<i>Chlamydomonas</i> sp. UWO241 exhibits constitutively high cyclic electron flow and rewired metabolism under high salinity
Bibliographic record
Abstract
ABSTRACT The Antarctic green alga Chlamydomonas sp. UWO241 (UWO241) was isolated from the deep photic zone of a permanently Antarctic ice-covered lake. Adaptation to permanent low temperatures, hypersalinity, and extreme shade has resulted in survival strategies in this halotolerant psychrophile. One of the most striking phenotypes of UWO241 is an altered photosystem I (PSI) organization and constitutive PSI cyclic electron flow (CEF). To date, little attention has been paid to CEF during long-term stress acclimation and the consequences of sustained CEF in UWO241 are not known. In this study, we combined photobiology, proteomics, and metabolomics to understand the underlying role of sustained CEF in high salinity stress acclimation. High salt-grown UWO241 exhibited increased thylakoid proton motive flux and an increased capacity for NPQ. A Bestrophin-like Cl - channel was identified in the whole cell proteomes and transcriptome of UWO241 which likely supports ion homeostasis during high transthylakoid pH. Under high salt, a significant proportion of the upregulated enzymes were associated with the Calvin Benson Bassham Cycle (CBB), secondary metabolite biosynthesis, and protein translation. Two key enzymes of the Shikimate pathway, DAHP synthase and chorismate synthase, were also upregulated, as well as indole-3-glycerol phosphate synthase, an enzyme involved in biosynthesis of L-tryptophan and indole acetic acid. In addition, several compatible solutes (glycerol, proline and sucrose) accumulated to high levels in high salt-grown UWO241 cultures. We suggest that UWO241 maintains constitutively high CEF with associated PSI-cytb 6 f supercomplex to support robust growth and strong photosynthetic capacity under a constant growth regime of low temperatures and high salinity.
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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 | 0.001 | 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".