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 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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".