Studies of Pseudomonas aeruginosa Mutants Indicate Pyoverdine as the Central Factor in Inhibition of Aspergillus fumigatus Biofilm
Bibliographic record
Abstract
Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) are common opportunistic bacterial and fungal pathogens, respectively. They often co-exist in airways of immunocompromised patients and individuals with cystic fibrosis, where they form biofilms and cause acute and chronic illnesses. Hence, the interactions between them have long been of interest, and known that Pa can inhibit Af in vitro. We have approached the definition of the inhibitory Pa molecules by studying 24 Pa mutants, with various genes deleted, for their ability to inhibit Af biofilms. The ability of Pa cells, or their extracellular products produced during planktonic or biofilm growth, to affect Af biofilm formation, preformed Af biofilm, or planktonic Af was studied in agar and liquid assays with conidia or hyphae. Four mutants, pvdD -/pchE- , pvdD- , lasR-/rhlR- , and lasR were shown defective in the various assays. This suggested a central place for the siderophore pyoverdine as the key inhibitory molecule, although additional quorum sensing-regulated factors likely contribute to the deficiency of the latter two mutants. Studies of pure pyoverdine substantiated these results and restored inhibition by pyoverdine deletion mutants. Added iron or hemin reversed the inhibition by pyoverdine or pyoverdine-producing Pa strains. The key inhibitor for Af biofilms produced by Pa is pyoverdine. The inhibitory mechanism is chelation of iron, and denial of iron to Af. All authors: No reported disclosures.
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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) | 0.001 | 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".