Overlooked signals: Highly stable quorum sensing molecule in phage lysates induces quorum sensing response
Bibliographic record
Abstract
Phage-bacterial interaction studies routinely apply phage lysates at final concentrations of up to 10% of the culture. Consequently, bacterial metabolites such as quorum sensing (QS) signaling molecules are transferred along with the phage lysate to recipient bacterial cells. Here, we show that the Pseudomonas aeruginosa QS molecules 3OC12-HSL and C4-HSL are rapidly degraded in phage lysates. In contrast, the hydrophobic QS molecule PQS is remarkably stable, for at least one year, due to its binding within outer membrane vesicles. Strikingly, we find that PQS exceeds concentrations of 10 µM in standard phage lysate preparations. We show that PQS carried over from phage lysates induces QS-controlled production of the virulence factor pyocyanin in P. aeruginosa . This PQS carryover does not oppose previous conclusions of phage infection-induced PQS production, as we show here, that this response is also triggered by PQS-free phage lysates. Since other bacterial species, including Paracoccus and Vibrio harveyi , also produce hydrophobic QS molecules that are bound within outer membrane vesicles, it is likely that phage lysates from these bacteria may similarly contain stable QS molecules. Collectively, we demonstrate that membrane-bound QS molecules may significantly confound QS-related physiological outcomes of phage-host interaction studies. This can be avoided by using QS synthase mutants for phage propagation or by purifying phage particles from lysates to eliminate QS molecule carryover.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".