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Two phenylquinolinones, including one new compound (1) and a previously isolated compound (2), were isolated from the ethyl acetate extracts of the fungus Aspergillus versicolor Y31-2, which was obtained from seawater samples collected from the Indian Ocean. The structures of these compounds were established by spectroscopic analyses. 4-(3-Hydroxyphenyl)-3-methoxyquinolin-2(1H)-one (1) exhibited moderate cytotoxicity against MCF-7 (human breast carcinoma cell line) and SMMC-7721 (human liver cancer cell line) cells with IC50 values of 16.6 and 18.2 μmol/L, respectively. To the best of our knowledge, this study represents the first reported account of the isolation of compounds 1 and 2 as the secondary metabolites of the seawater derived fungus Aspergillus versicolor from the Indian Ocean. 相似文献
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Seven bacterial clones with alginate-utilizing activity were isolated from rotten kelp. By activity test, the Vibrio sp.QD-5 with the potential alginate-degrading capability was chosen to carry out the draft genome sequencing, and the result showed that the Vibrio sp. QD-5 containing an alginate lyase gene cluster. One of these genes, aly-IV,was cloned and characterized for the first time. After overexpression, Aly-IV, with a molecular mass of about62 kDa and a theoretical isoelectric point(pI) of 5.12, was purified to a specific activity of 1 256.78 U/mg and showed highest activity at 35°C in the Tris-HCl buffer at pH of 8.9. Moreover, the enzyme activity was enhanced by the metal ions of Na~+, K~+ and Mg~(2+) under certain concentration. Aly-IV degraded favorably polyG blocks in an endo-type, yielding monomer and dimer as the main products. Due to its high substrate specificity, Aly-IV could be used as a potential tool for production of polyG oligosaccharides with low degree of polymerization(DP) and for determining the fine structure of alginate. 相似文献
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以海洋弧菌(Vibrio sp.QD-5)的基因组为模板,使用设计的褐藻胶裂解酶引物进行PCR扩增。将目的基因克隆至pet-22b(+)载体后进行测序。测序结果显示,基因aly-Ⅱ的大小为2 170bp,预测编码含有723个氨基酸的蛋白质。对该蛋白质进一步进行了生物信息学分析。利用ProtParam和ProtScale对蛋白质的理化性质进行分析,结果表明,蛋白质Aly-Ⅱ的理论分子质量为85.6kDa,理论等电点为5.1,并且是一种亲水性蛋白。利用软件MEG 6.0对蛋白质Aly-Ⅱ进行系统发育分析,结果显示,蛋白质Aly-Ⅱ很可能是PL-17家族的褐藻胶裂解酶。利用同源建模法构建蛋白质Aly-Ⅱ的三维结构,Aly-Ⅱ含有2个结构域,分别为(α/α)6toroid结构域和β-sheet结构域。 相似文献
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