The ZnuABC operon is important for <i>Yersinia ruckeri</i> infections of rainbow trout, <i>Oncorhynchus mykiss</i> (Walbaum)
Bibliographic record
Abstract
Signature-tagged mutagenesis was used to identify genes essential for survival of Yersinia ruckeri in its natural host, rainbow trout, Oncorhynchus mykiss. A mini-Tn5-Km2 signature-tagged mutant, C6-1, was missing from rainbow trout kidney at 7 days after an immersion challenge. The transposon insertion in C6-1 was in a homologue of the znuA gene of Escherichia coli that encodes ZnuA, a zinc-binding periplasmic protein of the high-affinity zinc transporter ZnuABC. Further sequencing of the C6-1 locus in Y. ruckeri identified homologues of two other genes: znuB, encoding a putative inner membrane permease, and znuC, encoding a putative ATPase. When present on a low-copy plasmid, the znuABC locus of Y. ruckeri fully restored growth of a zinc transport-deficient DeltaznuABC mutant of E. coli. Unlike DeltaznuABC mutants of E. coli and Salmonella typhimurium, the DeltaznuABC mutant of Y. ruckeri did not demonstrate significantly slower growth in zinc-deficient M9 minimal medium or in Luria-Bertani (LB) medium supplemented with the metal chelators EDTA and tetrakis-(2-pyridylmethyl)-ethylenediamine (TPEN). In LB medium, the znuA::lacZ and znuCB::lacZ transcriptional fusions of Y. ruckeri were derepressed by addition of EDTA and TPEN and were repressed by addition of zinc and manganese. In a competitive challenge by immersion, the DeltaznuABC mutant was unable to compete with the parental strain and survived poorly in rainbow trout kidney, indicating that the ZnuABC transporter has a role in establishing and maintaining a rainbow trout infection by Y. ruckeri.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.000 | 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".