Temperature dependence of the superconducting energy gaps in Ca9.35La0.65(Pt3As8)(Fe2As2)5 single crystal.

We measured the optical reflectivity R(ω) for an underdoped (Ca0.935La0.065)10(Pt3As8)(Fe2As2)5 single crystal and obtained the optical conductivity [Formula: see text] using the K-K transformation. The normal state [Formula: see text] at 30 K is well fitted by a Drude-Lorentz model with two Drude components (ωp1 = 1446 cm-1 and ωp2 = 6322 cm-1) and seven Lorentz components. Relative reflectometry was used to accurately determine the temperature dependence of the superconducting gap at various temperatures below Tc. The results clearly show the opening of a superconducting gap with a weaker second gap structure; the magnitudes for the gaps are estimated from the generalized Mattis-Bardeen model to be Δ1 = 30 and Δ2 = 50 cm-1, respectively, at T = 8 K, which both decrease with increasing temperature. The temperature dependence of the gaps was not consistent with one-band BCS theory but was well described by a two-band (hence, two gap) BCS model with interband interactions. The temperature dependence of the superfluid density is flat at low temperatures, indicating an s-wave full-gap superconducting state.

Long-term health and germline transmission in transgenic cattle following transposon-mediated gene transfer.

BACKGROUND: Transposon-mediated, non-viral gene delivery is a powerful tool for generating stable cell lines and transgenic animals. However, as multi-copy insertion is the preferred integration pattern, there is the potential for uncontrolled changes in endogenous gene expression and detrimental effects in cells or animals. Our group has previously reported on the generation of several transgenic cattle by using microinjection of the Sleeping Beauty (SB) and PiggyBac (PB) transposons and seeks to explore the long-term effects of this technology on cattle. RESULTS: Transgenic cattle, one female (SNU-SB-1) and one male (SNU-PB-1), reached over 36 months of age with no significant health issues and normal blood parameters. The detection of transgene integration and fluorescent signal in oocytes and sperm suggested the capacity for germline transmission in both of the founder animals. After natural breeding, the founder transgenic cow delivered a male calf and secreted milk containing fluorescent transgenic proteins. The calf expressed green fluorescent protein in primary cells from ear skin, with no significant change in overall genomic stability and blood parameters. Three sites of transgene integration were identified by next-generation sequencing of the calf's genome. CONCLUSIONS: Overall, these data demonstrate that transposon-mediated transgenesis can be applied to cattle without being detrimental to their long-term genomic stability or general health. We further suggest that this technology may be usefully applied in other fields, such as the generation of transgenic animal models.

Development of genome engineering technologies in cattle: from random to specific.

The production of transgenic farm animals (e.g., cattle) via genome engineering for the gain or loss of gene functions is an important undertaking. In the initial stages of genome engineering, DNA micro-injection into one-cell stage embryos (zygotes) followed by embryo transfer into a recipient was performed because of the ease of the procedure. However, as this approach resulted in severe mosaicism and has a low efficiency, it is not typically employed in the cattle as priority, unlike in mice. To overcome the above issue with micro-injection in cattle, somatic cell nuclear transfer (SCNT) was introduced and successfully used to produce cloned livestock. The application of SCNT for the production of transgenic livestock represents a significant advancement, but its development speed is relatively slow because of abnormal reprogramming and low gene targeting efficiency. Recent genome editing technologies (e.g., ZFN, TALEN, and CRISPR-Cas9) have been rapidly adapted for applications in cattle and great results have been achieved in several fields such as disease models and bioreactors. In the future, genome engineering technologies will accelerate our understanding of genetic traits in bovine and will be readily adapted for bio-medical applications in cattle.

Efficient generation of transgenic cattle using the DNA transposon and their analysis by next-generation sequencing.

Here, we efficiently generated transgenic cattle using two transposon systems (Sleeping Beauty and Piggybac) and their genomes were analyzed by next-generation sequencing (NGS). Blastocysts derived from microinjection of DNA transposons were selected and transferred into recipient cows. Nine transgenic cattle have been generated and grown-up to date without any health issues except two. Some of them expressed strong fluorescence and the transgene in the oocytes from a superovulating one were detected by PCR and sequencing. To investigate genomic variants by the transgene transposition, whole genomic DNA were analyzed by NGS. We found that preferred transposable integration (TA or TTAA) was identified in their genome. Even though multi-copies (i.e. fifteen) were confirmed, there was no significant difference in genome instabilities. In conclusion, we demonstrated that transgenic cattle using the DNA transposon system could be efficiently generated, and all those animals could be a valuable resource for agriculture and veterinary science.

Developmental competence and cryotolerance of caprine parthenogenetic embryos cultured in chemically defined media.

In animal reproduction technologies, the in vitro embryo culture system has advanced over the past few decades. However, in vitro cultured embryos still have reduced functional and physiological abilities compared with those from in vivo conditions, and many factors of oviduct and uterine environments have not yet been revealed. Here, we demonstrated the in vitro culture of domestic goat (Capra hircus) embryos using two types of culture media, modified synthetic oviductal fluid (mSOF) and a two-step chemically defined medium (DI/II). To obtain parthenogenetic goat embryos, oocytes were matured in vitro in tissue culture media-199 supplemented with 10% fetal bovine serum for 22 to 24 hours, and activated with 5 µM, Ca(2+) ionomycin for 4 minutes, followed by 1.9 mM, 6-dimethylaminopurine treatment for 4 hours. After 2 days of embryo culture in different culture media, there were no significant differences in cleavage rates (96.6% vs. 95.4% in mSOF vs. DI/II, respectively). However, the DI/II group showed improved development competence to blastocysts (64.6% vs. 82.3% in mSOF vs. DI/II, respectively) and the total cell number of blastocysts (144.3 ± 9.2 vs. 264.4 ± 15.2 in mSOF vs. DI/II, respectively) at Day 7. After the cryopreservation of early-stage blastocysts at Day 6 via the conventional slow-freezing procedure, the surviving embryos were analyzed. The re-expansion rate after freezing and thawing was significantly higher in DI/II (39.66% vs. 67.69% in mSOF vs. DI/II, respectively), but there were no statistical differences in total cell numbers (142.3 ± 12.1 vs. 172.1 ± 11.6 in mSOF vs. DI/II, respectively), apoptotic index (4.9 ± 0.8% vs. 3.8 ± 0.7 in mSOF vs. DI/II, respectively), and the gene expression levels (BAX, GLUT1, MnSOD, and OCT4) among the re-expanded blastocysts. Overall, our data reported that the defined in vitro culture media for goat embryos were established with high efficiency, which will be very useful for goat embryo production.

Oxamflatin improves developmental competence of porcine somatic cell nuclear transfer embryos.

Abstract Aberrant epigenetic nuclear reprogramming of somatic nuclei is a major cause of low success in cloning. It has been demonstrated that treatment of histone deacetylase inhibitors (HDACi) enhances developmental potential of somatic cell nuclear transfer (SCNT) embryos by alteration of epigenetic status. The aim of the present study was to investigate the effect of oxamflatin, a novel HDACi, on the developmental competence of porcine SCNT embryos. Treatment with 1 µM oxamflatin for 9 h after activation of SCNT embryos increased both in vitro and in vivo developmental competence. Treatment of SCNT embryos with 1 µM oxamflatin significantly increased blastocyst rate and total cell number in blastocysts (33.3±6.0 and 73.1±1.6, respectively) than that of controls (10.3±3.7 and 54.1±3.5, respectively) or scriptaid (16.4±4.6 and 64.4±2.1, respectively). Moreover, oxamflatin showed significant higher overall cloning efficiency from 0.9% to 3.2%, whereas scriptaid demonstrated 0% to 1.8%. In conclusion, these results indicate that oxamflatin treatment improves the developmental competence of porcine SCNT embryos.

Production of transgenic bovine cloned embryos using piggybac transposition.

Transgenic research on cattle embryos has been developed to date using viral or plasmid DNA delivery systems. In this study, a different gene delivery system, piggybac transposition, was employed to investigate if it can be applied for producing transgenic cattle embryos. Green or red fluorescent proteins (GFP or RFP) were transfected into donor fibroblasts, and then transfected donor cells were reprogrammed in enucleated oocytes through SCNT and developed into pre-implantation stage embryos. GFP was expressed in donor cells and in cloned embryos without any mosaicism. Induction of RFP expression was regulated by doxycycline treatment in donor fibroblasts and pre-implantational stage embryos. In conclusion, this study demonstrated that piggybac transposition could be a mean to deliver genes into bovine somatic cells or embryos for transgenic research.