Indoor and outdoor levels,sources, and health risk assessment of mercury in dusts from a coal-industry city of China

To understand the mercury (Hg) pollution characteristics and health risks in indoor and outdoor dust of Huainan residential areas, 122 dust samples were collected indoors and outdoors. Average Hg contents in indoor and outdoor dusts of Huainan city were 0.321 ± 0.724 (n = 61) and 0.072 ± 0.163 (n = 61) mg/kg respectively. The average Hg content in indoor dust was characterized by PJ (Panji district) > XJJ (Xiejiaji district) > DT (Datong district) > TJA (Tianjiaan district), and in the order of PJ > DT > XJJ >TJA in outdoor dust. According to enrichment factor and geo-accumulation index, the enrichment degree and pollution intensity for Hg are ranked as “very high enrichment” and “heavily polluted” in indoor dust, and “significant enrichment” and “moderately polluted” in outdoor dust Hg concentrations in indoor dust were highly significantly associated with the coal combustion and frequency of open windows, and Hg concentrations in outdoor dust were significantly associated with the coal combustion and traffic density. The inhalation of Hg vapor is the main route of Hg exposure to adult and children. The hazard risks of Hg for different exposure ways in indoor and outdoor dust were more risk for children than for adults, but have no obvious health risk for them.     

外源木聚糖酶在枯草芽胞杆菌中信号肽筛选

[目的]本试验旨在筛选引导表达外源木聚糖酶基因高效分泌的信号肽,为枯草芽胞杆菌木聚糖酶高效分泌表达系统提供元件.[方法]构建信号肽筛选载体,载体是以含壮观霉素抗性基因的大肠-枯草穿梭载体为基本骨架,目标蛋白为耐碱性木聚糖酶,可在麦芽糖启动子Pglv诱导下表达.从枯草芽胞杆菌A1747基因组中扩增获得24个Sec途径信号肽,并将其全部链接到至筛选载体上,并在枯草芽胞杆菌WB700中实现表达分泌.重组菌在3%麦芽糖诱导下培养24h后用DNS法测定上清酶活.[结果]成功构建信号肽筛选载体pGPSX及24个表达载体,实现木聚糖酶表达分泌.且不同信号肽对于引导外源木聚糖酶分泌能力不同,其中YnfF信号肽引导分泌目标蛋白效率最高,上清酶活为37.2IU/mL.[结论]试验证明在枯草杆菌中对外源蛋白进行信号肽筛选是提高其分泌的有效途径,并获得了针对木聚糖酶高效分泌信号肽YnfF.     

Anaerobic/aerobic conditions and biostimulation for enhanced chlorophenols degradation in biocathode microbial fuel cells

Anaerobic/aerobic conditions affected bacterial community composition and the subsequent chlorophenols (CPs) degradation in biocathode microbial fuel cells (MFCs). Bacterial communities acclimated with either 4-chlorophenol (4-CP) or 2,4-dichlorophenol (2,4-DCP) under anaerobiosis can degrade the respective substrates more efficiently than the facultative aerobic bacterial communities. The anaerobic bacterial communities well developed with 2,4-DCP were then adapted to 2,4,6-trichlorophenol (2,4,6-TCP) and successfully stimulated for enhanced 2,4,6-TCP degradation and power generation. A 2,4,6-TCP degradation rate of 0.10 mol/m³/d and a maximum power density of 2.6 W/m³ (11.7 A/m³) were achieved, 138 and 13 % improvements, respectively compared to the controls with no stimulation. Bacterial communities developed with the specific CPs under anaerobic/aerobic conditions as well as the stimulated biofilm shared some dominant genera and also exhibited great differences. These results provide the most convincing evidence to date that anaerobic/aerobic conditions affected CPs degradation with power generation from the biocathode systems, and using deliberate substrates can stimulate the microbial consortia and be potentially feasible for the selection of an appropriate microbial community for the target substrate (e.g. 2,4,6-TCP) degradation in the biocathode MFCs.     

利用微嫁接技术促进麻疯树再生不定芽的生长

该研究以麻疯树种子实生苗的小芽和芽条为接穗,以带有胚根的实生苗下胚轴为砧木进行无菌微嫁接,试图建立新的有效微嫁接方法,解决农杆菌介导的麻疯树遗传转化体系中再生的转化不定芽难以顺利发育成完整植株的问题。结果表明:(1)抗生素对嫁接苗的生长有显著的抑制作用。(2)进行微嫁接所用砧木的苗龄以5d为宜。(3)进行微嫁接时适宜采用的砧木类型为带有部分胚根的下胚轴。(4)嫁接苗在0.3mg/L IBA+2mg/L谷氨酰胺+1/2MS培养基上的生长效果最好。(5)嫁接苗的移栽成活率最高可达76.40%。(6)以小芽或芽条为接穗的嫁接苗均可正常生长。该研究建立的麻疯树微嫁接体系,为解决麻疯树转化不定芽或芽条生长发育困难的问题提供了一条新的途径。     

Overexpression of Puroindoline a gene in transgenic durum wheat (Triticum turgidum ssp. durum) leads to a medium–hard kernel texture

Durum wheat is the second-most widely grown wheat species, and is primarily used in the production of pasta and couscous. The grain utilization of durum wheat is partly related to its very hard kernel texture because of the lack of the D genome and consequentially the Puroindoline genes. Our previous study reported the transformation of durum wheat with the Puroindoline a (Pina) gene. Here, we characterized the transgenic durum wheat lines expressing the Pina gene, and studied the effects of PINA on grain texture and other kernel characteristics. SDS-PAGE and Western blotting results demonstrated that starch-bound PINA levels of Pina-overexpressing lines were lower than that of Pina-positive control, common wheat cv. Chinese Spring, suggesting a weak association of PINA protein with starch granules in the absence of Pinb. Grain hardness analysis and flour milling tests indicated that the overexpression of PINA resulted in decreased grain hardness and increased flour yield in transgenic durum wheat lines. The agronomic performance of the transgenic and control lines was also examined and it was found that no significant differences in measured traits were observed between Pina-overexpressing and control lines in the 2-year field trials. Since grain hardness strongly affects milling and end-use qualities, the development of medium–hard-textured durum wheat lines is not only of significance for our knowledge of grain hardness and Puroindolines, but also has practical implications for plant breeders and food technologists for the expansion of utilization of durum wheat.     

定量蛋白质组学研究揭示知母可缓解2型糖尿病模型大鼠肝脏代谢异常

2型糖尿病（type 2 diabetes mellitus,T2DM）是一种在全球范围内广泛存在的代谢性疾病,不及时治疗可能会引发众多危及生命的并发症。肝脏代谢在糖尿病发生发展的过程中扮演着至关重要的角色。目前已有报道中药知母用于缓解胰岛素抵抗及糖尿病,但其能否缓解糖尿病中肝脏代谢的异常仍有待深入研究。因此,提取了高脂饮食和化学药物链脲佐菌素（streptozotocin,STZ）诱导的2型糖尿病大鼠模型、知母提取物处理的2型糖尿病大鼠模型、高脂饮食大鼠模型以及正常饮食大鼠对照组的肝脏蛋白,通过基于质谱的定量蛋白质组学串联质量标签（tandem mass tag,TMT）标记技术获得定量蛋白质组数据。利用生物信息学软件对各组数据进行层次聚类分析及主成分分析,并以P<0.05,差异倍数（fold change）>1.5作为阈值标准进行火山图分析,发现知母提取物治疗组相较未治疗组与正常对照组更接近,表明肝脏组织定量蛋白质组数据能够反映知母提取物对2型糖尿病大鼠模型的治疗效果。筛选获得了表达水平与知母提取物治疗密切相关的关键蛋白簇。利用在线网站分析蛋白簇的GO功能与KEGG通路,发现知母缓解2型糖尿病模型大鼠肝脏脂肪酸代谢异常可能与关键蛋白Ndufa6和Prkar2b的表达水平回调有关。     

Inheritance and Expression of Copies of Transgenes 1Dx5 and 1Ax1 in Elite Wheat （Triticum aestivum L.） Varieties Transferred from Transgenic Wheat through Conventional Crossing

To study the inheritance and expression of multiple copies of transgenes from transgenic wheat lines, three crosses between transgenic wheat lines B72-8-11b and B102-1-2 and Chinese elite wheat varieties Chuan89-107 and Email 8 were carried out. Chuan89-107×B72-8-11b, Chuan89-107×B102-1-2 and Email 8×B72-8-11b, and F_1 plants were selfed or backcrossed to obtain different generation populations. Protein analysis in grains of F_1 and F_2 and backcross progenies of BC_1F_1, BC_1F_2, BC_1F_3, BC_2F_1, BC_2F_2 and BC_2F_3 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the transgenes lDx5 and lAx1 were expressed and segregated in the target wheat according to Mendelian laws. A range of lDx5 expression levels were observed in the progenies of Chuan89-107×B72-8-11b and Emai 18×B72-8-11b, but the expression levels of lAx1 in progenies of Chuan89-107×B102-1-2 rarely changed. It suggested that the two foreign genes had different mechanisms of expression in the cross progeny, even though they were produced in the same way and the foreign lDx5 gene of 5-10 copies had the more complicated expression mechanism than the lAx1 gene of 4-5 copies.     

A Novel High Capacity Positive Electrode Material with Tunnel‐Type Structure for Aqueous Sodium‐Ion Batteries

Aqueous sodium‐ion batteries have shown desired properties of high safety characteristics and low‐cost for large‐scale energy storage applications such as smart grid, because of the abundant sodium resources as well as the inherently safer aqueous electrolytes. Among various Na insertion electrode materials, tunnel‐type Na_0.44MnO₂ has been widely investigated as a positive electrode for aqueous sodium‐ion batteries. However, the low achievable capacity hinders its practical applications. Here, a novel sodium rich tunnel‐type positive material with a nominal composition of Na_0.66[Mn_0.66Ti_0.34]O₂ is reported. The tunnel‐type structure of Na_0.44MnO₂ obtained for this compound is confirmed by X‐ray diffraction and atomic‐scale spherical aberration‐corrected scanning transmission electron microscopy/electron energy‐loss spectrum. When cycled as positive electrode in full cells using NaTi₂(PO₄)₃/C as negative electrode in 1 m Na₂SO₄ aqueous electrolyte, this material shows the highest capacity of 76 mAh g^?1 among the Na insertion oxides with an average operating voltage of 1.2 V at a current rate of 2 C. These results demonstrate that Na_0.66[Mn_0.66Ti_0.34]O₂ is a promising positive electrode material for rechargeable aqueous sodium‐ion batteries.