The effect of prolonged hypoxic exposure on chemoreceptor morphology of bowfin ( <i>Amia calva</i> ) with and without access to air
Bibliographic record
Abstract
The fish literature is peppered with evidence of two types of putative oxygen chemoreceptors: internal receptors that sense changes in blood PO 2 and external receptors that sense changes in water PO 2 . The exact location and morphology of these cells remains unknown. Our goal was to identify these elusive chemoreceptors using a facultative air breather, the bowfin. One group of fish were exposed to prolonged hypoxia (42 torr for 7 days) and had access to the surface of the water to breathe (hypoxic but not hypoxaemic). Another group of fish were exposed to the same hypoxic protocol but did not have access to the surface to breathe (hypoxic and hypoxaemic). Following exposure the fish were sacrificed and their gills sampled. We identified 3 types of putative oxygen chemoreceptors. Type I cells were found near the efferent filament artery, had no cellular projections and were immunopositive for serotonin (5‐HT), acetylcholine (ACh), synaptic vesicle (SV2) markers and were innervated (zn‐12). Type II cells were bipolar neurons found in the central venous sinus (cvs) and immunopositive for 5‐HT, ACh, SV2 and zn‐12. Type III cells were also found in the cvs, had no cellular projections and were immunopositive for 5‐HT but not for SV2 or ACh and were rarely innervated. Type I cells were significantly larger in bowfin without access to air than in bowfin with access to air, suggesting that these cells are internal chemoreceptors.
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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".