The Seasonal Variation of the Concentrations of Ozone, Sulfur Dioxide, and Nitrogen Oxides in Two Nigerian Cities

A combination of multivariate statistical methods including factor analysis, principal component analysis, principal component regression, and multiple linear regression (MLR) were employed to evaluate the influence of seasons on the concentrations of ozone, sulfur (IV) oxide, and oxides of nitrogen in ambient air of Nigerian cities of Lagos and Ilorin. The former city is located in the coastal area, and it is highly congested with a high intensity of marine, vehicular, and industrial activities, and the latter city is a medium size town, located in the central guinea savannah zone of Nigeria. Samples were collected using a high-volume sampler from near the ground at various sites of diverse human and industrial activities, during wet and dry seasons from 2003 to 2006. The PCA reveals three distinct groupings during the day for all data, which is a reflection of different factors contributing to the atmospheric chemistry of these cities. The predicted ozone concentration values by MLR agree fairly well with the measured data. The dependence of ozone on meteorological parameters including relative humidity, air temperature, and sun exposure and the precursor pollutants depends on weather and the anthropogenic activities. The results for the two cities indicate that reduction in the level of NO₂ is accompanied by an increase in the level of ozone, suggesting the interconversion between the two via photochemical activity.     

不同冬夏寄主棉蚜种群重复序列引物DNA多态性分析

应用重复序列引物ＰＣＲ技术研究了中国不同冬夏寄主上棉蚜种群的ＤＮＡ多态性,通过筛选出的３种适用于棉蚜的重复序列引物,用它们的扩增结果进行相似性指数Ｉｓ和Ｎｅｉ’ｓ遗传距离Ｄ的计算,并根据遗传距离对所研究的棉蚜种群做聚类分析,结果表明,用遗传距离指标可以将冬夏寄主上的棉蚜分开,并且在不同的冬寄主之间,较适宜越冬的不同寄主上的棉蚜呈现出更大的相似性。在实验数据的分析过程中,还发现遗传距离指标比相似性指     

填埋垃圾和渗滤液中CH4氧化菌的丰度研究

应用实时荧光定量聚合酶链式反应(Real-Time Quantitative Polymerase Chain Reaction,简称实时荧光定量PCR)技术对填埋场垃圾和渗滤液中CH₄氧化菌的pmoA基因进行定量分析. 结果表明:实时荧光定量PCR技术可用于渗滤液和垃圾中CH₄氧化菌的定量分析. 对于厌氧和准好氧填埋,初期渗滤液中CH₄氧化菌的数量均高于稳定期;准好氧填埋体渗滤液中CH₄氧化菌的数量均高于厌氧填埋体. 准好氧填埋垃圾中CH₄氧化菌的数量随着填埋龄的增加呈先增加后降低的趋势,并在填埋后的9个月左右达到最大值,与准好氧填埋体CH₄产生的规律相似. 同时,准好氧填埋垃圾中CH₄氧化菌的数量随着距导气管距离的增加而降低,但不同填埋时期的变幅不同,与准好氧填埋体O₂和CH₄的迁移规律有关. 此外,对渗滤液和垃圾样品的研究表明,准好氧填埋体垃圾填埋层内部存在大量的CH₄氧化菌,具有显著的CH₄氧化能力.      

升级A/O工艺污水处理系统中抗生素抗性基因的分布与去除研究

针对北方某采用升级A/O工艺的生活污水处理厂,使用实时荧光定量PCR技术,探究污水厂中ARGs的分布及各处理工艺段对ARGs的去除效果.结果表明：四环素抗性基因（tetA、tetC和tetM）、磺胺抗性基因（sul1和sul2）、大环内酯抗性基因（ermA和ermF）和喹诺酮抗性基因（parC和gyrA）在污水和污泥中均被检出.污水厂进水中ARGs的绝对丰度为2.65×10³~1.01×10⁶ copies·mL^-1,升级A/O工艺未能有效削减ARGs,出水中ARGs的绝对丰度为9.22×10³~1.15×10⁶ copies·mL^-1,污泥中ARGs的绝对丰度为8.07×10⁷~2.65×10¹¹ copies·g^-1.深度处理工艺对ARGs的去除效率对比结果显示,生物活性炭工艺对ARGs的削减效果优于紫外消毒.     

基于PMA-定量PCR选择性检测技术的病原菌消毒特性研究

建立了一种核酸染料propidium monoazide(PMA)与定量PCR技术联合选择性检测活性病原菌的技术(PMA-qPCR),以大肠杆菌作为模式菌,研究了氯和一氯胺消毒对病原菌的灭活特性.结果表明,PMA染料能够分别去除99.94%和99.99%的来自非活性大肠杆菌和沙门氏菌的DNA,PMA-qPCR技术能够有效区分活性菌与非活性菌;PMA-qPCR技术得到的氯和一氯胺消毒对大肠杆菌的灭活曲线符合一级动力学方程,灭活速率常数分别为 2.24 L·(mg·min)^-1和0.0175 L·(mg·min)^-1,低于平板培养法得到的灭活速率常数;当大肠杆菌的去除率达到99%时,采用PMA-qPCR技术检测需要的ct值相比于平板培养法从0.6 mg·L^-1·min上升到0.9 mg·L^-1·min(氯消毒)和从20 mg·L^-1·min上升到超过100 mg·L^-1·min(一氯胺消毒);随着ct值的升高,常规qPCR的检测结果基本不变,因此常规qPCR不能够反映氯和一氯胺消毒对病原菌的灭活效果.作为一种新的表征消毒特性的检测技术,PMA-qPCR技术有助于更为准确地评价氯和一氯胺消毒对病原菌的灭活效果.     

慢生型大豆根瘤菌的遗传多样性研究

采用选择性扩增片断长度多态性 (简称AFLP)DNA指纹技术对来自泰国北部的 2 45株慢生型大豆根瘤菌进行遗传多样性的研究 .通过AFLP图谱揭示出该地区的慢生型大豆根瘤菌有较显著的遗传多样性 .从 2 45株中选择出 92个代表株用计算机进行的树状图分析结果表明 ,所分析的菌株在 82 %的相似性水平上聚类成 8个群 .对这 92个代表株的部分菌株和慢生型大豆根瘤菌的参比菌株进行多聚酶链反应 (PCR)扩增的 16SrDNA的 4种限制性内切酶长度多态 (简称 16SrDNAPCR RFLP)分析 ,得出 2个不同的 16SrDNAPCR RFLP类型的菌株 ,分别与慢生型大豆根瘤菌的参比菌株Bradyrhizobiumjaponicum和Bradyrhizobiumelkanii相同 .图 1表 2参 14     

小麦高分子量谷蛋白亚基基因的PCR及AS-PCR标记

选用高分子量麦谷蛋白亚基(HMW-GS)在Glu-D1位点已知的 26个普通小麦品种,包括 15个 (TriticumaestivumL. )川育系列品种及其 11个亲本,根据其亚基Dx5和Dy10基因的特异序列设计引物.通过对Dx5基因的PCR扩增及对Dy10基因的AS-PCR扩增,结果表明,所设计的引物对Dx5和Dy10都能扩增出特异条带,而携有Dx5基因的材料同时也携有Dy10基因.说明用所设计的引物可快速有效的鉴定出普通小麦中是否带有优质的 5 10亚基.图 4参 15     

Detection of dioxygenase genes present in various activated sludge

GOAL, SCOPE AND BACKGROUND: Activated sludge from refineries contains various microorganisms that could utilize aromatics under aerobic conditions due to the oxygenase enzymes. Dioxygenase enzymes are oxygenases, which are involved in the ring cleavage step of aromatic hydrocarbons. In this study, the selected catabolic loci involved in ring cleavage have been monitored in the activated sludge samples at different time intervals. The investigation of the dioxygenase genes in the Effluent Treatment Plants (ETPs) and evaluation of their presence at different time points provides a clue for the aromatic utilizing potential of the inherent microbial flora. METHODS: The catabolic gene loci pheB, xylE, tod-isp, bed and nahG responsible for the enzymes catechol 1,2-dioxygenase, catechol 2,3-dioxygenase, toluene dioxygenase-iron-sulphur protein component, benzene dioxygenase and naphthalene dioxygenase were used respectively. The time dependent change in eubacterial population was demonstrated by the amplification of 16S rDNA product, followed by restriction digestion. The template DNA was obtained from the activated sludge collected from ETPs. The supporting physiological data for the overall performance of sludge was developed using respirometric analysis. The on-site COD and MLSS analysis for ETP was used in final evaluation. The study was carried out with samples collected from three different ETPs and also from a selected ETP at different time intervals. RESULTS AND DISCUSSION: The respirometric studies were carried out with phenol, catechol, toluene, and naphthalene to arrive at the target genotypes for further study by PCR protocol. The respirometric analysis coupled with the COD and MLSS analysis represented the physiological capacity of the various sludges. Initially, the tracking protocol was optimized by using different sludge samples, which were collected from refineries. The selected genotypes were amplified and their presence has been confirmed using Southern analysis. The gene loci tod-isp, bed and xylE were commonly observed at various time intervals of the sludge from the same source. The gene loci pheB and nahG were found to be relatively rare. CONCLUSION: The 16S rDNA PCR products after restriction digestion produced different DNA fingerprint patterns, suggesting that the microbial community composition was diverse in the three sources. Similarly, the presence of the catechol 2,3-dioxygenase, benzene dioxygenase and toluene dioxygenase genes confirmed the aromatic degrading potential in the various sludges. The probes could not pick the nahG and pheB genes. However, the respirometeric assay suggested that the oxidative capacity to use naphthalene as a substrate exists. RECOMMENDATION AND PERSPECTIVE: Our study of the diversity at various time points from the ETP provided an overview of the shifts of the catabolic composition of the sludge. This also depends on the influential parameters like the incoming pollutant level and the environmental conditions that are prevailing and often changing from time to time. The results of direct DNA extraction and PCR amplification do reflect the relative abundance of a particular catabolic genotype, which could be used to monitor the efficiency of treatment.     

水源型水库抗生素抗性基因赋存特征研究

饮用水水源地中抗生素抗性基因会威胁生态安全和人类健康.为了探究抗生素抗性基因(Antibiotic Resistance Genes,ARGs)在金泽水源型水库中的赋存特征,以及水库净化措施对抗生素抗性基因的净化作用,选择微生物活性较高的夏季时期采集水样,采用高通量荧光定量PCR和16S rRNA实时荧光定量PCR进行研究.结果表明,该水库检出62种ARGs;多重抗药类、氨基糖苷类和磺胺类ARGs为水库内占主导的抗性基因.抗生素抗性基因绝对丰度从水库的预处理区至生态净化区,再至输水区呈逐渐降低的趋势,表明水库净化措施对削减ARGs含量有一定作用.抗性基因丰度与可移动基因元件(Mobile Genetic Elements,MGEs)丰度存在显著相关性(p0.05),表明MGEs对ARGs的水平转移、传播和富集具有重要作用.     

1株筛自柴油污染土壤的铜绿假单胞菌对萘的降解特性研究

从柴油污染土壤中筛选分离出1株萘降解菌HD-5,经16S r DNA序列分析鉴定为铜绿假单胞菌(Pseudomonas aeruginosa),对功能基因进行PCR扩增证实该菌株中含有萘双加氧酶基因nah.采用生物强化、生物刺激以及二者相结合的方式修复萘含量为0.5%的自配污染土壤,综合比较了在不同修复方式下土壤中萘的降解率,修复过程中土壤FDA水解酶活和脱氢酶活的变化,以及运用定量PCR的方法动态分析了总细菌基因拷贝数和nah基因拷贝数.结果表明,在生物强化(B)、生物刺激(S)以及生物强化与生物刺激相结合(BS)这3种修复方式下,31 d后萘去除率分别为71.94%、62.22%和83.14%,BS组在修复过程中土壤FDA水解酶活和脱氢酶活明显高于另外两组,31 d后BS组土壤中总细菌基因拷贝数和nah基因拷贝数分别增长了约2.67×1011g-1和8.67×108g-1.上述研究结果表明筛选得到的萘降解菌株在土壤中具有良好的定植特性,在生物刺激与该降解菌株的共同作用下,可以有效地实现土壤中萘降解,这对此类污染生物修复过程研究具有一定的指导意义.