Semenogelin, the Main Protein of Semen Coagulum, Inhibits Human Sperm Capacitation by Interfering With the Superoxide Anion Generated During This Process
Bibliographic record
Abstract
Semenogelin (Sg), the major protein of the human semen coagulum, is present at high concentrations in seminal vesicle secretions. It is degraded by the prostate-specific antigen (PSA) to generate peptides of various biological activities that were found on and inside spermatozoa. Our aim was to determine the effect of Sg on capacitation, which is the series of transformations that spermatozoa must undergo to become fertile. At concentrations of 0.1 to 1.0 mg/mL (600- to 20-fold lower than those of semen), Sg did not affect sperm motility (%) but completely prevented capacitation induced by fetal cord serum ultrafiltrate; a partial inhibition of capacitation was noted with 0.03 mg Sg/mL. There was also a dose-dependent decrease in the tyrosine phosphorylation of fibrous sheath proteins and in the O2-.-related chemiluminescence. Ribonuclease (RNase), which has as high an isoelectric point (pI = 9.7) as Sg (pI = 9.5), also prevented sperm capacitation and O2-.-related chemiluminescence but to a lower extent, suggesting that one mechanism of Sg action on spermatozoa could be related to its positive charge at physiological pH. Sg at 1, but not 0.3 or 0.1 mg/mL, scavenged the O2-. generated by the mix of xanthine + xanthine oxidase and modified the kinetics of the reaction; RNase did not have such effects. Therefore, Sg is a potential scavenger for O2-. but probably also affects the sperm oxidase. Spermatozoa rapidly processed Sg; a high proportion of Sg was degraded after 15 minutes of incubation. The resulting polypeptide patterns were reminiscent of those obtained with PSA as a proteolytic enzyme. These data suggest that Sg, its degradation products, or both may be natural regulators of sperm capacitation and could prevent this process from occurring prematurely. One mechanism by which Sg acts could involve an interference with the O2-. that is normally generated during this process.
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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) | 0.000 | 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) | 0.001 | 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".