Sodium-hydrogen exchangers in C. elegans and their potential role in hypodermal H+ excretion, Na+ uptake, ammonia excretion and acid-base balance
Bibliographic record
Abstract
Cation/proton exchangers of the Cation proton antiporter 1 (CPA1) subfamily (NHEs, SLC 9) play an important role in many physiological processes, including cell volume regulation, acid-base homeostasis and ammonia excretion. The soil nematode Caenorhabditis elegans expresses nine paralogues (NHX-1 to -9) of these transporters, which all contain the highly conserved amiloride binding motif. The current study was undertaken to investigate the role of the cation/proton exchanger in hypodermal Na+ and H+ fluxes as well in ammonia excretion processes. Measurements using the scanning ion-selective electrode technique (SIET) showed that the hypodermis promotes H+ secretion as well as a Na+ uptake, indicating the participation of a cation/proton exchanger. Interestingly, while both fluxes, as well as whole body ammonia excretion rates were partially inhibited by amiloride (100 µmol l-1), no effect was observed on the H+ efflux and ammonia excretion rates when animals were exposed to 100 µmol l-1 EIPA, suggesting participation of apical Na+ channels in Na+ uptake, but probably not NHX transporters. In response to stress induced by starvation or exposure to 1 mmol l-1 NH4Cl (HEA), pH = 5.5, pH = 8.0), body pH stayed fairly constant, with changes of mRNA expression levels detected in intestinal NHX-2 and hypodermal NHX-3. Excretory cell NHX-9 was altered by exposure to pH 5.5 or 8.0 but not by HEA. In conclusion, the study suggest that apical localized EIPA-sensitive sodium/hydrogen exchangers do play a role in ammonia excretion and Na+ uptake in the hypodermis of C. elegans.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".