Light induced transthylakoidal proton gradient is a key signal driving the downward migration of motile diatoms in sediments
Bibliographic record
Abstract
Pennate diatoms are photosynthetic microorganisms capable of directed motility in response to light. In sedimentary habitats, many epipelic pennate diatoms exhibit photophobic migration under high light, a behaviour critical for avoiding photodamage and key to ecological success. While the ecophysiological significance of this behaviour is well-documented, the mechanisms linking light sensing to motility remain poorly understood. This study investigated whether the transthylakoidal proton gradient (ΔpH), generated under high light, intervenes in the signal transduction mechanism driving photophobic migration. The impact of the ΔpH inhibitors Nigericin and Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) on the vertical migration of benthic pennate diatoms was monitored using non-destructive imaging chlorophyll fluorometry on intertidal diatom-dominated microphytobenthos biofilms. The results showed that ΔpH inhibition significantly reduced the downward, high light-avoiding, migratory response, supporting the hypothesis that ΔpH plays a central role in mediating this response. Additionally, results showed that the effective quantum yield of PSII and non-photochemical quenching (NPQ) were impacted by ΔpH inhibition with a dose-dependent effect. These findings strongly support ΔpH as an integrative signal linking physiological and behavioural photoprotection mechanisms and suggest that ΔpH may also modulate intracellular signalling, explaining the efficient capacity of pennate diatoms to cope with high light exposure in benthic habitats.
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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 | 0.000 |
| 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 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".