Ricinosomes and endosperm transfer cell structure in programmed cell death of the nucellus during <i>Ricinus</i> seed development
Bibliographic record
Abstract
The ricinosome (precursor protease vesicle) is an organelle found exclusively in plant cells. Ricinosomes contain a 45-kDa pro-cysteine endopeptidase (CysEP) with a C-terminal KDEL endoplasmic reticulum retention signal. CysEP is a member of a unique group of papain-type cysteine peptidases found specifically in senescing and ricinosome-containing tissues. During seed development in the castor oil plant (Ricinus communis L.), the cells of the nucellus are killed as the major seed storage organ, the cellular endosperm, expands and begins to accumulate reserves. The destruction of the maternal seed tissues is a developmentally programmed cell death. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling revealed that nuclear DNA fragmentation occurs in the nucellar cells adjacent to the expanding endosperm. These cells exhibit ultrastructural features consistent with programmed cell death, including vesiculation of the cytosol, development of irregularly shaped nuclei, vacuolar collapse, and shrinkage of the cytoplasm. Ricinosomes containing the CysEP were identified in the nucellar cells by light and electron microscopy and immunocytochemistry. Both proCysEP and mature CysEP are present in protein extracts of the nucellar tissues during seed development. Upon collapse of the nucellar cells, the content of the ricinosomes is released into the cytoplasm, where the activated CysEP digests the remaining proteinaceous cellular debris. Digestion products of the nucellar cells are presumed taken up by the outermost cells of the endosperm, which have labyrinthine ingrowths of the outer walls typical of transfer cells.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".