A Differential Mechanism Is Involved During Heparin- and Cryopreservation-Induced Capacitation of Bovine Spermatozoa
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
After ejaculation, mammalian spermatozoa must undergo capacitation to fertilize. Capacitation of bovine spermatozoa occurs in vitro in medium supplemented with heparin. Semen cryopreservation is an important tool for assisted reproduction, although the fertility of frozen-thawed spermatozoa is reduced, possibly due to precocious capacitation-like changes that are known to occur. Our purpose was to clarify the mechanisms involved in bull sperm cryocapacitation induced by cryopreservation. Our general hypothesis is that the signaling pathways that lead to capacitation are triggered by the cryopreservation procedure. Ejaculated bovine semen was divided into two aliquots and diluted in extender; one was then kept fresh, whereas the second was cryopreserved. Western blots of extracted sperm proteins with anti-phosphotyrosine antibody showed that capacitation, induced by either heparin in fresh sperm or cryopreservation (cryocapacitation), is associated with a differential profile of phosphotyrosine-containing proteins. Immunolocalization of phosphotyrosine-containing proteins in the fresh and cryopreserved spermatozoa showed that, after thawing, cryocapacitated sperm displayed labeling over the acrosomal region, whereas for fresh sperm, this labeling appeared after 5-h incubation with heparin. The chlortetracycline assay and the ability of the sperm to undergo the lysophosphatidylcholine-induced acrosome reaction were used to confirm that a subpopulation of cryopreserved sperm is capacitated at thawing, irrespective of heparin inclusion. Since glucose is known to inhibit heparin-induced capacitation, the semen extender was modified to include glucose as a means of inhibiting cryocapacitation; however, cryocapacitation was not prevented according to the chlortetracycline assay and profile of phosphotyrosine-containing sperm proteins.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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