The VxrAB two-component system is important for the polymyxin B-dependent activation of the type VI secretion system in <i>Vibrio cholerae</i> O1 strain A1552
Bibliographic record
Abstract
The type VI secretion system (T6SS) is used by bacteria for virulence, resistance to grazing, and competition with other bacteria. We previously demonstrated that the role of the T6SS in interbacterial competition and in resistance to grazing is enhanced in Vibrio cholerae in the presence of subinhibitory concentrations of polymyxin B. Here, we performed a global quantitative proteomic analysis and a targeted transcriptomic analysis of the T6SS-known regulators in V. cholerae grown with and without polymyxin B. The proteome of V. cholerae is greatly modified by polymyxin B with more than 39% of the identified cellular proteins displaying a difference in their abundance, including T6SS-related proteins. We identified a regulator whose abundance and expression are increased in the presence of polymyxin B, vxrB, the response regulator of the two-component system VxrAB (VCA0565-66). In vxrAB, vxrA and vxrB deficient mutants, the expression of both hcp copies (VC1415 and VCA0017), although globally reduced, was not modified by polymyxin B. These hcp genes encode an identical protein Hcp, which is the major component of the T6SS syringe. Thus, the upregulation of the T6SS in the presence of polymyxin B appears to be, at least in part, due to the two-component system VxrAB.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".