28 CLONED EMBRYOS CAN BE PRODUCED USING DONOR CELLS OBTAINED FROM A 72-HOUR COOLED CARCASS
Bibliographic record
Abstract
There are few reports on the use of cells from a dead mammal for nuclear transfer (NT). So far, most calves have been cloned from live adult cows or fresh fetal samples. The ability to produce cloned animals using postmortem tissue can provide an additional application to the field of NT. This study was conducted to investigate whether viable cells could be obtained from tissues chilled for 72 h and whether these cells could be used for NT. Bovine oocytes isolated from slaughterhouse ovaries were matured in TCM199 supplemented with 10% fetal calf serum (FBS), 50 µg/mL sodium pyruvate, 1% v:v penicillin-streptomycin (10,000 U/mL penicillin G, 10,000 µg/mL streptomycin), 10 ng/mL EGF, 0.5 µg/mL FSH, and 5 µg/mL LH. A cell line (MC) was established from leg muscle of a cow carcass stored at 0°C for 72 h. Tissues from muscle were cut into small pieces. Tissue explants were cultured in DMEM-F12 supplemented with 10% FBS at 37°C in 5% CO2 in air. Bovine granulosa cells (GC) were isolated from ovarian follicles and used for NT as control cells. Prior to NT, all somatic cells were allowed to grow to confluency (G1/G0) in DMEM-F12 medium supplemented with 10% FBS. Cumulus cells were removed by vortexing with hyaluronidase at 18 h after the start of maturation. Matured oocytes labeled with DNA fluorochrome Hoechst 33342 were enucleated under UV to ensure full removal of the chromatin. A single cell was inserted into the perivitelline space of the enucleated oocyte. Oocyte-cell couples were fused by a DC pulse of 133V/500 µm for 25 µs. After fusion, NT units were activated using a combination of calcium ionophore (5 µM), cytochalasin D (2.5 µg/mL) and cycloheximide (10 µg/mL) and cultured for 7 days in BARC or G1.3-G2.3 medium. Differences (developmental potential and cell numbers) among groups were analyzed by one-way ANOVA after arcsin square transformation. The results are summarized in Table 1. The results suggest that viable cells can be obtained from muscle of a cow carcass stored at cold temperature for 72 h and that these cells have ability to generate NT blastocysts at rates similar to those obtained with fresh GCs. In addition, G1.3 and G2.3 culture medium supported embryo development better than BARC medium. Table 1. In vitro development of NT embryos This study was supported by a grant from TUBITAK, Turkey (VHAG-1908 and Turkey-Hungary bilateral project VHAG-2022).
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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) | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.004 |
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".