Carbofuran degradation mediated by three related plasmid systems

Two carbofuran-metabolizing Sphingomonas strains, TA and CD, were isolated from soils with differing histories of exposure to carbofuran. These strains were compared with a previously described strain, Sphingomonas sp. CFO6, with regard to growth rate, formation of metabolites, and plasmid content and structure. Extensive regions of similarity were observed between the three different plasmid systems as evidenced by cross hybridization. In addition, all three systems harbor IS1412, an insertion sequence (IS) element involved in heat-induced loss of carbofuran phenotype in CFO6, and heat-induced carbofuran deficient mutants of all three strains correlated with loss of IS1412. A carbofuran deficient mutant of TA generated by induction of IS elements was complemented by reintroduction of the wild-type plasmid, confirming the presence of genes required for carbofuran metabolism on this plasmid. Carbofuran metabolism in these three strains is clearly linked via plasmids of different numbers and sizes that share extensive common regions, and carbofuran-degrading genes may be associated with active IS elements.     

氰化物污染的植物修复可行性研究

氰化物是目前世界范围内最常使用的提取黄金和白银等贵重金属的沥滤剂,其对自然生态环境的污染和破坏以及对人畜和其它生物的毒性作用是众所周知的.本试验用一自行设计的生物反应器来观察黄豆(Glycine max(L)Merr.)和玉米(Zea mays L.)对氰化物污染土壤的原位修复的可能性.室温条件下(23.0～26.0℃),低浓度的氰化物污染液对(≤45.5 CN mg·L^-1)二种测试植物的生长没有产生任何毒性作用;而在高浓度的氰化物试验组(≥91.0 CNmg·L^-1),二种测试植物的生长都出现了明显的滞长现象(生长率下降大于10%),但没有观察到其它毒性反应.同时二种测试植物的叶片细胞用来测定植物细胞线粒体中的氰丙氨酸合成酶(β-cyanoalanine synthase)转化氰化物的潜力.实验是在一封闭的玻璃器皿(100mL)中进行的(100mL的氰化钾溶液中加入1.5g(鲜重)植物的叶片,氰化钾溶液的浓度大约1.0 CNmg·L^-1).在为期28 h的时间内,水溶液中超过90%的氰化物被植物的叶片去除;黄豆和玉米的的叶片细胞对氰化物去除率分别测定为4.43mg CN·kg^-1(鲜重)·h^-1和3.42mg CN·kg^-1(鲜重)·h^-1.本实验结果表明,植物对氰化物污染的土壤原位修复方法是一种可行的和有效的选择.     

Dissipation of phorate in different types of soils

Summary Studies on the dissipation of phorate in different types of soils of Kerala, India, were carried out. The residues of the insecticide persisted most in the forest soil followed by alluvial, red, laterite and sandy soils in the descending order. The half-life periods of the insecticide estimated by chemical and bioassay methods approximated to one another. Correlations of the persistence of the insecticide with the properties of the soil revealed that organic matter played a dominant role in prolonging the persistence of the insecticide in the soils.Part of Ph.D. thesis of Senior author presented to Kerala Agricultural University, Vellanikkara, Trichur District, Kerala State, India.     

《生物资源学》教材与课程建设初探

生物资源与水资源、土地资源、矿产资源、能源资源和气候资源等都是人类赖以生存与发展的最为重要的物质基础,其中生物资源主要包括生物遗传资源、生物质资源和生物信息资源三大类型。生物资源学是现代生命科学、资源科学和工程科学等相关领域交叉和衍生出的新兴学科,已在国内外部分高校作为新专业进行开设。《生物资源学导论》是在高等教育出版社和中国生物工程学会生物资源专委会的倡议与指导下完成的国内首部生物资源系列教材,在出版后的两年多时间内,已在国内部分高等院校的课程建设中得到使用。本文简要地综述了《生物资源学导论》教材的二次开发与利用和新形态教材的建设与应用,以及《生物资源学》课程建设的基本情况,以期为我国生物资源学学科教育事业的发展尽绵薄之力。     

有机污染环境植物修复技术

利用物理、化学方法修复有机污染环境,费用昂贵,而且还可能使当地的生态资源难以再利用,对于大面积污染土壤也难以实施。植物修复,利用植物吸收、降解以及根际圈降解的作用方式将有机污染物从环境中彻底去除,具有处理费用相对低廉、对环境扰动少和使资源可持续利用的特点,目前已成为环境科学领域的一大热点和前沿。本文对环境中主要有机污染物的发生机理、近年来植物修复有机污染的研究进展做一综述,并对有机污染植物修复的强化措施进行了展望。     

小黄鱼育幼期吕泗渔场的饵料浮游动物特征

根据2008年6月在吕泗渔场(31.90°N-32.10°N、121.70°E-121.95°E)海域生态环境调查资料,分析了该区饵料浮游动物种类分布、优势种、数量分布、多样性等特征。结果表明:该区共出现饵料浮游动物31种(不含浮游幼体和腔肠动物),种类数和丰度均以桡足类占据优势;该区总生物量均值为845.54mg.m-3,其中大潮时为895.58mg.m-3,分布趋势为北部高于南部,小潮时为795.49mg.m-3,分布趋势为中部较高;6月吕泗渔场饵料浮游动物优势种分别是真刺唇角水蚤(Labidocera euchaeta)、中华哲水蚤(Calanus sini-cus)、小拟哲水蚤(Paracalanus parvus)、太平洋纺锤水蚤(Acartia pacifica)、火腿许水蚤(Schmackeria poplesia)、长轴螺(Peraclis reticulata)、长额刺糠虾(Acanthomysis longirostris);大潮时真刺唇角水蚤和中华哲水蚤优势度最高均为0.19,小潮时真刺唇角水蚤优势度最高为0.40;在吕泗渔场,6月饵料浮游动物生物量较高,优势种数较多,反映出该渔场小黄鱼饵料环境的稳定性,为小黄鱼幼体生长提供了良好的饵料条件。     

土壤有机污染植物修复的机理与影响因素

在综述大量国内外文献的基础上,分析了土壤有机污染植物修复的机理,重点介绍了国内外在植物吸收转运、植物根际降解和植物修复模型的研究进展。同时,从污染物的物理化学性质、植物种类、土壤性质、共存有机物和气象条件5个方面分析了影响土壤有机污染植物修复的主要因素,并展望了该领域的研究方向：深化植物修复机理,完善植物修复模型。加强植物-微生物协同修复的机理研究和技术应用,利用表面活性剂提高植物修复效率,加强复合有机污染植物修复研究。     

短尾猴样品常见污染的检测方法

为检测在野外通过非损伤取样法采集到的短尾猴样品是否受到其它常见哺乳动物及人源的污染,收集包括短尾猴(Macaca thibetana)、人以及7种常见哺乳动物的毛发、血液、粪便、精液或肌肉组织样品,提取并纯化基因组DNA,利用14对微卫星引物扩增不同物种的STR位点,以确定其在短尾猴样品检测中的应用价值。扩增结果表明,TH01等13对引物在人和短尾猴中均能扩增且扩增产物长度未见明显差异,F13A01产物长度在人和短尾猴之间相差240bp碱基,只有FGA位点在常见动物猪、羊、牛、狗、兔、小白鼠及豚鼠都未见扩增产物;因此,FGA、F13A01座位较高的分辨能力,可以排除短尾猴样品是否受到人及常见哺乳动物的污染,通过特异性STR引物结合PCR方法,检测短尾猴野外非损伤取样获得的样品是否受到哺乳动物及人源DNA污染,此方法简单、稳定性高、可重复性好,在短尾猴的遗传多样性分析及亲缘关系鉴定中有较大的应价值。     

A simple method for calculating decomposition and accumulation of ‘young’ soil organic matter

Summary In previous simple models describing decomposition of organic matter, the rate of decomposition was usually assumed to be constant. Experimental evidence has shown this is not true. The objective of this study was therefore to find a relationship between decomposition rate and time. This resulted in an equation (Eqn 5), that can be used for many types of organic materials, provided their apparent initial age is known. This age is related to the humification coefficient and varies from 1 year for green matter to 14 years for some peats. Formulas to calculate accumulation and decomposition of young soil organic matter were also derived.It was demonstrated that apparent differences in soil organic matter quality, found after 25 years of different fertilizing practices, were related to the proportion of young soil organic matter.     

Silicate weathering in temperate forest soils: insights from a field experiment

Few studies of silicate mineral weathering have been conducted in carbonate-bearing temperate forest soils. With climate and vegetation held constant, we compared soil mineralogy and major element chemistry of soil waters from a carbonate-free temperate aspen forest site in the Cheboygan watershed, northern Michigan, with that from carbonate-containing soils from experimental tree-growth chambers (low- vs. high- fertility). All soils were well-drained sands (quartz, Na-rich plagioclase, and K-feldspar) with minor amounts of carbonate present only in the experimentally manipulated soils. The Na⁺ concentrations in soil waters corrected for atmospheric deposition (Na*) were used to compare relative rates of plagioclase feldspar weathering across sites. In natural soil water profiles, maximum concentrations of Na*, Si, and dissolved organic carbon (DOC) were observed by a depth of 15 cm, a soil zone free of carbonate minerals. Mean Na* and DOC concentrations were different in the three soils, and increased in the order natural soil < low-fertility chambers < high-fertility chambers. While low pH environments are generally viewed as enhancing weathering rates, here higher Na* appears to be related to high DOC, which is consistent with observed increases in active organic functional groups as pH increases. Our results suggest that under a specific vegetative cover, the soil carbon environment affects the weathering flux observed. Our study also suggests that disturbed soils provide an enhanced physical and chemical environment for weathering. Generalized silicate weathering models may benefit from including the enhancing effects of organic anions at moderate pH in addition to precipitation and temperature.     

Electrophoretic subfractionation of low and high molecular weight humic acids fractions

Summary Soil humic acid was fractionated on a molecular weight basis either using Sephadex gel filtration or electrophoresis on a discontinuous polyacrylamide gel. Low and high molecular weight fractions obtained by these two methods were choosen for subsequent subfractionation using electrophoretic methods. The high and low molecular weight fractions yielded several subfractions after separation by isotachophoresis or isoelectric focusing. Components of the high molecular weight fractions occupied the upper portion of the mobility train; components of the low molecular weight fractions lead the mobility train. Adsorption by Sephadex was avoided by using 4M urea as an eluent. The elution of the humic substances adsorbed to the polyacrylamide gel matrix was achieved by using a 0.1M Tris –0.025M EDTA solution.     

集约高产农业生态系统有机物分解及土壤呼吸动态研究

以河北省吴桥县龙王河中心试区内的集约农业生态系统为例 ,借用生态学的方法 ,用网袋法测定了集约高产田 ( HYF)和中产田 ( MYF)小麦秸秆、小麦根、玉米秸秆和玉米根等 4种有机物的分解动态 ;用隔离罐 -碱液吸收法测定了土壤的呼吸动态 ;并以此推算了 2种农田土壤 C的矿化率和平衡系数 .结果表明 ,集约高产田的有机物分解与中产田没有明显区别 ,土壤呼吸量分别为 1 878.5和 1 72 5.7g CO2 ·m- 2 · a- 1.土壤 C的矿化率分别为 5.64%和 5.48% ,平衡系数分别为 1 .84和 1 .86,表明集约高产并没有降低土壤 C的正平衡     

短尾猴样品中常见哺乳动物及人源污染的特异性研究

为检测在野外通过非损伤取样法采集到的短尾猴样品,是否受到其它常见哺乳动物及人源的污染,收集包括短尾猴(Macaca thibetana)、人以及7种常见哺乳动物的毛发、血液、粪便、精液或肌肉组织样品,用14对微卫星引物扩增不同物种的STR位点。结果表明,FGA位点在常见动物猪、羊、牛、狗、兔、小白鼠及豚鼠都未见扩增产物:TH01等14对引物在人和短尾猴中均能扩增,扩增产物长度未见明显差异;F13A01产物长度在人和短尾猴之间差异显著。因此,通过FGA、F13A01特异性座位的扩增可以排除短尾猴样品是否受到人及常见哺乳动物的污染。此方法简单、稳定性高、可重复性好,在短尾猴的分子遗传学研究中有较大的应用价值。     

Effect of temperature and time of storage of dry soil samples on a chemical index of N availability

Summary The effect was studied of storage temperature on the index of available soil N wich uses U.V. absorbance of a 0.01M NaHCO₃ extract as an indicator. The U.V. absorbance was found to increase at a non-linear rate for four soils stored at temperatures of 50, 75, and 150°C. The change in extract absorbance due to extended soil storage at each of these temperatures was positively correlated to the percent organic matter, percent N, C/N value and concentration of humic substances in soils, but not to the extract absorbance prior to soil storage. These findings were not consistent with room temperature storage data which showed a linear increase in extract absorbance with soil storage time. The change in absorbance for the room temperature case was not related to any of the soil parameters mentioned above. Analysis of a soil stored at 105°C showed an increase in ninhydrin-detectable N, protein N and Kjeldahl N of the NaHCO₃ extract, while the apparent molecular weight distribution of extracted organic matter (as determined by gel filtration) showed only a slight change. As a comparison to the NaHCO₃ extract, a boiling CaCl₂ extract of the same soil was also analyzed; and the absorbance at 260 nm was found to increase in a curvilinear fashion with starage time at 75°C but to less of an extent than was noted with the NaHCO₃ extract. Nitrogen availability indexes based on the U.V. absorbance of these extracts, particularly those utilizing the NaHCO₃ extract, would be significantly affected by soil storage at elevated temperatures.Paper No. 6176 of the J. Ser. of the Pennsylvania Agric. Exp. Stn. Authorized for publication January 26, 1981.     

Nitrogen supply from some soil types with various organic-matter treatments

Summary An evaluation of the N release by soil organic matter can be obtained by measurements of the course of soil mineral nitrogen on uncropped objects. This N mineralization was studied during several years on some soil types with incorporations of various organic matter. The real N mineralization on a given soil with similar inputs of organic matter varied little from year to year. On the other hand, the net result of NO ₃ ^– -N increase between spring and autumn showed wider variation, especially due to N losses.