Pyrene and Phenanthrene Influence on Soil Microbial Populations

Two studies were conducted to evaluate microbial populations in polycyclic aromatic hydrocarbon-contaminated soil. Captina silt loam was freshly exposed to (1) 0 or 2000 mg pyrene/kg and sampled after 10- and 61-wk incubation and (2) 0 or 505 mg pyrene + 445 mg phenanthrene/kg and sampled after a 21-wk incubation. Microbial numbers were determined by plate-count techniques. Isolated bacteria, selected degraders, and wholesoil extracts were analyzed by fatty acid methyl ester analysis (FAME). In the pyrene experiment, pyrene did not affect total bacterial or fungal numbers, but pyrene degraders increased from undetectable levels to 7.09 log₁₀ degraders/g in the contaminated soil. The FAME analysis of bacterial isolates detected no pyrene effect, but wholesoil FAME indicated an increase in the contaminated soil of a fatty acid characteristic of protozoa and a major fatty acid detected in isolated degraders. In the pyrene + phenanthrene experiment, the contaminants had no impact on bacterial, fungal, or actinomycete numbers but increased degrader numbers. No effect of pyrene + phenanthrene was detected by isolate FAME, but whole-soil FAME indicated an effect similar to that in the pyrene experiment. The results indicate that pyrene, although not impacting microbial numbers, may have altered the soil microbial composition and that Captina silt loam can develop an effective degrader population under tested conditions.     

Pyrene and Phenanthrene Influence on Soil Microbial Populations

Two studies were conducted to evaluate microbial populations in polycyclic aromatic hydrocarbon-contaminated soil. Captina silt loam was freshly exposed to (1) 0 or 2000?mg pyrene/kg and sampled after 10- and 61-wk incubation and (2) 0 or 505?mg pyrene + 445?mg phenanthrene/kg and sampled after a 21-wk incubation. Microbial numbers were determined by plate-count techniques. Isolated bacteria, selected degraders, and wholesoil extracts were analyzed by fatty acid methyl ester analysis (FAME). In the pyrene experiment, pyrene did not affect total bacterial or fungal numbers, but pyrene degraders increased from undetectable levels to 7.09 log₁₀ degraders/g in the contaminated soil. The FAME analysis of bacterial isolates detected no pyrene effect, but wholesoil FAME indicated an increase in the contaminated soil of a fatty acid characteristic of protozoa and a major fatty acid detected in isolated degraders. In the pyrene + phenanthrene experiment, the contaminants had no impact on bacterial, fungal, or actinomycete numbers but increased degrader numbers. No effect of pyrene + phenanthrene was detected by isolate FAME, but whole-soil FAME indicated an effect similar to that in the pyrene experiment. The results indicate that pyrene, although not impacting microbial numbers, may have altered the soil microbial composition and that Captina silt loam can develop an effective degrader population under tested conditions.     

菲污染土壤的微生物修复机制

菲(Phenanthrene)是存在于煤焦油中,含三个苯环的稠环芳烃。除了具有"三致"作用外,菲稳定的化学结构和高辛醇-水分配系数等特性,使其具备较强的抗降解能力,易在环境中富集,破坏土壤微生态结构,降低农作物品质,威胁人类健康。而且随着化石燃料的长期大量使用,受菲污染的土地面积也急速增加,给人类的健康及生产活动带来极大的威胁。因此,有效清除土壤中菲及其他多环芳烃污染物,净化环境,具有重要的现实意义。微生物降解作为治理菲污染的方法之一,具有高效、低成本、环境友好的特点,受到研究者的高度重视。本文从菲降解菌的种类、降解机理、分子机制、影响修复等因素及微生物与植物联合修复五个方面进行综述,为进一步利用环境微生物,开发高效菲降解菌,治理菲污染提供参考。     

Heterogeneous Catalytic Oxidation of Phenanthrene by Hydrogen Peroxide in Soil Slurry: Kinetics,Mechanism, and Implication

The degradation of phenanthrene sorbed on soil has been carried out using a H₂O₂/goethite heterogeneous catalytic oxidation process. The effect of operating variables, such as the goethite concentration, pH, H₂O₂ concentration, soil organic matter, and bicarbonate ions has been investigated. The reaction followed pseudo-first order kinetics. The rate constants were evaluated and varied between 2.0×10^?4 and 1.1×10^?3?min^?1 depending on the H₂O₂ concentration. The highest rate of degradation of phenanthrene was observed at a H₂O₂ concentration of 5?M and 134.0?g/kg goethite. The intermediate product formed during the degradation of phenanthrene was identified to be salicylic acid that finally degraded to CO₂ and H₂O. H₂O₂ consumption continued as the OH radical attacked the salicylic acid. More than 80% consumption of the 5?M H₂O₂ took place within 30?min, and the degradation was almost complete after 3?h of reaction. Neutral pH was found to be effective in the removal of phenanthrene. Both soil organic matter (SOM) and bicarbonate ions in the soil inhibited the oxidation rate of phenanthrene.     

一种从人血凝块中提取基因组DNA的方法

介绍了一种新的从人血凝块中提取基因组DNA的方法,用该方法提取的DNA成功地应用于PCR和限制性酶切等后续实验中。基本过程为首先机械粉碎,然后高盐高EDTA溶液处理,含蛋白酶K和SDS的消化液变换温度消化,苯酚氯仿抽提。     

Removal of polycyclic aromatic hydrocarbons from oil-contaminated Kuwaiti soil

In the uncontaminated farm soil, more than 80% of the supplemented acenaphthene, fluoranthene, and pyrene (100 mg/100 g soil) decreased in 90 days, while ratio of removal was about 20%, 30%, and 0%, respectively, in the Kuwaiti oil-contaminated soil. Simultaneous addition of naphthalene, phenanthrene, and anthrathene (100 mg of each compound/100 g soil) led the acenaphthene to a decrease of about 20% to 45% but not of fluoranthene and pyrene. Addition of the farm soil to the Kuwaiti soil did not enhance the decrease of these three PAHs.     

A Simple Silica-based Method for Metagenomic DNA Extraction from Soil and Sediments

A new method is described for extraction of metagenomic DNA from soil and sediments which is based on DNA adsorption to silica without the use of phenol, ethanol precipitation or a cesium chloride gradient. High-quality DNA was obtained, and PCR inhibition was overcome by adding bovine serum albumin and adjusting magnesium concentration. By using PCR-DGGE with Firmicutes and lactic acid bacteria-specific primers the extracted metagenomic DNA was shown to contain a mixture of bacterial genomes. This method can be used for screening bacterial diversity in soil and sediment samples.     

血液基因组DNA的快速提取方法

目的:研究血液中基因组DNA的简便快速提取方法。方法:取新鲜抗凝血,以红细胞裂解液除去红细胞,再破碎白细胞,除去杂蛋白,获得基因组DNA。结果:所得基因组DNA完整、无断裂,含量和纯度均较高。以所提基因组DNA作为模板能很好的扩增出p21因子启动子序列,因此该法所提取的DNA是完整可靠的。结论:该法能简便、快速、安全、廉价的提取血液中的基因组DNA,并适用于临床检测和分子生物学研究。     

从土壤中提取DNA方法比较

设计并比较了3种直接从土壤中提取DNA的方法。试验结果表明:3种方法都可以从土壤中提取到分子量大于23.13 kb的DNA的片段,每克干土DNA的提取量为2.5~31μg,不同方法间在DNA产量、纯度等方面存在较大差异。     

Alkyl Polyglucoside (APG) Amendment for Improving the Phytoremediation of Pb-PAH Contaminated Soil by the AquaticPlant Scirpus triqueter

This study assessed the potential abilities of Scirpus triqueter for phytoremediation of soils contaminated with Pb-PAHs, amended with environment-friendly surfactant alkyl polyglucoside (APG). The effects of APG on the removal of PAHs from soil and the plant uptake and translocation of Pb were tested with plant growth and soil enzymatic activities. Experiments demonstrated that APG has an ability to facilitate PAH degradation and Pb uptake in the plant body at appropriate concentrations (20–40mg L^?1). The highest PAH removal rate was observed in 30 mg L^?1 APG treatment, and the highest accumulation of Pb was detected as 40 mg L^?1 APG. Experiments documented the effects of APG on plant growth, soil enzymatic activity, bioaccumulation and translocation of Pb in Scirpus triqueter. Results indicated that the addition of appropriate APG enhanced PAH removal rate and increased plant uptake and translocation of Pb.     

一种简单有效且适于土壤微生物多样性分析的DNA提取方法

参照Zhou[11]的方法进行了改进,获得了一种简单、有效的DNA提取方法.此方法操作简单、从大量样品改为小量样品的提取,利用高浓度的PEG沉淀,不作回收纯化,所提DNA片段较大,在23 kb以上,每克土的DNA提取量从3.74～15.28 μg,OD260/OD230比值在0.89～1.21范围内,用真菌和细菌核糖体特异性引物进行PCR扩增,均获得较好的结果,DGGE图谱显示丰富性较高,可用于细菌多样性和真菌多样性的分析.此方法能够从4种不同性质土壤中提取出DNA,但提取盐渍土壤和碱性土壤的效果更好一些,为土壤微生物群落结构的多样性分析奠定良好的基础.     

川芎及土壤中毒死蜱残留检测提取方法

为建立川芎植株和土壤中农药毒死蜱残留检测的最佳提取方法,利用气相色谱-质谱法测定毒死蜱残留量,并采用正交设计,考察提取溶剂、提取时间、提取次数和溶剂量对农药毒死蜱回收率的影响,优选提取方法。川芎地上部分和根茎中毒死蜱残留的最佳提取方法为：乙腈3倍量超声提取2次,每次15 min。土壤中毒死蜱残留的最佳提取方法为：乙酸乙酯10倍量震荡提取2次,每次30 min。经方法学验证,筛选建立的提取方法均达到农药残留分析要求,该方法可行。     

熏蒸法测定土壤微生物量碳的改进

自从Ｊｅｎｋｉｎｓｏｎ和Ｐｏｗｌｓｏｎ［１］创造熏蒸培养方法测定土壤微生物量碳，发展到用多种方法来测定土壤微生物量，如土壤ＡＴＰ含量分析方法［２］，基质诱导呼吸法［３］，精氨酸氨化法［４］，熏蒸浸提法［５］，脂肪酸、ＤＮＡ、ＲＮＡ等微生物细胞成分分析...     

A Rapid Screening Method for the Determination of Seventy Pesticide Residues in Soil Using Microwave-Assisted Extraction Coupled to Gas Chromatography and Mass Spectrometry

A rapid screening method using microwave-assisted extraction (MAE) in combination with gas chromatography and mass spectrometry for the determination of 70 pesticide residues in soil was established. The pesticides included 27 organophosphorus pesticides (OPPs), 29 organochlorine pesticides (OCPs), nine pyrethroids, and five carbamates. Parameters that could affect the efficiency of extraction, such as temperature, time, and solvent, were investigated. The condition of the extraction, under which recoveries of all 70 pesticides ranged from 70% to 120%, was optimized with a 1:1 (V/V) mixture of acetone and hexane, a temperature of 100°C, and an extraction time of 10 min. All compounds studied could be recovered in good yields and with relative standard deviations (RSDs) lower than 20%. The linearity of the method for all the pesticides was greater than 0.99 over a concentration range of 0.1–5 μg/g. The detection limits varied from 0.5 to 211.25 ng/g. Interday and intraday precision analyses yielded RSDs of 1.2%–11.7% and 3.6%–15.1%, respectively. This method, which was as effective as Soxhlet extraction and accelerated solvent extraction (ASE), proved to be accurate and precise. When the proposed method was used to examine environmental samples, the obtained results were in good agreement with those obtained using Soxhlet extraction.     

土壤样品中DNA提取方法的比较

对土壤样品中提取DNA方法的有效性进行了比较研究。如果以细胞有效裂解和DNA产率为标准,用冻融进行预处理再结合SDS和溶菌酶的化学裂解方法,是效果最佳的DNA抽提方法,细胞裂解率为82%,DNA产率达20.8μg/g。为了去除PCR抑制物,将DNA样品进一步用柱纯化,回收率为80%。纯化后的DNA样品可用于16SrDNA扩增及其他分子操作。     

一种快速有效提取植物和真菌DNA和RNA的简易方法

本文利用一种真菌核酸的快速提取方法提取了3种真菌的DNA和RNA,并将该法略作改进用于烟草DNA和RNA的提取.同时,通过低温保藏试验评价核酸提取液和提取产物的稳定性和有效性;利用凝胶电泳、PCR和RT-PCR等方法比较分析核酸质量;并将提取效果与传统方法或试剂盒的提取效果进行比较,以分析其有效性.结果表明,改进后的提取方法是一种简单、方便和有效的实验方法,不仅可用于真菌也可用于植物DNA和RNA提取,用这种方法提取得到的DNA和RNA在低温保存条件下比较稳定,能较长时间保持其原有活性.     

Integrated Approach for Polycyclic Aromatic Hydrocarbon Solubilization from the Soil Matrix to Enhance Bioremediation

Polycyclic aromatic hydrocarbons (PAHs) are known to be toxic to living organisms and have been identified as carcinogenic. In this study, a pathway of surfactant flushing, chemical oxidation, and biological treatment is proposed to remediate the soils polluted with the hydrophobic PAHs. Different surfactants such as Tween 80, Brij 35, sodium dodecyl sulfate (SDS), and polyethylene glycol (PEG) 6000 were tested in order to increase the PAH solubilization from the soil matrix. The maximum desorption efficiency of naphthalene and anthracene were found to be 56.5% and 59%, respectively, when Brij and SDS were used. The soluble PAH in the aqueous phase was amended with sodium thiosulfate (3%) to oxidize the PAH into a more bioavailable form. The chemical oxidation with subsequent biodegradation by Pseudomonas aeruginosa exhibited the relatively high PAH degradation rate (1.24 times higher) when compared with chemical oxidation alone. These results display the efficiency of chemical pretreatment of PAH-contaminated soil for improved bioremediation.     

Microwave-Assisted Process (MAPTM) for the Extraction of Contaminants from Soil

Laboratory-scale tests were performed to evaluate the use of Environment Canada's patented Microwave-Assisted Process (MAP_TM) for the extraction of petroleum hydrocarbons from contaminated soil. The purpose of these tests was to determine the potential for using the process for large-scale processing of contaminated soil. Tests were performed using three soil types: a certified sediment and certified soil, both contaminated with polycyclic aromatic hydrocarbons (PAHs), and spiked peat soil contaminated with long-chain petroleum hydrocarbons. The test methods used were based on existing MAP techniques that have been proven for the sample preparation of contaminated soils for analytical purposes. The parameters evaluated concentrated on those that are amenable to a continuous large-scale process running at atmospheric pressures. This meant using solvents that are inexpensive and readily available in large volumes, low solvent to material ratios, and optimized energy inputs. In general, it was found that microwaves could be used to enhance the solvent extraction of the contaminants from the soil and that the properties of the soil greatly affected the extent to which the contaminants were removed.     

Influence of Soil Organic Matter on Copper Extraction from Contaminated Soil

Column experiments of copper extraction from four contaminated soils characterized by a content of Soil Organic Matter (SOM) ranging from 1% to 25% are presented and discussed. The extraction was performed by flushing the soil with an aqueous solution of a sodium salt of ethylene diamminotetraacetic acid (EDTA). Preliminary tests were performed on a soil containing 25% of organic matter, to investigate the influence of pH, concentration and volumes of EDTA on its chelant action and on the dissolution of SOM. Having selected the optimal conditions for the extraction process, a further series of tests was conducted on the four soils to evaluate the influence of organic content on copper extraction yields. EDTA solutions at 0.01 M, 0.05 M, 0.1 and 0.2 M were injected at 0.33 ml/s; copper and organic matter extraction yield were determined. At a pH of 5, 15 pore volume (PV) of a solution containing 0.05M EDTA, extracted about 99% of copper contained by the soil with the higher organic matter content. Under the same conditions, and for soil with > 6% SOM, extraction yields over 80% were achieved, while at lower organic content, copper extraction was dramatically reduced. This was attributed to the formation of highly stable copper-humate complexes and to their increasingly dissolution that occurred in the soils with higher organic matter level.

Experimental tests performed at different contamination levels (1200 mg/kg, 2400 mg/kg) showed that EDTA extraction effectiveness also depended upon initial soil Cu concentration.