Continuous monitoring of growth detects photoperiod-dependent oscillations in growth rates of <i>Chlorella vulgaris</i>
Bibliographic record
Abstract
The green alga Chlorella vulgaris Beij. exhibits minimal capacity to adjust exponential growth rates in response to photon flux density (PFD) when monitored on a discontinuous basis. We hypothesized that modulation of maximum growth rates in C. vulgaris by PFD is a photoperiod-dependent phenomenon. The use of the photobioreactors to monitor continuous growth allowed us to detect repetitive daily oscillations in growth which were photoperiod-dependent. The rate of change in optical density (OD735) during the daily light period was two-fold greater in cells grown at 28 °C with a PFD of either 2000 or 150 μmol photons·m−2·s−1 when C. vulgaris was grown under a daily light–dark cycle. Concomitantly, oscillations of the chlorophyll fluorescence parameters paralleled the oscillations observed in growth rate. When cultures were shifted from a 12 h photoperiod with low light to continuous light (CL), the growth oscillations disappeared. In contrast, oscillations in the fluorescence parameters persisted even after the shift from a 12 h photoperiod to CL. We suggest that the nocturnal catabolism of starch reserves in conjunction with changes in cellular volume coupled with the diurnal changes in DNA content, as quantified by changes in Vybrant Green fluorescence yield, indicate that these growth oscillations reflect synchronized cellular division in C. vulgaris that is not evident when growth is assayed discontinuously.
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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".