Rapid amino acid cycling in arctic and antarctic soils

Amino acids constitute one of the largest inputs of organic nitrogen (N) to most polar soils and have been hypothesized to be important in regulating vegetational succession and productivity in Arctic ecosystems. Our understanding of amino acid cycling in these soils, however, is poor. The aim of this study was to investigate the size and rate of turnover of the amino acid pool in a range of Arctic and Antarctic soils. Our results indicate that in polar soils with either high or low ornithogenic inputs the amino acid pool is small in comparison to the inorganic N pool (NO^–₃ and NH⁺₄). The free amino acid pool constituted only a small proportion of the total dissolved organic nitrogen (DON) pool in these soils. Here we show that these low concentrations may be due to rapid use by the soil microbial community in both Arctic and Antarctic soils. The turnover of the amino acid pool in soil was extremely rapid, with a half-life ranging from 2 to 24 h, indicating that this N pool can be turned over many hundred times each summer when polar soils are frequently unfrozen. The implications of amino acids in N cycling and plant and microbial nutrition are discussed.     

Applying metabolic fingerprinting to ecology: The use of Fourier-transform infrared spectroscopy for the rapid screening of plant responses to N deposition

The potential for metabolic fingerprinting via Fourier-transform infrared (FT-IR) spectroscopy to provide a novel approach for the detection of plant biochemical responses to N deposition is examined. An example of spectral analysis using shoot samples taken from an open top chamber (OTC) experiment simulating wet ammonium deposition is given. Sample preparation involved oven drying and homogenisation via mill grinding. Slurries of a consistent dilution were then prepared prior to FT-IR analysis. Spectra from control, 8 and 16 kg N ha^–1 yr^–1 treatments were then subjected to cross-validated discriminant function analysis. Ordination diagrams showed clear separation between the three N treatments examined. The potential for using Calluna vulgaris (L.) Hull as a bioindicator of N deposition is further evident from these results. The results also clearly demonstrate the power of FT-IR in discriminating between subtle phenotypic alterations in overall plant biochemistry as affected by ammonium pollution.     

池州悬钩子的食用价值与茶多酚含量研究

研究了池州市悬钩子属植物的食用价值与其中茶多酚(TP)的含量,目的是为了综合利用悬钩子属植物,促进其全面开发,提高经济效益.用正交实验法确定了提取TP的最佳实验条件,用分光光度法测定其含量.从分析结果看,悬钩子属植物中含有一定量的TP.因此,在开发悬钩子属植物果实作为第三代水果资源时,从其茎叶中提取TP具有一定的经济价值,这对促进悬钩子资源的开发与利用是很有意义的.     

液固比对含重金属水泥熟料制品中重金属释放的影响

通过模拟煅烧试验制取水泥熟料,参照JGJ 55-2000（《普通混凝土配比设计规程》）制取混凝土样品,参考SR003.1和NEN 7375浸出试验,分别研究液固比对粒状及块状混凝土样品中重金属（Cr、Ni和As）释放的影响。结果表明,在不同液固比条件下粒状混凝土中的重金属浸出浓度为Cr>Ni>As,Cr、As浸出浓度基本保持不变,分别为2 500 μg/L左右和5～6 μg/L,Ni在液固比（L∶S）<6时,浸出浓度随着液固比的增加而降低,在L∶S>6时,浸出浓度较稳定,为35.7～41.5 μg/L;浸出量均随着液固比的增加而增大。液固比（L∶S）<10时,块状混凝土中重金属累积释放量及扩散系数均随液固比的增加而增大,当L∶S>10时两者基本保持不变。     

水中安替比林的紫外光降解研究

以波长为254 nm的紫外杀菌灯为光源,研究了水溶液中消炎镇痛药物安替比林（PZ）的光降解行为;考察了初始pH值及水中其他物质对PZ光降解的影响,探讨了PZ光解机制,并分析其降解产物及光解途径。结果表明,安替比林的光降解遵循拟一级反应动力学规律,pH值变化对光解速率基本没有影响。安替比林直接光降解占主导作用,活性氧类物种（ROS）对安替比林间接光解基本没有贡献。腐殖酸对安替比林光降解有抑制作用,而NO^-₃,HCO^-₃,Cl^-对安替比林光降解没有明显作用。GC-MS分析表明安替比林在紫外辐射下生成甲酰胺,乙酰胺,2-羟基吲哚-3-酮,2,4（1氢,3甲基）-喹唑啉二酮,1-甲基-2-羟基苯并咪唑,2-羟基苯并恶唑等一系列具有安替比林母体苯环结构的化合物,表明安替比林侧链上N—N键断裂导致其最终降解。     

外来生物入侵关键点控制管理体系——基于风险管理的研究

将风险管理理论与外来生物入侵风险分析相结合，借鉴食品质量控制中的关键点控制原理，提出了防止外来生物入侵风险的关键点控制方法。针对人类有意引种、随人类活动无意引入以及自然传入3类外来生物入侵的传入途径，在入侵途径上确定若干个风险控制关键点，有针对性地提出了相应的控制措施，以减小外来生物的入侵风险，提高我国在防止外来生物入侵方面的管理与控制效率。     

环境污染事故风险预测评估模式研究

从环境风险到环境污染事故演变的一般规律入手,提出了环境污染事故风险预测评估模式,为环境污染事故风险评估、预防与应急响应提供科学手段。环境污染事故风险预测评估模式的提出,一方面丰富和发展了环境安全与应急响应理论;另一方面,对公共安全、企业安全管理与应急响应等工作具有一定指导意义。     

电晕等离子体烟气脱硫脱硝机理及影响因素探讨

综述了国内外关于电晕等离子体烟气脱硫脱硝机理的研究成果,分析了电压、电极极性、气体温度、水蒸汽和氨气等对去除率的影响,并提出今后发展所需解决的问题.     

氯氰菊酯降解菌的筛选鉴定及其降解特性研究

从农药厂废水排放口附近的污泥中分离到1株能降解氯氰菊酯的细菌LQ-3.根据其形态、生理生化特征和16S rDNA(GenBank Accession No.FJ222585)序列分析,将该菌株鉴定为Starkeya sp..LQ-3菌株只能以共代谢方式降解氯氰菊酯,在有酵母粉、蛋白胨、葡萄糖等营养物质存在的条件下,5 d内对20 mg·L-1氯氰菊酯的降解率达到72.1%.LQ-3菌株降解氯氰菊酯的最适温度为30 ℃左右,pH值为7～8.LQ-3菌株还能降解功夫菊酯、甲氰菊酯、联苯菊酯和溴氰菊酯.酶的定域试验表明,LQ-3菌株降解氯氰菊酯的酶属于胞外酶.     

生物处理过程中活性污泥对氯代芳香化合物吸附性能的研究

本文研究了邻二氯苯 和邻氯酚生物处理过程中在活性污泥上的吸附特性及影响因素。通过测定等温吸附曲线,表明这两种有机化合物在活性污泥上的吸附符合线性吸附等温式：属于在疏水键力作用下的表面物理吸附,对难溶于水的邻二氯苯具有较强的吸附能力。