THE ACTIVITY OF AMINO ACID TRANSPORT SYSTEMS IS DYNAMIC IN GROWING AND MATURING MOUSE OOCYTES
Notice bibliographique
Résumé
In the ovarian follicle, the surrounding granulosa cells support oocyte development at least partly by supplying it with metabolic substrates, including amino acids. In pre-implantation embryos, characterization of amino acid requirements and activity of transport systems during development has helped lead to the optimization of embryo culture conditions. However, little is known about these systems in oocytes or follicles. Determining the activity of amino acid transport systems and the changes in their activity at different stages of oocyte development could help optimize media for oocyte growth and maturation in vitro, as well as increase the understanding of how the oocyte gains its independence from granulosa cells to exist as a healthy, competent gamete. Our objective was to survey the activity of amino acid transport systems in growing and maturing mouse oocytes. Using radio-labeled amino acids, we first assessed the activity of transport systems in freshly-collected GV and MI oocytes and MII eggs. The initial test for the presence of a transport system included demonstrating saturable transport of a preferred substrate and inhibition of its transport by a established competitive inhibitor. As previously shown, system GLY (Glyt1) was inactive in GV oocytes but activity developed at the MI stage and then increased 3 fold at the MII stage. Beta-amino acid transporter (system Beta) activity was not detected in GV oocytes and appeared at the MI stage, remaining constant in MII stage oocytes. In contrast, system b0,+ activity was present at a constant level throughout meiotic maturation, as assessed with test substrates arginine, lysine and glutamine. System L (leucine-preferring) activity was also present at all stages of maturation but decreased by approximately 40% between the MI and MII stages. Cystine transport was found to occur via system xc−; activity was present throughout maturation but increased a little more than 2-fold between the MI and MII stages. Finally, system ASC was found to account for constant alanine transport activity at all stages of maturation, whereas activities of systems CAT, N, A, XAG− and B0,+ were not detected. Our preliminary data indicate that at least some of these amino acid transport systems develop in the oocyte during oocyte growth. Together, our data indicate that, in the oocyte, the activities of some amino acid transport systems develop and change during meiotic maturation, possibly as a response to oocyte independence from the granulosa cells, which begins at ovulation. Supported by the Program on Oocyte Health, Canadian Institutes of Health Research, Institute of Human Development, Child and Youth Health (HGG62293). (poster)
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».