New permanent stem cell niche for development and regeneration in a chordate
Bibliographic record
Abstract
Abstract Stem cell niches are defined as the microenvironments where stem cells home, receiving stimuli defining their fate. In vertebrates, stem cell niches are stable and physically confined compartments. Botryllus schlosseri is an invertebrate colonial chordate where temporary stem cell niches have been identified in adult individuals that are cyclically resorbed and replaced by a new generation of clonal zooids. B. schlosseri also displays remarkable regenerative abilities, being capable of whole-body regeneration, but the cellular source of these processes is still unknown. Here we identified by means of a high-resolution morphological characterization a new putative stem cell niche in the ampullae of the circulatory system acting as a stem cell source during asexual reproduction. Stem cells of the ampullae travel via the circulatory system and contribute to the development of several organs and could explain where stem cells contributing to whole-body regeneration are stored. The ampullae niches are stable during the life cycle and regeneration of B. schlosseri , while additional niches of the zooid are dynamically established and colonised by circulating stem cells. Our results reveal an unprecedented dynamicity of stem cell niches in highly regenerative invertebrates.
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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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".