Temporal shifts in cyanobacterial communities at different sites on the Nakdong River in Korea

The studies of cyanobacterial blooms resulting from eutrophication or climate change and investigation of changes in the cyanobacterial community in freshwater environments are critical for the management of drinking water. Therefore, we investigated the cyanobacterial communities at 6 sites along the Nakdong River in South Korea from May 2012 to October 2012 by using high-throughput sequencing techniques and studied their relationship with various geochemical factors at sampling sites. Diverse genera (total of 175 genera) were detected within the cyanobacteria, and changes in their compositions were analyzed. The genus Prochlorococcus predominated in the May samples, especially in those obtained from the upstream part of the river, whereas the relative abundance of Microcystis and Anabaena increased with increase in water temperature. The relationship between the cyanobacterial community and environmental factors was analyzed by canonical correlation analysis, and the correlation between harmful cyanobacteria and chemical factors was analyzed by nonmetric multidimensional scaling ordination. Various environmental factors such as dissolved oxygen, pH, electric conductivity, temperature were found to affect the cyanobacterial communities in the river. The results of this study could help in the management of freshwater environments and in maintenance of drinking water quality.     

多重耐药鲍曼不动杆菌耐药性及16S rRNA甲基化酶基因检测的意义

目的：探讨多重耐药鲍曼不动杆菌的耐药性及16SrRNA甲基化酶基因检测的临床意义,为临床合理使用抗生素和控制院内感染提供依据。方法收集2011年3月至2013年12月在南昌市第二人民医院住院的ICU患者各种临床标本分离的多重耐药鲍曼不动杆菌52株。采用纸片扩散（K-B）法对52株多重耐药鲍曼不动杆菌行抗生素药敏试验,采用聚合酶链反应（PCR）检测16SrRNA甲基化酶基因（armA、rmtA、rmtB、rmtC、rmtD、rmtE和npmA基因）表达情况。结果52株多重耐药鲍曼不动杆菌对米诺环素、头孢哌酮/舒巴坦、美罗培南和亚胺培南耐药率分别为44．2％、53．8％、75．0％和78．8％,对其余14种抗生素耐药率均在90．0％以上。52株多重耐药鲍曼不动杆菌中有38株检出armA基因表达,表达率为73．1％（38/52）;其余均未检出。结论多重耐药鲍曼不动杆菌主要携带armA型16SrRNA甲基化酶耐药基因。米诺环素、头孢哌酮/舒巴坦对多重耐药鲍曼不动杆菌有较好的抗菌活性,而多重耐药鲍曼不动杆菌对其他多种抗生素呈多重耐药性。     

Effect of wastewater composition on archaeal population diversity

Distribution and occurrence of Archaea and methanogenic activity in a laboratory scale, completely mixed anaerobic reactor treating pharmaceutical wastewaters were investigated and associated with reactor performance. The reactor was initially seeded with anaerobic digester sludge from an alcohol distillery wastewater treatment plant and was subjected to a three step feeding strategy. The feeding procedure involved gradual transition from a glucose containing feed to a solvent stripped pharmaceutical wastewater and then raw pharmaceutical wastewater. During the start-up period, over 90% COD removal efficiency at an organic loading rate (OLR) of 6 kg COD m(-3)d(-1) was achieved with glucose feeding, and acetoclastic methanogenic activity was 336 ml CH4 gTVS(-1)d(-1). At the end of the primary loading, when the feed contained solvent stripped pharmaceutical wastewater at full composition, 71% soluble COD removal efficiency was obtained and acetoclastic methanogenic activity decreased to half of the rate under glucose feed (166 ml CH4 gTVS(-1)d(-1)). At the end of secondary loading with 60% (w/v) raw pharmaceutical wastewater, COD removal dropped to zero and acetoclastic methanogenic activity fell to less than 10 ml CH4 gTVS(-1)d(-1). Throughout the course of the experiment, microbial community structure was monitored by DGGE analysis of 16S rRNA gene fragments. Five different archaeal taxa were identified and the predominant archaeal sequences belonged to methanogenic Archaea. Two of these showed greatest sequence identity with Methanobacterium formicicum and Methanosaeta concilii. The types of Archaea present changed little in response to changing feed composition but the relative contribution of different organisms identified in the archaeal DGGE profiles did change.     

Social diversity and construction era of neighborhoods with traditional design features: Portland and Atlanta compared

This paper compares neighborhoods with more traditional features in two very different cities. As expected, in Portland the majority are socially diverse and in Atlanta they are low‐income. However, in both cities about a quarter are high‐income. In Atlanta the latter are located in older neighborhoods, whereas in Portland they are also in areas combining newer and older housing. A return to valuing a more traditional urbanism may explain the signs of revitalized central cities in both places. Our findings, however, indicate it may be accompanied by the relocation of low‐income neighborhoods to areas where activities are not readily accessible.     

可持续建筑的评价工具——CASBEE及其应用分析

日本的建筑环境综合性能评价体系自2002年问世以来得到了很好的应用和发展,有许多值得借鉴之处。介绍了CASBEE的概况;阐述了CASBEE-住宅(独户独栋)评价工具的评价内容和表示方法;结合实例分析了环境效率指标BEE的计算和BEE分级图、雷达图、柱状图在评价结果表达中的应用及意义;并对CASBEE-住宅评价工具的特点和作用进行了总结,对我国推进可持续建筑发展的相关工作将会有所帮助。     

TISTD反应器中的菌群结构及生态变化

以两相一体式污泥浓缩消化反应器(Two-phase Integrated Sludge Thickening and Digestion reactor,TISTD)为对象,研究了反应器稳定运行期间菌群结构及反应器负荷改变时其内部生态结构的变化.在以30％的投配率稳定运行时,从产酸相和产甲烷相分别取样、培养和分离出20...     

从低碳建筑到零碳建筑--概念辨析

低碳建筑和零碳建筑概念均源自低碳经济理念,存在多种定义及描述。本文经比较分析,提出了全生命周期零碳建筑概念,周全且目标明确。但在实践中,需结合实际确定阶段性目标和计划,循序渐进地推动建筑由低碳往零碳发展。     

16S rRNA基因文库对水基泥浆降解菌群的分析

采用SBR法强化驯化对海洋钻井水基泥浆具有一定降解功能的活性污泥菌群,并采用16S rRNA基因文库分析法分析其细菌群落的结构.分析结果表明,经SBR法驯化的活性污泥样品中存在着丰富的细菌种类,这些菌种大部分是厌氧菌或兼性厌氧的烃类降解菌,其中以假单胞菌属为代表的优势菌群具有降解长链石油烃的功能;被驯化的菌种还包括硝酸盐还原菌、硫酸盐还原菌和能够降解长链脂肪酸并与产甲烷菌共生的菌种等,促进了反应器中物质和能量的循环流动.     

城市建成环境对鸟类多样性的影响机制研究评述及展望

城市化带来的环境变化是生物多样性的主要威胁,但城市同样也是生物多样性保护的热点地区。因此,分析和预测城市环境变化对生物多样性的影响对于维护城市生态系统服务,提升人类福祉至关重要。目前,越来越多的研究对城市建成环境进行了详细的分类,分别量化了各个城市特征对生物多样性水平的影响。然而,对影响城市内生物多样性水平的因素仍缺乏多尺度、全球性的分析。借助Web of Science和CNKI,对来自全球37个城市的111篇文献进行了建成环境下鸟类多样性研究方法和结果的系统性分析,并在归纳关键性城市建成环境要素的基础上,提出了以生物多样性为导向的建成环境优化策略,指出了鸟类多样性保护和城市可持续发展的未来方向。     

低碳建筑的未来

建筑环境在很多发达国家引起的国家温室气体排放量已高达50%。因此,各国政府正寻求适当的对策解决气候变化所带来的威胁。建筑环境显然需要担当一个重要的角色。需要强而有力的政府领导,确保提供长期经济规划、商业投资、法规和激励机制,以确保业界迅速响应。本文讨论了英国政府的零碳建筑物策略对低能耗建筑设计的影响及产生的意外的后果。作者强调不同行业利益相关者和政府之间应有的对话和合作,以制定政策架构,鼓励业界积极创新,以提供符合成本效益的解决方案,真正应对气候变化所带来的挑战。     

Composition of bacterial and archaeal communities in freshwater sediments with different contamination levels (Lake Geneva, Switzerland)

The aim of this study was to compare the composition of bacterial and archaeal communities in contaminated sediments (Vidy Bay) with uncontaminated sediments (Ouchy area) of Lake Geneva using 16S rRNA clone libraries. Sediments of both sites were analysed for physicochemical characteristics including porewater composition, organic carbon, and heavy metals. Results show high concentrations of contaminants in sediments from Vidy. Particularly, high contents of fresh organic matter and nutrients led to intense mineralisation, which was dominated by sulphate-reduction and methanogenesis. The bacterial diversity in Vidy sediments was significantly different from the communities in the uncontaminated sediments. Phylogenetic analysis revealed a large proportion of Betaproteobacteria clones in Vidy sediments related to Dechloromonas sp., a group of dechlorinating and contaminant degrading bacteria. Deltaproteobacteria, including clones related to sulphate-reducing bacteria and Fe(III)-reducing bacteria (Geobacter sp.) were also more abundant in the contaminated sediments. The archaeal communities consisted essentially of methanogenic Euryarchaeota, mainly found in the contaminated sediments rich in organic matter. Multiple factor analysis revealed that the microbial community composition and the environmental variables were correlated at the two sites, which suggests that in addition to environmental parameters, pollution may be one of the factors affecting microbial community structure.     

Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash

Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U_max) and saturation value constant (K_B) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.     

Assessment of phylogenetic diversity of bacterial microflora in drinking water using serial analysis of ribosomal sequence tags

We examined chlorinated drinking water samples from three different surface water treatment plants for bacterial 16S rDNA diversity using the serial analysis of V6 ribosomal sequence tag (SARST-V6) method. A considerable degree of diversity was observed in each sample, with an estimated richness ranging from 173 to 333 phylotypes. The community structure shows that there are differences in bacterial evenness between sampled sites. The taxonomic composition of the microbial communities was found to be dominated by members of the Proteobacteria (57.2-77.4%), broadly distributed among the classes Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Additionally, a large proportion of sequences (6.3-36.5%) were found to be distantly related to database sequences of unknown phylogenetic affiliation. Given the apparent significance of this bacterial group in drinking water, a 16S rDNA analysis was performed and confirmed their presence and phylogeny. Notwithstanding the potential under-representation of certain bacterial phyla using the SARST-V6 primer pairs, as revealed by a refined computer algorithm, our results suggest that 16S rDNA corresponding to a variety of eubacterial groups can be detected in finished drinking water, suggesting that this water may contain a higher level of bacterial diversity than previously observed.     

Use of molecular techniques for the analysis of foam-causing bacteria in Al Bireh oxidation ditch,Palestine

Activated sludge foaming, a worldwide problem, usually consists of filamentous bacteria occurring predominantly in the mixed liquor. Because of a lack of pure cultures of most filamentous bacteria and the limited amount of characterisation data, molecular approaches were used to investigate dominant filamentous bacterial strains associated with foaming in Al Bireh Wastewater Treatment Plant in Palestine. Applying denaturing gradient gel electrophoresis (DGGE), 16S rRNA cloning and sequencing showed the dominance of several filamentous bacteria including Microthrix parvicella, Nocardia sp., Hyphomicrobium facilis, Chloroflexi, Candidates TM7 and Nocardioides oleivorans.