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Synthesis of gefarnate catalyzed by lipase
No full text吉法酯(Gefarnate)是一种异戊间二烯化合物,化学名为5,9,13-三甲基-4,8,12-十四三烯酸-3',7'-二甲基-2',6'-辛二烯醇酯。本文主要目的是通过对脂肪酶催化法尼基乙酸和香叶醇的酯化反应合成吉法酯的化学反应条件进行优化,初步建立一套条件温和且污染小的酶催化法制备吉法酯的合成工艺。本文在脂肪酶(Lipozyme 435)催化法尼基乙酸和香叶醇发生酯化反应的条件下,系统研究了酶催化剂、溶剂、投料比、温度等合成条件对酯化反应的影响;结果表明,以Lipozyme 435(0.2 eq)作为催化剂,环已烷作为溶剂,在30 ℃条件下得到了78.4%的GC收率。该方法具有反应条件温和,副反应少,产率高,催化剂可重复利用等优点,这为进一步吉法酯的工业化合成奠定了良好的基础
Nitrogen removal from wastewater using the bioelectrochemical technology: a review
No full text生物电化学系统(BES)因兼有污染物去除与能量回收等优点,近年来已成为环境污染治理领域的关注热点.对生物电化学技术在脱氮方面的基本原理、含氮污染物的转化途径进行综述,主要的生物脱氮过程包括阴极反硝化、阳极氨氧化以及阴极同步硝化反硝化等,而非生物脱氮过程包括NH_3/NH_4~+的跨膜转移、氨气逃逸等.总结已报道的BES中主要脱氮微生物及其脱氮机制,BES中多数反硝化菌属于变形菌门(Proteobacteria);硝化细菌主要是亚硝化菌属(Nitrosomonas)和硝化杆菌属(Nitrobacter);在同步硝化反硝化过程中,电极上的硝化、反硝化菌有明显的分层现象.最后阐述了生物电化学脱氮技术在生活污水、渗滤液、地下水处理等领域的最新应用研究,通过改变反应器构型以及运行模式等条件构建不同BES处理各类污水,以达到去除污染物同时回收电能或资源的目的.基于目前BES的优势,认为减少脱氮中间产物(NO_2~-- N、N_2O)的积累及扩大BES规模对电能输出和污染物去除效果的影响将是未来的研究方向
From nature reserve to national park system pilot: Changes of environmental coverage in the Three-River-Source National Park and implications for amphibian and reptile conservation
No full text三江源地区具有丰富的高原生物多样性,是我国重要的生态安全屏障。作为我国第一个体制试点的国家公园,三江源国家公园将被建成青藏高原大自然保护展示和生态文化传承区。为更好地服务于三江源国家公园建设,本研究从海拔、年均温和年降水等方面,在环境空间上系统比较了国家公园与三江源和可可西里自然保护区的差异;以4种两栖爬行动物即高原林蛙(Rana kukunoris)、倭蛙(Nanorana pleskei)、西藏齿突蟾(Scutiger boulengeri)和青海沙蜥(Phrynocephalus vlangalii)分布点环境条件在国家公园内外的异同为例,探讨分布受环境制约大、扩散能力弱的物种保护在国家公园建设中可能面临的机遇和挑战。结果表明,国家公园与已建自然保护区在地理空间上重叠较大,但它们在自然环境上的差别很明显;自然保护区内两栖爬行类所偏好的环境条件较多未包含在国家公园内。鉴于三江源的区位特殊性及对气候变化的敏感性,区域内两栖爬行动物等对环境依赖性强、扩散能力弱物种的有效保护不仅有助于保持物种遗传多样性和区域生态系统的完整性,也有利于更好地实现国家公园目标定位并服务于生态文明建设。为此,在国家公园内,应开展两栖爬行动物种群动态和群落结构的长期监测,加强基础生物学研究,掌握环境变化对两栖爬行动物分布、遗传、行为、形态、种群动态及群落可能产生的影响,实现区域内两栖爬行动物及其类似物种在环境变化下的永续生存
Chemical constituents of n-butanol fraction from Tibetan medicine Gentianae Szechenyii Spray
No full text目的研究藏药大花龙胆Gentiana szechenyii花枝乙醇提取物的正丁醇部位的化学成分。方法通过制备高效液相色谱法分离纯化,利用各种谱学技术鉴定化合物的结构。结果从大花龙胆花枝乙醇提取物的正丁醇部位分离得到6个化合物,分别鉴定为大花龙胆酯苷A(1)、大花龙胆苷A(2)、异金雀花素-2-O-吡喃葡萄糖苷(3)、异金雀花素(4)、乌奴龙胆苷D(5)和平龙胆酯苷(6)。结论化合物1为1个新的环烯醚萜苷类化合物,命名为大花龙胆酯苷A
Extraction of components with different polarities from Dendrobium and their inhibitory action on lung cancer cells
No full text为探究石斛(Dendrobium)的不同极性成分对人肺癌细胞抑制作用的差异,寻找到石斛抗癌活性成分高效提取的方法,采用极性不同的溶剂和方法对金钗石斛(D. nobile)、迭鞘石斛(D. denneanum)的药用成分分别进行提取以及层析柱纯化,以CCK-8实验检测不同极性提取物对人肺癌细胞和正常细胞的抑制作用,同时采用傅里叶变换红外光谱仪分别对石斛的乙醚和乙醇提取物成分进行检测和比较.结果显示,石斛的不同极性成分抑癌作用差异显著,石斛的抑癌成分极性较小,易溶于乙醚.经石油醚预洗后的石斛乙醚提取物对肺癌细胞的抑制作用较强,100 mug/mL的金钗石斛与迭鞘石斛提取物对肺癌A549细胞的24 h抑制率分别为45%和40%.而传统中药成分提取中常用的水和乙醇对石斛抗癌成分的提取效率较低.红外光谱分析亦显示石斛的乙醚提取物与乙醇提取物化学成分上存在较大差别,因此对于石斛抗癌成分的提取应采用极性较小的乙醚等溶剂.此外,发现金钗石斛的特定极性组分C具有较强的抑制肺癌细胞作用,其100 mug/mL的浓度对肺癌A549细胞的24 h抑制率达到97%,可作为石斛抗癌新药筛选的来源.因此,金钗石斛和迭鞘石斛的抑癌成分具有特定的极性,结果可为石斛抗癌成分及抗癌作用的进一步研究和利用提供参考
Data mining and analysis for simple sequence repeats in expressed sequence tags from barley
No full text大麦是一种古老的栽培作物,也是分子遗传学研究中常用的模式植物,为满足大麦基因作图、遗传多样性、种质资源鉴定和分子辅助育种等研究的需求,拟在NCBI公共数据库基础上,开发基于表达序列标签(EST)的简单序列重复(SSR)分子标记.从NCBI数据库中获得了525 781条大麦EST序列,将这些序列进行聚类和去冗余后共获得61 902个Unigene,随后通过MISA软件搜索Unigene中的SSR位点,并设计引物9 659对,最后通过电子PCR(E-PCR)和普通PCR对引物进行验证.结果显示:(1)61 902个Unigene中含有SSR位点24 648个,其中复合SSR位点5 843个,约占3.42%,单纯SSR位点23 805个,约占96.58%;(2)经E-PCR验证后发现9 659对SSR引物中有1 060对(11%)能够成功扩增出产物;(3)随机选取的11对引物经普通PCR验证发现,这些引物都能在2份野生大麦品种、2份栽培大麦品种及1份小麦、硬粒小麦、荆州黑麦和节节麦中成功扩增.本研究表明日益丰富的EST公共数据库是大麦SSR分子标记的重要来源;利用EST公共数据库、SSR搜索软件,结合E-PCR验证是开发SSR分子标记省时高效的手段
ISOLATION OF DEGRADING BACTERIA FROM OIL BASE MUD DRILLING CUTTINGS AND ITS DEGRADING CHARACTERISTICS
No full text以四川珙县油基泥浆钻井岩屑为研究材料,筛选出10株能以石油为碳源和能源生长的降解菌,并以石油降解率为筛选依据,筛选出2株高效降解菌(C-1、C-2) ,通过16S rDNA序列分析对其进行初步鉴定和降解特性研究。结果表明: C-1、C-2的降解率为39% ~ 40%,分别为芽孢杆菌属Bacillus sphaericus、Bacillus subtilis;降解特性分析表明:在接种量为10%、pH为7、温度为35 ℃、n(N) ∶ n(P) = 12∶ 1、盐浓度为0.5%的最优条件下,C-1和C-2对石油的去除率分别为46.08%、48.94%,补充N、P后降解率基本未变化,说明岩屑中大部分可生化降解成分已全部降解,部分难降解的物质(如长链烷烃、多环芳烃等)仍在岩屑中
Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient
No full textUnderstanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523-4685 m) on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3-47.5% higher than those of other regional and global flora, whereas the leaf N and N: P were 10.2-75.8% lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub) could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m), likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N: P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer), their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N: P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most important factor explaining the overall leaf C : N: P variations, despite the broad climate gradient on the plateau. Temperature and drought induced shifts in shrub type distribution will influence the nutrient accumulation in mountainous shrubs
METHANE OXIDATION BACTERIA COMMUNITY STRUCTURES IN NANLING MOUNTAIN FOREST SOIL OF CHINESE CLIMATIC ECOTONE
No full textMicrobial oxidation is regarded as the only biological sink for atmospheric methane (CH4). The operators of methane oxidation in forest soils are still poorly understood, especially for forests in China. This study investigated the soils from Nanling Mountain forest near the Tropic of Cancer. All together 10 OTUs (Operational Taxonomic Unit) were obtained, with the ratio of type I/type II methanotrophs higher in the forest soil of south plot (similar to 1.6) than that of the north plots (0-0.9). Methylocaldum, Methylobacter-like/Upland Soil Cluster a Rold 1 (USC alpha R1), Tropical Upland Soil Cluster1 (TUSC1) dominate methane oxidation bacteria (MOB) community. Among them USC alpha contributed a bigger part in the north plots (about 50%) comparing with south plot (about 7%). The pmoA genes of dominant Methylocaldum MOB and those closely related to sequences of Methylocystis and Methylosinus MOB were detected in the south plot did not in the north plots. USC alpha R1, USC alpha R3 and Methylobacter-like methanotrophs tended to prefer soil environment of higher acidity. On the contrary, Upland Soil Cluster gamma methanotrophs tended to prefer neutral comparatively easier. The Shannon diversity index of methanotrophic community was positively related to pH but negatively related to bulk density (P < 0.05 for both), and the Simpson diversity index showed the similar tendency. The results indicate that there is heterogeneity of methanotrophic community in the Nanling climatic transition region
Pollen morphology of subfamily Caryophylloideae (Caryophyllaceae) and its taxonomic significance
No full textThe Pollen morphology of subfamily Caryophylloideae (Caryophyllaceae) from different phytogeographical region of Pakistan has been evaluated. In this research, 16 species belong to 6 genera of subfamily Caryophylloideae have been studied using light (LM) and scanning electron microscopy (SEM) for both qualitative and quantitative characters. Different palyno-morphological features were observed including; pollen ornamentation, pore ornamentation, echini arrangement, echinidensity, number of pori, size of polar and equatorial diameter, P/E ratio, exine thickness, and size of pore were studied. The palyno-morphological characters of subfamily Caryophylloideae have taxonomically significant in identification and delimitation of species. Two pollen types, i.e., subspheroidal (15 species) and prolate (one species Vaccaria hispanica) were observed. Microechinate-punctate and microechinate-perforate pollen ornamentation were examined. Two pollen types of pori, i.e., prominent (5 species) and sunken (11 species) ornamentation have been reported. Three types of echini arrangement have been reported irregular, regular and rather regular, while three type of echinidensity (i.e., medium, dense and sparse) were observed. Pori numbers were found different in different species range from 5 in Silene apetala to 19-35 in Silene vulgaris. Based on different palyno-morphological characters, taxonomic key was develop for quick and accurate identification. The quantitative data were processed using SPSS software for average, minimum, maximum, and standard error