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Vascular smooth muscle cells (VSMCs) are exposed to mechanical cyclic stretch in vivo, which play important roles in maintenance of vascular homeostasis and regulation of pathological vascular remodeling. Reversible protein phosphorylation is crucial for intracellular signaling transduction. However, the dynamic phosphorylated profile induced by cyclic stretch in VSMCs is still unclear. Using the stable isotope labeling by amino acid in cell culture, VSMCs were labeled and exposed to 10% physiological cyclic stretch in vitro at 1.25 Hz for 0 min, 15 min, 30 min, 1 h and 6 h, respectively. Using TiO2 beads and liquid chromatography tandem mass spectrometry, the temporal phosphoproteomic profiles in response to cyclic stretch were then detected. Bioinformatics analysis including fuzzy c-means clustering, functional classifications, and Ingenuity Pathway Analysis were applied to further reveal the potential mechanotranduction networks. The results indicated that protein kinase C (PKCs) family, Rho-associated coiled-coil containing protein kinase 1 (ROCK1) and Akt may participate in cyclic-stretch induced VSMC functions. Cyclic stretch repressed the expression of ROCK1, while it had no significant effect on the phosphorylation of PKCα/βII, PKCζ/λ and PKCδ/θ. PKCθ was activated first at short time-phase (15 min and 30 min), and again at long time-phase (6 h, 12 h and 24 h). The activation of p-PKCμ was immediate and short-term, similar to p-Akt. Our present in vitro work hence revealed that cyclic stretch activates complex mechanotransduction networks, suggesting that novel mechanoresponsive molecules, i.e., PKCθ, PKCμ, and ROCK1, may participate in the mechanotransduction and modulation VSMC functions.  相似文献   
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CD36 is a scavenger receptor with multiple ligands and cellular functions, including facilitating cellular uptake of free fatty acids (FFAs). Chronic alcohol consumption increases hepatic CD36 expression, leading to the hypothesis that this promotes uptake of circulating FFAs, which then serve as a substrate for triglyceride (TG) synthesis and the development of alcoholic steatosis. We investigated this hypothesis in alcohol-fed wild-type and Cd36-deficient (Cd36−/−) mice using low-fat/high-carbohydrate Lieber-DeCarli liquid diets, positing that Cd36−/− mice would be resistant to alcoholic steatosis. Our data show that the livers of Cd36−/− mice are resistant to the lipogenic effect of consuming high-carbohydrate liquid diets. These mice also do not further develop alcoholic steatosis when chronically fed alcohol. Surprisingly, we did not detect an effect of alcohol or CD36 deficiency on hepatic FFA uptake; however, the lower baseline levels of hepatic TG in Cd36−/− mice fed a liquid diet were associated with decreased expression of genes in the de novo lipogenesis pathway and a lower rate of hepatic de novo lipogenesis. In conclusion, Cd36−/− mice are resistant to hepatic steatosis when fed a high-carbohydrate liquid diet, and they are also resistant to alcoholic steatosis. These studies highlight an important role for CD36 in hepatic lipid homeostasis that is not associated with hepatic fatty acid uptake.  相似文献   
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孢粉学是解决植物分类中疑难类群物种微形态分化的重要方法,随着分子系统学的发展,结合这两门学科的优势可以更加有效地解决疑难类群的分类学问题。鳞盖蕨属(Microlepia)是一个分类困难的疑难类群,采用孢粉学与分子系统学一一对应的方法,以及居群取样方式,选取280份样本,联合4个叶绿体片段(rbcL、trnL-F、psbA-trnH和rps4),采用最大似然法和贝叶斯法构建该属的系统发生关系,在此基础上对凭证标本中100份材料的孢子进行观察和分析。综合分子系统学和孢粉学的研究结果,得出结论:(1)在形态学研究中广泛被接受的15个物种得到了单系支持,并厘清了分类困难的复合群;(2)发现边缘鳞盖蕨(M. marginata)可能存在隐性种;(3)建议恢复过去归并处理为异名的瑶山鳞盖蕨(M. yaoshanica)、罗浮鳞盖蕨(M. lofoushanensis)、四川鳞盖蕨(M. szechuanica)以及滇西鳞盖蕨(M. subspeluncae);(4)提出鳞盖蕨属可能存在杂交现象;(5)提出鳞盖蕨属完整的属下分类建议。  相似文献   
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In our previous study, we demonstrated that episomal vectors based on the characteristic sequence of matrix attachment regions (MARs) and containing the cytomegalovirus (CMV) promoter allow transgenes to be maintained episomally in Chinese hamster ovary (CHO) cells. However, the transgene expression was unstable and the number of copies was low. In this study, we focused on enhancers, various promoters and promoter variants that could improve the transgene expression stability, expression magnitude (level) and the copy number of a MAR‐based episomal vector in CHO‐K1 cells. In comparison with the CMV promoter, the eukaryotic translation elongation factor 1 α (EF‐1α, gene symbol EEF1A1) promoter increased the transfection efficiency, the transgene expression, the proportion of expression‐positive clones and the copy number of the episomal vector in long‐term culture. By contrast, no significant positive effects were observed with an enhancer, CMV promoter variants or CAG promoter in the episomal vector in long‐term culture. Moreover, the high‐expression clones harbouring the EF‐1α promoter tended to be more stable in long‐term culture, even in the absence of selection pressure. According to these findings, we concluded that the EF‐1α promoter is a potent regulatory sequence for episomal vectors because it maintains high transgene expression, transgene stability and copy number. These results provide valuable information on improvement of transgene stability and the copy number of episomal vectors.  相似文献   
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