<i>Pseudomonas aeruginosa</i> produces an extracellular deoxyribonuclease that is required for utilization of DNA as a nutrient source
Bibliographic record
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that occupies a wide variety of environmental niches. Extracellular DNA is ubiquitous in various environments and is a rich source of carbon, nitrogen and phosphate. Here we show that P. aeruginosa is capable of using DNA as a nutrient source. Under phosphate-limiting conditions, or when DNA is supplied as a source of phosphate, expression of PA3909 is induced. PA3909 encodes an extracellular deoxyribonuclease (DNase), which is required for degradation of DNA and utilization of DNA as a source of carbon, nitrogen and phosphate. Stabilization of PA3909 by the addition of excess Mg(2+) and Ca(2+) was required for DNase activity in culture supernatants. Extracellular DNase activity was seen in multiple P. aeruginosa strains and isolates from cystic fibrosis patients. The primary Xcp type II secretion system but not the Hxc type II secretion system is required for DNase activity and the ability to use DNA as a source of nutrients. This study identifies an extracellular DNase produced by P. aeruginosa that enables degradation of extracellular DNA into an accessible source of carbon, nitrogen and phosphate. DNase production by P. aeruginosa also has important implications for virulence and biofilm formation.
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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 | 0.001 |
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".