Non-Invasive Assessment of Spent Bovine Culture Media Using Proton Nuclear Magnetic Resonance.
Notice bibliographique
Résumé
Early embryonic mortality is a great determinant of reproductive efficiency in mammals, including cattle. In in vitro production, approximately 90% of oocytes undergo fertilization following in vitro maturation; however, of these fertilized oocytes approximately 30-40% will reach the blastocyst stage. Factors involved in early embryonic mortality include oocyte and sperm quality, genetic factors, environmental and oxidative stresses, and largely in in vitro production, sub-optimal culture conditions. Current methods of embryo viability evaluation depend on morphological assessment, which in spite of its importance, is a poor predictor of embryo viability. Development of refined biological techniques like metabolomics has enabled us to explore the health of a cell based on its secreted metabolite constituents. Advanced analytical techniques, such as proton nuclear magnetic resonance (H1 NMR) has little chemical bias, gives detailed structural information of isolated metabolites and allow metabolites to be measured simultaneously with minimal sample preparation. We hypothesize that, embryos developing at different rates differ in their metabolomic signatures. The specific objective of study was to determine the metabolomic signatures of slow growing and fast growing embryos at timed stages of development, thereby determining possible biomarkers of embryo competency. Oocytes were collected from ovaries obtained from a local abattoir and then matured and fertilized in vitro using standard protocols. Presumptive zygotes were either placed for individual culture in 25 μl media drops. Media samples from fast growing embryos were collected at 2-cell (31 hours post fertilization), 4-cell (42 hours post fertilization), 8-cell (49 hours post fertilization) or 16-cell (72 hours post fertilization) and from slow growing embryos, which required additional 8 to 12 hours to reach equivalent embryo stage. The 18 μl media collection was diluted in 600 μl of 100% deuterium oxide (D2O) which included the internal reference standard TSP (sodium 3-(trimethyl-2,2,3,3)-1-propionic acid-d4). H1 NMR analysis was performed using a 600MHz Bruker NMR spectrometer. Preliminary data indicates distinct differences between metabolomic fingerprints of plain media, 2-cell, 4-cell, 8-cell, and 16-cell slow growing and fast growing groups. Specifically, slow growing embryos had lower lactate uptake and increased pyruvate production, while fast growing embryos demonstrated higher levels of pyruvate uptake. Moreover, in the presence of hydrogen peroxide, a reactive oxygen species, pyruvate can be decarboxylated to produce acetate, a metabolite which is higher in slow growing embryos compared to fast growing embryos. The data suggests that slow growing embryos have a slower metabolism and lower utilization of media substrates, as well as an increased response to oxidative stress. The results provide evidence towards the use of metabolomics for the development of a non-invasive tool for assessing embryo viability and the discovery of potential embryo viability biomarkers. (poster)
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 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 | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| 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 | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
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 ».