Expression pattern of pluripotent markers in different embryonic developmental stages of buffalo (Bubalus bubalis) embryos and putative embryonic stem cells generated by parthenogenetic activation

Haploid embryos and embryonic stem cells to produce offspring with predetermined parental genomes in cattle

Selection strategies are performed post-fertilization when the random combination of paternal and maternal genomes has already occurred. It would be greatly advantageous to eliminate meiotic uncertainty by selecting genetically superior gametes before fertilization. To achieve this goal, haploid embryonic cells and embryonic stem cell lineages could be derived, genotyped, and used to substitute gametes. On the paternal side, androgenetic development can be achieved by removing the maternal chromosomes from the oocyte before or after fertilization. We have shown that once developed into an embryo, haploid cells can be removed for genotyping and, if carrying the selected genome, be used to replace sperm at fertilization. A similar strategy can be used on the maternal side by activating the oocyte parthenogenetically and using some embryonic cells for genotyping while the remaining are used to produce diploid embryos by fertilization. Placed together, both androgenetic and parthenogenetic haploid cells that have been genotyped to identify optimal genomes can be used to produce offspring with predetermined genomes. Successes and problems in developing such a breeding platform to achieve this goal are described and discussed below.

Perspectives of pluripotent stem cells in livestock

The recent progress in derivation of pluripotent stem cells (PSCs) from farm animals opens new approaches not only for reproduction, genetic engineering, treatment and conservation of these species, but also for screening novel drugs for their efficacy and toxicity, and modelling of human diseases. Initial attempts to derive PSCs from the inner cell mass of blastocyst stages in farm animals were largely unsuccessful as either the cells survived for only a few passages, or lost their cellular potency; indicating that the protocols which allowed the derivation of murine or human embryonic stem (ES) cells were not sufficient to support the maintenance of ES cells from farm animals. This scenario changed by the innovation of induced pluripotency and by the development of the 3 inhibitor culture conditions to support naïve pluripotency in ES cells from livestock species. However, the long-term culture of livestock PSCs while maintaining the full pluripotency is still challenging, and requires further refinements. Here, we review the current achievements in the derivation of PSCs from farm animals, and discuss the potential application areas.

Parthenogenetic activation of buffalo (Bubalus bubalis) oocytes: comparison of different activation reagents and different media on their developmental competence and quantitative expression of developmentally regulated genes

This study was carried out to compare the efficacy of different methods to activate buffalo A + B and C + D quality oocytes parthenogenetically and to study the in vitro developmental competence of oocytes and expression of some important genes at the different developmental stages of parthenotes. The percentage of A + B oocytes (62.16 ± 5.06%, range 53.8-71.3%) was significantly higher (P < 0.001) compared with that of C + D oocytes (37.8 ± 5.00%, range 28.6-46.1%) retrieved from slaughterhouse buffalo ovaries. Among all combinations, ethanol activation followed by culture in research vitro cleave medium gave the highest cleavage and blastocyst yields for both A + B and C + D grade oocytes. Total cell numbers, inner cell mass/trophectoderm ratio and apoptotic index of A + B group blastocysts were significantly different (P < 0.05) from their C + D counterpart. To determine the status of expression patterns of developmentally regulated genes, the expression of cumulus-oocyte complexes, fertilization, developmental competence and apoptotic-related genes were also studied in parthenogenetically produced buffalo embryos at different stages, and indicated that the differential expression patterns of the above genes had a role in early embryonic development.

An invertebrate signal transducer and activator of transcription 5 (STAT5) ortholog from the disk abalone, Haliotis discus discus: Genomic structure, early developmental expression, and immune responses to bacterial and viral stresses

Signal transducer and activator of transcription (STAT) family members are key signaling molecules that transduce cellular responses from the cell membrane to the nucleus upon Janus kinase (JAK) activation. Although seven STAT members have been reported in mammals, very limited information on STAT genes in molluscans is available. In this study, we identified and characterized a STAT paralog that is homologous to STAT5 from the disk abalone, Haliotis discus discus, and designated as AbSTAT5. Comparison of the deduced amino acid sequence for AbSTAT5 (790 amino acids) with other counterparts revealed conserved residues important for functions and typical domain regions, including the N-terminal domain, coiled-coil domain, DNA-binding domain, linker domain, and Src homology 2 (SH2) domains as mammalian counterparts. Analysis of STAT phylogeny revealed that AbSTAT5 was clustered with the molluscan subgroup in STAT5 clade with distinct evolution. According to the genomic structure of AbSTAT5, the coding sequence was distributed into 20 exons with 19 introns. Immunologically essential transcription factor-binding sites, such as GATA-1, HNF, SP1, C/EBP, Oct-1, AP1, c-Jun, and Sox-2, were predicted at the 5'-proximal region of AbSTAT5. Expression of AbSTAT5 mRNA was detected in different stages of embryonic development and observed at considerably higher levels in the morula and late veliger stages. Tissue-specific expressional studies revealed that the highest level of AbSTAT5 transcripts was detected in hemocytes, followed by gill tissues. Temporal expressions of AbSTAT5 were analyzed upon live bacterial (Vibrio parahemolyticus and Listeria monocytogenes), viral (viral hemorrhagic septicemia virus), and pathogen-associated molecular pattern (lipopolysaccharides and Poly I:C) stimulations, and significant elevations indicated immune modulation. These results suggest that AbSTAT5 may be involved in maintaining innate immune responses from developmental to adult stages in the disk abalone. Further, this study provides a basis for structural and functional exploration of STAT members in the invertebrate JAK/STAT signaling pathway.