A mutation in the folA promoter delays adaptation to minimal medium by Escherichia coli K-12
Why this work is in the frame
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Bibliographic record
Abstract
In its natural environment, Escherichia coli is subjected to frequent changes in nutrients and physical parameters such as temperature. Adapting to new conditions requires an orderly progression of events. We show that a folA mutant that overexpressed dihydrofolate reductase because of a C to T promoter mutation, adapted very slowly when transferred from rich medium at 37 degrees C to glucose minimal medium at 42 degrees C. It adapted more rapidly when serine and threonine were added. At 37 degrees C, it was more sensitive than its parent to serine, pyruvate and valine. We propose that the mutant does not increase synthesis of serine and threonine normally upon transfer to minimal medium. This results in a limited availability of serine, threonine and isoleucine during adaptation. Phenotypically, this is manifested as a growth delay at 42 degrees C and an increased sensitivity to isoleucine restriction at 37 degrees C.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Open science | 0.000 | 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 it