The role of the V‐type H <sup>+</sup> ‐ATPase in CAPA‐treated Malpighian tubules in the yellow fever mosquito, <i>Aedes aegypti</i>
Bibliographic record
Abstract
Haematophagus insects, such as the female Aedes aegypti mosquito, face the challenge of excess ion and water intake after engorgement on a blood meal. To cope with this, adult female A. aegypti utilize their highly adapted excretory system that includes the Malpighian ‘renal’ tubules (MTs), which are under rigorous control by several hormones to regulate transepithelial movement of ions/water. Originating in the nervous system, the mosquito anti‐diuretic hormone is a member of the CAPA peptide family and is a homolog of the vertebrate neuromedin U peptide. CAPA peptides inhibit fluid secretion of MTs stimulated by select diuretic factors, 5HT and DH 31 through the NOS/cGMP/PKG pathway. However, the anti‐diuretic signalling mechanism and downstream cellular targets, such as ion channels and transporters, remain unclear. Active ion transport in A. aegypti MTs is driven by the principal cells, whose brush‐border membrane is densely packed by the V‐type H + ‐ATPase (VA), serving as the primary energizer for transepithelial secretion of electrolytes and water. Due to its predominant role in fluid secretion, the VA is a likely target for diuretic and anti‐diuretic factors. The effect of endocrine factors and the VA inhibitor, bafilomycin, on fluid secretion rate by MTs was measured using an in vitro bioassay. Bafilomycin was found to inhibit fluid secretion stimulated by serotonin (5HT) and the calcitonin‐related diuretic hormone (DH 31 ), while having no inhibitory action on MTs stimulated with the corticotropin‐releasing factor (CRF)‐related diuretic hormone. CAPA and bafilomycin treatment led to alkalization of the secreted fluid suggesting inhibition of the apical VA, which may lead to constrained entry of cations (Na + and K + ) across the apical membrane of MTs. VA activity was increased in adult female MTs treated with DH 31 , whereas CAPA treatment reduced VA activity, comparable to saline levels. Furthermore, a VA antibody was used to determine protein localization and expression in DH 31 and CAPA‐treated MTs. In DH 31 ‐incubated MTs, the VA was exclusively localized to the apical memrane of the MTs, whereas VA immunoreactivity was observed in both the apical membrane and cytosol of CAPA‐treated tubules. These results suggest a novel mechanism for CAPA inhibition, blocking the VA to hinder fluid secretion. A. aegypti mosquitoes are vectors of a variety of pathogens leading to illnesses, such as Dengue fever, Yellow fever, and the Zika virus. The current results advance our knowledge of the anti‐diuretic control of the A. aegypti MTs, suggesting that CAPA targets the VA to inhibit diuresis. Investigating the pathway of CAPA inhibition and its role in countering diuresis will help provide a deeper understanding of this critical physiological process. Studying the excretory system and discerning the underlying mechanisms behind ion and fluid transport may aid in developing novel pest management strategies to better control Aedes population and lessen its prominence as a disease vector.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".