In vitro spectrofluorometric determination of chlorophyll de novo synthesis in chlorophyll-deficient phenotypes of <i>Pennisetum glaucum</i> (L.) R.Br
Bibliographic record
Abstract
Blocks in chlorophyll (Chl) biosynthesis in crude extracts of well-defined chlorophyll-deficient seedlings and green siblings from five Pennisetum glaucum (L.) R.Br. genotypes and the ability of these genotypes to relieve such blocks in crude extract mixtures were studied with low temperature (77 K) fluorescence spectroscopy. Dark-adapted green seedling extracts exhibited F657, F685, and F735 peaks corresponding with protochlorophyllide (Pchlide), Chl from photosystem II and from photosystem I, respectively. Extracts of white seedlings from white stripe mutants and an albino mutant exhibited F657 peaks indicative of Pchlide, whereas the extracts of yellow seedlings from yellow stripe mutants exhibited F657 and F678 peaks representing Pchlide and chlorophyllide (Chlide) accumulation, respectively. Addition of their green sibling's extract resulted in the appearance of F685 and F735 peaks, suggesting de novo relief of the blocks and photoreduction of Pchlide to Chl(ide). Incubating a mixture of crude extracts of yellow seedlings from two different yellow stripe mutants did not alter their peaks, indicating a lack of reconstitution because of a common limiting factor in the two yellow seedling sources. Likewise, the mixture of crude extract of yellow seedlings with that of white seedlings from white stripe mutants displayed no Chl peaks. Spontaneous greening in the mixture of crude extracts of yellow seedlings with that of albino mutant and its failure in other reconstitution experiments suggests that Chl synthase in albino seedlings enabled the conversion of Chlide to Chl in vitro. The factors governing the in vitro reconstitution and its implications in genetic complementation are discussed.Key words: chlorophyll-deficient mutants, blocks in chlorophyll biosynthesis, crude extracts, in vitro synthesis of chlorophyll.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".