The fliR gene contributes to the virulence of S. marcescens in a Drosophila intestinal infection model
Bibliographic record
Abstract
Serratia marcescens is an opportunistic bacterium that infects a wide range of hosts including humans. It is a potent pathogen in a septic injury model of Drosophila melanogaster since a few bacteria directly injected in the body cavity kill the insect within a day. In contrast, flies do not succumb to ingested bacteria for days even though some bacteria cross the intestinal barrier into the hemolymph within hours. The mechanisms by which S. marcescens attacks enterocytes and damages the intestinal epithelium remain uncharacterized. To better understand intestinal infections, we performed a genetic screen for loss of virulence of ingested S. marcescens and identified FliR, a structural component of the flagellum, as a virulence factor. Next, we compared the virulence of two flagellum mutants fliR and flhD in two distinct S. marcescens strains. Both genes are required for S. marcescens to escape the gut lumen into the hemocoel, indicating that the flagellum plays an important role for the passage of bacteria through the intestinal barrier. Unexpectedly, fliR but not flhD is involved in S. marcescens-mediated damages of the intestinal epithelium that ultimately contribute to the demise of the host. Our results therefore suggest a flagellum-independent role for fliR in bacterial virulence.
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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) | 0.001 | 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".