18:2 in liver. This shows that allometric patterns differ between endotherms and ectotherms as well as between tissues. After accounting for phylogeny, however, almost all these relationships lose significance except for overall unsaturation. No relationship between calcium-ATPase activity and mass or phospholipid composition was detected. This study shows that membrane unsaturation of cypriniforms decreases with mass, but that genetic cues unrelated to size account for differences in the relative abundance of individual fatty acids. The membrane pacemaker concept accurately predicts general membrane properties such as unsaturation, but fails to explain finer scale allometric patterns. Future examinations of the membrane pacemaker hypothesis will have to take into account that allometric patterns vary between endotherms and ectotherms and between tissues of the same animal class.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".