Investigating survival mechanisms of Yersinia ruckeri in rainbow trout, Oncorhynchus mykiss
Bibliographic record
Abstract
Yersinia ruckeri' causes hemorrhagic septicemia of salmonid fish. We hypothesized that the ability to persist inside infected fish was a key component of virulence strategy of 'Y. ruckeri' and aimed to identify survival-essential genes of 'Y. ruckeri' serotype 1 strain, RS1154. After two rounds of screening of 1056 miniTn5Km2 signature-tagged mutants, 25 mutants that did not survive in kidney at 7 days post-infection in immersion infected rainbow trout were selected for further study. Sequencing of interrupted genes in selected mutants identified genes homologous to ' znuA', which encodes a component of a zinc transporter in ' Escherichia coli', and 'uvrY', which encodes the response regulator of BarA-UvrY two-component system (TCS) in 'E. coli'. The 'uvrY' mutant was hypersensitive to H2O 2-mediated killing and was less invasive to 'Epithelioma papulosum cyprini' fish cells than wild type (WT) bacteria, but was not affected in serum sensitivity or growth under iron-limiting conditions. In a competitive infection with WT, the 'uvrY' mutant had lower infection loads in rainbow trout kidney. When present in a low-copy plasmid, the 'znuACB' locus of 'Y. ruckeri' fully restored growth of a zinc-transport deficient [Delta]' znuACB' mutant of 'E. coli' in Luria-Bertani (LB) medium supplemented with 2.0 mM ethylenediamine tetraacetic acid (EDTA), indicating that 'znuACB' locus of 'Y. ruckeri' is likely involved in zinc transport. Unlike [Delta]'znuACB' mutants of 'E. coli', [Delta]'znuACB' mutant of ' Y. ruckeri' did not show poor growth in zinc-deficient M9 medium and LB medium supplemented with metal chelators, EDTA and tetrakis-(2-pyridylmethyl)-ethylenediamine, suggesting presence of additional zinc transporters in 'Y. ruckeri '. The 'znuA' mutant of 'Y. ruckeri' was out-competed by WT in rainbow trout kidney. Survival of 'Y. ruckeri' in rainbow trout was also reduced with mutations in gene homologs encoding an O-antigen polymerase (' wzy'), peptidoglycan deacetylase ('pdaA'), protease ('ptrA'), bundle-forming pili ('rcpA'), ATPase of DNA segregation ('parA') and transposase of Tn7, bacteriophage tail fiber-like protein and genes of unknown functions. Characterization of survival-essential genes in fish helps identify new virulence genes and contributes to understanding survival strategies and pathogenic mechanisms of ' Y. ruckeri'.
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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".