Analysis of epithelial K+ transport in Malpighian tubules of<i>Drosophila melanogaster</i>: evidence for spatial and temporal heterogeneity
Bibliographic record
Abstract
Transport of K(+) by the lower, main and distal segments of the Malpighian tubules of Drosophila melanogaster was analyzed using self-referencing K(+)-selective microelectrodes. Transport properties of the Malpighian tubules of Drosophila melanogaster change along their length. Self-referencing ion-selective (SeRIS) microelectrode measurements (relative to the bath concentration of 20 mmoll(-1)) showed a 1% reduction (P<0.05) of [K(+)] in the unstirred layer adjacent to the main segment of the Malpighian tubules, confirming secretion of K(+) from the bath to the tubule lumen. Conversely, SeRIS measurements showed a 0.7% increase (P<0.05) in [K(+)] in the unstirred layer adjacent to the lower segment of Malpighian tubules, confirming reabsorption of K(+) from the luminal fluid to the bath. Measurements using SeRIS also showed that the distal segment neither secreted nor reabsorbed K(+). There was pronounced spatial heterogeneity in K(+) transport by the lower segment and the main segment; not all morphologically similar cells participated equally in K(+) transport, nor did all main segment cells respond equally to stimulation of K(+) transport by cyclic AMP. Pronounced temporal heterogeneity in K(+) reabsorption by the lower Malpighian tubules was also observed. We suggest that this reflects periodic reduction in K(+) reabsorption due to retention of fluid within the lower segment when the ureter contracts.
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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) | 0.000 | 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 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".