乙草胺、甲胺磷及组合对农田黑土细菌种群生长及多样性的毒性效应

应用传统及分子微生物生态学16S rDNA-PCR DGGE(Denaturing Gradient Gel Electrophoresis)等研究方法,分别对不同浓度乙草胺、甲胺磷及其乙草胺-甲胺磷二元组合胁迫下黑土中细菌活细胞数量(CFU Colony Forming Units)、种群丰富度(Richness)及其结构变化规律进行了研究.结果表明:单因子乙草胺及甲胺磷对细菌CFU产生急性毒性效应,但是长期毒性效应不显著;高浓度乙草胺-甲胺磷的二元组合对细菌CFU产生复合毒性效应,其对细菌CFU的复合抑制率明显高于相应组合中各单因子.乙草胺对可培养自生固氮菌表现出强烈刺激的作用,甲胺磷表现为严重抑制作用;而所有乙草胺-甲胺磷二元组合却对自生固氮菌CFU表现为复合毒性效应,其复合毒性明显高于相应组合中各单因子对自生固氮菌的毒性效应.应用16S rDNA-PCR DGGE技术研究结果显示:乙草胺、甲胺磷及乙草胺-甲胺磷组合不同程度地降低了黑土中细菌种群在分子水平上的丰富度,并使其种群组成和结构均发生了显著变化.     

Toxic effects of acetochlor and methamidophos on earthworm Eisenia fetida in phaiozem, northeast China

Introduction W ith the increase in types and am ount of pollutants releasing into soil ecosystem s, research on the joint effects of m ore than one pollutant in soil-plant, soil-anim al and soil-m icroorganism system s is increasingly concerned (Zhou and …     

乙草胺、铜污染共存对土壤甲胺磷蚯蚓降解过程的影响研究

为揭示利用蚯蚓活动强化甲胺磷降解的可行性,采用了微宇宙培养方法,通过有蚯蚓和无蚯蚓的对比实验,考察了乙草胺和铜分别与甲胺磷共存条件下污染黑土中甲胺磷降解过程的动态变化.结果表明,无论是否加入蚯蚓,甲胺磷单一污染的土壤中甲胺磷的降解符合一级反应动力学规律;蚯蚓活动能促进甲胺磷降解过程的进行.土壤中乙草胺或铜与甲胺磷共存时,均明显地干扰了甲胺磷降解过程随时间的动态变化;根据化学结构分析,推测两者对甲胺磷降解规律的影响机制可能类似.铜与甲胺磷复合污染的土壤中甲胺磷含量明显高于乙草胺与甲胺磷复合组,说明铜较乙草胺对土壤甲胺磷降解过程的延缓作用更强.     

乙草胺与硫酸铜对黑土微生物的复合生态影响

为了探究2种不同类型农药联合施用对土壤微生物的复合生态影响,以除草剂乙草胺和杀菌剂硫酸铜为例,采用传统毒理学方法和BIOLOG法对其进行评价.结果表明,乙草胺和硫酸铜的联合施用对细菌、放线菌和真菌活菌量以及土壤脱氢酶活性基本呈现急性抑制效应,但随时间延长其作用逐渐减弱甚至发生逆转,而对土壤底物诱导呼吸强度表现为明显促进.利用Shannon、Simpson和McIntosh多样性指数模型和主成分分析法对BIOLOG数据进行分析,表明2种农药的联合施用显著破坏了黑土微生物群落物种多样性的丰富度和均一性,主成分分析法也表明土壤微生物群落碳源利用多样性发生了改变.     

Effect of methamidophos on soil fungi community in microcosms by plate count, DGGE and clone library analysis

Methamidophos was widely used a pesticide in northern China. The potential influences of methamidophos on soil fungal community in black soil were assessed by plate count, 28S rDNA-PCR-DGGE, and clone library analysis. Three methamidophos levels (50, 150, and 250 mg/kg) were tested in soil microcosms. Results from plate count during a 60-d microcosm experiment showed that high concentrations of methamidophos (250 mg/kg) could significantly stimulate fungal populations. DCGE (denaturing gradient gel electrophoresis) fingerprinting patterns showed a significant difference between the responses of culturable and total fungi communities under the stress of methamidophos. Shannon diversity indices calculated from DGGE profiles indicated that culturable fungi in all microcosms with methamidophos treatment increased after 1 week of incubation. However, the diversity indices of total fungi decreased in the first week, as compared to the stimulation of culturable fungi. At the 8th week, however, all the microcosms treated by methamidophos were similar to the control microcosms in community structure as suggested by the Shannon diversity indices for both culturable and total fungi. In contrast, after 1 week the fungal structure of culturable and unculturable both were disturbed to different extent under the stresses of methamidophos by clustering analysis. Clone sequencing analysis indicated the stimulation of pathogenic and unculturable fungal populations by methamidophos treatment, suggetsing potential risks of plant disease outbreak.     

Single and joint stress of acetochlor and Pb on three agricultural crops in northeast China

In order to evaluate ecological risk of agrochemicals in agricultural environment, single and joint toxic effects of an important herbicide and a typical heavy metal on root elongation of crops were investigated. Seeds of the three crops including wheat （Triticum aestivum）, Chinese cabbage （Brassica pekimensis） and soybean （Glycine max） as the main crops in northeast China were exposed to acetochior as a herbicide and lead （Pb） as a heavy metal using the pot-culture method, and meadow brown soil as one of the main soils distributed in northeast China was applied in the investigation. The results indicated that the interactive effects of the two pollutants on root elongation of the three crops were very complicated although they had markedly significant （P〈0.01） linear interrelationships based on the regression analyses. When the concentration of added Pb^2＋ reached 200 mg/kg, acetochlor and Pb had an antagonistic effect on the inhibition of root elongation of the three crops. However, acetochlor and Pb had significantly （P〈0.05） synergic effects on the inhibition of root elongation when concentration of added Pb^2＋ was up to 1000 mg/kg. At the low concentration of added Pb, joint toxicity of acetochlor and Pb was more dependent on the concentration of Pb. Among the three crops, wheat was the most sensitive to the toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.     

Diversity of free-living nitrogen-fixing microorganisms in wastelands of copper mine tailings during the process of natural ecological restoration

Biological nitrogen fixing is an important source of nitrogen input in the natural ecological restoration of mine wastelands. The diversity of nifH genes in tailings samples under di erent plant communities in Yangshanchong and Tongguanshan wastelands in Tongling, was analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach. The nitrogen-fixing microorganism community in the upper layer of tailings of Tongguanshan wasteland discarded in 1980 showed higher Shannon-Wiener diversity index than that in Yangshanchong wasteland discarded in 1991. The diversity of nifH genes in Yangshanchong wasteland of copper mine tailings did not display a consistent successional tendency with development of plant communities during the process of natural ecological restoration. Phylogenetic analysis of 25 sequences of nifH gene fragments retrieved from the DGGE gels indicated that there were mainly two taxa of free-living nitrogen-fixing microorganisms, Proteobacteria and Cyanobacteria living in the wastelands investigated, most of which were unique and uncultured. Canonical correspondence analysis (CCA) based on the relationship between band patterns of DGGE profile and physico-chemical properties of tailings samples showed that the diversity of nifH genes in di erent tailing samples was mainly a ected by loss of ignition, water content, pH and available Zn contents of wastelands. The dominant plant species and development period of plant communities by ameliorating pH, reducing the toxicity of heavy metals, increasing organic matter and water content a ected the diversity and structure of the free-living nitrogenfixing microorganisms in wastelands of copper mine tailings.     

Impact of acetochlor on ammonia-oxidizing bacteria in microcosm soils

Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised ...     

甲胺磷、乙草胺和铜单一与复合污染对黑土环境安全的胁迫研究

以黑土为环境介质,通过急性毒性试验法研究了东北黑土区普遍存在的2种农用化学品甲胺磷和乙草胺与重金属Cu对赤子爱胜蚓(Eiseniafoetida)的单一与复合毒性效应.单一毒性试验结果表明,3者对蚯蚓均有毒性,顺序为甲胺磷>乙草胺>Cu.复合毒性实验结果表明,2种有机农药与重金属Cu复合毒性效应十分复杂,与不同的浓度组合及染毒历时有关,一般随时间的延长,毒性加剧.2种有机农药通过不同途径毒害蚯蚓,复合毒性效应表现为协同作用.可见,3者对土壤生态系统环境安全性和土壤健康质量存在潜在危害,同时这几种污染物的共存进一步加大了潜在危害性,且复合毒性效应与各组浓度组合及污染暴露时间密切相关.     

乙草胺铜离子复合污染对黑土农田生态系统中土著细菌群落的影响

采用传统毒性评价手段和现代分子生物学技术相结合的方法 ,研究乙草胺和金属铜的复合污染对黑土农田生态系统中土著细菌群落的影响 .结果表明 ,乙草胺 铜复合污染比其单一污染更能降低细菌总数以及固氮菌、硅酸盐细菌和矿化磷细菌活菌量和土壤脱氢酶的活性 ,更能促进土壤呼吸强度的增加 ;利用以 16SrDNA为基础的变性梯度凝胶电泳 (DGGE)分析各处理样品间的相似程度 ,发现复合污染明显影响微生物群落结构 .由相似系数结果表明 :长期未施农药土壤、农药单一与复合污染土壤 3者间存在细菌群落的显著差异 ,并且乙草胺 Cu2 复合污染土壤与长期施用农药土壤具有较高相似性 (相似系数达 74 1% ) .     

乙草胺降解菌A-3的筛选及其降解特性

采用富集培养的方法从农药厂污泥和长期受乙草胺污染的土壤中分离到1株能以乙草胺为氮源生长的细菌命名为A-3,经16S rRNA鉴定,菌株A-3属于粘着剑菌属(Ensifer adhaerens).研究结果表明,菌株A-3能以乙草胺作为唯一氮源生长并高效降解乙草胺.在含10 mg/L乙草胺的无机盐培养基中培养10 d后,菌...     

我国重点城市水源及水厂出水中乙草胺的残留水平

利用固相萃取-气质联用法调查了我国36个重点城市145个水源水和209个出厂水中乙草胺的残留水平.水源水中乙草胺的检出率为66.9%,平均浓度为33.9 ng·L-1,水厂处理对乙草胺的去除效果有限.按不同区域划分,东北地区的检出浓度最高;按水源类型划分,湖库水中浓度远高于河流水和地下水;按水系划分,辽河水系和沿海地区的检出率和检出浓度最高.     

Vertical diversity of sediment bacterial communities in two different trophic states of the eutrophic Lake Taihu, China

Vertical diversity of sediment bacterial communities in 2 different trophic states (macrophyte-dominated and algae-dominated) of the large shallow eutrophic Lake Taihu, China, were investigated using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA sequence analysis. Clustering analysis of DGGE profiles showed that different clusters were recognized in different depths of sediment cores in the 2 lake trophic states. Analyses of the bacterial diversity, as estimated by the Shannon index (H'), showed that different sediment layers of the macrophyte-dominated state had higher diversity than the algae-dominated state. In addition, bacterial diversity of the sediment in the macrophyte-dominated state changed abruptly throughout the layers, but bacterial diversity of the algae-dominated state decreased gradually with sediment depth. Phylogenetic analysis showed that Proteobacteria was the most abundant phylum in the middle sediment of the 2 lake trophic states. In the macrophyte-dominated state, clone sequences related to Betaproteobacteria (50.0%) were the most abundant, followed by Epsilonproteobacteria (21.1%), Acidobacteria (7.9%), Deltaproteobacteria (7.9%), Chloroflexi (7.9%), and Bacteroidetes (5.3%); whereas in the algae-dominated state, sequences affiliated with Betaproteobacteria (84.4%) were predominant, followed by Deltaproteobacteria (12.5%) and Acidobacteria (3.1%). Canonical correspondence analysis showed that organic matter and pH play key roles in driving the vertical changes of bacterial community composition.     

Rhodococcus sp. T3-1菌株降解乙草胺的特性

以乙草胺为唯一碳源,通过摇瓶培养研究了Rhodococcus sp.T3-1对乙草胺的降解特性.结果表明,菌株T3-1降解乙草胺的最适温度为37℃,且其在pH值6~10的范围内对100mg/L乙草胺的降解率均在96%~97%之间.该菌株在接种量为5%条件下,14h内可将200mg/L的乙草胺降解95.5%;乙草胺的降解速率与乙草胺初始浓度呈负相关,与菌株T3-1的初始接种量呈正相关.菌株T3-1还可以降解丁草胺,但不能降解丙草胺、异丙草胺和吡草胺.     

Adsorption-desorption behavior of acetochlor to soils in the presence of some environmental substances

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太湖冬季军团菌（Legionella spp．）的分布和多样性

军团菌（Legionellas pp．）广泛存在于各种水体中,对人类的健康造成了一定的安全隐患．为了解太湖在冬季是否存在军团菌,以及它的分布和多样性,本研究于2010年2月,在全太湖32个点位采样,使用巢式PCR对样品中军团菌进行检测,并用变性梯度凝胶电泳（denaturing gradient gel eletrop...     

应用PCR-DGGE技术分析黄海冷水团海域的细菌群落组成

利用PCR-DGGE技术对2个季节(2006-04和2006-10)的黄海冷水团海域的细菌群落组成和优势菌群进行了分析.通过软件Glyko Bandscan分析DGGE图谱,4月份所有站位的条带数相近(约17条),多样性丰富;10月份,在冷水团范围以内站位的条带约16条,其多样性也较丰富;而在冷水团范围以外站位的条带少(约12条),其多样性较低.细菌16S rDNAV3区特征片段经DGGE分离、条带切割,共得到24条条带,克隆、测序后,进行系统进化分析,结果显示这24条带分别归属于2个细菌类群:变形细菌门(Proteobacteria)和拟杆菌门(Bacteroides).在24条序列中有16条分别与变形细菌亚群的γ和δ-Proteobacteria相似,有5条与拟杆菌门相似.时空分析发现,4月份所有站位水体(海水温度为7-12℃)的细菌群落组成和10月份(冷水团存在期)冷水团内部水体(海水温度低于10℃)的细菌群落组成相同(都包括γ-Proteobacteria、δ-Proteobacteria和Bacteroides),与10月份冷水团外部水体(海水温度大于19℃)的(包括γ-Proteobacteria和Bacteroides)不同.优势菌群也存在同样的分布特点,4月份所有站位水体的优势菌群与10月份冷水团内部水体的优势菌群也相同(都是γ-Proteobacteria),而10月份冷水团外部水体不同的站位优势菌群不同.该海域细菌群落组成和优势菌群的分布特点,可能与冷水团的形成有一定的相关性.     

镉和乙草胺复合污染对玉米生理特性的影响

采用盆栽试验,研究了镉与乙草胺复合污染对玉米幼苗MDA含量和抗氧化酶活性的影响。结果表明,镉单独处理,低浓度下MDA的含量变化不大,当镉浓度大于30 mg/kg时,MDA的含量急剧上升;超氧化物歧化酶SOD、CAT在浓度为30 mg/kg时活性达到最高,之后随浓度的增大,其活性逐渐降低;POD的活性随着镉浓度的增大逐渐升高,且100 mg/kg时达到最高。镉与乙草胺复合处理,低镉浓度下MDA的含量与对照组CK相比差异显著,处理浓度越大,MDA含量越高;SOD、CAT的活性变化趋势与单镉处理时相类似,但变化幅度更加明显;POD的活性则随着浓度的增大继续升高。镉与乙草胺复合处理对玉米幼苗的毒害程度要大于单镉处理,并且施加乙草胺的浓度越大,玉米受毒害程度越深。     

超声波促进好氧/缺氧污泥消化过程中细菌群落结构分析

应用基于16S rDNA的PCR-DGGE对超声波-好氧/缺氧污泥消化过程中微生物种群的多样性进行研究.通过SDS细胞裂解法提取不同时期污泥中的基因组DNA,采用通用引物进行V3区域PCR扩增,长约190 bp的PCR产物经DGGE分离后,获得污泥微生物群落的DNA特征指纹图谱,对条带进行切胶测序,使用序列数据进行同源性分析并建立系统发育树.DGGE图谱表明,在反应器运行的不同时期,微生物群落结构发生动态演替.5、10、15、20、25 d微生物相似性与0 d相比分别为61.2%、48.2%、46.4%、42.6%、41.7%,总细菌Shannon指数经历了一个从逐渐减少到趋于稳定的过程,这表明超声波改变污泥内部性质,导致微生物多样性的降低.UPGMA聚类分析将DGGE图谱区分为三大族群并对应于不同运行时期.测序结果表明,超声波-好氧/缺氧污泥消化中微生物群落主要为Firmicute、Genuscitrobacter、Bacilli、α-Proteobacteria、β-Proteobacteria.     

游离羟基及表面活性剂对乙草胺光解的影响

以高压汞灯为光源,以p-亚硝基-N,N-二甲基苯胺(PNDA)作为·OH自由基的探针,研究了H2O2及表面活性剂0206-B(苯乙烯苯酚聚氧乙烯醚和十二烷基苯磺酸钙混剂)对除草剂乙草胺在水中间接光解作用的影响.结果表明,H2O2对水中乙草胺具有光敏化降解作用,其敏化作用效应与·OH有关;而0206-B对乙草胺具有光猝灭降解作用,光猝灭降解作用效应与0206-B减少水溶液中的·OH自由基含量有关.乙草胺直接光解与H2O2作用的乙草胺间接光解相同的产物有Rf(比移值)为0.12、0.52、0.61、0.72的化合物;H2O2敏化降解抑制了乙草胺直接光解产物Rf为0.04、0.10、0.18、0.21、0.79的化合物产生,但促进乙草胺间接光解Rf为0.45、0.66的新光解产物生成.