Measures of CTmax and gene expression in <em>Daphnia</em> clones acclimated to three temperatures
Bibliographic record
Abstract
The theory of optimal cell size postulates that cell size imposes constraints on oxygen delivery in larger cells due to their smaller surface-to-volume ratios. Smaller cells, with a higher surface to volume ratio, have an increased capacity to take up oxygen, which might result in an increased heat tolerance (CTmax). However, the precise mechanisms linking cell size, body size, and heat tolerance remain unclear. We obtained contrasts in cell size by raising size-matched diploid and triploid juvenile Daphnia at different temperatures. Daphnia raised at lower temperatures had larger cells than those raised at higher temperatures. Triploid clones had larger cells than diploid clones at 16°C, 20°C, and 24°C. CTmax increased with acclimation temperature and was negatively correlated with both cell and body size. Triploid clones had lower CTmax values than both subarctic and temperate diploid clones at 16°C and 20°C. Heat shock significantly increased the expression of Hsp70 and catalase, but these were not correlated with CTmax or ploidy, suggesting that heat tolerance was not directly linked to heat-shock proteins or oxidative stress responses. These findings highlight the role of cell size and polyploidy in shaping the heat tolerance and geographic distribution of ectotherms.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.016 | 0.008 |
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".