Roles of the Extraintestinal Pathogenic <i>Escherichia coli</i> ZnuACB and ZupT Zinc Transporters during Urinary Tract Infection
Bibliographic record
Abstract
Roles of the ZnuACB and ZupT transporters were assessed in Escherichia coli K-12 and uropathogenic E. coli (UPEC) CFT073. K-12 and CFT073 Deltaznu DeltazupT mutants demonstrated decreased (65)Zn(2+) uptake and growth in minimal medium. CFT073Deltaznu demonstrated an intermediate decrease of (65)Zn(2+) uptake and growth in minimal medium, whereas the CFT073DeltazupT mutant grew as well as CFT073 and exhibited a less marked decrease in (65)Zn(2+) uptake. CFT073 mutants grew as well as the wild type in human urine. In competitive infections in CBA/J mice, the DeltazupT mutant demonstrated no disadvantage during urinary tract infection. In contrast, the UPEC Deltaznu and Deltaznu DeltazupT strains demonstrated significantly reduced numbers in the bladders (mean 4.4- and 30-fold reductions, respectively) and kidneys (mean 41- and 48-fold reductions, respectively). In addition, in single-strain infection experiments, the Deltaznu and Deltaznu DeltazupT mutants were reduced in the kidneys (P = 0.0012 and P < 0.0001, respectively). Complementation of the CFT073 Deltaznu DeltazupT mutant with the znuACB genes restored growth in Zn-deficient medium and bacterial numbers in the bladder and kidneys. The loss of the zinc transport systems decreased both motility and resistance to hydrogen peroxide, which could be restored by supplementation with zinc. Overall, the results indicate that Znu and ZupT are required for growth in zinc limited-conditions, that Znu is the predominant zinc transporter, and that the loss of Znu and ZupT has a cumulative effect on fitness during UTI, which may in part be due to reduced resistance to oxidative stress and motility.
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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) | 0.000 | 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 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".