Exploring the Targets of Reactive Oxygen Species and Defense against Oxidative Stress in <i>Campylobacter jejuni</i> Using a Multiomics Approach
Bibliographic record
Abstract
Campylobacter jejuni is a major cause of human gastroenteritis. Pathogenesis depends on survival in reactive oxygen species (ROS) that are produced endogenously and by host phagocytes and microbiota. Label-based proteomics by LC-MS/MS quantified 1347 proteins (83.0% of the predicted proteome) in response to hydrogen peroxide (10 μM/0.5 mM) and superoxide-inducing paraquat (PQ; 2 μM/10 μM). Antioxidants including catalase (KatA) and alkylhydroperoxide reductase (AhpC), were induced, consistent with the oxidative stress response. Changes to nutrient transporters (SdaC/PutP/LctP) correlated with the intracellular abundance of substrates (serine/proline/lactate). ROS significantly elevated the abundance of the outer membrane protein Cj1170c, and Δ cj 1170c bacteria were compromised for survival in H 2 O 2 and under osmotic stress. PQ induced intracellular accumulation of threonine and homoserine, while Δ cj1170c bacteria were depleted of these metabolites. ROS targets cysteine thiols that can be irreversibly modified to sulfinic and sulfonic (SO 2 H/SO 3 H) acids. We identified 1334 Cys-SO 2 H/SO 3 H-modified peptides (867 sites in 495 proteins) using SCX negative and HILIC positive selection coupled to LC-MS/MS. Many sites were modified without exogenous H 2 O 2, suggesting that C. jejuni maintains an oxidative intracellular environment potentially related to microaerophilicity. Fe–S clusters were the primary targets of ROS. ROS trigger molecular remodeling associated with in-host growth, while overoxidizable Cys sites provide targets for redox-based antimicrobials.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".