Kinetic analysis of zinc accumulation in the gills of juvenile rainbow trout: Effects of zinc acclimation and implications for biotic ligand modeling
Bibliographic record
Abstract
Abstract Juvenile rainbow trout were acclimated to hard water (Ca2+ = 1.0 mM, Mg2+ = 0.2 mM; hardness = 120 mg CaCO3/L) and hard water plus 250 μg/L Zn (3.8 μM). After 30 d of exposure, there was no difference in the total Zn levels of the gills of Zn-exposed and control fish (˜70 μg Zn/g gill). Exposure of both groups to a range of Zn concentrations (0–2,900 μg/L Zn) for up to 7 d also had no effect on the measured total Zn levels in the gills. However, using radiolabeled 65Zn, measurement of new Zn appearance in the gills was possible. Trout were exposed to a range of Zn concentrations (with 65Zn) and the gills were sampled at times ranging from 0.5 to 72 h. The fast turnover pool of Zn in the gills increased with increasing acute Zn exposure concentration, while the maximum size of the fast pool was about ninefold larger in Zn-acclimated fish (4.14 μg Zn/g gill) versus control fish (0.45 μg Zn/g gill). At all sampling times, gill 65Zn accumulation exhibited saturation kinetics, allowing calculation of binding capacity (Bmax) and affinity (Kd). In both control and Zn-acclimated trout, Kd decreased rapidly (affinity increased) from 0.5 to 3 h and then remained constant up to 72 h. Bmax increased rapidly from 0.5 to 3 h in both groups, then the rate of increase began to subside but was still increasing from 24 to 72 h. At all times, the Kd of Zn-acclimated fish was higher (i.e., lower affinity) and Bmax was greater than controls. The stabilized Kds (>3 h) were approximately 280 μg/L total Zn (log K = 5.6 as Zn2+) and 575 μg/L total Zn (log K = 5.3 as Zn2+) in control and Zn-acclimated fish, respectively. The Bmax of control fish at 0.5 h was 0.37 μg Zn/g gill and increased to 8.63 μg Zn/g gill by 72 h. The Bmax of Zn-acclimated fish increased from 0.70 to 11.61 μg Zn/g gill over the same time period. Preexposure to 250 μg/L Zn appeared to have little effect on acute zinc toxicity, though the 96-h LC50s for both groups were relatively high (˜3,000 μg/L Zn) in comparison to previous measurements. The relationship between gill binding constants for different metals and relative toxicity is critically assessed with respect to biotic ligand modeling.
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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".