Strategies of ionoregulation in the freshwater nymph of the mayfly (<i>Hexagenia rigida</i>)
Bibliographic record
Abstract
This study investigated ionoregulatory strategies used by freshwater (FW) nymphs of the mayfly (Hexagenia rigida). Like other FW organisms, H. rigida nymphs maintain hemolymph ion levels (in mM: Na+∼102; Cl−∼84; K+∼6; pH∼7.35) far in excess of their surroundings. This appears to be accomplished by the combined actions of the alimentary canal, Malpighian tubules (MTs) and tracheal gills. The alimentary canal contributes in a region-specific manner; a view supported by (1) spatial differences in the activity of basolateral Na+-K+-ATPase (NKA) and apical V-type H+-ATPase (VA) and (2) region-specific Na+ and K+ flux rates. Both indicate a prominent role for the hindgut (rectum) in K+ reabsorption. MTs also exhibit region-specific differences in Na+ and K+ flux rates that are coupled with an organized but tortuous architecture. NKA and VA activities were highest in MTs versus all other organs examined. Tracheal gills were found to be sites of Na+ uptake but no difference in Na+ uptake was found between gills taken from different regions of the abdomen or spatially along individual gills. This is likely because each gill exhibited a dense population of NKA and/or VA immunoreactive cells (putative ionocytes). Data provide new insight into how FW mayfly nymphs regulate salt and water balance using the alimentary canal, MTs and tracheal gills as well as the first direct evidence that tracheal gills acquire ions from FW.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".