Mechanisms behind Pb-induced disruption of Na<sup>+</sup>and Cl<sup>−</sup>balance in rainbow trout (<i>Oncorhynchus mykiss</i>)
Bibliographic record
Abstract
The mechanism of Pb-induced disruption of Na(+) and Cl(-) balance was investigated in the freshwater rainbow trout (Oncorhynchus mykiss). Na(+) and Cl(-) influx rates were reduced immediately in the presence of 2.40 +/- 0.24 and 1.25 +/- 0.14 muM Pb, with a small increase in efflux rates occurring after 24-h exposure. Waterborne Pb caused a significant decrease in the maximal rate of Na(+) influx without a change in transporter affinity, suggesting a noncompetitive disruption of Na(+) uptake by Pb. Phenamil and bafilomycin markedly reduced Na(+) influx rate but did not affect Pb accumulation at the gill. Time-course analysis in rainbow trout exposed to 0, 0.48, 2.4, and 4.8 microM Pb revealed time- and concentration-dependent branchial Pb accumulation. Na(+)-K(+)-ATPase activity was significantly reduced, with 4.8 microM exposure resulting in immediate enzyme inhibition and 0.48 and 2.4 microM exposures inhibiting activity by 24 h. Reduced activity was weakly correlated with gill Pb accumulation after 3- and 8-h exposures; this relationship strengthened by 24 h. Reduced Na(+) uptake was correlated with gill Pb burden after exposures of 3, 8, and 24 h. Immediate inhibition of branchial carbonic anhydrase activity occurred after 3-h exposure to 0.82 +/- 0.05 or 4.30 +/- 0.05 microM Pb and continued for up to 24 h. We conclude that Pb-induced disruption of Na(+) and Cl(-) homeostasis is in part a result of rapid inhibition of carbonic anhydrase activity and of binding of Pb with Na(+)-K(+)-ATPase, causing noncompetitive inhibition of Na(+) and Cl(-) influx.
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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 | 0.001 |
| Research integrity | 0.001 | 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".