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Contents With an aim to improve the efficiency of yak-bovine interspecies somatic cell nuclear transfer (i SCNT), this study investigated the effect of different culture systems on the development, quality and gene expression profile of yak-bovine i SCNT embryo. Reconstructed embryos were cultured in modified synthetic oviductal fluid (m SOF) or relative defined culture medium ( RDCM) with 5% or 20% oxygen tension. Relative m RNA abundance of Oct-4, IFNT, IGF-2, Bax, GPX-1, SOD-1, CAT and GSS was analysed in blastocysts with q RT-PCR. The blastocyst formation rate in RDCM under 5% oxygen tension was significantly higher than that under 20% oxygen tension ( P < 0.05). The total cell number of blastocyst derived from RDCM with 20% oxygen tension was lower than that of other groups, whereas the group of RDCM with 5% oxygen tension showed a beneficial effect on apoptosis index and tolerance to cryopreservation ( P < 0.05). However, under the same oxygen tension, the m RNA abundance of IFNT of RDCM groups was higher than that of the m SOF groups. In addition, high oxygen tension during in vitro culture ( IVC) with RDCM significantly increases the m RNA expression of oxidative stress-related genes ( GPX-1, SOD-1, CAT and GSS) ( P < 0.05). 3, 4-Dihydroxyflavone ( DHF) during high oxygen tension was able to improve the cloned blastocyst formation rate in RDCM ( P < 0.05). These results for the first time showed that low oxygen tension and RDCM could improve the developmental competence and quality and alleviate the oxidative stress for yak-bovine i SCNT embryo during IVC. [ABSTRACT FROM AUTHOR]

Contents Notable distinctions between an embryonic stem cell (ESC) and somatic cell are that an ESC can maintain an undifferentiated state indefinitely, self-renew, and is pluripotent, meaning that the ESC can potentially generate cells representing all the three primordial germ layers and contribute to the terminally differentiated cells of a conceptus. These attributes make the ESC an ideal source for genome editing for both agricultural and biomedical applications. Although, ESC lines have been successfully established from rodents and primates, authentic ungulate stem cell lines on the contrary are still not available. Outstanding issues including but not limited to differences in pluripotency characteristics among the existing ESC lines, pre-implantation embryo development, pluripotency pathways, and culture conditions plague our efforts to establish authentic ESC lines from farm animals. In this review, we highlight some of these issues and discuss how the recent derivation of induced pluripotent stem cells (iPSCs) might augur the establishment of robust authentic ESC lines from farm animals. [ABSTRACT FROM AUTHOR]

Contents The survival and development of pre-implantation embryos are determinant factors affecting the outcome of animal reproduction. It is essential to transfer the expression of the genetic material from maternal sources, that is the ovum to the zygote before implantation to ensure successful development. Differentiation and transformation of blastomeres initiated during the morula and blastocyst stages is an important step of the embryonic development prior to implantation. We collected morula and early blastocyst samples from pure-bred Landrace pigs in vivo to study the differential gene expression patterns at these two stages. Total RNA was extracted from individual embryos and two rounds of amplification were employed. Two micrograms of antisense RNA, targets, were prepared and hybridized with each of four custom made oligo microarrays representing 24 000 porcine genes. The analyses of replicate hybridizations showed that among the 24 000 genes, 162 genes were expressed fivefold or greater in the morula compared to early blastocysts and 2126 genes were expressed fivefold or greater in early blastocysts compared to the morula. Of these differentially expressed genes, 1429 genes were functionally annotated with related human Gene Ontology terms. In addition to basic metabolic processes, genes related to signal transduction, transportation and cell differentiation were found in both stages and were up-regulated as embryo development proceeded. Real time polymerase chain reaction was utilized to quantify 12 genes differentially expressed in the 2 embryonic stages and validated the reliability of major evidences shown in microarrays. In conclusion, we have obtained a preliminary landscape of genes differentially expressed during the transition from morula to early blastocysts in pigs and showed a generally increased transcriptional activity, perhaps in preparation for implantation. Our results provide an opportunity to study the functions of these genes in relation to the development and survival of pre-implantation porcine embryos. [ABSTRACT FROM AUTHOR]