Low microbial abundance and community diversity within the egg capsule of the oviparous cloudy catshark ( <i>Scyliorhinus torazame</i> ) during oviposition
Bibliographic record
Abstract
Abstract Vertebrate embryos are protected from bacterial infection by various maternally derived immune factors before the embryonic organs are fully developed. However, the defense mechanisms employed by elasmobranch embryos during development remain poorly understood. This study attempted to elucidate the embryonic defense mechanism of elasmobranchs by investigating the intracapsular environment of freshly laid eggs of the oviparous cloudy catshark ( Scyliorhinus torazame ). The egg capsule of oviparous elasmobranchs is tightly sealed until pre-hatching (early opening of the egg capsule), after which seawater flows into the capsule and the embryos are consequently exposed to the surrounding seawater. We first experimentally examined the resistance of embryos to potential bacterial infections and found that the early embryos were highly vulnerable to environmental pathogens, suggesting that the embryos are protected from the threat of infection before pre-hatching. Indeed, the intracapsular environment of freshly laid eggs exhibited a significantly low bacterial density that was maintained until pre-hatching. Furthermore, the microbiome inside eggs just after oviposition differed markedly from the microbiomes of rearing seawater and adult oviducal gland epithelia; these eggs were predominantly populated by an unidentified genus of Sphingomonadaceae. Overall, this study provides compelling evidence that early embryos of oviparous cloudy catshark are incubated in a clean intracapsular environment that potentially plays a significant role in embryonic development in oviparous elasmobranchs. Our results suggest that maintenance of this clean condition might be attributable to bactericidal or bacteriostatic activities associated with the egg jelly and/or oviducal gland.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.002 | 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".