Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells
Bibliographic record
Abstract
Resisting Arsenic The discovery of a bacterium living in the extreme conditions of Mono Lake, California, created a major controversy because it was claimed to be able to grow solely on arsenic and could substitute arsenate for phosphate in its key macromolecules, including DNA. Working with the same Halomonas spp. bacterium, known as GFAJ-1, and ultrapure reagents, Erb et al. (p. 467 ) found that the bacterium needed a low level of phosphate (1.6 µM) to grow at all. Rather than significant specific arsenic incorporation, when the organism was grown in 40 mM arsenic, its nucleic acids acquired a trace of arsenic. Similarly, Reaves et al. (p. 470 ) found that GFAJ-1 could not grow in the absence of phosphate and, moreover, that its growth was not stimulated by the addition of arsenate, although a trace amount of arsenic was also detected in DNA. Thus, GFAJ-1 shows no particular facility to substitute arsenic for phosphate, when phosphate is limiting, but it can tolerate high concentrations of the poison while efficiently scavenging phosphate.
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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 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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 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".