A proteomic analysis of penicillin resistance in <i>Streptococcus pneumoniae</i> reveals a novel role for PstS, a subunit of the phosphate ABC transporter
Bibliographic record
Abstract
Resistance to penicillin is widespread in the Gram-positive bacterium Streptococcus pneumoniae, and while several mutations are known to be implicated in resistance other mechanisms are likely to occur. We used a proteomic screen of two independent mutants in which resistance was selected in vitro. We found a number of differentially expressed proteins including PstS, a subunit of the phosphate ABC transporter of S. pneumoniae. This protein was increased in both mutants, a phenotype correlated to increased RNA expression of the entire phosphate ABC transporter operon. Inactivation of the pstS gene led to increased susceptibility to penicillin in the wild-type strain. To further link the expression of the ABC phosphate transporter with penicillin resistance, we looked at pstS mRNA levels in 12 independent clinical isolates sensitive and resistant to penicillin and found an excellent correlation between resistance and increased expression of pstS. Inactivation of pstS in one of the clinical isolates significantly reduced penicillin resistance. Global approaches are ideally suited for the discovery of novel factors in the biology of resistance.
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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".