The isotopic composition of atmospheric total gaseous mercury (TGM) and particle-bound mercury (PBM) and mercury (Hg) in litterfall samples have been determined at urban/industrialized and rural sites distributed over mainland China for identifying Hg sources and transformation processes. TGM and PBM near anthropogenic emission sources display negative δ(202)Hg and near-zero Δ(199)Hg in contrast to relatively positive δ(202)Hg and negative Δ(199)Hg observed in remote regions, suggesting that different sources and atmospheric processes force the mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) in the air samples. Both MDF and MIF occur during the uptake of atmospheric Hg by plants, resulting in negative δ(202)Hg and Δ(199)Hg observed in litter-bound Hg. The linear regression resulting from the scatter plot relating the δ(202)Hg to Δ(199)Hg data in the TGM samples indicates distinct anthropogenic or natural influences at the three study sites. A similar trend was also observed for Hg accumulated in broadleaved deciduous forest foliage grown in areas influenced by anthropogenic emissions. The relatively negative MIF in litter-bound Hg compared to TGM is likely a result of the photochemical reactions of Hg(2+) in foliage. This study demonstrates the diagnostic stable Hg isotopic composition characteristics for separating atmospheric Hg of different source origins in China and provides the isotopic fractionation clues for the study of Hg bioaccumulation.
Germ cells of most animals critically depend on piRNAs and Piwi proteins. Surprisingly, piRNAs in mouse oocytes are relatively rare and dispensable. We present compelling evidence for strong Piwi and piRNA expression in oocytes of other mammals. Human fetal oocytes express PIWIL2 and transposon-enriched piRNAs. Oocytes in adult human ovary express PIWIL1 and PIWIL2, whereas those in bovine ovary only express PIWIL1. In human, macaque, and bovine ovaries, we find piRNAs that resemble testis-borne pachytene piRNAs. Isolated bovine follicular oocytes were shown to contain abundant, relatively short piRNAs that preferentially target transposable elements. Using label-free quantitative proteome analysis, we show that these maturing oocytes strongly and specifically express the PIWIL3 protein, alongside other, known piRNA-pathway components. A piRNA pool is still present in early bovine embryos, revealing a potential impact of piRNAs on mammalian embryogenesis. Our results reveal that there are highly dynamic piRNA pathways in mammalian oocytes and early embryos.
The aim of this study is to explore the roles of circular RNA (circRNA) Cdr1as on cisplatin resistance in ovarian cancer and explore the underlying mechanisms. We investigated the expression of circRNAs in five paired cisplatin-sensitive and cisplatin-resistant tissues of ovarian cancer by microarray analysis. The quantitative real-time PCR analysis was to investigate the expression pattern of Cdr1as in cisplatin-resistant ovarian cancer patient tissues and cell lines. Then, the effects of Cdr1as on cisplatin resistance, cell proliferation, and apoptosis were assessed in ovarian cancer cells. In this study, Cdr1as was observed to be downregulated in cisplatin-resistant patient tissues and cell lines. Overexpression of Cdr1as inhibited cell proliferation and promoted the cisplatin-induced cell apoptosis in ovarian cancer cells. Then we demonstrated that repressed Cdr1as promoted the miR-1270 expression, and miR-1270 could bind to the predicted binding site of Cdr1as. Furthermore, we found that miR-1270 displayed its role via modulating the Suppressor of Cancer Cell Invasion (SCAI) expression. Importantly, we demonstrated that Cdr1as was downregulated in serum exosomes from cisplatin-resistant patients. In summary, our study demonstrated that Cdr1as sensitizes ovarian cancer to cisplatin by regulating the miR-1270/SCAI signaling pathway.
The electron acceptor 2-(1,1-dicyanomethylene) rhodanine is a promising alternative to cyanoacrylic acid as an anchoring group for organic dyes. For example, the RD-II-based dye-sensitized solar cell has an overall conversion efficiency of 7.11 % and long-term stability.
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