Laboratory and clinical Pseudomonas aeruginosa strains do not bind glycosphingolipids in vitro or during type IV pili-mediated initial host cell attachment
Bibliographic record
Abstract
The glycosphingolipids (GSLs) gangliotriaosylceramide (Gg(3)) and gangliotetraosylceramide (Gg(4)) have been implicated as receptors for type IV pili (T4P)-mediated Pseudomonas aeruginosa epithelial cell attachment. Since P. aeruginosa T4P are divided into five groups, the authors determined whether GSLs in general, and Gg(3) and Gg(4) in particular, are specifically bound and required for host epithelial cell attachment of clinical and laboratory strains within these groups. An enterohaemorrhagic Escherichia coli strain, CL56, known to bind to both Gg(3) and Gg(4), provided a positive control. TLC overlay showed no binding of more than 12 P. aeruginosa strains to either Gg(3) or Gg(4) (or other GSLs), while CL56 Gg(3)/Gg(4) binding was readily detectable. GSL ELISA similarly demonstrated no significant P. aeruginosa binding to Gg(3) or Gg(4), compared with CL56. Using a selective chemical inhibitor, epithelial cell GSL synthesis was abrogated, and Gg(3) and Gg(4) expression deleted, but P. aeruginosa attachment was not impaired. Target cell attachment was mediated by T4P, since non-piliated, but flagellated, mutants were unable to bind to the target cells. CFTR (cystic fibrosis transmembrane conductance regulator) has also been implicated as a receptor; however, in this work, overexpression of CFTR had no effect on P. aeruginosa binding. It is concluded that neither Gg(3) nor Gg(4) are specifically recognized by P. aeruginosa, and that endogenous GSLs do not have a role in the attachment of live intact P. aeruginosa to cultured lung epithelial cells. In contrast to whole piliated P. aeruginosa, T4P sheared from such bacteria showed significant Gg(3) and Gg(4) binding, which may explain the results of other studies.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".