SC1 sustains the self-renewal capacity and pluripotency of chicken blastodermal cells by inhibiting the phosphorylation of ERK1 and promoting the phosphorylation of Akt.

Small molecules discovered during the recent years can be used to regulate the growth of embryonic stem cells (ES cells). Chicken blastodermal cells (cBCs) play an important role in both basic and transgenic researches as an important ES cell. However, the regulatory mechanism of small molecules involved in the self-renewal and pluripotency of cBCs remains unknown. This study revealed that the small molecule, SC1, can maintain cBCs in an undifferentiated, pluripotent state in serum- and feeder-free E8 media without leukaemia inhibitory factor. Furthermore, SC1 inhibits downregulation of pluripotency-related genes caused by retinoic acid and promotes the proliferation of cBCs. Furthermore, the results of this study indicated that SC1 functions by inhibiting ERK1 phosphorylation and promoting Akt phosphorylation, thus promoting the expression of pluripotency-related genes and maintaining the pluripotency of cBCs. The results also demonstrated that SC1 sustains the self-renewal capacity and pluripotency of cBCs cells by inhibiting ERK1 phosphorylation and promoting Akt phosphorylation. This kind of regulatory mechanism might be conserved in avian ES cells. Other molecules, similar to SC1, might provide insights into the molecular mechanisms that control the fate of stem cells and ultimately help in-vivo stem cell biology and therapy.

Retinoic acid promotes expression of germline-specific genes in chicken blastoderm cells by stimulating Smad1/5 phosphorylation in a feeder-free culture system.

BACKGROUND: Producing transgenic chickens with chicken blastodermal cells (cBCs) is inefficient due to the extremely low germline transmission capacity of cBCs. As chicken primordial germ cells (PGCs) have been reported as an efficient method for producing transgenic chickens, the inefficiency of cBCs could potentially be resolved by inducing them to differentiate into germ cells. However, whether chemical inducers are able to enhance cBCs germline competence in vitro is unknown and the molecular mechanisms of differentiation of chicken pluripotent cells into germ cells are poorly understood. RESULTS: We cultured cBCs with a monolayer morphology in E8 medium, a xeno- and feeder-free medium. We showed that retinoic acid (RA) treatment increased expression of germ cell-specific genes in cBCs. Using western blot, we determined that RA stimulated Smad1/5 phosphorylation. Moreover, Smad1/5 activation regulates the expression of germ cell-specific genes, as co-treatment with a Smad1/5 phosphorylation inhibitor or activator alters expression of these genes. We also demonstrate that Smad1/5 is required for RA-induced differentiation by RNA interference knockdown. CONCLUSION: Our results demonstrated that E8 medium is able to maintain cBC growth for weeks and RA treatment induced germ cell differentiation of cBCs through the BMP-Smad1/5 signaling pathway.

Evidence of nuclide migration from high-level radioactive waste glass via geogas.

Characteristics of high-level radioactive waste transport in glass as gases were studied. A transmission electron microscope was used to observe the morphology of the substance after penetrating the high-level radioactive waste glass and the bentonite soil column, and the composition of the substance was analyzed using electron probe energy spectroscopy. The results show that the radionuclides in the high-level radioactive waste glass were transported out of the glass, the bentonite was penetrated by the geogas, and the transported substance occurred as nanometer-size particles and particle aggregates.

The effects of vacancy ordering on diffusion: a statistical study.

In this paper we investigate the interconnection between vacancy-ordered phases and vacancy self-diffusion. Here, we investigate three ordered phases on a square lattice with energetics defined by two separate Hamiltonians. In the first case we used a classical antiferromagnetic Ising model Hamiltonian in order to generate a 'checkerboard' type ordered structure. In the second case, we used a modified Ising model with competing influence of second and third nearest-neighbors, which resulted in both 'hatch' and 'labyrinthine' structures, depending on concentration. To understand how vacancy-ordering affects diffusion, we determined the tracer diffusivity using rejection-free kinetic Monte Carlo and compared disordered and ordered structures. Finally, we developed an analytical model describing diffusion in the ordered 'checkerboard' structure and found that it was able to predict apparent activation energies in the ordered and disordered structures. Our results suggest that it is short-range order rather than long-range order that most significantly affects tracer diffusion.

Microstructures and Electrochemical Dissolution Characteristics of Additive-Manufactured Stainless Steel 304 on Different Sections at Low Current Density.

Additive manufacturing (AM) is a burgeoning technology for fabricating complex components with high efficiency and low material waste. However, the surface of AM parts is rough owing to partially melted powders and severe surface fluctuation. Electrochemical machining (ECM) is a suitable postprocessing method to finish the surface of the AM parts, and the low current density is usually employed. Our study illustrates the electrochemical dissolution characteristics of the horizontal and vertical sections of the AM SUS 304 component under a low current density and the electrochemical finishing process to obtain smooth surfaces. Linear and fan-shaped melt pools are observed on the horizontal and vertical sections, respectively. Moreover, the melt pool boundaries are vulnerable to dissolution and separate the hollows, basins, and swellings formed after electrochemical dissolution. The two sections display similar current efficiency and polarization because of the single austenitic phase and the identical and uniform elemental content distribution. The top and side surfaces of the AM sample could be efficiently smoothened via ECM by eliminating the partially melted powders and significantly reducing the surface roughness. The numerous band humps make the top surface of the AM sample difficult to smoothen compared with the side surface under the point effect of the electric field.

Efficient knock-in at the chicken ovalbumin locus using adenovirus as a CRISPR/Cas9 delivery system.

In this study, efficient knock-in (KI) of human epidermal growth factor (hEGF) cDNA at the ovalbumin (OV) locus in cultured chicken cells was achieved using adenovirus as a delivery for CRISPR/Cas9 elements and optimizing donor vector construction. The strategy of recruiting donor DNA to the insertion site further improved the KI efficiency. The inserted hEGF cDNA can expressed in primary oviduct cells and secreted hEGF promoted proliferation of Hela cells. Moreover, we achieved efficient KI in blastoderm cells without altering their induction in vitro and obtained germline chimeric KI chicken embryos by transplanting KI blastoderm cells as well as injecting adenovirus directly, in vivo. Our results provided an efficient KI method for chicken cells and embryos, and lay the foundation for more convenient production of KI chicken at the OV locus, which will promote the development of oviduct-specific bioreactor.

Retinoic acid (RA) and bone morphogenetic protein 4 (BMP4) restore the germline competence of in vitro cultured chicken blastodermal cells.

Chicken blastodermal cells (BCs) are pluripotent stem cells derived from early embryos and may be easily obtained and manipulated. However, in vitro cultured BCs have extremely low germline capacity, which may limit their applications. Research on the germ cell differentiation of mammalian pluripotent cells using chemical-inducing agents has gained popularity, and tremendous achievements have been made. Whether chemical-inducing agents allow acquirement of germline competence in BCs is, however, questionable. In this study, retinoic acid (RA) and bone morphogenetic protein 4 (BMP4) promoted the expression of germline-specific genes and restored the germline competence of in vitro cultured BCs. Moreover, BCs induced with RA and BMP4 could efficiently produce gonadal chimeric chick embryos. These results may greatly enhance the potential applications of BCs in biotechnology and basic research.

Clinicopathological characteristics and prognosis of metaplastic carcinoma of the breast.

Metaplastic carcinoma of the breast (MBC) is a rare and heterogeneous type of neoplasm. Knowledge about its clinical characteristics, prognostic significance and optimal treatment modalities is fragmentary and controversial. The present retrospective study aimed to investigate the prognostic value of the clinicopathological features and different therapeutic strategies in MBC. For this purpose, the medical records of 69 MBC patients subjected to surgical resection for MBC at the Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) were reviewed. A total of 69 MBC cases were followed up for 9-139 months. The 5-year disease-free survival (DFS) rate was 52.2% and the overall survival (OS) rate was 60.2%. Survival analysis revealed that large tumor size and lymph node (LN) metastases were correlated with shortened 5-year DFS and OS rates. In addition, chemotherapy significantly improved the prognosis of patients with LN metastasis, while radiation therapy (RT) significantly improved the 5-year OS and DFS rates of MBC patients with tumors ≥5 cm or with >4 metastatic LNs. In conclusion, MBC is a clinically aggressive subtype of breast cancer associated with a large tumor size. Chemotherapy may be recommended for certain subtypes of MBC with LN positivity, and RT may be a component of multimodality therapy for some MBC patients.

Polycomb repressive complex 1 (PRC1) regulates meiotic initiation of ovarian germ cells in chick embryos.

Meiosis is essential for gametogenesis and exhibits sex-specific property during embryonic development. Retinoic acid (RA) signalling initiates germ cell meiosis by activating Stra8 (stimulated by RA gene 8). Although additional factors are involved in regulating the meiotic initiation of germ cells, their regulatory mechanisms are unclear. In this study, we found that Polycomb repressive complex 1 (PRC1) is largely expressed in chicken ovarian germ and somatic cells during early stages of meiosis. We demonstrated that PRC1 regulates Stra8, pluripotent factors and paracrine factors (Notch ligands) leading to a synergistic effect on the suppression of germ cell meiotic initiation. Finally, we observed that repression of PRC1 resulted in precocious meiotic initiation and apoptosis of ovarian cells in vivo. These results aid in understanding the regulation of meiotic initiation in germ cells by PRC1 and provide evidence to support the hypothesis that regulation of meiotic initiation is conserved in higher vertebrates.