Ecological risk assessment for key industrial development zones in the areas surrounding the Bo Sea in China

Although industrial zones have been attracting attention around the world due to their huge regional economic contributions, ecological risk assessment for industrial zones has gained little attention. In high ecological risk locations, landslides, earthquakes, and floods often occur, often causing extensive damage, including loss of human lives and property. However, during planning, development, and management of industrial zones, only the socioeconomic risks are usually taken into account and the risks of ecological factors affecting industries are often ignored. In this article, we put forward a procedure to link different risk factors and their GIS-determined spatial variation to estimate the ecological risk to key industrial zones in the 98,200 km² area surrounding the Bo Sea. The ecological risk factors in this region are mainly rainstorms, geological risks, storm surges, seawater intrusion, soil erosion, and earthquakes. The key industrial development zones located in this area were classified into three industry types according to the sensitivity of the industry to different ecological risk factors. Using historical data and hierarchical analytic process as well as weighted ecological risk values, industry susceptibility was determined. We integrated the risk values of each ecological factor with the susceptibility of each industry type to each ecological factor in order to quantify the total risk associated with each key industry zone in the region. The results showed that high ecological risk existed in Liaodong and Laizhou Bay and Tianjin and Dalian seashore.     

Highly selective anti-Prelog synthesis of optically active aryl alcohols by recombinant Escherichia coli expressing stereospecific alcohol dehydrogenase

Biocatalytic asymmetric synthesis has been widely used for preparation of optically active chiral alcohols as the important intermediates and precursors of active pharmaceutical ingredients. However, the available whole-cell system involving anti-Prelog specific alcohol dehydrogenase is yet limited. A recombinant Escherichia coli system expressing anti-Prelog stereospecific alcohol dehydrogenase from Candida parapsilosis was established as a whole-cell system for catalyzing asymmetric reduction of aryl ketones to anti-Prelog configured alcohols. Using 2-hydroxyacetophenone as the substrate, reaction factors including pH, cell status, and substrate concentration had obvious impacts on the outcome of whole-cell biocatalysis, and xylose was found to be an available auxiliary substrate for intracellular cofactor regeneration, by which (S)-1-phenyl-1,2-ethanediol was achieved with an optical purity of 97%e.e. and yield of 89% under the substrate concentration of 5 g/L. Additionally, the feasibility of the recombinant cells toward different aryl ketones was investigated, and most of the corresponding chiral alcohol products were obtained with an optical purity over 95%e.e. Therefore, the whole-cell system involving recombinant stereospecific alcohol dehydrogenase was constructed as an efficient biocatalyst for highly enantioselective anti-Prelog synthesis of optically active aryl alcohols and would be promising in the pharmaceutical industry.     

Molecular dynamics simulations on the conformational transitions from the GA98 (GA88) to GB98 (GB88) proteins

We performed conventional and targeted molecular dynamics simulations to address the dynamic transition mechanisms of the conformational transitions from the G_A98 protein with only 1 mutation of Leu45Tyr to G_B98 and from the G_A88 protein with 7 mutations of Gly24Ala, Ile25Thr, Ile30Phe, Ile33Tyr, Leu45Tyr, Ile49Thr, and Leu50Lys to G_B88. The results show that the conformational transition mechanism from the mutated 3α G_A98 (G_A88) state to the α+4β G_B98 (G_B88) state via several intermediate conformations involves the bending of loops at the N and C termini firstly, the unfolding of αA and αC, then the traversing of αB, and the formation of the 4β layer with the conversion of the hydrophobic core. The bending of loops at the N and C termini and the formation of the crucial transition conformation with the full unfolded structure are key factors in their transition processes. The communication of the interaction network, the bending directions of loops, and the traversing site of αB in the transition of G_A98 to G_B98 are markedly different from those in G_A88 to G_B88 because of the different mutated residues. The analysis of the correlations and the calculated mass center distances between some segments further supported their conformational transition mechanisms. These results could help people to better understand the Paracelsus challenge. Copyright © 2016 John Wiley & Sons, Ltd.     

Elucidation of the effect of aptamer immobilization strategies on the interaction between cell and its aptamer using atomic force spectroscopy

The immobilization strategy of cell‐specific aptamers is of great importance for studying the interaction between a cell and its aptamer. However, because of the difficulty of studying living cell, there have not been any systematic reports about the effect of immobilization strategies on the binding ability of an immobilized aptamer to its target cell. Because atomic force spectroscopy (AFM) could not only be suitable for the investigation of living cell under physiological conditions but also obtains information reflecting the intrinsic properties of individuals, the effect of immobilization strategies on the interaction of aptamer/human hepatocarcinoma cell Bel‐7404 was successively evaluated using AFM here. Two different immobilization methods, including polyethylene glycol immobilization method and glutaraldehyde immobilization method were used, and the factors, such as aptamer orientation, oligodeoxythymidine spacers and dodecyl spacers, were investigated. Binding events measured by AFM showed that a similar unbinding force was obtained regardless of the change of the aptamer orientation, the immobilization method, and spacers, implying that the biophysical characteristics of the aptamer at the molecular level remain undisturbed. However, it showed that the immobilization orientation, immobilization method, and spacers could alter the binding probability of aptamer/Bel‐7404 cell. Presumably, these factors may affect the accessibility of the aptamer toward its target cell. These results may provide valuable information for aptamer sensor platforms including ultrasensitive biosensor design. Copyright © 2015 John Wiley & Sons, Ltd.     

假马鞭曲叶病毒和中国胜红蓟黄脉病毒C4蛋白是RNA沉默的抑制子

为了研究中国胜红蓟黄脉病毒(Ageratum yellow vein Chin virus,AYVCNV)和假马鞭曲叶病毒(Stachytarpheta leafcurl virus,StaLCV)C4蛋白的功能,利用烟草脆裂病毒(Tobacco rattle virus,TRV)载体在本氏烟(Nicotianabenthamiana)中分别表达了这两种病毒的C4蛋白,结果发现它们均能在本氏烟中引起类似于病毒侵染的症状,推测AYVCNV和StaLCV的C4蛋白是病毒的致病因子;在RNA沉默的抑制试验中,AYVCNV和StaLCV的C4蛋白均能够在表达gfp基因的转基因本氏烟(16c)上抑制由gfp基因正义链引起的基因沉默的建立,证明它们都是RNA沉默的抑制子。     

检测人结肠癌组织端粒酶活性的TRAP方法研究

对检测人结肠癌组织端粒酶活性的端粒酶重复序列扩增法(TRAP)进行了研究.当Mg^2＋浓度为1.8 mmol/L、退火温度为55℃时,能得到可靠的检测结果.影响检测结果可靠性的另两个因素是抽提物的反应用量和阳性片段的污染.