漆酶降解阴离子型聚丙烯酰胺/聚丙烯酸酯活性的理性设计

为探究漆酶降解聚丙烯酸酯（PAA）/阴离子型聚丙烯酰胺（HPAM）的微观机理,采用对接模拟了其结构模型与枯草芽孢杆菌漆酶（B. subtilis laccase）的结合.根据-CDOCKER_Energy score打分最高的原则,对获得的最佳结合构象进行分析.然后基于亲和力虚拟氨基酸突变进行丙氨酸（ALA）扫描和饱和突变.结合模式分析表明,HPAM比PAA可更深地埋入活性口袋,B. subtilis laccase对HPAM的亲和力和结合能皆高于PAA.相互作用分析表明,疏水相互作用可能对B. subtilis laccase与底物的结合起到促进作用,而氢键作用会阻碍该酶与底物的结合.通过ALA扫描进一步得知,ARG487、GLY486和TYR133是B. subtilis laccase降解HPAM的关键氨基酸残基,而ASP113和TYR133是B. subtilis laccase降解PAA的关键氨基酸残基.通过饱和突变表明,ASP113>ARG可以提高B. subtilis laccase降解PAA的活性,这些数据为理性设计增强活性的B. subtilis laccase突变体提供了理论参考.     

沉管隧道对接端深基坑止水墙水下爆破对周围环境的影响研究

基于爆破动态效应的现场监测数据,研究了襄阳汉江鱼梁州沉管隧道对接端深基坑止水墙水下爆破对邻近建(构)筑物和周围水域的不利影响.结果 表明:爆源附近方圆50 rn范围内属于爆破振动近场区、方圆50～150 m范围内属于爆破振动过渡区、方圆150 m范围外属于爆破振动远场区;爆破振动近场区内薄壁支护结构爆破振动速度呈现高峰...     

Improved direct molecular diagnosis and rapid fetal sexing

Adaptations of the techniques of modern molecular biology to prenatal diagnosis has opened new avenues for the detection of genetic diseases. We have taken advantage of the rapid adhesion of colony forming cells in cultured amniotic fluid samples to develop an improved method for molecular diagnosis. By employing the cell adherence regime sickle cell diagnosis using Mst II can be undertaken directly. In addition, hybridization with a cloned repetitive sequence that is of Y origin and has limited autosomal homology permits rapid fetal sexing in 3 to 4 days without compromising conventional cytogenetic or biochemical analysis. This combination of techniques provides a useful adjunct to convential prenatal genetic diagnosis in the second trimester.     

糖蜜酒精蒸馏废液色素研究

采用凝胶渗透色谱方法测定从甘蔗糖蜜酒精废液中提纯的色素的分子量。通过吸收光谱、原子吸收光谱、氨基酸分析、溶剂析出等方法，确定色素的成分。结果表明，该色素具有三个不同分子量的组分，重均分子量分别为21889、987和439Da。主要有酚类色素、焦糖色素和美拉德色素等3种色素，其质量分数分别为20%、67.7%和12.3%。色素中铁质量分数为0.12%，水解氨基酸质量分数为5.23%。     

Holographic QSAR of selected esters

The HQSAR (Holographic QSAR) method, which has been recently developed, can offer the ability to rapidly and easily generate QSAR models of high statistical quality and predictive value. HQSAR analysis requires selecting values for parameters that specify the size of the hologram that is to be used, and the size and type of fragment substructures that are to be encoded. The color coding is provided by HQSAR to reflect which molecular fragments may be important contributors to the biological activity. In this work, we studied the quantitative structure activity relationship of selected esters using the HQSAR method. A robust HQSAR model with r² (non-cross-validated regression coefficient) of 0.981 and q² (cross-validated regression coefficient) of 0.912, was developed after optimizing the fragment size and the hologram length. The color coding analysis, which has rarely been reported before, was done here to explain the outlier successfully.     

环境微生态研究中的分子生物学新技术

随着分子生物学的发展,可用于环境微生态研究的新方法新手段不断出现.利用这些分子生物学技术,可直接对环境样品的总DNA进行分析,绕开菌株分离和培养瓶颈,可以最大限度地获得相关微生物的遗传信息,全面地分析环境中微生物的多样性.对目前广泛应用于环境微生态研究的分子生物学新技术,包括rDNA基因序列分析、变性梯度凝胶电泳、温度梯度凝胶电泳、单链构象多态性、限制性片段长度多态性、随机扩增多态性DNA、核酸杂交和DNA芯片等技术进行了综述.     

硫化氢自动在线分析仪中SCRUBBER替代材料的研制

在一定缓冲溶液介质条件下,通过盐类在溶液中的离子交换对分子筛进行改性处理,制备H2S在线分析仪中进口SCRUBBER替代材料。结果表明200μg/L下SO2的滤除效率〉99.9%、200mg/L下H2S转化率〉99.4%,完全符合H2S分析仪要求,且明显好于美国SCRUBBER材料,成本降低80%。     

Inhibition of thrombin by functionalized C60 nanoparticles revealed via in vitro assays and in silico studies

The studies on the human toxicity of nanoparticles (NPs) are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs (C₆₀ NPs) have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C₆₀ NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C₆₀ NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C₆₀ NPs, of greater hydrophobicity and hydrogen bond (HB) donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive inhibitors. Molecular docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C₆₀ NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C₆₀ NPs relevant to their anticoagulation effect.     

New molecular method to detect denitrifying anaerobic methane oxidation bacteria from different environmental niches

The denitrifying anaerobic methane oxidation is an ecologically important process for reducing the potential methane emission into the atmosphere. The responsible bacterium for this process was Candidatus Methylomirabilis oxyfera belonging to the bacterial phylum of NC10. In this study, a new pair of primers targeting all the five groups of NC10 bacteria was designed to amplify NC10 bacteria from different environmental niches. The results showed that the group A was the dominant NC10 phylum bacteria from the sludges and food waste digestate while in paddy soil samples, group A and group B had nearly the same proportion. Our results also indicated that NC10 bacteria could exist in a high pH environment (pH 9.24) from the food waste treatment facility. The Pearson relationship analysis showed that the pH had a significant positive relationship with the NC10 bacterial diversity (p < 0.05). The redundancy analysis further revealed that the pH, volatile solid and nitrite nitrogen were the most important factors in shaping the NC10 bacterial structure (p = 0.01) based on the variation inflation factors selection and Monte Carlo test (999 times). Results of this study extended the existing molecular tools for studying the NC10 bacterial community structures and provided new information on the ecological distributions of NC10 bacteria.     

Extra-pair paternity, offspring mortality and offspring sex ratio in the socially monogamous coal tit (Parus ater)

Females of many socially monogamous bird species commonly engage in extra-pair copulations. Assuming that extra-pair males are more attractive than the females’ social partners and that attractiveness has a heritable component, sex allocation theory predicts facultative overproduction of sons among extra-pair offspring (EPO) as sons benefit more than daughters from inheriting their father’s attractiveness traits. Here, we present a large-scale, three-year study on sex ratio variation in a passerine bird, the coal tit (Parus ater). Molecular sexing in combination with paternity analysis revealed no evidence for a male-bias in EPO sex ratios compared to their within-pair maternal half-siblings. Our main conclusion, therefore, is that facultative sex allocation to EPO is absent in the coal tit, in accordance with findings in several other species. Either there is no net selection for a deviation from random sex ratio variation (e.g. because extra-pair mating may serve goals different from striving for ‘attractiveness genes’) or evolutionary constraints preclude the evolution of precise maternal sex ratio adjustment. It is interesting to note that, however, we found broods without EPO as well as broods without mortality to be relatively female-biased compared to broods with EPO and mortality, respectively. We were unable to identify any environmental or parental variable to co-vary with brood sex ratios. There was no significant repeatability of sex ratios in consecutive broods of individual females that would hint at some idiosyncratic maternal sex ratio adjustment. Further research is needed to resolve the biological significance of the correlation between brood sex ratios and extra-pair paternity and mortality incidence, respectively.