Naive hypomethylated embryonic pluripotent stem cells (ESCs) are developmentally closest to the preimplantation epiblast of blastocysts, with the potential to contribute to all embryonic tissues and the germline, excepting the extra-embryonic tissues in chimeric embryos. By contrast, epiblast stem cells (EpiSCs) resembling postimplantation epiblast are relatively more methylated and show a limited potential for chimerism. Here, for the first time, we reveal advanced pluripotent stem cells (ASCs), which are developmentally beyond the pluripotent cells in the inner cell mass but with higher potency than EpiSCs. Accordingly, a single ASC contributes very efficiently to the fetus, germline, yolk sac and the placental labyrinth in chimeras. Since they are developmentally more advanced, ASCs do not contribute to the trophoblast. ASCs were derived from blastocysts in two steps in a chemically defined medium supplemented with Activin A and basic fibroblast growth factor, followed by culturing in ABCL medium containing ActA, BMP4, CHIR99021 and leukemia inhibitory factor. Notably, ASCs exhibit a distinct transcriptome with the expression of both naive pluripotency genes, as well as mesodermal somatic genes; Eomes, Eras, Tdgf1, Evx1, hand1, Wnt5a and distinct repetitive elements. Conversion of established ESCs to ASCs is also achievable. Importantly, ASCs exhibit a stable hypermethylated epigenome and mostly intact imprints as compared to the hypomethylated inner cell mass of blastocysts and naive ESCs. Properties of ASCs suggest that they represent cells at an intermediate cellular state between the naive and primed states of pluripotency.

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Graphitic carbon nitride (CN) suffers from rapid recombination of photoexcited charges due to the existing highly symmetrical tri-s-triazine ring and long charge diffusion path, resulting in moderate photocatalytic activity. The bridged phenyl embedded in the CN structure was used to reduce the symmetry of the tri-s-triazine ring. In addition, the CN material was constructed with a porous and hollow sphere structure to shorten the diffusion path of charge carriers. Herein, simple thermal polymerization of a trimesic acid-doped melamine–cyanuric acid (MCA) supramolecular was employed to construct phenyl-bridged graphitic carbon nitride (Ph-CN-MCA) with a hollow sphere structure composed of porous nanosheets for visible-light catalytic H2 evolution. The porous and hollow sphere-structured Ph-CN-MCA possessed increased degree of polymerization, more negative conduction band potential, enlarged Brunauer–Emmett–Teller (BET) surface area, and shortened charge diffusion path. In addition, bridged phenyl embedded in the Ph-CN-MCA structure not only accelerated the dissociation of photogenerated carriers but also narrowed the band gap and extended the visible-light absorption. Further, the separated highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of Ph-CN-MCA facilitated the spatial dissociation of photogenerated charges, which was also confirmed by theoretical calculations. As a consequence, compared with the reference CN-MA catalyst prepared from melamine, Ph-CN-MCA showed approximately 48.42 times the photocatalytic H2 evolution under visible-light irradiation. The developed synthetic method herein highlights that phenyl-bridged graphitic carbon nitride with a porous and hollow sphere structure could provide an efficient platform to boost the dissociation of photoexcited charge carriers and photocatalytic H2 evolution.

Transcriptional inactivation of breast cancer gene 1 (BRCA1) by DNA methylation is a frequent event in sporadic breast cancers. To investigate whether BRCA1 methylation is associated with survival in Chinese patients with sporadic breast cancer, BRCA1 methylation was determined using methylation specific PCR in 536 sporadic breast cancers. Survival curves for patients with methylated and unmethylated BRCA1 were compared using the log-rank tests. Twenty-six percent (139/536) of patients exhibited BRCA1 methylation in their tumors. The degree of BRCA1 methylation was correlated with clinical stages of breast cancer, but was not significant. Patients with BRCA1 methylated tumors had a significantly worse 5-year disease-free survival (DFS) and 5-year disease-specific survival (DSS) than did patients with unmethylated tumors (DFS: 73.2% vs 82.6%, P = 0.045; DSS 80.5% vs 87%, P = 0.038, two-sided). In conclusions, BRCA1 methylation is a frequent event in breast cancer and is associated with poor clinical outcome in Chinese women with breast cancer. (1,2) It is well known that germline mutations of BRCA1 lead to familial breast cancer. The reported BRCA1 mutation rate was up to 45% in familial breast cancer, but only 1% in sporadic breast cancer.(3) However, downregulation of BRCA1 is a very frequent event in sporadic breast cancer and correlates with its progression. (4) Most housekeeping genes and 40% of tissue-specific genes contain CpG islands around the transcription starting sites. Methylation of these CpG islands silences gene transcription epigenetically. Aberrant methylation of tumor suppressor genes including BRCA1 is a frequent event that may play an important role in carcinogenesis.(5-8) It was reported that DNA methylation was the major cause of transcriptional silence of BRCA1, ranging from 13-40% in sporadic breast cancer.(9-11) Recently, Xu et al. reported that BRCA1 methylation was correlated with the prognosis of Caucasian patients with breast cancers.(12) However, the role of BRCA1 methylation is not well characterized in prognosis of sporadic breast cancers among other populations. In the present study, we determined the methylation status of BRCA1 in 536 Chinese patients with sporadic breast cancer and investigated whether the BRCA1 methylation was associated with clinical outcomes. Materials and MethodsStudy patients. A total of 611 patients with operable primary breast cancer (stage I-III) who had enough tumor DNA samples were selected from a pool of 857 consecutive breast cancer patients treated at the Breast Center, Peking University School of Oncology, from December 1994 to September 1999. A PCR product could not be obtained due to poor-quality DNA in 75 of 611 available DNA samples. Thus, 536 patients with sporadic primary breast cancer were analyzed in the present study. Pathological diagnosis was performed for all patients. The patient ages ranged from 25 to 86 years, with a median of 49 years. A total of 290 patients were premenopausal, and 246 patients were postmenopausal. The stage of th...

Inhibitors of Mek1/2 and Gsk3b, known as 2i, and, together with leukemia inhibitory factor, enhance the derivation of embryonic stem cells (ESCs) and promote ground-state pluripotency (2i/L-ESCs). However, recent reports show that prolonged Mek1/2 suppression impairs developmental potential of ESCs, and is rescued by serum (S/L-ESCs). Here, we show that culturing ESCs in Activin A and BMP4, and in the absence of MEK1/2 inhibitor (ABC/L medium), establishes advanced stem cells derived from ESCs (esASCs). We demonstrate that esASCs contributed to germline lineages, full-term chimeras and generated esASC-derived mice by tetraploid complementation. We show that, in contrast to 2i/L-ESCs, esASCs display distinct molecular signatures and a stable hypermethylated epigenome, which is reversible and similar to serum-cultured ESCs. Importantly, we also derived novel ASCs (blASCs) from blastocysts in ABC/L medium. Our results provide insights into the derivation of novel ESCs with DNA hypermethylation from blastocysts in chemically defined medium.

Amino acid ionic liquids (AAILs) are widely considered as biocompatible and biodegradable green absorbents, solvents and catalysts that have been utilized in sustainable chemistry. Several AAILs containing the ether functionalized...

A series of nickel-aluminium, cobalt-aluminium and zinc-aluminum layered double hydroxides were synthesized by urea hydrolysis (UH) and reverse micelle (RM) methods and then applied for the cycloaddition of carbon dioxide to propylene oxide (PO) under solvent-free and ambient conditions. The most efficient catalyst was zinc-aluminum layered double hydroxide prepared by RM (denoted as ZnAl-RM) and it showed, in the presence of a co-catalyst of tetrabutylammonium bromide, 96% propylene carbonate (PC) yield in 12 h at 25 8C and 1 MPa carbon dioxide. It is noteworthy for the same catalyst system that 74% PC yield was achieved in 24 h at room temperature (about 25 8C) and atmospheric carbon dioxide pressure. The high catalytic performance of the ZnAl-RM and tetrabutylammonium bromide system should result from cooperative effects between zinc ion and bromine ion. Moreover, the ZnAl-RM and tetrabutylammonium bromide system showed excellent versatility, which was also an active catalyst to the transformation of carbon dioxide and other epoxides into corresponding cyclic carbonates under mild temperature and pressure conditions.

Magnetic visible-light-driven photocatalyst, porous C/ZnFeO (denoted as C/ZFO-CE) was fabricated via a CO-mediated ethanol route. CO-mediated ethanol route largely mitigated the solvent strength and facilitated the homogenous deposition of ZnFeO (ZFO) through the coordination of metallic cation with CO and HCO anions, which were hydrolyzed from CO and HO, thereby avoiding additional precipitant. Moreover, the HCO, CO and NO in the system acted as templates for the formation of porous C avoiding the additional organic mesoporous templates, thus reducing the synthesis cost. For the degradation of RhB and phenol, the C/ZFO-CE system in presence of minute HO exhibited remarkably improved catalytic performance compared with the systems of HO, ZFO, C/ZFO-CE, C/ZFO-E (C/ZnFeO synthesized in pure ethanol) and C/ZFO-E in the presence of minute HO. Furthermore, 2.0 mL of HO (30%) combined with C/ZFO-CE obtained the maximum degradation efficiencies of 100% for RhB within 60 min and 91% for phenol within 120 min. The high efficiency for degradation of pollutants over C/ZFO-CE catalyst in the presence of minute HO was possibly attributed to the strong harvest of visible light, the improved separation efficiency of the photoinduced charges and the overall ˙OH production by the "photo-Fenton" process. The existence of ˙OH during photodegradation process was evidenced via the PL-TA (photoluminescence-terephthalic acid) technique, ESR spectra and trapping experiments of active species using different scavengers. Furthermore, a possible reaction mechanism involving the Fenton-like reaction for the photodegradation of pollutants is proposed based on the experimental results.