硫化氢对水分逆境胁迫下大豆叶际和根内微生物群落结构的影响

【目的】 研究硫化氢(hydrogen sulfide, H2S)对水分逆境胁迫下大豆叶际和根内微生物群落结构的影响。【方法】 利用16S rRNA基因进行高通量测序,并结合生物信息学分析(α多样性、β多样性、物种组成、共现网络分析等)对NaHS处理前后大豆叶际和根内微生物群落进行分析。【结果】 在大豆正常水分情况下,NaHS的添加会降低叶际微生物生境内的多样性,增加其特有物种,并提高根内微生物的多样性,但在重度干旱下NaHS的添加并未表现出类似的效应。此外,外源添加NaHS会改变细菌共现网络属性,由于叶际和根内区域的微生物群落的聚集度都很高,接种根瘤菌和添加NaHS对其无显著影响。NaHS的添加对叶际操作分类单元(operational taxonomic unit, OTU)的相对丰度影响较小,但是导致了根内OTU的相对丰度减少,而在重度干旱下,这种现象尤为明显。无论是在叶际区域还是在根内区域,不同的微生物类群在接种根瘤菌和添加NaHS下均得到了富集。【结论】 在水分逆境胁迫下,H₂S的调控对大豆叶际微生物群落结构影响不明显,但是对根内微生物群落结构的影响较为明显,通过改变细菌共现网络属性,降低根内总OTU的相对丰度,进而影响大豆对水分逆境环境的适应性。     

三元(碱-表面活性剂-聚合物)复合驱油藏采出水微生物群落特征

与水驱技术相比,向油藏中注入碱、表面活性剂和聚合物(简称三元复合驱,ASP)能大幅提高石油采收率,但这些驱油剂对油藏中微生物多样性与群落结构的影响尚亟待阐明,这对油田水质管理与腐蚀控制均具有的重要意义. 本研究采用高通量测序技术解析了大庆油田ASP油藏4口油井采出水中的微生物多样性与群落结构. 结果表明: ASP油藏采出水的pH高达9.65. 采出水中微生物Shannon多样性指数为2.00～3.56,采出井间菌群多样性存在差异. 在门、纲、属分类水平上,变形菌门(85.5%～98.3%)、γ-变形菌纲(83.7%～97.8%)、栖碱菌属(51.8%～82.5%)是绝对优势菌群. 共检测到12个属的潜在硫化氢产生菌,以硫磺单胞菌属丰度最高(0.4%～7.4%). 与已发表的水驱油藏研究结果相比,三元复合驱油藏采出水微生物群落组成独特,呈嗜/耐碱趋势,其多样性偏低,群落结构更单一.     

生物竞争排斥对油藏微生物群落结构变化影响

【目的】海上S油田采用生物竞争排斥技术治理油藏硫化氢产出取得一定成效,本研究通过揭示该技术对油藏环境中微生物群落结构的影响,尝试研究硫化氢治理过程中产生效果差异的因素。【方法】采用高通量测序分析等方法对加入硝酸盐、亚硝酸盐等药剂后,治理效果低效井、高效井及未治理井中不同微生物群落结构变化进行分析。【结果】与低效井和未治理井相比,高效井中的反硝化菌和石油降解菌种类和丰度明显增加,其中石油降解菌增加24.14%,反硝化细菌增加5.23%;Fe²⁺、Zn²⁺等离子的存在对不同井间治理效果差异和微生物群落变化具有一定影响。【结论】海上油田硫化氢治理中,生物竞争排斥技术不仅可以明显降低硫化氢产出,同时对油藏微生物群落环境也影响显著,微生物群落结构分析可作为硫化氢治理效果评价的重要指标,为海上油田硫化氢治理工作提供技术支持。     

The Process of Microbial Sulfate Reduction in Sediments of the Coastal Zone and Littoral of the Kandalaksha Bay of the White Sea

Microbiological and biogeochemical investigations of the coastal zone and the littoral of the Kandalaksha Bay of the White Sea were carried out. The material for investigations was obtained in the series of expeditions of the Institute of Microbiology, Russian Academy of Sciences, in August 1999, 2000, 2001, and in March 2003. The studies were conducted on the littoral and in the water area of the Kandalaksha Preserve, the Moscow University Belomorsk Biological Station, and the Zoological Institute Biological Station, Russian Academy of Sciences. Sediment sampling on the littoral was carried out in the typical microlandscapes differing in the sediment properties and macrobenthos distribution. The maximal sulfate reduction rate (SRR) was shown for the shallow part of the Chernorechenskaya Bay (up to 2550 g S/(dm³ day)) and in the Bab'ye More Bay (up to 3191 g S/(dm³ day)). During the winter season, at a temperature of –0.5 × 0.5°C, the SRR in the sediments of the Kartesh Bay was 7.9 × 13 g S/(dm³ day). In the widest limits, the SRR values varied in the sediment cores sampled on the littoral. The minimal values (11 g S/(dm³ day)) were obtained in the core samples on the silt–sandy littoral. The littoral finely dispersed sediments rich in organic matter were characterized by high SRR values (524–1413 g S/(dm³ day)). The maximal SRR values were shown for the sediments present within the stretch of decomposing macrophytes, in local pits at the lower littoral waterline, and in the mouth of a freshwater stream (51–159 mg S/(dm³ day)). A sharp difference in the level of H₂S production in the type microlandscapes was shown. The average hydrogen sulfide production in finely dispersed sediments constituted 125 mg S/(m² day); in stormy discharge deposits, 1950 mg S/(m² day); in depressions under stones and in silted pits, 4300 mg S/(m² day). A calculation made with regard to the area of microlandscapes with increased productivity shows that the daily H₂S production per 1 km² of the littoral (August) is 60.8 to 202 kg S/(km² day), while the organic carbon consumption for sulfate reduction per 1 km² of the littoral is 46 to 152 kg C_org/(km² day).     

包埋法固定化对硫氧化微生物菌群结构和功能的影响

【目的】为探讨包埋法固定化过程对硫氧化菌群硫化物去除能力及菌群微生物群落结构的影响,【方法】以聚乙烯醇-海藻酸钠-活性炭为载体,对硫氧化菌群进行了固定化,并采用富含硫化物的无机盐培养基,对比固定化与非固定化硫氧化菌群对硫化物的氧化去除能力。同时,利用PCR-DGGE技术,探讨硫氧化菌群在固定化前后以及在硫化物氧化去除过程中微生物群落结构变化。【结果】在对硫氧化菌群进行固定化之后,12 h之内对硫化物的最大去除能力从1000 mg/L下降为600 mg/L。硫氧化菌群的微生物群落结构发生了明显变化,但菌群中的硫氧化菌Catenococcus thiocycli未受影响,硫氧化菌Thioclava pacifica在菌群中的地位反而得到了强化。【结论】受制于底物在载体材料中的扩散迁移效率,硫氧化菌群对硫化物的氧化去除能力在固定化之后有所下降。由于不同微生物对固定化形成的微环境的适应能力以及对载体附着能力的不同,固定化对硫氧化菌群的微生物群落结构产生较大影响。     

用ERIC-PCR结合分子杂交监测焦化废水处理系统(A2/O)中微生物群落结构的变化

建立一种不依赖纯培养 ,可以在废水处理工业现场使用的监测微生物群落结构变化的分子技术。以处理焦化工业废水(A2 /O生物膜工艺 )不同构筑物中的悬浮污泥的微生物群落为研究对象 ,每周采样 1次 ,连续 4周。获得悬浮污泥总 DNA的ERIC- PCR指纹图谱 ,结合分子杂交进一步区分相同条带间的不同序列信息。结果表明 ,在缺氧池 (A2池 )和好氧池 (O池 )之间 ,各个采样点的 ERIC- PCR图谱差异不大 ,悬浮污泥在各构筑物之间交流充分 ;同一采样点的图谱在不同采样时期具有明显差异 ,显示了在此期间微生物群落的连续动态变化过程。通过对生物膜系统中悬浮污泥的微生物群落结构的指纹图谱分析 ,可开发出对该系统微生物群落结构动态变化进行检测的技术     

除臭微生物的筛选复配及其在堆肥中的应用

【目的】从沼渣和硫铁矿场土壤中分离可以去除氨氮和硫化物的微生物,并筛选复配后应用于堆肥中,以减少畜牧业粪便处理时臭气的释放量,改善工作环境。【方法】利用选择培养基分别筛选除氨和除硫的微生物,并进行16SrRNA基因序列分析鉴定,挑选效果较好的菌株进行组合,复配出微生物除臭剂将其应用于粪便堆肥中,通过检测现场氨气和硫化氢浓度初步评估其除臭效果。【结果】分离出了12株除氨微生物和5株除硫微生物,挑选出5株效果较好的菌株分别标记为N-2、N-5、N-6、N-11和S-3。复配实验表明菌株N-5+N-6+N-11+S-3组成的微生物除臭剂效果最佳,对NH4+-N和S2–去除率最高,分别为82.46%和84.84%。同时,堆肥应用实验证明微生物除臭剂具有除臭功效,尤其是在堆肥前期,在第7天翻堆的过程中氨气和硫化氢释放量相对于对照组减少了62.84%和53.12%。堆肥结束,与对照组相比,微生物除臭剂组氨氮含量低于对照组33.62%。【结论】本研究获得的微生物除臭剂有效降低了畜禽粪便堆肥过程中恶臭气体的释放,在改善畜牧业粪便堆肥处理环境方面具有较大的应用潜力。     

Radioisotopic tracing of carbon monoxide conversion by anaerobic thermophilic prokaryotes

The rate of CO conversion by a pure culture of a thermophilic CO-oxidizing, H₂-producing bacterium Carboxydocella sp. strain 1503 was determined by the radioisotopic method. The overall daily uptake of ¹⁴CO by the bacterium was estimated at 38–56 μmol CO per 1 ml of the culture. A radioisotopic method was developed to separate and quantitatively determine the products of anaerobic CO conversion by microbial communities in hot springs. The new method was first tested on the microbial community from a sample obtained from a hot spring in Kamchatka. The potential rate of CO conversion by the anaerobic microbial community was found to be 40.75 nmol CO/cm³ sediment per day. 85% of the utilized ¹⁴CO was oxidized to carbon dioxide; 14.5% was incorporated into dissolved organic matter, including 0.2% that went into volatile fatty acids; 0.5% was used for cell biomass production; and only just over 0.001% was converted to methane.     

Impacts of single‐walled carbon nanotubes on microbial community structure in activated sludge

Aims: Single‐walled carbon nanotubes (SWNTs) are likely to become increasingly widespread and yet their environmental impact is not well understood. The purpose of the current study was to evaluate the impact of SWNTs on microbial communities in a ‘sentinel’ environmental system, activated sludge batch‐scale reactors. Methods and Results: Triplicate batch reactors were exposed to SWNTs and compared to control reactors exposed to impurities associated with SWNTs. Automated ribosomal intergenic spacer analysis (ARISA) was used to assess bacterial community structure in each reactor. SWNT exposure was found to impact microbial community structure, while SWNT‐associated impurities had no effect, compared to controls. 16S rRNA gene sequence analysis indicated that dominant phylotypes detected by ARISA included members of the families Sphingomonadaceae and Cytophagacaceae and the genus Zoogloea. ARISA results indicated an adverse impact of SWNTs on the sphingomonad relative to other community members. Changes in community structure also occurred in both SWNT‐exposed and control reactors over the experimental time period and with the date on which activated sludge was obtained from a wastewater treatment facility. Conclusions: These results indicate that SWNTs differentially impact members of the activated sludge reactor bacterial community. Significance and Impact of the Study: The finding that community structure was affected by SWNTs indicates that this emerging contaminant differentially impacted members of the activated sludge bacterial community and raises the concern that SWNTs may also affect the services it provides.     

Effects of flooding on a wetland bird community

The Lake Izunuma–Uchinuma was extensively flooded in 1998 and vast areas (approximately 200 ha) of rice fields were submerged for the first time since the land was reclaimed in 1963. When the numbers of birds in 1998 were compared with those in normal years (1995–1997), the numbers of black-crowned night herons (Nycticorax nycticorax L.), cattle egrets (Bubulcus ibis L.) and black kites (Milvus migrans Boddaert) increased during the flooding, and the numbers of ducks, especially dabbling ducks (seven species of 11 Anas spp.) were high even after the flooding, while the numbers of the little grebe Tachybaputus ruficollis Pallas were diminished by the flooding.     

硫化氢合成酶抑制剂金丝桃素的体内外抗结肠癌作用研究

为研究金丝桃素对硫化氢合成酶活性的影响,探索金丝桃素作为胱硫醚-β-合成酶(CBS)抑制剂的体内外抗结肠癌作用。本研究通过亚甲蓝法测定金丝桃素和氨基氧乙酸(AOAA)对CBS产H2S活性的抑制作用,以HT29人结肠癌细胞和移植HT29细胞的裸鼠肿瘤模型为抗肿瘤研究对象,测定金丝桃素体内外抗肿瘤作用。结果表明,来源于贯叶连翘(Hypericum perforatum L.)的化合物金丝桃素是CBS的高效选择性抑制剂,其IC50为7.9±1.42μmol/L。金丝桃素能显著抑制HT29人结肠癌细胞的增殖,其IC50为22.2±2.25μmol/L。基因沉默实验表明CBS蛋白可能是金丝桃素在细胞内的潜在靶标之一。意外的是,目前普遍使用的CBS抑制剂AOAA抑制HT29细胞增殖作用非常弱,其IC50为152.5±35.68μmol/L。此外,不同剂量的金丝桃素(5~30mg/kg·d)均能显著减少裸鼠肿瘤体积和重量,30mg/kg·d剂量皮下给药2周后,和对照组相比肿瘤重量减少了68%。以上结果表明金丝桃素作为CBS的选择性抑制剂具有显著的抗结肠癌作用。     

土壤微生物群落构建理论与时空演变特征

土壤微生物作为陆地生态系统的重要组成部分,直接或间接地参与几乎所有的土壤生态过程,在物质循环、能量转换以及污染物降解等过程中都发挥着重要作用。对土壤微生物时空演变规律及其形成机制的研究,不仅是微生物演变和进化的基础科学问题,也是预测微生物及其所介导的生态功能对环境条件变化响应、适应和反馈的理论依据。讨论了土壤微生物群落的定义、测度方法和指标,认为群落是联系动植物宏观生态学与微生物生态学的基础,群落构建机制是宏观和微观生态学都需要研究的核心科学问题;从生态学的群落构建理论出发,阐述了包括生态位理论/中性理论、过程理论和多样性-稳定性理论在土壤微生物时空演变研究中的应用,以及微生物群落在时间和空间上的分布特征及其尺度效应;确立了以微生物群落构建理论为基础、不同时空尺度下土壤微生物群落演变特征为主要内容的微生物演变研究的基本框架。     

The Impact of H2 Addition on Dechlorinating Microbial Communities

Laboratory-scale column experiments were performed to investigate the effects of membrane-supplied H₂ on tetrachloroethene (PCE) dechlorination and microbial community composition. Columns were filled with aquifer material from one of two TCE-contaminated sites and fed a PCE-spiked anaerobic minimal medium for approximately 1 year. For each experiment, one or more experimental columns were supplied with H₂ via gas-permeable hollow-fiber membranes with one control column not receiving any H₂. After approximately 1 year of operation, aquifer material samples were collected along the length of the columns. Bacterial communities in the samples were analyzed by amplifying the highly variable V3 region of the 16S rRNA gene and separating amplicons using denaturing gradient gel electrophoresis. Microbial community profiles in H₂-fed (continuous or pulsed delivery) columns were compared with those in untreated control columns and microbial community profiles were also compared with dechlorination profiles. Selected bands were sequenced for identification. Supply of the simple electron donor H₂, changed the microbial community composition, but did not decrease overall diversity. Continuous H₂ addition via hollow-fiber membranes enriched for Dehalococcoides-like species, whose relative abundance correlated with enhanced dechlorination activity. PCE was completely dechlorinated to ethene in columns packed with aquifer material from Cape Canaveral, Florida; PCE was dechlorinated to only cis-dichloroethene, however, in columns packed with aquifer material from a TCE-contaminated wetland near Minneapolis, Minnesota. Unexpectedly, Dehalococcoides-like populations were detected in samples from both sets of column experiments. These results suggest that the mere detection of Dehalococcoides-like species in a sample of aquifer material is not a sufficient indicator of the potential to dechlorinate PCE to ethene via biostimulation by H₂.     

钾肥对甘蔗根际微生物多样性和群落构建过程的影响

微生物丰富种群和稀有种群在生态系统中发挥着防止病原体传播、控制养分循环和促进污染物降解等关键作用,但目前在农田生态系统中关注较少。本研究使用高通量测序技术和构建生态模型系统评估了不同施钾量(0、75、150、225和300 kg·hm^-2)对甘蔗根际土壤细菌和真菌的丰富种群及稀有种群多样性、驱动因素和群落构建过程的影响。结果表明: 施钾肥能够显著改变甘蔗土壤养分含量和酶活性特征,在施钾量为300和225 kg·hm^-2时土壤养分含量和酶活性分别达到最高。甘蔗根际土壤微生物的丰富种群集中在几个优势类群中,施钾肥能够极显著改变根际微生物物种组成和群落结构。施钾肥条件下土壤脲酶、有机质和过氧化氢酶等是影响细菌和真菌丰富种群与稀有种群群落结构的主要限制性因子。同时施钾肥对根际细菌群落的影响大于真菌,对丰富种群的影响大于稀有种群。施钾肥后甘蔗根际细菌和真菌群落构建过程主要由确定性过程驱动,细菌群落中异质选择占主导过程,而真菌群落中同质选择占主导过程,同时细菌和真菌丰富种群和稀有种群的群落构建也受确定性过程驱动。综上表明,施钾对甘蔗土壤养分和酶活性存在显著影响,增施钾肥有助于增加细菌和真菌丰富种群及稀有种群的多样性,调控甘蔗根际土壤微生物群落构建过程。     

Microbial analysis of a phototrophic sludge producing hydrogen from acidified wastewater

Based on DNA-cloning analysis, the microbial community of a phototrophic sludge producing H₂ from an acidified wastewater was composed of 81% of a species resembling Rhodobactercapsulatus (with 99.2% similarity) and two unidentified species of the Bacillus/Clostridium group. The sludge produced a biogas comprising 82 ± 2% H₂, 13 ± 2% CO₂, 4.5 ± 0.5% N₂, and 0.5 ± 0.2% H₂S.