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1.
为研究As(砷)污染对微生物多样性的影响,找寻有利于As污染修复的抗As菌种,利用高通量测序技术分析As胁迫〔w(As)分别为0、80、100、150、200和400 mg/kg,依次记为AT0组、AT80组、AT100组、AT150组、AT200组和AT400组〕对湿地生境中土壤微生物多样性及群落结构特征的影响.结果表明:As污染会引起微生物多样性和群落结构的变化,但并不是简单的负相关.在各处理组中,AT80组的土壤中微生物多样性最高,OTU(operational taxonomic units)数高达1 849,较未经As处理的AT0组增加了58.9%,说明低As胁迫在一定程度上会刺激As敏感微生物的生长繁殖,如Desulfovibrio(脱硫弧菌属)和Allobaculum等菌属,使群落结构更加复杂多样.高w(As)(400 mg/kg)对微生物有明显的抑制作用,导致某些物种消亡和多样性下降.As胁迫会诱导抗As微生物〔如Pseuomonas(假单胞菌属)〕成为优势类群,群落结构趋于稳定、单一.微生物群落结构对不同w(As)胁迫有明显的响应特征,可作为As污染湿地土壤质量评价的灵敏指标.在AT400组中存在大量的Pseudomonas veronii,可为As污染湿地微生物修复提供借鉴.研究显示,微生物对As污染具有较为敏感的响应,其中,Proteobacteria(变形菌门)和Firmicutes(厚壁菌门)为As污染生境中微生物优势门类并且与非专性吸附态As和谷胱甘肽含量呈正相关.   相似文献   

2.
杨雷峰  尹华  彭辉  李跃鹏 《环境科学》2017,38(2):721-727
十溴联苯醚(BDE-209)作为溴系阻燃剂的主要代表之一,所造成的沉积物环境污染问题日益引起人们的重视.本研究利用河边常见植物再力花(Thalia dealbata)作为修复植物,引入外源微生物短短芽孢杆菌(Brevibacillus brevis)和铅黄肠球菌(Enterococcus casselifavus)以强化修复效果,通过盆栽试验模拟沉积物环境,考察了外源菌对植物根际修复沉积物中BDE-209的强化作用效果,以及不同处理组,沉积物中微生物数量、有机酸含量和微生物碳源利用能力的变化.结果发现,外源菌处理组中BDE-209的去除率高于相应的对照组,其中以加入B.brevis根际处理组BDE-209的去除率最好(66%),大于非根际处理组和无植物处理的对照组(37.93%和39.27%).植物的根际作用可以提高底泥中BDE-209的去除率、微生物的数量、有机酸含量和碳源利用能力.  相似文献   

3.
Parasite-mediated selection may affect the evolution of cognitive abilities because parasites may influence development of the brain, but also learning capacity. Here, we tested some predictions of this hypothesis by analyzing the relationship between complex behaviours (feeding innovations (as a measure of behavioural flexibility) and ability to detect foreign eggs in their nests (i.e. a measure of discriminatory ability)) and abundance of microorganisms in different species of birds. A positive relationship would be predicted if these cognitive abilities implied a larger number of visited environments, while if these skills favoured detection and avoidance of risky environments, a negative relationship would be the prediction. Bacterial loads of eggshells, estimated for mesophilic and potentially pathogenic bacteria (i.e. Enterococcus, Staphylococcus and Enterobacteriaceae), were used as a surrogate of probability of contact with pathogenic bacteria. We found that bird species with higher feeding innovation rates and rejection rates of experimental brood parasitic eggs had higher density of bacteria on their eggshells than the average species. Since the analysed groups of microorganisms include pathogenic bacteria, these results suggest that both feeding innovation and ability to recognize foreign eggs are costly and highlight the importance of parasite-mediated selection in explaining the evolution of cognitive abilities in animals.  相似文献   

4.
Most wood-feeding insects need an association with microbes to utilize wood as food, and some have special organs to store and convey the microbes. We report here the discovery of the microbe-storage organ (mycangium) in stag beetles (Coleoptera: Lucanidae), which develop in decayed wood. The mycangium, which was discovered in the abdomen, is present in all adult females of 22 lucanid species examined in this study, but absent in adult males. By contrast, adult insects of both sexes of selected Passalidae, Geotrupidae, and Scarabaeidae, which are related to Lucanidae, lacked mycangia similar to those of the lucanid species. Yeast-like microbes were isolated from the mycangium of five lucanid species. DNA sequence analyses indicate that the microbes are closely related to the xylose-fermenting yeasts Pichia stipitis, Pichia segobiensis, or Pichia sp. known from the gut of a passalid species.  相似文献   

5.
李胜君  胡菏  李刚  王蕊  赵建宁  张贵龙  修伟明 《环境科学》2022,43(10):4735-4744
有机物料作为生态友好型的化肥替代品为农业生态系统带来了巨大的经济和环境效益.然而,在化肥减量的基础上添加有机物料会对土壤氮(N)循环产生何种影响依旧知之甚少.在此,设置了常规施肥(NPK)、化肥减量(NPKR)、化肥减量配施秸秆(NPKRS)、化肥减量配施有机肥(NPKRO)、化肥减量配施秸秆和有机肥(NPKROS)共5种施肥处理,采用实时定量PCR方法测定微生物N循环功能基因丰度,并估算微生物N转化遗传潜力.结果表明,与NPK处理相比,有机物料添加显著增加了参与有机N分解、N固定和N还原的异养微生物数量,而降低了执行氨氧化的自养微生物丰度.因此,异养微生物的比例增加,自养微生物的比例降低.施肥措施变化显著提高了微生物N存储和气态N排放潜力,降低了NO3-淋溶潜力,N2 O还原潜力也有所提升.基于距离的冗余分析(db-RDA)表明,5种施肥处理间N循环功能基因丰度差异显著(PERMANOVA,P=0.002),NH4+是驱动这种变化的关键因子,施用有机肥有利于异养N循环功能微生物,并且同时加入秸秆增强了这种影响.Pearson相关分析表明N存储潜力和气态N排放潜力均与NH4+含量显著负相关;NO3-淋溶潜力与SOC和TN含量显著负相关,而与NH4+含量显著正相关.综上所述,在化肥减量基础上添加有机物料有利于增加农田土壤N库,降低土壤N淋溶损失,甚至在特定环境下可以降低N2 O排放的环境风险.  相似文献   

6.
Degradation of pyrene by immobilized microorganisms in saline-alkaline soil   总被引:4,自引:0,他引:4  
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is very difficult in saline-alkaline soil due to the inhibition of microbial growth under saline-alkaline stress. The microorganisms that can most effectively degrade PAHs were screened by introducing microorganisms immobilized on farm byproducts and assessing the validity of the immobilizing technique for PAHs degradation in pyrene-contaminated saline-alkaline soil. Among the microorganisms examined, it was found that Mycobacterium sp. B2 is the best, and can degrade 82.2% and 83.2% of pyrene for free and immobilized cells after 30 days of incubation. The immobilization technique could increase the degradation of pyrene significantly, especially for fungi. The degradation of pyrene by the immobilized microorganisms Mucor sp. F2, fungal consortium MF and co-cultures of MB+MF was increased by 161.7% (P < 0.05), 60.1% (P < 0.05) and 59.6% (P < 0.05) after 30 days, respectively, when compared with free F2, MF and MB+MF. Scanning electron micrographs of the immobilized microstructure proved the positive effects of the immobilized microbial technique on pyrene remediation in saline-alkaline soil, as the interspace of the carrier material structure was relatively large, providing enough space for cell growth. Co-cultures of different bacterial and fungal species showed different abilities to degrade PAHs. The present study suggests that Mycobacterium sp. B2 can be employed for in situ bioremediation of PAHs in saline-alkaline soil, and immobilization of fungi on farm byproducts and nutrients as carriers will enhance fungus PAH-degradation ability in saline-alkaline soil.  相似文献   

7.
饮用水快速砂滤池优势微生物群落的代谢功能解析   总被引:2,自引:2,他引:0  
快速砂滤池广泛应用于饮用水处理中,其净水效能一直被认为是物理化学作用,而对滤池表面附着微生物的净水作用仍不明晰.为了解析滤池中微生物的群落构成和功能特征,研究对国内8个城市的11座饮用水快滤池的进出水和滤料进行采样分析.进出水水质分析结果表明经过滤池处理,溶解性有机碳(DOC)有少量去除,氨氮(NH_4~+-N)显著降低,硝酸盐氮(NO_3~--N)显著增加,总氮(TN)未发生明显变化.利用宏基因组技术获得了滤池中微生物群落的构成和功能信息,滤池优势菌属(相对丰度占前10%)共14种,包括两类氨氧化细菌Nitrospira和Nitrosomonas.对优势菌属的功能基因信息进行分析,发现优势微生物菌群具有更高的碳水化合物、氮、硫和异生物质代谢功能丰度. Aeromonas的碳水化合物代谢基因相对丰度最高,Bradyrhizobium的氮、硫及异生物质代谢基因的相对丰度最高,说明这两种菌是影响饮用水水质的重要菌属.通过评价各个优势菌属对异生物质的代谢潜能,发现Bradyrhizobium、Sphingomonas、Methyloglobulus、Sphingopyxis和Klebsiella是饮用水快速砂滤池中降解微量有机污染物的关键菌.  相似文献   

8.
稻田土壤固碳功能微生物群落结构和数量特征   总被引:6,自引:4,他引:6  
研究不同类型稻田土壤自养微生物数量和多样性差异及其影响因子,对全面认识稻田生态系统的固碳潜力及其机制具有重要意义.鉴于此,本文选取4种典型稻田土壤,通过室内培养实验对具备卡尔文循环途径碳同化微生物进行了研究.利用荧光定量PCR(qPCR)、克隆文库以及末端限制性长度多态性分析(T-RFLP)技术,研究了卡尔文循环关键酶(1,5二磷酸核酮糖羧化酶/加氧酶Rubis CO)的2种编码基因(cbbL和cbbM)的丰度和多样性.结果表明,与培养前相比,培养45 d后碳同化自养微生物数量有所增加,cbbL基因丰度比cbbM基因高3个数量级.不同稻田土壤中碳同化功能微生物优势种群存在差异,且这些微生物大多不能归类到已知的细菌类群中,部分可归类的与变形菌和放线菌有较高相似度.RDA分析结果显示土壤有机碳(SOC)、阳离子交换量(CEC)、pH、黏粒、粉粒和砂粒含量对碳同化功能微生物群落结构有显著影响.本文的研究结果对于理解微生物在碳循环过程中的作用具有一定的科学意义,也可以为稻田土壤肥力科学化管理和构建低碳农业提供科学依据.  相似文献   

9.
反硝化过程对于废水生物脱氮工艺的运行、土壤肥分的流失以及N2O的排放均具有重要意义,但参与反硝化过程的微生物种类繁多且多数不可培养,导致对自然环境中反硝化微生物的种群结构及功能的研究具有很大难度.现代非培养分子技术的发展使得对反硝化微生物进行原位、准确、全面的研究成为可能.对反硝化功能基因进行指纹图谱分析、定量PCR或者利用FISH等技术可以有效确定反硝化菌的组成和数量,通过检测反硝化酶和mRNA可将反硝化菌的种群鉴定与代谢活性联系起来,最近新出现的同位素底物标记技术甚至可直接确定反硝化菌的碳源利用情况.重点介绍了上述各种现代非培养技术对反硝化细菌种群结构和功能的研究现状,以期为深入了解反硝化微生物的多样性和功能特性提供参考.  相似文献   

10.
土壤微生物积极参与生态系统的物质循环和转化.人类活动造成全球氮沉降量激增,引起土壤微生物群落结构和功能的改变,进而导致生态系统失衡.2014年6月—2015年5月在缙云山柑橘林建立野外模拟氮沉降试验样地,原位设置4个施肥水平:对照(N0,0 g·m~(-2)·a~(-1))(以N计,下同)、低氮(N20,20 g·m~(-2)·a~(-1)),中氮(N4 0,40 g·m~(-2)·a~(-1))和高氮(N60,60 g·m~(-2)·a~(-1)).施氮处理2 d后,采用磷脂脂肪酸(PLFA)标记法和ACE(Automated Soil CO_2Exchange Station,UK)自动土壤呼吸监测系统对土壤微生物群落结构、土壤温湿度进行测定.研究表明:(1)不同季节土壤微生物对氮沉降的响应各异,春季氮沉降抑制土壤微生物量,夏、秋、冬季N40处理提高了土壤微生物量,N20、N60表现为抑制土壤微生物量;氮沉降对土壤温度有显著影响,但对土壤湿度影响不明显(p0.05).(2)土壤微生物丰富度指数和Shannon-Wiener多样性指数在中氮沉降条件下达最大;Pielou均匀度指数则表现不一致,春季和夏季在中氮浓度下最大,秋季在高氮处理下最大,冬季则在低氮处理下最大.(3)土壤温度与放线菌呈显著负相关(p0.01);土壤湿度与细菌和总PLFA呈显著正相关(p0.01),与放线菌呈显著正相关(p0.05).综合分析表明,土壤微生物受土壤温度和含水量的共同影响,氮沉降降低了土壤微生物含量,此研究结果支持了氮沉降抑制土壤微生物的认识.  相似文献   

11.
Prodigiosin is a reddish antibiotic pigment that plays an important role in the biocontrol of plant diseases by the bacterium Serratia marcescens. However, its activity is unstable under agricultural conditions; further, it can be degraded by various environmental factors. To examine the effect of epiphytic microbes on the stability of prodigiosin used for biological control processes, we collected a total of 1,280 bacterial isolates from the phylloplane of cyclamen and tomato plants. Approximately 72% of the bacterial strains isolated from the cyclamen plants and 66% of those isolated from the tomato plants grew on minimal agar medium containing 100 μg ml−1 prodigiosin. Certain isolates obtained from both plant species exhibited prodigiosin-degrading activity. We compared the 16S rRNA gene sequences derived from the isolates with sequences in a database. The comparison revealed that the sequences determined for the prodigiosin-degrading isolates were homologous to those of the genera Pseudomonas, Caulobacter, Rhizobium, Sphingomonas, Janthinobacterium, Novosphingobium, and Rathayibacter. These results indicate that indigenous epiphytic microorganisms may interfere with the interaction between plant pathogens and biocontrol agents by degrading the antibiotics produced by the agents.  相似文献   

12.
All higher eukaryotes have established symbiotic relationships with diverse microorganisms. One of the most well-characterized symbiotic systems is that of termites and their intestinal microorganisms, which digest cellulose. Recently, diverse types of symbioses between gut microbes and host organisms including humans have received growing attention for various features of their complex interactions beyond nutrition. In termites, researchers are beginning to explore such function of gut symbionts, but only the contribution to internal immunity against entomopathogen is known in a few species. Here, we report that gut symbionts of the dampwood termite Zootermopsis nevadensis protect nests from the spread of the commensal bacterium Serratia marcescens, which has pathogenic potential. Defaunated termites dispersed S. marcescens in the surrounding environment by feeding on the bacteria, which then survived passage through their alimentary tracts, while non-defaunated termites did not. Loss of gut symbionts caused a significant reduction in intestinal acetate, which is an important carbon source for termites. Culture experiments showed that acetate had significant inhibitory effects on S. marcescens at a concentration as low as 12 mM, which indicated that the intestinal acetate of non-defaunated termites (40–130 mM) was capable of suppressing this bacterium. These results suggest that digestive derivatives produced by intestinal symbionts play an essential role in nest hygiene in addition to their nutritional function for termites. Our study provides a better understanding of the multifunctionality of symbiotic relationships in diverse organisms beyond nutrition.  相似文献   

13.
铜胁迫对小麦根系微域微生物群落的影响   总被引:2,自引:1,他引:1  
葛艺  徐民民  徐绍辉  徐艳 《环境科学》2021,42(2):996-1003
小麦是我国主要的粮食作物,土壤重金属污染会严重威胁作物生长和粮食安全.大量研究表明根际微生物在调控作物发育和抗逆性方面具有非常重要的作用.因此,本研究通过高通量测序技术研究铜胁迫条件下小麦根际微生物群落的变化,从微生物学角度揭示铜污染胁迫对小麦根际的影响作用.采用盆栽培养试验对铜污染处理中小麦非根际、根际以及根内微生物进行测序后,分别比较小麦不同根系分区环境中的微生物群落结构和多样性.结果发现,所有处理中小麦的根内微生物多样性均显著(P<0.001)低于根际和非根际微生物多样性,表明根表作为微生物进入根内环境的门户,对根内微生物的定殖起着过滤和筛选的作用.铜污染胁迫降低了根际土环境中的微生物多样性,且差异显著(P<0.05);而在非根际和根内环境中,尽管铜污染胁迫降低了对应根系分区中的微生物多样性,但差异不显著(P>0.05).变形菌门(Proteobacteria)和放线菌门(Actinobacteria)是小麦根际和非根际环境中的共有优势菌群,通过比较发现铜污染胁迫对这两种优势菌门的影响作用较小.另外,芽孢杆菌属(Bacillus)、假黄色单胞菌属(Pseudoxanthomonas)和鞘氨醇单胞菌属(Sphingomonas)等菌属具有较强的抗逆性,能够在铜污染胁迫下存活且能够为植物提供营养物质.  相似文献   

14.
To better understand the diversity of metal resistance genetic determinant from microbes that survived atmetal tailings in northwest of China, a highly elevated level of heavymetal containing region, genomic analyses was conducted using genome sequence of three native metal-resistant plant growth promoting bacteria (PGPB). It shows that: Mesorhizobium amorphae CCNWGS0123 contains metal transporters from P-type ATPase, CDF (Cation Diffusion Facilitator), HupE/UreJ and CHR (chromate ion transporter) family involved in copper, zinc, nickel as well as chromate resistance and homeostasis. Meanwhile, the putative CopA/CueO system is expected to mediate copper resistance in Sinorhizobium meliloti CCNWSX0020 while ZntA transporter, assisted with putative CzcD, determines zinc tolerance in Agrobacterium tumefaciens CCNWGS0286. The greenhouse experiment provides the consistent evidence of the plant growth promoting effects of these microbes on their hosts by nitrogen fixation and/or indoleacetic acid (IAA) secretion, indicating a potential in-site phytoremediation usage in themining tailing regions of China.  相似文献   

15.
16.
为研究不同来源再生水灌溉对土壤微生物群落结构的影响,以地下水灌溉土壤为对照,采用Illumina MiSeq高通量测序技术对长期利用生活源和工业源再生水灌溉的土壤微生物群落结构进行分析,进一步探究土壤环境因子及其相互作用对微生物群落结构的影响.结果表明,与地下水灌溉相比,长期生活源再生水灌溉可显著提高土壤中TOC、 DOC、 Eh、 NH~+_4-N和TP的含量,长期工业源再生水灌溉导致Cd、 Cr、 Cu、 Pb和Zn在表层土壤大量累积.再生水灌溉显著增加了土壤中Acidobacteria和Planctomycetes的相对丰度,降低了Firmicutes和Tectomicrobia的相对丰度,且不同来源再生水对土壤中功能微生物的影响不同,生活源再生水灌溉可显著增加Chloroflexi和Nitrospirae的相对丰度,而工业源再生水灌溉对Actinobacteria具有显著的抑制作用.db-RDA分析结果表明,生活源再生水灌溉土壤菌群主要受TN、 TP、 DOC和Eh影响(P0.05),工业源再生水灌溉土壤菌群主要受重金属影响(P0.05).长期再生水灌溉可改变土壤环境因子间的相互作用,进而影响微生物群落结构,生活源再生水灌溉土壤中微生物主要受DOC、 TN和TP等营养物质含量的增加和氧化还原条件的改变控制,工业源再生水灌溉土壤中微生物与重金属的积累显著相关.  相似文献   

17.
The ability of nonhuman animals to project individual actions into the future is a hotly debated topic. We describe the caching behaviour of tayras (Eira barbara) based on direct observations in the field, pictures from camera traps and radio telemetry, providing evidence that these mustelids pick and cache unripe fruit for future consumption. This is the first reported case of harvesting of unripe fruits by a nonhuman animal. Ripe fruits are readily taken by a variety of animals, and tayras might benefit by securing a food source before strong competition takes place. Unripe climacteric fruits need to be harvested when mature to ensure that they continue their ripening process, and tayras accurately choose mature stages of these fruits for caching. Tayras cache both native (sapote) and non-native (plantain) fruits that differ in morphology and developmental timeframes, showing sophisticated cognitive ability that might involve highly developed learning abilities and/or prospective thinking.  相似文献   

18.
我国流域水环境呈现典型的复合污染特征,亟需发展基于生物效应的生态风险评估方法,以实现环境管理和生态修复的精准化.在野外原位暴露下受试生物受到多种污染物的共同胁迫,可以准确表征研究位点复合污染所产生的生态风险.原位生物测试较传统实验室生物测试具有更高的环境真实性和生态相关性,较野外生物监测对生物体承受的外源污染压力更清晰、可控.综述了基于原位生物测试的水生态风险评估技术,旨在促进该技术在我国水环境监测中的应用,提高生态风险评估的准确度.总结了国内外近年来原位生物测试的研究特色,详细阐述了实施过程中受试生物选择、暴露装置设计和研究位点选择的原则,以及原位生物测试方法在水环境生态风险评估中的应用案例.结果表明:①对原位生物测试实施要素进行规范化形成标准,将有利于该方法在环境管理中的推广应用.②利用原位生物效应、原位生物体内浓度以及二者与环境浓度相结合进行风险评估,是原位生物测试在生态风险评估中的三类应用类型.③原位生物暴露与被动采样的联合应用可同步获取原位生物效应和污染物生物可利用浓度,有利于实现全面准确的风险评估,应用潜力较大.研究表明,选用本土模式生物,采用多层次的毒性终点,设计简单有效的暴露装置,并同时考虑原位生物效应和环境浓度将有利于原位生物测试方法在我国的发展.   相似文献   

19.
分别以黏土矿物坡缕石和海泡石作为钝化材料,对重金属镉污染的酸性水稻土壤进行原位钝化修复田间示范试验,考察了两种黏土矿物在不同添加剂量下对稻谷产量、糙米镉含量及土壤中有效态镉含量等变化的影响,用以表征修复效果.同时,深入研究了两种黏土矿物对土壤pH、土壤水解氮、有效磷含量及相关酶活性的影响以表征其对土壤环境质量的影响,并对各项理化指标之间的相关性进行分析.结果表明,田间示范条件下两种黏土均提高了土壤pH,降低了土壤中镉的生物有效性,明显降低了糙米中镉含量.其中,经2.00 kg·m-2坡缕石和2.25 kg·m-2海泡石处理后,糙米镉含量最大降幅分别为54.6%和73.5%,分别降低至0.32和0.18 mg·kg-1.土壤过氧化氢酶、脲酶、酸性磷酸酶及蔗糖酶的活性均得到不同程度的提高,表明经钝化修复后土壤中相关代谢反应得到恢复;两种黏土矿物对土壤中水解氮含量无明显影响,但降低了土壤有效磷含量.综合总体表现,两种黏土矿物可被推荐作为镉污染酸性稻田土壤的原位钝化修复材料.  相似文献   

20.
生物法合成纳米金是一种环境友好且经济高效的合成途径,受到广泛关注.普遍认为微生物合成纳米金是通过胞外分泌生物大分子而实现的一种自发脱毒过程.同时,相关研究表明低浓度的重金属离子对菌株胞外酶的活性会产生一定的影响,进而会对菌株合成纳米金的能力产生影响.基于此,本研究选择一株前期筛选得到的真菌Trichoderma sp. WL-Go,探究不同金属离子诱导菌株对其合成的纳米金特性的影响.结果表明,经Co~(2+)、Al~(3+)、Zn~(2+)、Sn~(2+)、Ni~(2+)等金属离子诱导后,菌株WL-Go合成纳米金的能力均有所提升,而Pb~(2+)、Cu~(2+)、Fe~(3+)与对照组相比,其合成的纳米金浓度及转化率都无明显变化.此外,Co~(2+)诱导菌株合成的纳米金呈现肉眼可见的团簇状,发生明显的团聚现象.本实验还考察了生物合成纳米金对4-硝基苯酚还原的催化特性,结果表明,Sn~(2+)和Pb~(2+)的诱导使菌株WL-Go合成的纳米金催化速率得到明显提升,而其他金属离子均有所抑制.最后选取革兰氏阳性菌Arthrobacter sp. W1和革兰氏阴性菌Escherichia coli BL21 (DE3)验证了不同金属离子诱导后合成的纳米金均具有良好的生物相容性.综上,本研究为对于拓宽纳米金的工业化应用前景有着重要意义.  相似文献   

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