30 USE OF ADULT STEM/PROGENITOR CELLS AS NUCLEAR DONORS TO PRODUCE CLONED PORCINE EMBRYOS
Notice bibliographique
Résumé
Incomplete or defective nuclear reprogramming may be responsible for low cloning efficiencies. Less differentiated stem cells are thought to be more easily reprogrammed, resulting in improved survival of cloned mice (Rideout WM III et al., 2000 Nat. Genet. 24, 109–110). Our objective was to establish porcine mesenchymal stem cell (MSC) cultures and use these as donor cells in nuclear transfer (NT). A bone marrow (BM) aspirate was collected from an anesthetized gilt. BM mononuclear cells were isolated by centrifugation over a density gradient (Histopaque-1077; Sigma, St. Louis, MO, USA), resuspended in low glucose DMEM (Gibco) plus 10% FBS and plated on flasks; fibroblast-like MSCs were later passaged. Ear skin fibroblast (SF) cultures from the same BM donor gilt were established. Cultures of MSC and SF were exposed to lipogenic, osteogenic or chondrogenic differentiation media (Pittenger MF et al., 1999 Science 284, 143–147) for 14 days. Cells cultured in DMEM with 10% FBS served as controls. Differentiation was assessed by histochemical methods. Calcium deposits and alkaline phosphatase (AP) activity (Vector Red AP Substrate Kit, Vector Labs) were indicative of osteogenic differentiation. MSCs cultured under osteogenic conditions were positive for AP activity and developed a black color after von Kossa staining, indicative of calcium deposition. Oil red O stain identified cellular lipid accumulation. When exposed to adipogenic differentiation media, 10–15% of MSCs developed an adipocyte phenotype with lipid droplet accumulation and oil red O staining. Lipogenic differentiation was not observed in SF and control cultures. Presence of acidic mucopolysaccharides associated with cartilage formation was determined by alcian blue stain. MSCs exposed to chondrogenic conditions were alcian blue-positive, and SF and control cultures were alcian blue negative. For NT, confluent (passage 2) MSC and SF cultures were exposed to roscovitine (15 µM; Sigma) for 24 h. In vitro-matured oocytes were enucleated and a single cell (MSC or SF) was transferred into the periviteline space. Cell-oocyte couplets were fused in Zimmerman’s medium with a single electric pulse (250 V/mm for 20 µs) delivered through a needle-type electrode. NT units were electrically activated (2 pulses of 100 V/mm for 60 µs separated by 5 s) in a chamber 1 h after fusion and transferred to NCSU-23 medium. Embryos were examined for cleavage and blastocyst formation at 2 and 7 days after NT, respectively. Cleavage rates were 53.3% (40/75) for MSC and 59.7% (46/77) for SF NT embryos. Development to blastocyst stage was 6.6% (5/75) in the MSC group and 1.2% (1/77) in SF group. In conclusion, we established an adult MSC line from a live animal using a minimally invasive BM aspiration technique. Additionally, MSC donor-derived NTs developed to the blastocyst stage. Further experiments will determine nuclear reprogramming in MSC-derived NT embryos.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».