Cryopreservation affects bovine sperm intracellular parameters associated with capacitation and acrosome exocytosis
Why this work is in the frame
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Bibliographic record
Abstract
Although semen cryopreservation is widely and commonly used in the bovine breeding industry, half the spermatozoa do not survive and most of those that do survive undergo numerous physiological changes that affect their fertilising ability. The aim of the present study was to determine how cryopreservation affects the intracellular events involved in sperm capacitation and acrosome reaction. Immediately after thawing and washing, almost 50% of spermatozoa were capacitated and more than 20% had lost their acrosome. The sperm cAMP concentration was lower than that in freshly ejaculated spermatozoa, but the cytosolic pH (pHcyt) was in the expected range. The free cytosolic Ca2+ concentration ([Ca2+]cyt) was higher than in fresh spermatozoa and cryopreserved spermatozoa had internally stored Ca2+. Phenylarsine oxide increased pHcyt and both cytosolic and stored Ca2+ concentrations, whereas orthovanadate enhanced acrosome loss and protein tyrosine phosphorylation (P-Tyr). Heparin increased the percentage of spermatozoa expressing the B (capacitated) chlortetracycline binding pattern, pHcyt, P-Tyr and Ca2+ storage. Moreover, positive correlations exist between capacitation, cAMP, P-Tyr and stored Ca2+, whereas the acrosome reaction is positively correlated with pHcyt and [Ca2+]cyt. These results demonstrate that sperm regulatory mechanisms may be affected by the cryopreservation procedure, but frozen-thawed sperm can still regulate their capacitation and acrosome reaction signalling pathways.
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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 | 0.000 | 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 | 0.000 | 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 it