N-Hydroxyarylamine O-Acetyltransferase-Deficient Escherichia coli Strains Are Resistant to the Mutagenicity of Nitro Compounds
Bibliographic record
Abstract
In Salmonella typhimurium, a single enzyme catalyzes both the acetyl CoA-dependent O-acetylation of hydroxylamines (a key step in the activation of mutagenic nitroaromatic compounds and related aromatic and heterocyclic amines) and the N-acetylation of aromatic amines. S. typhimurium Ames test mutants lacking this activity are highly resistant to the genotoxic effects of nitro compounds. However, such mutants have not yet been obtained in Escherichia coli. We used a PCR-based method to engineer a null mutation (deletion) of the nhoA gene encoding the enzyme in E. coli and we transduced this mutation into a lacZ strain background suitable for use in mutation assays. In E. coli, as in S. typhimurium, nhoA mutants show marked resistance to nitro compound mutagenicity. The new strains provide a clean background for expression of recombinant N-acetyltransferases.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 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".