Pyrosequencing analysis of bacterial diversity in 14 wastewater treatment systems in china

To determine if there is a core microbial community in the microbial populations of different wastewater treatment plants (WWTPs) and to investigate the effects of wastewater characteristics, operational parameters, and geographic locations on microbial communities, activated sludge samples were collected from 14 wastewater treatment systems located in 4 cities in China. High-throughput pyrosequencing was used to examine the 16S rRNA genes of bacteria in the wastewater treatment systems. Our results showed that there were 60 genera of bacterial populations commonly shared by all 14 samples, including Ferruginibacter, Prosthecobacter, Zoogloea, Subdivision 3 genera incertae sedis, Gp4, Gp6, etc., indicating that there is a core microbial community in the microbial populations of WWTPs at different geographic locations. The canonical correspondence analysis (CCA) results showed that the bacterial community variance correlated most strongly with water temperature, conductivity, pH, and dissolved oxygen (DO) content. Variance partitioning analyses suggested that wastewater characteristics had the greatest contribution to the bacterial community variance, explaining 25.7% of the variance of bacterial communities independently, followed by operational parameters (23.9%) and geographic location (14.7%). Results of this study provided insights into the bacterial community structure and diversity in geographically distributed WWTPs and discerned the relationships between bacterial community and environmental variables in WWTPs.     

肾缺血增强大鼠延髓腹外侧头端区神经元电话动和Fos蛋白表达

在67只切断两侧缓冲神经的麻醉Sprague-Dawley大鼠,应用细胞外记录的电生理方法和免疫组织化学技术,分别观察肾缺血对延髓腹外侧头端区巨细胞旁外侧核神经元自发放电活动和Fos蛋白表达的影响.所得结果如下(1)左肾动脉阻断后,28个单位的放电频率由11.40±1.08增至21.1±1.74spikes/s(P<0.001),血压和心率无明显变化(P>0.05);(2)在17个放电单位中,应用腺苷受体拮抗剂8-苯茶碱(8-phenyltheophylline,10mg/kg)可明显抑制肾缺血的兴奋效应(P<0.05);(3)肾缺血后,延髓腹外侧头端区的Fos蛋白样免疫反应神经元显著增加(P<0.01);(4)预先应用8-苯茶碱可明显减弱肾缺血所激活的Fos蛋白表达反应(P<0.05).以上结果提示肾缺血增强延髓腹外侧头端区神经元的放电活动和Fos蛋白表达,而此作用可能与肾脏缺血所产生的腺苷激活肾内感受器有关.     

单面针的生物碱研究

自芸香科(Rutaceae)花椒属植物单面针(Zanthoxylum nitidum var. fastuosum How ex Huang)的根皮中分得五种已知生物碱:乙氧基白屈菜红碱(ethoxychelerythrine)(Ⅰ);氯化光花椒碱(nitidine chloride)(Ⅱ);去甲基白屈菜红碱(des-N-methychelerythrine)(Ⅲ);α—别隐品碱(α-allocryptopine)(Ⅳ);鹅掌揪宁(liriodenine)(Ⅴ).     

Molecular cloning and expression analysis of RrNHX1 and RrVHA-c genes related to salt tolerance in wild Rosa rugosa

Salt stress is one important factor influencing the growth and development of plants, and salt tolerance of plants is a result of combined action of multiple genes and mechanisms. Rosa rugosa is not only an important ornamental plant, but also the natural aromatic plant of high value. Wild R. rugosa which is naturally distributed on the coast and islands of China has a good salt tolerance due to the special living environment. Here, the vacuolar Na⁺/H⁺ reverse transporter gene (NHX1) and the vacuolar H⁺-ATPase subunit C gene (VHA-c) closely related to plant salt tolerance were isolated from wild R. rugosa, and the expression patterns in R. rugosa leaves of the two genes under NaCl stress were determined by real-time quantitative fluorescence PCR. The results showed that the RrNHX1 protein is a constitutive Na⁺/H⁺ reverse transporter, the expression of the RrNHX1 gene first increased and then decreased with the increasing salt concentration, and had a time-controlled effect. The RrVHA-c gene is suggestive of the housekeeping feature, its expression pattern showed a similar variation trend with the RrNHX1 gene under the stress of different concentrations of NaCl, and its temporal expression level under 200 mM NaCl stress presented bimodal change. These findings indicated that RrNHX1 and RrVHA-c genes are closely associated with the salt tolerance trait of wild R. rugosa.     

Functional role of BLAP75 in BLM-topoisomerase IIIalpha-dependent holliday junction processing

The BLAP75 protein combines with the BLM helicase and topoisomerase (Topo) IIIalpha to form an evolutionarily conserved complex, termed the BTB complex, that functions to regulate homologous recombination. BLAP75 binds DNA, associates with both BLM and Topo IIIalpha, and enhances the ability of the BLM-Topo IIIalpha pair to branch migrate the Holliday junction (HJ) or dissolve the double Holliday junction (dHJ) structure to yield non-crossover recombinants. Here we seek to understand the relevance of the biochemical attributes of BLAP75 in HJ processing. With the use of a series of BLAP75 protein fragments, we show that the evolutionarily conserved N-terminal third of BLAP75 mediates complex formation with BLM and Topo IIIalpha and that the DNA binding activity resides in the C-terminal third of this novel protein. Interestingly, the N-terminal third of BLAP75 is just as adept as the full-length protein in the promotion of dHJ dissolution and HJ unwinding by BLM-Topo IIIalpha. Thus, the BLAP75 DNA binding activity is dispensable for the ability of the BTB complex to process the HJ in vitro. Lastly, we show that a BLAP75 point mutant (K166A), defective in Topo IIIalpha interaction, is unable to promote dHJ dissolution and HJ unwinding by BLM-Topo IIIalpha. This result provides proof that the functional integrity of the BTB complex is contingent upon the interaction of BLAP75 with Topo IIIalpha.     

Numerical simulation of two-phase non-Newtonian blood flow with fluid-structure interaction in aortic dissection

The behavior of blood cells and vessel compliance significantly influence hemodynamic parameters, which are closely related to the development of aortic dissection. Here the two-phase non-Newtonian model and the fluid-structure interaction (FSI) method are coupled to simulate blood flow in a patient-specific dissected aorta. Moreover, three-element Windkessel model is applied to reproduce physiological pressure waves. Important hemodynamic indicators, such as the spatial distribution of red blood cells (RBCs) and vessel wall displacement, which greatly influence the hemodynamic characteristics are analyzed. Results show that the proximal false lumen near the entry tear appears to be a vortex zone with a relatively lower volume fraction of RBCs, a low time-averaged wall shear stress (TAWSS) and a high oscillatory shear index (OSI), providing a suitable physical environment for the formation of atherosclerosis. The highest TAWSS is located in the narrow area of the distal true lumen which might cause further dilation. TAWSS distributions in the FSI model and the rigid wall model show similar trend, while there is a significant difference for the OSI distributions. We suggest that an integrated model is essential to simulate blood flow in a more realistic physiological environment with the ultimate aim of guiding clinical treatment.     

互叶白千层油化学成分的研究

采用水蒸汽蒸馏收集互叶白千层芳香油,对该油进行ＧＣ／ＭＳ／ＤＳ定性分析及其总离于流图的面积归一化定量分析,鉴定出２５种化合物,其中含氧化合物６种,碳氢化合物１９种。直接影响该油商品价值的化学成分４－萜品醇含量约为１７％,桧樟脑含量约为２．４％。     

用核酸斑点杂交法比较油桐尺蠖核型多角体病毒与某些昆虫杆状病毒的同源性

有关核型多角体病毒基因同源性的研究报道不多,结果也不甚一致。目前,国内外普遍用SDS-PAGE法分析昆虫杆状病毒结构多肽,以限制性内切酶谱法测定基因组大小,借此区分来自不同宿主的病毒株,和基因组密切相关     

天然产酮类化合物

酮（Xanthone）又称苯骈色原酮,是一类黄色或无色的酚性化合物,具有与黄酮类（Flavonoids）相似的颜色反应及色谱特性,因此曾被归入黄酮类讨论,但从其光谱特征看酮与黄酮是有区别的。 酮类主要分布于龙胆科（Gentianaceae）、藤黄科（Guttiferae）、桑科（Moraceae）和远志科（Polygalaceae）。但有一特殊例外：芒果甙（mangiferin-2-C-β-D-毗哺葡萄糖基-1,3,6,7-四羟基酮）不仅广布于被子植物的漆树科、藤黄科、豆科、山榄科、大风子科、百合科、鸢尾科、禾本科等,而且在蕨类植物的水龙骨科（Polypodiaceae）中也有发现。