Reactive oxygen species and protein modifications in spermatozoa†
Bibliographic record
Abstract
Cellular response to reactive oxygen species (ROS) includes both reversible redox signaling and irreversible nonenzymatic reactions which depend on the nature and concentration of the ROS involved. Changes in thiol/disulfide pairs affect protein conformation, enzymatic activity, ligand binding, and protein-protein interactions. During spermatogenesis and epididymal maturation, there are ROS-dependent modifications of the sperm chromatin and flagellar proteins.The spermatozoon is regulated by redox mechanisms to acquire fertilizing ability. For this purpose, controlled amounts of ROS are necessary to assure sperm activation (motility and capacitation). Modifications of the thiol groups redox status of sperm proteins are needed for spermatozoon to achieve fertilizing ability. However, when ROS are produced at high concentrations, the established oxidative stress promotes pathological changes affecting sperm function and leading to infertility. Sperm proteins are sensitive to high levels of ROS and suffer modifications that impact on motility, capacitation, and the ability of the spermatozoon to recognize and bind to the zona pellucida and damage of sperm DNA. Thiol oxidation, tyrosine nitration, and S-glutathionylation are highlighted in this review as significant redox-dependent protein modifications associated with impairment of sperm function and alteration of paternal genome leading to infertility. Peroxiredoxins, the primary antioxidant protection in spermatozoa, are affected by most of the protein modifications described in this review. They play a significant role in both physiological and pathological processes in mammalian spermatozoa.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".