Branchial localization of acid (A‐type) and base (B‐type) excreting ionocytes in Amazonian stenohaline freshwater <scp> <i>Potamotrygon</i> </scp> ray
Bibliographic record
Abstract
Abstract The branchial epithelium of Potamotrygon —a member of the only strictly freshwater elasmobranch family Potamotrygonidae—was observed via immunohistochemistry, and two distinct forms of ionocytes were identified. The acid (A‐type) and base (B‐type) secreting cells with respective basolateral–apical localizations of Na + /K + ‐ATPase–Na + /H + exchanger 3 in A‐type and V‐type H + ‐ATPase–pendrin Cl − /HCO 3 − exchanger in B‐type were detected and morphometric changes in response to acid–base disturbances (3 mmol/kg body mass acid [HCl] or base load [NaHCO 3 ] by intraperitoneal injection) were characterized. A‐type cells were found in distinct follicular clusters in the interlamellar region, while B‐type cells were found individually in both the filament and lamellar epithelia. Lamellar B‐type cells were more abundant and larger, with greater fluorescence than their filament counterparts. The B‐type cells responded to the base load by increasing in number in the filament and showed a more peripheral H + ‐ATPase distribution, indicative of activation by translocation to the basolateral membrane labyrinth. A‐type cells decreased in size with the base load. In contrast, no changes in A‐type or B‐type cells were observed with the acid load compared to the sham group. Together, these results indicate that the stenohaline Potamotrygon rays have branchial ion uptake cells that allow them to effectively ionoregulate under the challenging ion‐poor water conditions of the Amazon.
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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 | 0.000 |
| 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".