PCR-DGGE解析阴离子交换膜生物反应器反硝化过程中微生物群落结构变化   总被引：3，自引：0，他引：3  

高孟春  梁方圆  杨丽娟  杨瑒  李冰  朱玉姣  顾雯  徐婕 《中国海洋大学学报(自然科学版)》2010,40(4)

通过扫描电镜和聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)方法考察了进水NO3-浓度变化对阴离子交换膜生物反应器微生物种群结构的影响。研究结果表明,在进水NO3-浓度从47.01 mg/L逐渐增加到168.55 mg/L的过程中,出水中NO3--N浓度满足我国饮用水水质标准中小于10 mg/L的要求。电镜扫描图显示微生物的形态结构发生了很大变化。对不同阶段的样品进行PCR-DGGE图谱和相似系数分析,发现随着反应的持续进行,微生物种群结构发生了演替变化,证实污泥微生物生态能够迅速进行优胜劣汰的筛选,调整内部微生物种群结构,从而达到适应环境的目的。  相似文献   

IMPROVEMENT OF SANDY SOIL WITH WATERCONSERVING MEMBRANE AND ITS EFFECT ON CROP GROWTH   总被引：1，自引：0，他引：1  

LIXiu-jun CUIXiang-hao LIQu-sheng 《中国地理科学(英文版)》2005,15(1):64-69

1INTRODUCTIONArid, semi-arid, and semi-humid areas abound in sandysoil, which causes water to leak into deep soil orgroundwater so that soil′s water-conserving capabilitybecomes lower and water is used with low efficiency.Water is one of the important fa…  相似文献   

A new matrix for multiphase couplings in a membrane porous medium          下载免费PDF全文

Xiaohui Chen  Michael A. Hicks  Hywel R. Thomas 《国际地质力学数值与分析法杂志》2018,42(10):1144-1153

The empirical Darcy's law of water transport in porous media, Fick's law of chemical diffusion, and Fourier's law of thermal transport have been widely used in geophysics/geochemistry for over 150 years. However, the strong couplings between water, temperature, and chemicals in a membrane porous medium have made these laws inapplicable and present a significant hurdle to the understanding of multiphase flow in such a material. Extensive experiments over the past century have observed chemical osmosis and thermal osmosis, but a model for understanding their underlying physicochemical basis has remained unavailable, because of the highly cross‐disciplinary and multiscale‐multiphase nature of the coupling. Based on the fundamental principles of nonequilibrium thermodynamics and mixture coupling theory, a rigorously theoretical and mathematical framework is proposed and a general model accounting for all of the coupled influences is developed. This leads to a simple and robust mathematical matrix for studying multiphase couplings in a membrane porous medium when all chemical components are electrically neutral.  相似文献   

An efficient flexible membrane boundary condition for DEM simulation of axisymmetric element tests          下载免费PDF全文

Ali Khoubani  T. Matthew Evans 《国际地质力学数值与分析法杂志》2018,42(4):694-715

The mechanical response of an assembly of particles depends on the applied boundary conditions. Robust calibration of numerical discrete systems to laboratory results is also a primary step in many studies of granular materials. In this study, a new membrane model was developed for simulating axisymmetric element tests. This membrane model uses a simple algorithm of an array of independently controlled walls and is computationally efficient. The effect of boundary flexibility on the system response was investigated by simulating a series of triaxial tests on dense and loose specimens. At the specimen scale, differences in shear strength and volume change of specimens were observed. It was shown that localization pattern depends on the applied boundary conditions. At the particle scale, particle‐membrane contact forces, coordination number, local void ratio, and anisotropy of fabric were all affected by the boundary flexibility.  相似文献   

Identification of the natural product 2,3,4,5-tetrabromo-1-methylpyrrole in Pacific biota, passive samplers and seagrass from Queensland, Australia     

Gaul S  Bendig P  Olbrich D  Rosenfelder N  Ruff P  Gaus C  Mueller JF  Vetter W 《Marine pollution bulletin》2011,62(11):2463-2468

Halogenated natural products (HNPs) are frequently detected in marine organisms. High HNP concentrations have previously been found in marine mammals from the Great Barrier Reef, Australia, including in the blubber of herbivorous dugongs (Dugong dugon). To identify the source of HNPs we initially focused on the analysis of Australian seagrass (Halophila ovalis) which serves as the principal food source for dugongs. GC/MS analysis of the seagrass indicated the presence of several organobromine compounds. One compound was identified as 2,3,4,5-tetrabromo-1-methylpyrrole (TBMP) by synthesis. Subsequent analysis of semipermeable membrane devices demonstrated that the photo-sensitive TBMP is widespread in the Great Barrier Reef (Queensland, Australia). The detection of larger TBMP concentrations in fish fillets from Chile and traces in mussels from New Zealand indicated that this potential HNP may be distributed throughout the Southern Pacific Ocean.  相似文献   

PAH body burden and biomarker responses in mussels (Mytilus edulis) exposed to produced water from a North Sea oil field: laboratory and field assessments     

Sundt RC  Pampanin DM  Grung M  Baršienė J  Ruus A 《Marine pollution bulletin》2011,62(7):1498-1505

In order to study the impact of produced water (PW) from a North Sea oil field on blue mussels (Mytilus edulis), chemical and biological markers were selected. A laboratory exposure (0.125%, 0.25% and 0.5% of PW) and a field study (6 stations 0.2-2 km from a PW discharge point) were conducted. In the laboratory study, PAH bioaccumulation increased in mussel soft tissue even at the lowest exposure dose. Micronuclei frequency demonstrated a dose-response pattern, whereas lysosomal membrane stability showed tendency towards a dose-response pattern. The same markers were assessed in the field study, biomarker analyses were consistent with the contamination level, as evaluated by mussel polycyclic aromatic hydrocarbons body burden. Overall, obtained results confirmed the value of an ecotoxicological approach for a scientifically sound characterisation of biological effects induced by offshore oilfield operational discharges.  相似文献   

Gene cloning and prokaryotic expression of recombinant outer membrane protein from Vibrio parahaemolyticus     

ԬҰ  ������  ����ƽ  ��ѩ÷ 《中国海洋湖沼学报》2011,29(5):952-957

Gram-negative Vibrio parahaemolyticus is a common pathogen in humans and marine animals. The outer membrane protein of bacteria plays an important role in the infection and pathogenicity to the host. Thus, the outer membrane proteins are an ideal target for vaccines. We amplified a complete outer membrane protein gene (ompW) from V. parahaemolyticus ATCC 17802. We then cloned and expressed the gene into Escherichia coli BL21 (DE3) cells. The gene coded for a protein that was 42.78 kDa. We purified the prote...  相似文献   

膜萃取与超声衍生联用-负化学源质谱法测定地下水中酚类化合物   总被引：1，自引：1，他引：0  

李晓亚  张莉  桂建业  张永涛  张辰凌  赵国兴  田来生 《岩矿测试》2014,33(2):270-274

酚类化合物由于极性较大,无法直接用气相色谱-质谱法测定,需要通过衍生来降低其极性,提高检测灵敏度;但是传统的衍生步骤繁琐,干扰因素多,操作难度大。本文对传统的前处理方法进行改进,建立了固相膜萃取、超声衍生负化学源质谱测定地下水中酚类化合物的方法。水样萃取后将萃取膜直接放入衍生瓶中,利用超声波的作用力将洗脱和衍生合二为一,超声完成后将溶液直接上机进行测定。测定低、中、高三个浓度水平的加标样品,各目标物的回收率均能达到70%~90%,检出限在0.25~0.35 μg/L之间,相对标准偏差小于10%,能够满足地下水中酚类物质的检测要求。本方法将洗脱和衍生集于一体,使用2 mL丙酮进行洗脱和衍生就可将全部目标物回收,简化了操作步骤,减少了有机溶剂的使用量;同时由于洗脱和衍生是在密闭的环境中进行,外界因素引入的干扰少,克服了二次污染的问题,测定数据更加可靠。  相似文献   

海藻胶低聚寡糖的化学氧化制备纯化技术及保水理化性质分析     

李海波  谢超  丁晨  黄菊  裘晓华  林琳 《海洋与湖沼》2015,46(4):915-921

海藻胶低聚寡糖是从马尾藻等藻类中提取出来的一种多糖类物质,具有抗氧化及保水等生物活性。本文采用氧化降解技术对海藻胶低聚寡糖的制备工艺进行了研究,通过对氧化过程中氧化剂浓度、反应温度、反应时间等进行研究,结果表明:当氧化剂H2O2添加浓度控制在6%左右,温度控制在60°C,时间控制在8h时,海藻胶降解为低聚寡糖的产率最高,达到60%左右。进一步对海藻胶低聚寡糖进行纯化,结果表明当温度控制在27°C,时间在2h时,分子量为6000—8000Da海藻胶低聚寡糖分离效率最高,达到70%以上,并对6000—8000Da海藻胶低聚寡糖的保水理化性能进行分析,结果表明6000—8000Da海藻胶低聚寡糖具有良好的保水性能。本研究可为开发一种安全、高效、节能、环保,适用于鱿鱼和虾仁等的生物保水剂提供理论基础。  相似文献   

半透产O_2￣(·-)体系的建立     

姜招峰  郑荧光  杨翰仪 《中国海洋大学学报(自然科学版)》1998,(1)

原有的产Ｏ·－２体系不适宜用作生物大分子的损伤研究。本实验以半透膜将产Ｏ·－２液相与待作用的样品液相分隔,使产Ｏ·－２液相中的组分选择性地透过至样品液相,对样品进行作用。这种半透产Ｏ·－２体系非常适于蛋白质、核酸等生物大分子损伤后的结构变化分析研究。本文给出了该体系用于生物大分子损伤以及结构变化研究的实验常数  相似文献