The effects of folate, choline and betaine on transmethylation in a methionine restricted piglet
Bibliographic record
Abstract
Methionine is an essential amino acid that is incorporated into protein and is also the primary methyl donor for transmethylation reactions via S‐adenosylmethionine (SAM), SAM is demethylated to S‐adenosylhomocysteine (SAH) with the majority of methyl groups either being transferred to DNA or used for synthesis of creatine (CR) and phosphatidylcholine (PC). SAH is converted to homocysteine (HCY) which can be oxidized or remethylated back to methionine by the methyl donors folate and choline (via betaine). 4–8 d old neonatal piglets were fed a diet devoid (n=8) or replete (n=7) of these methyl donors. After 5 d, dietary methionine was reduced to 80% of requirement. On day 8, animals received a constant infusion of [ 3 H]methyl‐methionine for 6 h to measure flux to PC, CR, and DNA. Methyl deficient pigs had a lower SAM/SAH ratio and higher plasma HCY (p<0.05). Methylation to CR, but not PC and DNA, was lower in methyl deficiency, suggesting this methylation reaction is most sensitive to methyl supply. Moreover, methylation of phosphatidylethanolamine to PC tended to be higher with methyl deficiency suggesting this pathway is upregulated when choline is deficient. Severe restriction of remethylation in piglets reduces methionine availability for creatine synthesis. (CIHR funded). Grant Funding Source: 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".