Zymogen activation and characterization of a major gelatin‐cleavage activity localized to the sea urchin extraembryonic matrix
Bibliographic record
Abstract
The hyaline layer (HL) is an apically located extracellular matrix (ECM) which surrounds the sea urchin embryo from the time of fertilization until metamorphosis occurs. While gelatin-cleavage activities were absent from freshly prepared hyaline layers, a dynamic pattern of activities developed in layers incubated at 15 or 37 degrees C in Millipore-filtered sea water (MFSW). Cleavage activities at 90, 55, 41, and 32 kDa were evident following incubation at either temperature. The activation pathway leading to the appearance of these species was examined to determine the minimum salt conditions required for processing and to establish precursor-product relationships. In both qualitative and quantitative assays, the purified 55 kDa gelatinase activity was inhibited by 1,10-phenanthroline (a zinc-specific chelator) and ethylenebis (oxyethylenenitrilo) tetraacetic acid (EGTA). Calcium reconstituted the activity of the EGTA-inhibited enzyme with an apparent dissociation constant (calcium) of 1.2 mM. Developmental substrate gel analysis was performed using various stage embryos. The 55 and 32 kDa species comigrated with gelatin-cleavage activities present in sea urchin embryos. Collectively, the results reported here document a zymogen activation pathway which generates a 55 kDa, gelatin-cleaving activity within the extraembryonic HL. This species displayed characteristics of the matrix metalloproteinase class of ECM modifying enzymes.
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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".