Carbon dots as a luminescence sensor for ultrasensitive detection of phosphate and their bioimaging properties

Highly blue fluorescence carbon dots were synthesized by one‐step hydrothermal treatment of potatoes. The as‐obtained C‐dots have been applied to bioimaging of HeLa cells, which shows their excellent biocompatibility and low cytotoxicity. The results reveal that C‐dots are promising for real cell imaging applications. In addition, the carbon dots can be utilized as a probe for sensing phosphate. Copyright © 2014 John Wiley & Sons, Ltd.     

水资源的忧虑

水是生态系统中生命必需元素得以无限循环的介质。没有水生态系统,生命就不能维持。在当今世界面临的人口、资源、环境三大问题中,水属于人类赖以生存和社会经济发展的重要物质资源,又和其它两个问题有着密切的关系。因此,水资源的开发、利用和管理已成为世界各国普遍重视的一个重要课题。     

葡萄叶绿体rbcL基因的结构分析

以玫瑰香葡萄（Ｖｉｔｉｓｖｉｎｉｆｅｒａ Ｌ．）为材料,克隆了含有叶绿体ｒｂｃ Ｌ基因的３．１ ｋｂ Ｂａｍ ＨⅠ片段,构建了该基因的限制性酶切图谱,测定了该基因的核苷酸序列。所测的核苷酸序列总长度为２００４ ｂｐ,其中基因的编码区为１４２８ ｂｐ,编码一个含４７５ 个氨基酸的蛋白质,其分子量约为５３ ｋＤ;测定基因的５上游含启动子的部分共３５８ ｂｐ,包括－ １０ 区（ＴＡＡＡＡＴ）、－ ３５区（ＴＴＧＣＧＣ）和ＳＤ 序列（ＧＧＡＧＧ）;基因的３下游区共２１８ ｂｐ,含有３ 个转录茎环终止结构。玫瑰香葡萄ｒｂｃ Ｌ基因编码区的核苷酸序列与烟草、矮牵牛、菠菜、苜蓿、水稻和玉米之间的同源性分别为９１．５％ 、９１．４％ 、９０．２％ 、８９．８％ 、８６．３％ 和８４．５％ ;推导出的氨基酸序列的同源性分别为９２．２％ 、９１．６％ 、９２．２％ 、９３．７％ 、９３．５％ 和９０．１％ 。     

秋茄（Kandelia candel）的区域性种群（population）遗传结构

在台湾北部淡水河河口沼泽地带的秋茄（水笔仔）,依其林冠高度略可分成高、矮两个亚种群（Subpopulation）。矮生秋茄长在地面较高的河边,高生秋茄则沿着一条潮溪,长在较低处。使用淀粉凝胶方法研究同功酶组合型式,判断这个地区的区域种群的遗传结构,发现生长在沼泽区内较干燥地带的秋茄和长在潮湿地带的秋茄遗传上的分化程度很低（Fst= 0.043）。这可能是因为区内的基因流传很顺畅,抵消了可能发生的种群分化。     

Amino acid substitution in the lactose carrier protein with the use of amber suppressors.

Five lacY mutants with amber stop codons at known positions were each placed into 12 different suppressor strains. The 60 amino acid substitutions obtained in this manner were tested for growth on lactose-minimal medium plates and for transport of lactose, melibiose, and thiomethylgalactoside. Most of the amino acid substitutions in the regions of the putative loops (between transmembrane alpha helices) resulted in a reasonable growth rate on lactose with moderate-to-good transport activity. In one strain (glycine substituted for Trp-10), abnormal sugar recognition was found. The substitution of proline for Trp-33 (in the region of the first alpha helix) showed no activity, while four additional substitutions (lysine, leucine, cysteine, and glutamic acid) showed low activity. Altered sugar specificity was observed when Trp-33 was replaced by serine, glutamine, tyrosine, alanine, histidine, or phenylalanine. It is concluded that Trp-33 may be involved directly or indirectly in sugar recognition.     

油梨果实的生长和内含物变化的观察

本文报道对油梨果实的生长及内含物的变化的观察结果．果实生长发育过程中,以６—７份生长最快,干物质及脂肪含量由低到高变化,以１１月份增加最快,蛋白质含量由高到低递诚．１１月份后含量相对稳定,总糖和维生素Ｃ含量随果实的发育程度而下降。     

银杏扦插繁殖试验

本文报道银杏扦插繁殖技术。采用不同插穗、机械处理、不同激素及浓度处理进行扦插繁殖试验．扦插成活率可达９０—１００％。     

Low METTL3 level in midgut of the Bombyx mori inhibit the proliferation of nucleopolyhedrovirus

N6-methyladeosine (m⁶A) plays an important role in virus infection and replication. Bombyx mori nuclear polyhedrosis is caused by Bombyx mori nucleopolyhedrovirus (BmNPV) infection. Expression levels of m⁶A-modification-related genes after the infection of BmNPV were detected at first. Then, expression levels of BmNPV nucleocapsid protein gene VP39 and envelope fusion protein gene GP64 after knockdown of METTL3in vitro were quantified to identify the effect of m⁶A modification on BmNPV. BmNPV firstly infects the larval midgut in case of oral infection. Subsequently, to clarify the relationship between m⁶A modification and resistance of the silkworm to BmNPV, we detected the expression levels of m⁶A-modification-related genes invivo before and after infection of BmNPV. The results indicated that low METTL3 level hindered the proliferation of BmNPV to some extent, and silkworm strain with low METTL3 level showed stronger resistance against BmNPV. This study will accumulate new experimental data for elucidating the resistance mechanism of silkworm against BmNPV.     

Isoform-selective inhibition of chrysin towards human cytochrome P450 1A2. Kinetics analysis,molecular docking,and molecular dynamics simulations

Our kinetics studies demonstrated that the nature product chrysin exhibited a high inhibitory affinity of 54 nM towards human cytochrome P450 1A2 and was comparable to α-naphthoflavone (49 nM), whereas it represented a moderate affinity of 5225 nM against human cytochrome P450 2C9. However, it remains unclear how this inhibitor selectively binds 1A2. To better understand the isoform selectivity of chrysin, molecular docking and molecular dynamics simulations were performed. Chrysin formed a strong H-bond with Asp313 of 1A2. The stacking interactions with Phe226 also contributed to its tight binding to 1A2. The larger and much more open active site architectures of 2C9 may explain the weaker inhibitory affinity of chrysin towards 2C9. The predicted binding free energies suggest that chrysin preferred 1A2 (ΔG_{bind, pred} = ?23.11 kcal/mol) to 2C9 (?20.41 kcal/mol). Additionally, the present work revealed that 7-hydroxy-flavone bound to 1A2 in a similar pattern as chrysin and represented a slightly less negative predicted binding free energy, which was further validated by our kinetics analysis (IC₅₀ = 240 nM). Results of the study can provide insight for designing novel isoform-selective 1A2 inhibitors.