Cardiolipin de novo biosynthesis is elevated but cardiolipin is not essential for nucleotide synthesis during entry into S phase of the mammalian cell cycle
Bibliographic record
Abstract
Cardiolipin (CL) is a key phospholipid involved in ATP generation. CL content doubles during S phase but the reason for this was unknown. Hela cells were serum depleted for 24 h. Serum addition resulted in a 6.5‐fold stimulation of [ 3 H]thymidine incorporation into cells compared to serum starved cells by 8 h confirming entry into S phase. Phospholipid mass of CL was unaltered at 8 h but doubled by 16 h post serum addition. The reason for the increase in CL mass was an increase in activity of CL de novo biosynthetic enzymes and their mRNA expression. CL de novo biosynthesis from D‐[ 14 C(U)]glucose was elevated 2‐fold by serum addition to quiescent cells compared to controls. In contrast, CL de novo biosynthesis from [1,3‐ 3 H]glycerol was reduced upon serum addition to quiescent cells compared to controls indicating a preferential utilization of glucose as the carbon source for CL biosynthesis during S phase. Finally, serum addition to serum starved Barth Syndrome lymphoblasts, which have reduced CL levels, resulted in a similar elevation in incorporation of [ 3 H]thymidine compared with that of an aged‐matched control indicating that normal CL level is not essential for nucleotide synthesis during S phase. In summary, induction of Hela cell entrance into the S phase of the eukaryotic cell cycle results in elevated de novo biosynthesis of CL from glucose and this is due to an up regulation of the activity and mRNA expression of de novo CL biosynthetic genes which account for the doubling of CL seen in S phase of the mammalian cell cycle. However, normal CL levels are not required to support nucleotide synthesis (Supported by HSFM, G.M.H is a CRC in Molecular Cardiolipin Metabolism).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".