The recalcitrance of clofibric acid to microbial degradation
Bibliographic record
Abstract
The presence of pharmaceutical compounds and their metabolites in aquatic systems has become a concern in the past few years due, in part, to their ubiquity in the environment.However, at present, the persistence and ecotoxicity of many of these compounds remains unknown.Clofibric acid is the active metabolite of clofibrate, a lipid regulator.It is detected in most aquatic systems where pharmaceutical contaminants are monitored and is reported to be persistent.(R)-mecoprop, a herbicide used on broad-leaved crops, is a structural isomer of clofibric acid.However, unlike clofibric acid, it can be degraded by at least some microorganisms including Sphingomonas herbicidovorans and Alcaligenes denitrificans.Biodegradation studies of both clofibric acid and its isomer mecoprop were performed by exposing the compounds to axenic cultures of microorganisms in shake flasks.While preliminary results revealed that clofibric acid was resistant to microbial degradation with several types of microorganisms, it was shown that Rhodococcus rhodochrous, a common soil microorganism, was capable of converting clofibric acid to clofibrate, its parent compound.Despite the fact that Sphingomonas herbicidovorans is capable of degrading (R)-mecoprop within a couple of days, results indicated that it is incapable of degrading clofibric acid under the same conditions.This suggests that the recalcitrance of clofibric acid is due to change in the position of a methyl group with respect to (R)-mecoprop.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".