Cyclic electron flow and ascorbate pathway play a role in survival of Chlamydomonas sp. UWO241 to long-term photooxidative stress
Bibliographic record
Abstract
Under environmental stress plants and algae employ a variety of strategies to avoid damage to the photosynthetic apparatus and maintain photosynthetic capacity. To date, most studies on stress acclimation have focused on model organisms possessing limited tolerance to elevated stress levels. We compared the long-term acclimatory capacities of a mesophilic alga (Chlamydomonas raudensis SAG 49.72; SAG 49.72) and an Antarctic halotolerant psychrophile (Chlamydomonas sp. UWO 241; UWO 241) by monitoring photobiology, cyclic electron flow (CEF) and ROS defense in cultures acclimated to long-term low temperature, high salinity or high light stress. SAG 49.72 responded to long-term stress by increasing chlorophyll a/b ratio and redistributing absorbed light energy from photosystem II (PSII) to photosystem I (PSI). In contrast, the psychrophile exhibited faster half times for P700+ re-reduction under all treatments, suggesting high CEF rates. High CEF was accompanied by increased capacity for nonphotochemical quenching. Last, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase, as well as a large ascorbate pool. Our results suggest that UWO 241 relies on high PSI-mediated CEF and ROS detoxification to protect the photosynthetic apparatus while minimizing energy expenditure on repairs.
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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 | 0.000 |
| 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 | 0.001 |
| 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 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".