Preliminary correlation of organic molecular tracers in residential wood smoke with the source of fuel

Polar cyclic di- and triterpenoids were analyzed in the extracts of residential wood combustion aerosols collected in suburban sections of Eugene, Oakridge and Corvallis, Oregon. Additional samples collected included alder wood, smoke from two wood stoves burning only alder or pine as fuel, soot from a stove burning alder and a fireplace where oak was the predominant fuel. Due to the relatively cooler temperatures present under the smoldering conditions of residential wood combustion, as compared to the active burning of forest fires and slash burns, incomplete combustion resulted in the preservation of high levels of the natural products.There were three distinct signatures which could be used to trace relative input from coniferous, alder and oak combustion products, i.e. diterpenoids, lupane-derived triterpenoids and friedelin, respectively. Conifer combustion products dominated the suburban smoke aerosols.     

乙醇型发酵过程优化及代谢调控分子机制

乙醇型发酵是3种主要厌氧产酸发酵类型之一.乙醇型发酵细菌具有高产氢效率、耐酸性、自凝集生长和发酵产物可直接被产甲烷利用等优势,因此被广泛关注和研究.近年来,在乙醇型发酵产氢过程优化和代谢途径研究方面取得了大量进展.本文对乙醇型发酵产氢反应器优化和运行控制、高效产氢细菌分离和代谢调控分子机制,以及耦合系统强化能源回收等研究进展进行了综述.此外,本文提出了乙醇型发酵的可持续高效产氢及代谢产物的定向回收梯级利用的思路,探讨了乙醇型发酵制氢技术的发展趋势和未来应用中存在的问题.     

附生假单胞菌信号分子对铜绿微囊藻磷代谢的影响

通过在不同的磷浓度和细胞浓度的铜绿微囊藻培养液中添加附生假单胞菌信号分子,研究了附生假单胞菌信号分子对铜绿微囊藻生长及磷代谢的影响．结果表明,与对照相比,附生假单胞菌信号分子能抑制高浓度铜绿微囊藻的生长,促使低浓度铜绿微囊藻衰亡,并可以促进在衰亡期藻细胞内磷的积累．附生假单胞菌的信号分子可以在附生假单胞菌-铜绿微囊藻种间起作用,影响铜绿微囊藻的生长和磷代谢。     

铜绿微囊藻生长代谢的密度依赖性特征及分子机制

蓝藻水华是淡水湖库普遍面临的水环境问题,目前水华形成机制研究大多关注外界环境因素而忽略了藻类自身及群体的关键调节作用.因此,本文以初始细胞密度为单一变量,考察了不同初始细胞密度条件下蓝藻生长、营养物质利用、叶绿素、藻毒素、胞外分泌物随时间的变化情况.结果发现,初始细胞密度会影响铜绿微囊藻的环境适应性和生长情况,当接种密度≥1×10⁶ cell·mL^-1,铜绿微囊藻适应期消失,初始细胞密度从1×10⁵ cell·mL^-1增加至1×10⁷ cell·mL^-1,最高细胞密度增加了68%,生长速率提高了21%,并且叶绿素变化趋势与生长情况一致.胞外分泌物随初始细胞密度增加而逐渐增加,有利于蓝藻细胞聚集成膜.当初始细胞密度较低（1×10⁵ cell·mL^-1）时,单细胞藻毒素分泌量反而增加,以提高蓝藻的环境适应能力.在高初始密度（1×10⁷ cell·mL^-1）条件下,铜绿微囊藻主要通过上调丙酮酸代谢和碳代谢,促进细胞生长增殖.因此,细胞密度是影响铜绿微囊藻生长代谢的重要因素,在蓝藻水华形成过程中可能发挥重要作用,水华防治应当在细胞密度较低的阶段进行.     

传播生态理念 助力民族团结——访深圳松禾成长关爱基金“飞越彩虹”公益项目志愿者郦红

<正>与郦红老师最早结缘于《冈特生态童话》的润色工作中,作为志愿者,那时还只是通过电邮知道了这个美丽的名字。后来在微信中看到了她在甘肃省阿克塞哈萨克族自治县小学支教的图片,才发现人如其名,美丽端庄。7月的北京,天气酷热,郦红老师如约而至。印象深刻的是她脸上始终挂着甜     

Docosahexaenoic acid (DHA) content of membranes determines molecular activity of the sodium pump: implications for disease states and metabolism

The omega-3 polyunsaturate, docosahexaenoic acid (DHA), plays a number of biologically important roles, particularly in the nervous system, where it is found in very high concentrations in cell membranes. In infants DHA is required for the growth and functional development of the brain, with a deficiency resulting in a variety of learning and cognitive disorders. During adulthood DHA maintains normal brain function and recent evidence suggests that reduced DHA intake in adults is linked with a number of neurological disorders including schizophrenia and depression. Here we report a high positive correlation between the molecular activity (ATP min^–1) of individual Na⁺K⁺ATPase units and the content of DHA in the surrounding membrane bilayer. This represents a fundamental relationship underlying metabolic activity, but may also represent a link between reduced levels of DHA and neurological dysfunction, as up to 60% of energy consumption in the brain is linked to the Na⁺K⁺ATPase enzyme.     

亚砷酸钠对酵母细胞H2S代谢的影响

以模式生物酿酒酵母为研究对象,采用醋酸铅试纸条法、BIGGY琼脂及qRT-PCR技术检测了不同浓度亚砷酸钠胁迫下H₂S产量及产H₂S酶编码基因表达的变化,以探讨砷化物对酵母细胞H₂S代谢的影响.结果显示,0.5~2 mmol·L^-1的亚砷酸钠可诱导酵母细胞内源H₂S的产生,且H₂S合成相关基因的相对表达量与对照相比均有不同程度的上调.经0.05~0.2 mmol·L^-1的外源H₂S预处理后,酵母细胞对砷的耐受性明显提高.研究表明,亚砷酸钠可影响酵母细胞H₂S代谢,而H₂S含量可在一定程度上调控砷对酵母的毒性.     

Control concept and countermeasures for shallow lakes'eutrophication in China

Research on lake eutrophication in China began in the early 1970s, and many lakes in China are now known to be in meso-eutrophic status. Lake eutrophication has been showing a rapidly increasing trend since 2000. Investigations show that the main reasons for lake eutrophication include a fragile lake background environment, excessive nutrient loading into lakes, excessive human activities, ecological degeneration, weak environmental protection awareness, and lax lake management. Major mechanisms resulting from lake eutrophication include nutrient recycling imbalance, major changes in water chemistry (pH, oxygen, and carbon), lake ecosystem imbalance, and algal prevalence in lakes. Some concepts for controlling eutrophication should be persistently proposed, including lake catchment control, combination of pollutant source control with ecological restoration, protection of three important aspects (terrestrial ecology, lake coast zone, and submerged plant), and combination of lake management with regulation. Measures to control lake eutrophication should include pollution source control (i.e., optimize industrial structural adjustments in the lake catchment, reduce nitrogen and phosphorus emission amounts, and control endogenous pollution) and lake ecological restoration (i.e. establish a zone-lake buffer region and lakeside zone, protect regional vegetation, utilize hydrophytes in renovation technology); countermeasures for lake management should include implementing water quality management, identifying environmental and lake water goals, legislating and formulating laws and regulations to protect lakes, strengthening publicity and the education of people, increasing public awareness through participation in systems and mechanic innovations, establishing lake region management institutions, and ensuring implementation of governance and management measures.     

Selenium metabolism in animals and humans

Ｓｅｌｅｎｉｕｍｍｅｔａｂｏｌｉｓｍｉｎａｎｉｍａｌｓａｎｄｈｕｍａｎｓ￥Ｐ．Ｄ．Ｗｈａｎｇｅｒ（ＤｅｐａｒｔｍｅｎｔｏｆＡｇｒｉｃｕｌｔｕｒａｌＣｈｅｍｉｓｔｒｙ，ＯｒｅｇｏｎＵｎｉｖｅｒｓｉｔｙ，Ｏｒｅｇｏｎ９７３３１－７３０１，ＵＳＡ）Ａｂｓｔ...     

PFOS暴露对肺癌细胞中信号通路的影响

为探讨全氟辛烷磺酸盐（PFOS）产生肺毒性的分子机制,采用细胞计数试剂盒（CCK-8）方法测定不同浓度PFOS对A549细胞活性的影响,并用二代测序方法测定PFOS暴露对A549细胞中miRNAs表达的影响,预测异常表达miRNAs的靶基因.通过生物信息学分析推断靶基因参与的信号通路及潜在的生物学功能.结果显示,低浓度PFOS（<00μmol/L）促进A549细胞增殖,高浓度PFOS抑制细胞增殖.暴露于300μmol/L PFOS中24h的A549细胞中108个miRNAs表达量显著上调,63个miRNAs表达量显著下调.差异表达miRNAs通过Ras、Rap1、HIF-1、ErbB和VEGF等信号通路参与细胞增殖、代谢和发育等生物学过程.这表明PFOS可通过影响细胞增殖和诱发炎症反应对肺造成威胁.     

双酚A诱导人乳腺癌MCF-7细胞上皮间质化的研究

双酚A(BPA)是一类典型的环境雌激素,能干扰机体正常内分泌系统.作为一种激素相关疾病,乳腺癌的发生发展与BPA暴露的关系已引起人们的关注.本研究旨在探讨BPA对人乳腺癌MCF-7细胞上皮细胞间质化(EMT)的诱导作用.经BPA处理的MCF-7细胞,采用MTT试验检测BPA对细胞活力的影响,Transwell试验检测BPA对细胞迁移能力的影响,Real-time RT-PCR、Western Blot检测BPA对上皮型蛋白标志物E-cadherin、间质型蛋白标志物Vimentin及EMT相关转录因子Snail表达的影响.结果发现,低浓度BPA能够促进MCF-7细胞的增殖,显著增强细胞的迁移能力.BPA处理能抑制E-cadherin的表达,促进Vimentin及Snail的表达.研究结果提示,BPA处理可能通过促进Snail的表达而调控EMT相关蛋白标志物的表达,进而增强乳腺癌MCF-7细胞的迁移能力.     

江南古陆中元古代地层的划分与对比

江南古陆是扬子板块与华夏板块长期活动拼贴而成,构造极为复杂,地层的划分与对比也是众说纷纭.通过对江南古陆的变质岩的研究,认为江南古陆大地构造可划分三个Ⅰ级构造地层区:扬子地层区、江南古陆地层区及华夏地层区.江南古陆地层区又可进一步划分Ⅱ级构造地层区5个(宜丰-景德镇-歙县构造地层分区、万年构造地层分区、赣东北构造地层分区、怀玉构造地层分区及丰城-鹰潭-龙游构造地层分区);各构造地层分区之间以构造(蛇绿)混杂岩亚带或韧性剪切带相拼接.双桥山群及周潭岩群仅分别分布在扬子地层区修水-祁门分区及华夏地层区北武夷地层分区内,而且是一套史密斯地层.而江南古陆内则发育非史密斯地层.     

Deoxyribonucleotide synthesis and the emergence of DNA in molecular evolution

DNA replication requires monomeric deoxyribonucleotides, which cannot be regarded as primary products of organic syntheses on a primitive earth. However, the present biosynthetic pathway — reductive elimination of the 2′-OH group from ribonucleotides, catalyzed by ribonucleotide reductases and thioredoxins — suggests an early, polyphyletic combination of protein-nucleotide interactions and metal catalysis. That key process had to precede the upcome of RNA-DNA dualism on the way from RNA-protein protocells to true organisms.     

Applying the concept of agrodiversity to indigenous soil and water conservation practices in eastern Kenya

Agrodiversity – the diversity of cropping systems, crop species and farm management practices has received increasing attention in recent years as a way of spreading risk and supporting food security in resource-poor farming systems. This paper discusses the dynamic aspects of indigenous soil and water conservation (ISWC) practices in a semi-arid part of Kenya. The objective is to show the range of sources of variability and diversity that prevail in this environment, the responses of farmers to this variability, and the way farmers' rationalise the heterogeneity of soil and water management practices. Methods used included participatory surveys and evaluations, on-farm monitoring, soil and rainfall data analyses, and questionnaire surveys. Sources of variability affecting cropping systems and land management practices included rainfall, soil fertility, farmer resource level and farm productivity. A decision-tree was developed to examine how biophysical and socio-economic variability affected farmers' choice of ISWC. Different ISWC structures dominated on sandy and stony soils, respectively. Low resource farmers tended to choose cheaper and less labour demanding techniques, and constructed smaller ISWC structures than better endowed farmers. The largest diversity of ISWC practices was found on newly-opened land with mixed soils. Moreover, on-farm productivity levels indicated that costly investments in SWC are unfeasible, as this would further increase the risk for negative returns to farming. The wider implications of the results are that SWC interventions in marginal areas should build on the existing agrodiversity and an understanding of the complex interactions between environmental and socio-economic factors that give rise to differences in farming systems and land management practices.