Characterization of the alternative oxidase of <i>Chlamydomonas reinhardtii</i> in response to oxidative stress and a shift in nitrogen source
Bibliographic record
Abstract
To study the transcriptional regulation of Aox1 , the major alternative oxidase (AOX) gene, we fused 1072 bp of its promoter to the promoterless arylsulfatase reporter gene. We find that the reporter is strongly activated when cells are shifted from a medium containing ammonium to one containing nitrate but is unresponsive to treatments known to induce Aox1 in higher plants – H 2 O 2 , antimycin A and cold stress. However, induction of Aox1 by all these factors was found when changes in gene expression were monitored using RNA blot analysis. Our data suggest that transcriptional upregulation of Aox1 by H 2 O 2 , antimycin A and cold‐stress requires one or more enhancers which are not found in the proximal promoter region of the gene. Interestingly, while nitrate, H 2 O 2 and cold stress result in increased AOX abundance and increased alternative pathway respiration, these changes are not seen when cells are treated with antimycin A. We find that H 2 O 2 , antimycin A and cold‐stress result in an increase in intracellular reactive oxygen species (ROS) but that a significant change in ROS does not occur when cells are shifted into a medium‐containing nitrate. Overall, our data are consistent with there being two distinct pathways regulating Aox1 transcription and AOX abundance in Chlamydomonas reinhardtii : one in response to oxidative stress and a second due to metabolic changes brought about by a shift in nitrogen source from ammonium to nitrate.
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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 | 0.000 | 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".