蓝藻水华形成过程对氮磷转化功能细菌群的影响

为探寻蓝藻水华形成过程中细菌群落结构和氮、磷转化功能菌群的动态变化,利用细菌16S rRNA基因的高通量测序和功能基因的荧光定量PCR(qPCR)方法,分析了在蓝藻水华过程中水体细菌群落组成及功能菌群的变化情况.高通量测序结果证明了蓝藻水华形成过程中细菌群落的多样性降低,细菌群落在水华期和非水华期具有不同的结构.随着水华过程中蓝藻密度的增加,水体中Actinobacteria和Bacteroidetes相对丰度减少,而Firmicutes相对丰度增加;蓝藻水华对聚磷菌(PAOs)具有富集作用,对硝化细菌具有抑制作用,而反硝化细菌的数量在中度水华条件下显著增加. qPCR结果显示,随着蓝藻水华的持续发展,硝化和反硝化功能基因丰度下降甚至消失,表明水体中氮转化过程可能受到抑制,此过程也有利于水华过程中微囊藻快速增殖对氮的需求,对水华蓝藻的生长具有正反馈作用.     

A/O工艺中污泥浓度对微生物群落结构的影响

采用A/O工艺处理淀粉厂区废水,结合Miseq高通量测序技术研究了不同污泥浓度（MLSS）对A/O工艺脱氮效果及微生物群落结构的影响.结果显示,当污泥浓度为4066mg/L时（1号池）,氨氮（NH₄⁺-N）平均去除率高达90.2%;而污泥浓度为2985mg/L时（2号池）,去除率仅为67.2%.两池体中优势菌门均为变形菌门、拟杆菌门、绿弯菌门和厚壁菌门,其中变形菌门和拟杆菌门平均丰度分别为40.65%、30.28%和25.25%、33.27%,其相对丰度比例差异较大.在功能基因层面,两池体中所有8个功能基因类别（KEGG,京都基因与基因组百科全书）排序相同,氮代谢相关基因中,硝化酶、反硝化酶、氨化酶的相关功能基因均在1号池中含量高.该工艺中污泥浓度对菌群结构影响显著,高污泥浓度有利于形成高效脱氮菌群结构.     

鄱阳湖入湖河口沉积物细菌群落特征

基于高通量测序技术分析了鄱阳湖入湖河口15处沉积物的细菌群落特征.结果发现鄱阳湖入湖河口细菌优势门类为Proteobacteria（32.1%）,Acidobacteria（16.6%）、Chloroflexi（14.4%）、Nitrospirae（8.8%）和Actinobacteria（6.0%）.在属分类水平上相对丰度最高的是norank_Acidobacteria（8.9%）和Nitrospira（8.4%）.根据采样点沉积物细菌群落结构差异,5条主要支流入湖河口可分成赣江-饶河-信江组和抚河-修水组.赣江-饶河-信江组Acidobacteria、Nitrospirae、Gemmatimonadetes和Latescibacteria丰度显著较高;抚河-修水组Actinobacteria、Bacteroidetes、Firmicutes、Ignavibacteriae和Deltaproteobacteria丰度显著较高.鄱阳湖主航道下游沉积物细菌群落结构与其它入湖河口差异明显,具有显著较高的Chloroflexi、Aminicenantes和Firmicutes丰度.pH值和有机碳是影响鄱阳湖入湖河口沉积物门分类种群的主要环境因子,pH值是影响赣江-饶河-信江组和抚河-修水组细菌群落结构差异的主要环境因子.以上研究结果有助于从微生物的角度分析鄱阳湖入湖河口生态系统的物质和能量循环机理.     

矿化垃圾生物反应器中的细菌多样性分析

为探究准好氧生物矿化垃圾床处理渗滤液过程中的微生物作用机理,研究建立了16S r DNA克隆文库及PCRRFLP技术以研究矿化垃圾反应器的细菌多样性。结果表明:矿化垃圾反应器细菌具有高度多样性,反应器内有36种细菌分别属于13个纲,变形菌纲占绝对优势占70%(其中β-变形占56.5%,γ-变形菌纲占10%),拟杆菌纲、鞘氨醇菌纲,芽孢杆菌纲也具有一定优势;3%的Nitrosomonas属是渗滤液氨氮转化成亚硝酸盐氮的主要功能微生物,由于亚硝酸盐氧化菌不存在或丰度极低,因此造成反应器内亚硝酸盐积累;Thauera属(17%)和Thiobacillus denitrificans属(10%)是反应器内主要优势微生物属,是反应器内反硝化脱氮的功能微生物,由于Thauera属在好氧条件下具有反硝化特性,Thiobacillus denitrificans为严格自养反硝化菌,因此反应器脱氮主要途径为好氧反硝化、自养反硝化。     

碱/超声预处理对头孢菌素菌渣破壁效果的影响

为提高头孢菌素菌渣的厌氧消化利用率,采用碱解与超声波破碎联合处理方法对头孢菌素菌渣进行细胞破壁,并通过正交实验和单因素实验研究pH值、含水率、声能密度和反应时间对破壁效果的影响。结果表明,最佳处理条件为:pH值为11.5、含水率为94%、声能密度为2 W/mL、反应时间为30 min,处理后SCOD溶解率为265.26%,总氮溶解率为155.28%,破壁效果明显。     

基于PLFA法分析亚硝氮、硝氮和氨氮对厌氧微生物细菌群落的影响

利用磷脂脂肪酸(PLFA)技术研究了亚硝氮、硝氮和氨氮在不同浓度水平下对中温厌氧颗粒污泥中厌氧细菌群落结构的影响.结果表明,高浓度亚硝氮(360 mg·L-1,以N计)、硝氮(300 mg·L-1,以N计)和氨氮(3000 mg·L-1,以N计)使系统COD去除率分别下降至3.49%、10.85%和71.53%,并使污泥表面主要细菌由杆菌变为球状菌;亚硝氮和硝氮引起厌氧细菌和革兰氏阳性菌的含量下降,氨氮引起革兰氏阴性菌的含量下降;PLFA香农-威尔多样性指数随着亚硝氮和硝氮浓度的升高从1.12分别下降至0.96和1.03,氨氮对PLFA香农-威尔多样性指数无明显影响.     

Enhancement of conservation knowledge through increased access to botanical information

Herbarium specimens are increasingly recognized as an important resource for conservation science and virtual herbaria are making specimens freely available to a wider range of users than ever before. Few virtual herbaria are designed with conservation use as a primary driver. Exceptionally, Brazil's Reflora Virtual Herbarium (RVH) was created to increase knowledge and conservation of the Brazilian flora. The RVH is closely integrated with the Flora of Brazil 2020 platform on which Brazil's new national Flora is under construction. Both resources are accessible via the Reflora home page and thousands of users move seamlessly between these Reflora resources. To understand how the Reflora resources are currently used and their impact on conservation science, we conducted a literature review and an online survey. We searched for publications of studies in which Reflora resources were used and publications resulting from Brazilian researchers who were part of Reflora's research and mobility program. The survey contained multiple choice questions and questions that required a written response. We targeted Reflora webpage visitors with the survey to capture a wider range of Reflora users than the literature review. Reflora resources were used for a variety of conservation-relevant purposes. Half the 806 scientific publications in which Reflora was cited and 81% of the 1069 survey respondents accessing Reflora resources mentioned conservation-relevant research outputs. Most conservation-relevant uses of the Reflora resources in scientific publications were research rather than implementation focused. The survey of Reflora users showed conservation uses and impacts of virtual herbaria were more numerous and diverse than the uses captured in the literature review. Virtual herbaria are vital resources for conservation science, but they must document use and impacts more comprehensively to ensure sustainability.     

几种可利用多氯联苯和多溴联苯醚植物内生菌的分离及初步鉴定

采用PDA、NA以及高氏一号培养基,分别从毛白杨、绦柳、荻以及二穗短柄草植株内分离、纯化出37株内生菌,其中34株为细菌,3株为放线菌.以分离纯化得到菌株各自对应的营养培养基并添加不同浓度的污染物对获得的37株内生菌进行污染物的耐受筛选,发现24株分别对20 mg·L-1的aroclor1254和BDE209具有一定的耐受性.利用无机盐培养基并添加污染物作为微生物唯一碳源筛选,发现菌株CPY-4和菌株SGL-1可以在只提供4-BDE的无机盐培养基中存活,菌株CPY-4,SGL-1、菌株4、菌株13可以在提供BDE209和aroclor1254的无机盐培养基中存活.形态学观察和16Sr DNA序列同源性分析,初步确定菌株SGL-1为克雷伯氏菌属,菌株CPY-4为地衣芽胞杆菌,菌株4和菌株13为肠杆菌属.     

THE EFFECTS OF SELECTED HERBICIDES ON BACTERIAL POPULATIONS IN AN AQUATIC ENVIRONMENT1

ABSTRACT: Heterotrophic, mesophilic bacteria derived from, and maintained in, a freshwater environment were subjected to three classes of herbicides. Diuron, 2,4,5-Trichlorophenoxyacetic acid, and paraquat, used as water soluble solutions, were added (0.7 and 1.4 mgA) to a laboratory culture of bacteria. Total numbers of the bacteria, representing several genera, were monitored for alteration of numbers and types. Temperature, pH, and dissolved oxygen were monitored and the culture medium was tested for residual herbicide. Alterations observed in populations were considered to result from herbicide additions. Each herbicide tested was found to affect bacterial populations differently. Reasons for observed differences are discussed. In this aquatic environment the herbicides remained qualitatively measurable for periods up to three weeks.     

Quantitative Analyses of Pollution-Indicator and Pathogenic Bacteria in Mumbai Waters from Ballast Water Exchange Perspective

As large numbers of ships either take in ballast from or discharge their ballast into the Mumbai Harbor region, it is pertinent to quantify microorganisms of health concerns and suggest on the suitability of water for ballasting purposes. To meet with this main aim, a selected set of general and pathogenic bacterial groups and their seasonal variations were studied from the Mumbai Harbor area. Sampling was carried out during postmonsoon (November 2001), pre-monsoon (April 2002) and monsoon (October 2002) periods. We quantified total coliforms and eight other groups of known human pathogenic bacteria from water, sediment, marine plant and animal samples collected in and around Mumbai Harbor. When compared with similar studies from other parts/harbors of the world, the Mumbai Harbor area has over 100-times higher levels of coliforms. The serotypes of Escherichia coli O157 and Shigella-Alkaligens Dispar group were abundant throughout the year. Even Vibrio cholerae, V. parahaemolyticus, Salmonella spp., campylobacters and aeromonads were present in large numbers. This comprehensive study, conducted with a view to quantify these bacterial groups and to evaluate the suitability of these waters for ballasting purposes, clearly suggests that both ballasting and deballasting be avoided in this region and alternative procedures should be developed for treating/handling ballast water.