不同定植年限核桃园土壤细菌群落多样性及碳代谢功能特征

为了解核桃园土壤细菌群落随定植年限的变化规律,采用高通量测序技术与Biolog ECO微平板相结合的方法,测定定植1～3、5、8～10、15和20～25年核桃园表层(0～20 cm)和亚表层(20～40 cm)土壤细菌群落多样性和碳代谢功能多样性,并与土壤理化性质进行相关性分析.高通量测序表明,核桃园土壤细菌群落存在明...     

土壤细菌类克隆群落及其结构的生态学特征

以16SrDNA分析方法为基础,获得来自不同土壤环境的细菌克隆群落（Cloning community),并分析了这些土壤细菌群落结构特征,在不同土壤环境中,细菌种类非常丰富,但其多样性将受到植被,土壤水分或土壤层次等因子的影响,表层土壤环境中细菌种类最丰富,多样性最高,且基因型中无明显的优势类群,不同土壤环境间细菌群落的相似性好低,表明群落结构以及空间隔离的复杂性。     

兰州市空气微生物群落的碳代谢特征及功能多样性研究

应用Biolog ECO技术和RDA分析研究了兰州市不同功能区,即风景区(Scenic Area,SA)、交通干线(Main Traffic Line,MTL)、公共服务区(Public Service Area,PSA)、文教区(Culture and Education Area,CEA)空气微生物群落代谢功能多样性及其与环境因子的相关性。结果表明,不同功能区的AWCD值在培养192 h后进入稳定期,对碳源总体利用能力呈现显著的区域性差异,SAPSACEA≈MTL。受环境因素影响,Mc Intosh指数差异明显,SA和PSA物种均一度较高。兰州市空气微生物相对利用率较高的碳源类型是酯类、氨基酸类及醇类,与主成分1显著相关的碳源有10种,其中氨基酸类是导致兰州市空气微生物群落代谢功能区域性差异的主要分异类型。环境因子与空气微生物群落代谢功能密切相关,温度、风速是不同功能区存在差异的主导因子。     

基于梯度稀释法分析细菌多样性对土壤碳代谢的影响

为探究土壤微生物多样性对土壤碳代谢过程的影响,利用梯度稀释法(处理D1、D3和D5分别为稀释10^-1、10^-3和10^-5倍)改变土壤样品中原始土壤微生物群落的多样性,以探究土壤微生物群落多样性减少对土壤碳代谢的影响。进行为期6周的预培养实验,以消除梯度稀释法对土壤样品中微生物群落丰度的影响,并通过Q-PCR和高通量测序测定预培养结束后3种土壤样品中细菌丰度及其基因多样性指数(ACE、Chao1、Shannon),以验证预培养实验结果。后加入等量葡萄糖(0.5g/100g干土)继续培养,并于培养期间测定3种处理土壤的碳矿化速率,进行biolog ECO板实验,分析计算各土壤样品中细菌的功能多样性指数(Shannon指数(H)、Simpson指数(D)、McIntosh指数(U))及碳源代谢强度。结果表明:(1)3种处理土壤样品碳矿化速率及累积碳矿化量大小排序为:D1> D3> D5,且D1与D3、D5处理均有显著差异(P<0.05)。(2)D1处理下土壤样品中微生物群落的孔平均颜色变化率(AWCD)、功能...     

外源纤维素诱导明显影响微生物土壤结皮细菌群落结构

【目的】微生物土壤结皮(Microbial soil crusts, MSCs)对于遏制土壤荒漠化、恢复荒漠地区生态环境起着重要作用。MSCs中的微生物, 特别是纤维素降解菌, 起着稳固、修复生态环境的功能。外源纤维素诱导是全面认识MSCs中纤维素降解细菌的多样性及其在MSCs形成和发展中的作用的重要途径。【方法】通过对微生物土壤结皮分别添加小麦秸杆(麦秸)、锯末木屑两类纤维素材料进行诱导, 以PCR-DGGE方法分析细菌群落变化。【结果】外源纤维素, 特别是麦秸的添加会迅速提高MSCs中细菌丰富度及多样性, 将细菌丰富度提高约66.7%, Shannon-Weiner指数提高约15.8%; 相同处理的样品聚类位置较近, 说明纤维素对于MSCs细菌菌群变化起主导作用; 细菌群落结构组成在添加纤维素诱导后发生了变化, 麦秸诱导样品与同时期对照样品差异最大, 但各样品中Firmieutes和Alphaproteobacteria始终为优势类群; 所得DGGE条带序列中有13条与纤维素降解菌序列同源性相近, 他们所代表的细菌很可能具有纤维素降解能力, 其中厌氧性的梭菌属(Clostridium)所占比例最大, 约为46.1%, 其次为芽孢杆菌属(Bacillus), 约占30%; 纤维素降解过程中, 诱导增加了MSCs发育有重要作用的一些类群如Microcoleus vaginatus和一些Alphaproteobacteria类群细菌等的丰度和多样性, 它们中有的可通过分泌多糖物质等增强土壤颗粒黏结、有的可以其固碳或固氮等能力提高土壤营养水平。【结论】为认识外源纤维素诱导MSCs细菌群落结构的变化规律, MSCs中纤维素降解细菌的多样性及纤维素降解细菌对MSCs形成和发展的作用提供了基础, 同时也为恢复荒漠生态系统实践方法提供了理论依据。     

人工和天然湿地芦苇根际土壤细菌群落结构多样性的比较

为认识人工湿地运行初期根际土壤细菌群落的结构多样性,本研究采用聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）的方法,比较了嘉兴石臼漾人工构筑生态湿地和白洋淀天然湿地府河河口区域芦苇根际土壤的细菌群落结构多样性。研究结果显示,嘉兴石臼漾湿地在运行初期（1~1.5年）,根际土壤细菌的物种丰富度已与白洋淀湿地相近,但香农指数和均匀度指数均显著低于白洋淀湿地;随着污染物浓度的降低,土壤细菌群落基因型多样性指数增大。     

滴灌对苜蓿根际土壤细菌多样性和群落结构的影响

【背景】细菌作为土壤微生物中的重要类群,能够有效促进土壤物质循环和能量流动,细菌多样性以及群落结构能够反映土壤的质量状况。【目的】了解滴灌条件下苜蓿根际土壤细菌群落结构及多样性变化,探讨土壤环境因子对细菌群落结构的影响。【方法】基于细菌16Sr RNAV3-V4区高通量测序技术,分析比较滴灌与自然降雨两种模式下生长的苜蓿根际与非根际土壤中细菌多样性和群落分布规律,然后采用冗余分析(Redundancy analysis,RDA)探讨土壤环境因子与细菌多样性的关系。【结果】苜蓿根际土壤中细菌多样性丰富,滴灌根际土壤中细菌多样性显著高于自然降雨根际土壤;土壤样品中共检测到细菌46门53纲116目220科469属,主要的优势菌门为变形菌门(Proteobacteria,25.27%-34.42%),其中α-变形菌纲(Alphaproteobacteria,11.41%-18.97%)为优势亚群,鞘氨醇单胞菌属(Sphingomonas,1.00%-4.54%)为优势属。相较于自然降雨,滴灌条件下苜蓿根际土壤细菌的6个门和16个属的群落结构发生显著变化;此外,RDA分析表明,不同环境因子对微生物群落的影响不同,滴灌根际土壤中9个细菌属的丰度与全磷、全钾、有效磷、碱解氮、有机质、土壤中性磷酸酶以及土壤脲酶的含量显著正相关。【结论】滴灌作为新型节水技术,在促进植物生长、提高产量、节约成本的基础上增加了植物根际土壤中细菌多样性和丰度,该结果为新型灌溉体制的改革以及土壤微生物资源的开发利用提供科学数据。     

转基因水稻对土壤微生物群落结构及功能的影响

以非转基因水稻为对照,以变性梯度凝胶电泳(DGGE)和Biolog技术为手段,研究了2种转基因水稻对土壤微生物群落结构及功能的影响。结果显示:转基因水稻仅在生长发育旺盛期对土壤细菌数量有显著影响;且不同品种转基因水稻土壤微生物间的遗传距离大于转基因水稻与对照间土壤微生物的距离,即2个转基因水稻品种对土壤微生物群落遗传多样性的影响均不显著;在水稻抽穗期,2种转基因水稻与其对照的土壤微生物群落在72h时的平均光密度呈现显著差异,而到了成熟期则差异不显著。土壤微生物群落多样性指数和均匀度指数也表现出类似趋势。本试验证明,在水稻生长发育旺盛时期,Mclntosh指数(u)是一个有效区分转基因水稻和非转基因水稻土壤微生物群落多样性的指标。     

四川松茸内生细菌群落结构与多样性

为了解松茸的内生细菌群落结构与多样性,以采自四川7个松茸主产区的14个松茸样品为材料,通过变性梯度凝胶电泳(DGGE)分析其内生细菌的群落结构与多样性差异.结果表明： 各个产区松茸样品的内生细菌群落结构与多样性存在明显差异.但采自相近地点、相似环境的松茸样品内生细菌群落结构相似性较高;样品的丰度范围为15～25,多样性指数依次为盐源＞冕宁＞会东＞木里＞雅江＞盐边＞小金;条带回收测序构建的系统发育树显示,松茸内生细菌种群丰富,各个产区松茸优势种群存在一定的差异,但假单胞菌属、爱文菌属、芽孢杆菌属在所有样品中均有分布,而且都占据一定的优势地位.产碱杆菌属与鞘氨醇杆菌属在大部分样品中为优势种群;而杜擀氏菌属、赖氨酸芽孢杆菌属在特定样品中为优势种群.表明松茸内生细菌具有丰富的多样性,研究结果可为筛选促进松茸生长的内生菌提供依据.     

黄土高原石油污染土壤微生物群落结构及其代谢特征

针对污染胁迫下土壤微生物群落变化和代谢变异等问题,基于平板稀释法和Biolog微平板分析方法,研究了陕北黄土高原石油污染土壤微生物群落结构、代谢特征及其功能多样性。结果表明,不同类群的土壤微生物对石油污染胁迫的响应不同,污染土壤细菌和真菌数量高出清洁土壤1个数量级,而污染土壤的放线菌数量极显著减少(P0.01);污染土壤和清洁土壤微生物对糖类和多聚物类碳源较易利用,污染土壤微生物总体上代谢碳源的种类和活性均低于清洁土壤。微生物群落主成分分析(PCA)表明,石油污染土壤和清洁土壤的微生物群落存在显著差异(P0.01),起分异作用的碳源主要为糖类,其次是羧酸类和氨基酸类;随着土壤石油含量增加,典型变量值变异(离散)增大,土壤微生物群落结构稳定性降低。微生物群落多样性分析表明,Shannon丰富度指数(H)、McIntosh均一度指数(U)和Simpson优势度指数(1/D)均达到极显著差异(P0.01),污染土壤微生物群落H和U低于清洁土壤,但是一定浓度的石油污染可以刺激土壤微生物群落中优势种群的生长,1/D增高。研究结果为陕北黄土高原石油污染区土壤微生物修复提供理论基础。     

Diversity of chlorophenol-degrading bacteria isolated from contaminated boreal groundwater

Chlorophenol-degrading bacteria from a long-term polluted groundwater aquifer were characterized. All isolates degraded 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol at concentrations detected in the contaminated groundwater (< 10 mg l^–1). Pentachlorophenol was degraded by three isolates when present alone. In two gram-positive isolates, 2,3,4,6-tetrachlorophenol was required as an inducer for the degradation of pentachlorophenol. The gram-positive isolates were sensitive to pentachlorophenol, with an IC₅₀ value of 5 mg/l. Isolates belonging to the Cytophaga/Flexibacter/Bacteroides phylum had IC₅₀ values of 25 and 63 mg/l. Isolates belonging to α-, β- and γ-Proteobacteria generally tolerated the highest pentachlorophenol concentrations (> 100 mg/l). Polychlorophenol-degrading capacity was found in strains of Nocardioides, Pseudomonas, Ralstonia, Flavobacterium, and Caulobacter previously not known to degrade polychlorophenols. In addition, six polychlorophenol-degrading sphingomonads were found. Received: 27 September 1998 / Accepted: 21 December 1998     

小叶锦鸡儿固沙林土壤G+与G-细菌碳代谢功能多样性

为探讨科尔沁沙地流动沙丘上建立小叶锦鸡儿固沙植被后,土壤微生物群落中革兰氏阴性菌和革兰氏阳性菌代谢功能的变化规律,采用Biolog-GN2和GP2微平板检测法,研究了9、16、26年生人工群落以及流动沙丘和天然小叶锦鸡儿群落土壤革兰氏阴性和革兰氏阳性菌碳源代谢的多样性变化特征。结果表明,流动沙丘建立小叶锦鸡儿固沙植被后,土壤革兰氏阴性菌多样性表现为持续缓慢增加的趋势,0～26年生群落Shannon指数由3.85逐渐增加到4.17,均匀度指数由0.85增加到0.94;而革兰氏阳性菌则表现为先显著降低,后逐渐增加的趋势。随着固沙群落年龄的增长,土壤微生物代谢糖类、羧酸类、双亲化合物类、聚合物类、胺/酰胺类和氨基酸类等碳源种类逐渐增加。26年生小叶锦鸡儿人工群落土壤革兰氏阴性和革兰氏阳性菌的碳源代谢模式已逐渐接近天然群落。     

美洲大蠊成虫肠道可培养细菌多样性研究

【目的】了解美洲大蠊成虫肠道可培养细菌的多样性。【方法】运用纯培养法、数值分类和16S rRNA基因序列的系统发育分析对样品中可培养细菌多样性进行研究。【结果】从NA培养基中分离得到54株细菌,根据形态观察和部分生理生化特性,选取32个代表性菌株进行16S rRNA基因序列的系统发育多样性分析。结果表明,数值分类中的代表菌株在82%相似水平上可分为12个表观群;这些分离菌株代表20个物种,属于4个大的系统发育类群(Proteobacteria,Bacteroidetes,Firmicutes,Actinobacteria)的10个科、15个属。多数菌株属于Proteobacteria门(15株,占46.9%)和Bacteroidetes门(10株,占31.3%)。【结论】美洲大蠊成虫肠道内存在较为丰富的细菌多样性。     

安徽铜陵河流附生细菌多样性

通过对铜陵地区不同河段的上覆水和沉积物的理化性质进行分析,结合聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）的方法,研究了铜陵不同河段中附生细菌的多样性及其与环境因子的关系。结果表明,8个河段中上覆水和沉积物的营养水平及重金属含量存在较大差异,不同河段附生细菌的多样性指数也存在差异。数据分析表明,铜陵河流中黄浒河附生细菌的多样性最高,顺安河下游和钟仓河附生细菌的多样性最低。这种差异主要与河段间上覆水和沉积物不同的营养水平、重金属含量水平等因素有关。附生细菌的香农-威纳多样性与上覆水中的氨态氮（NH3-N）、总氮（TN）、总磷（TP）、可溶性正磷酸盐（PO3-4-P）和高锰酸盐指数（COD Mn）呈显著或极显著负相关,与沉积物中镉（Cd）、铜（Cu）和锌（Zn）的含量具有显著或极显著正相关性。     

污染土壤中有机磷农药降解菌的分离及其多样性

采用添加有机磷农药的选择性培养基,在长期受有机磷农药污染的土壤中分离到7株有机磷农药降解菌,经生理生化鉴定和系统发育分析,菌株mp-1鉴定为Pseudaminobactersp.,菌株mp-2为Alcaligenessp.,菌株mp-7为Brucellasp.,其他菌株为Ochrobactrumsp.。16SrDNA序列同源性比较、系统发育分析和染色体ERIC-PCR指纹图谱扩增表明有机磷农药长期污染的土壤中有机磷农药降解菌具有丰富的多样性。     

云南兰坪铅锌矿区细菌多样性研究

目的研究云南省兰坪铅锌矿区矿石样品中的细菌群落结构。方法构建细菌16S rRNA高变区基因文库。结果矿石内部细菌种类丰富多样,文库测序结果表明矿石样品中细菌分属于4个门,27个属;其中变形菌门（Proteobacteria）类群是优势种群,占所有细菌总克隆数的51.7%,而且大多数属于γ-变形菌纲亚群。各克隆序列分析结果表明,其中部分细菌序列与已报道物种的相似性较低。结论表明云南省兰坪铅锌矿矿石样品中可能存在新的细菌种类。     

Molecular diversity and hydrolytic enzymes production abilities of soil bacteria

Soil is an integral part of ecosystem which is niche for varieties of microflora. The present study was investigated to isolate varied strains of bacteria from soil samples of three different geographical regions of Tamil Nadu (India) and evaluate their hydrolytic enzymes (amylase, cellulase, and inulinase) producing potentialities. Among 72 bacterial cultures isolated from Ambattur Industrial Estate, Neyveli Lignite Corporation, and Arignar Anna Zoological Park regions, 41.66, 38.88, and 36.11% of isolates were observed amylase, cellulase, and inulinase producers, respectively. On the other hand, 20.83% of total bacteria isolated from all three regions exhibited concurrent production of amylase, cellulase, and inulinase. Potent isolates depicting maximum enzyme activities were identified as Bacillus anthracis strain ALA1, Bacillus cereus strain ALA3, Glutamicibacter arilaitensis strain ALA4, and Bacillus thuringiensis strain ALA5 based on molecular characterization tools. Further, the thermodynamics parameters, open reading frames (ORFs) regions, and guanine-cytosine (GC) content were determined by distinct bioinformatics tools using 16S rRNA sequences of strains. Minimum free energy values for strain ALA1, strain ALA3, strain ALA4, and strain ALA5 were calculated as −480.73, −478.76, −496.63, and −479.03 kcal/mol, respectively. Mountain plot and entropy predicted the hierarchical representation of RNA secondary structure. The GC content of sequence for strain ALA1, strain ALA3, strain ALA4, and strain ALA5 was calculated as 53.06, 52.94, 56.78, and 53.06%, respectively. Nine ORFs were obtained for strain ALA1, strain ALA3, and strain ALA5 while 10 ORFs were observed for strain ALA4. Additionally, bootstrap tree demonstrated close resemblance of strains with existing bacteria of similar genus. Findings showed higher variability of bacterial diversity as hydrolytic enzymes producers in the investigated geographical regions.     

Phylogenetic and phenotypic diversity of 4-chlorobenzoate-degrading bacteria isolated from soils

Twenty numerically dominant 4-chlorobenzoate (4-CBA)-degrading bacteria were isolated from agricultural soils. The isolates were able to utilize 4-CBA as a sole source of carbon and energy. A total of 65% of the isolates was identified to the species level by fatty acid methyl ester (FAME) analysis, and the isolates were strains of Micrococcus, Pseudomonas, Oerskovia, Cellulomonas, and Arthrobacter species. The chromosomal DNA patterns of the isolates obtained by polymerase chain reaction (PCR) amplification of repetitive extragenic palindromic (REP) sequences were distinct from each other. Most of the isolates grew rapidly in 4-CBA medium, but their substrate utilization capabilities were generally restricted. Plasmid DNAs were detected from 55% of the isolates, and one strain, HR7, was shown to have self-transmissible, 4-CBA degradative plasmids. 4-CBA degradative enzymes were inducible by the presence of 4-CBA and most of the isolates appeared to mineralize it through 4-hydroxybenzoate rather than 4-chlorocatechol.     

Analysis of the bacterial strains using Biolog plates in the contaminated soil from Riyadh community

Routine manufacture, detonation and disposal of explosives in land and groundwater have resulted in complete pollution. Explosives are xenobiotic compounds, being toxic to biological systems, and their recalcitrance leads to persistence in the environment. The methods currently used for the remediation of explosive contaminated sites are expensive and can result in the formation of toxic products. The present study aimed to investigate the bacterial strains using the Biolog plates in the soil from the Riyadh community. The microbial strains were isolated using the spread plate technique and were identified using the Biolog method. In this study we have analyzed from bacterial families of soil samples, obtained from the different sites in 5 regions at Explosive Institute. Our results conclude that Biolog MicroPlates were developed for the rapid identification of bacterial isolates by sole-carbon source utilization and can be used for the identification of bacteria. Out of five communities, only four families of bacteria indicate that the microbial community lacks significant diversity in region one from the Riyadh community in Saudi Arabia. More studies are needed to be carried out in different regions to validate our results.