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311.
312.
Responses of activities, abundances and community structures of soil denitrifiers to short-term mercury stress 总被引:3,自引:0,他引:3
Zhifeng Zhou Yuanming Zheng Jupei Shen Limei Zhang Yurong Liu Jizheng He 《环境科学学报(英文版)》2012,24(3):369-375
The responses of activities, abundances and community structures of soil denitrifiers to mercury (Hg) stress were investigated through a short-term incubation experiment. Four soil treatments with different concentrations of Hg (CK, Hg25, Hg50, and Hg100, denoted as 0, 25, 50, and 100 mg Hg/kg dry soil, respectively) were incubated for 28 days. Soil denitrification enzyme activity (DEA) was measured at day 3, 7 and 28. The abundances and community structures of two denitrification concerning genes, nirS (cd1-nitrite reductase gene) and nosZ (nitrous oxide reductase gene), were analyzed using real-time PCR and denaturing gradient gel electrophoresis (DGGE). Results showed that soil DEA was significantly stimulated in the treatments of Hg25 and Hg50 compared with others at day 7. Meanwhile, no difference in the abundances of soil nirS and nosZ was found between Hg spiked treatments and CK, except the lower abundance of nirS (P<0.05) in the Hg added treatments compared with that in the CK at day 28. The community structures of denitrifiers based on nirS gene presented obvious change at day 7 along with the Hg additions, however, no variation was found in all treatments based on the nosZ gene. The results indicated that Hg (Hg25 and Hg50) had a strongly short-term stimulation on soil DEA, and nirS gene is more sensitive than nosZ gene to Hg stress. 相似文献
313.
Lake Taihu, a large, shallow hypertrophic freshwater lake in eastern China, has experienced lake-wide toxic cyanobacterial blooms annually during summer season in the past decades. Spatial changes in the abundance of hepatotoxin microcystin-producing and non-microcystin producing Microcystis populations were investigated in the lake in August of 2009 and 2010. To monitor the densities of the total Microcystis population and the potential microcystin-producing subpopulation, we used a quantitative real-time PCR assay targeting the phycocyanin intergenic spacer (PC-IGS) and the microcystin synthetase gene (mcyD), respectively. On the basis of quantification by real-time PCR analysis, the abundance of potential toxic Microcystis genotypes and the ratio of the mcyD subpopulation to the total Microcystis varied significantly, from 4.08× 104 to 5.22× 107 copies/mL, from 5.7% to 65.8%, respectively. Correlation analysis showed a strong positive relationship between chlorophyll-a, toxic Microcystis and total Microcystis; the abundance of toxic Microcystis correlated positively with total phosphorus and ortho-phosphate concentrations, but negatively with TN:TP ratio and nitrate concentrations. Meanwhile the proportion of potential toxic genotypes within Microcystis population showed positive correlation with total phosphorus and ortho-phosphate concentrations. Our data suggest that increased phosphorus loading may be a significant factor promoting the occurrence of toxic Microcystis bloom in Lake Taihu. 相似文献
314.
315.
将以原油驯化所得的纯培养微生物菌株作为模板,采用PCR(聚合酶链式反应)法,用扩增细菌16S rDNA的一对通用引物(8 f,1492 r)对模板扩增,并用限制性内切酶R saI和M spI对PCR产物进行ARDRA多态性分析。聚类去除重复菌株后60株菌株可分为11种不同分类操作单元(OTU),同时得出每个分类操作单元的数量。实验结果表明,此方法可快速去除重复菌株并反映出菌株间的系统进化关系;同时实验数据可构建成库,使后续分离菌株的筛选工作只需比对数据即可完成。 相似文献
316.
The expression levels of cytochrome P450 1A, p53 and vitellogenin were investigated in three different tissues of male medaka fish after exposure to diclofenac that is one of the main concerns among pharmaceuticals frequently found in sewage treatment plant (STP) effluents. The results showed that cytochrome P450 1A, p53 and vitellogenin were highly expressed in tissue-specific gene expression patterns after exposure to 8 mg/l and 1 μg/l of diclofenac. These elevated expression levels of three biomarkers suggested that diclofenac has potential to cause cellular toxicity, p53-related genotoxicity and estrogenic effects. It is also noteworthy that diclofenac has the potential to cause these effects even at an environmentally relevant concentration of diclofenac, 1 μg/l. 相似文献
317.
基于高通量定量PCR研究城市化小流域微生物污染特征 总被引:2,自引:0,他引:2
水体微生物污染(包括致病菌、病毒、寄生虫)会引起多种传染病和寄生虫病,对生产生活用水安全和人体健康造成重要威胁。本研究应用基于Taq Man探针的高通量荧光定量PCR技术对厦门市后溪流域冬季微生物污染进行检测,包含了5种粪便污染源(人源、反刍动物源、猪源、家禽源、狗源)微生物源示踪分子标记物与12种病原微生物。结果表明,该流域在上游及水库5个位点没有粪便污染,仅在其中一个水库位点检测出棘阿米巴,微生物污染极小;中下游检测出人类、反刍动物、猪、家禽、狗粪便污染,并且检测出产气荚膜梭菌、肠聚集性大肠杆菌、肠毒素型大肠杆菌、幽门螺杆菌、霍乱弧菌、副溶血弧菌、棘阿米巴、克雷伯氏肺炎杆菌等病原菌,其中流经旧城区居民生活生产区水样微生物污染严重,下游新城区微生物污染较小。这些结果暗示着城市人类活动是流域微生物污染主要来源,应从污染源头加强微生物污染控制。 相似文献
318.
A. Kleyböcker T. Lienen M. Liebrich M. Kasina M. Kraume H. Würdemann 《Waste management (New York, N.Y.)》2014,34(3):661-668
In order to increase the organic loading rate (OLR) and hereby the performance of biogas plants an early warning indicator (EWI-VFA/Ca) was applied in a laboratory-scale biogas digester to control process stability and to steer additive dosing. As soon as the EWI-VFA/Ca indicated the change from stable to instable process conditions, calcium oxide was charged as a countermeasure to raise the pH and to bind long-chain fatty acids (LCFAs) by formation of aggregates. An interval of eight days between two increases of the OLR, which corresponded to 38% of the hydraulic residence time (HRT), was sufficient for process adaptation. An OLR increase by a factor of three within six weeks was successfully used for biogas production. The OLR was increased to 9.5 kg volatile solids (VS) m?3 d?1 with up to 87% of fat. The high loading rates affected neither the microbial community negatively nor the biogas production process. Despite the increase of the organic load to high rates, methane production yielded almost its optimum, amounting to 0.9 m3 (kg VS)?1. Beneath several uncharacterized members of the phylum Firmicutes mostly belonging to the family Clostridiaceae, a Syntrophomonas-like organism was identified that is known to live in a syntrophic relationship to methanogenic archaea. Within the methanogenic group, microorganisms affiliated to Methanosarcina, Methanoculleus and Methanobacterium dominated the community. 相似文献
319.
反硝化细菌在人工湿地对N元素去除的过程中发挥着关键作用.为了解湿地类型、基质、植被和水力负荷及物理参数对人工湿地反硝化功能细菌丰度的影响,构建了9个不同工艺组合的人工湿地小试装置.利用实时荧光定量PCR技术检测湿地基质中反硝化功能基因nirS,nirK和nosZ的丰度.结果显示,湿地中nirS,nirK和nosZ丰度(以每ng总DNA中的拷贝数计)分别为4.88×103~2.13×105 copies/ng,1.2×101 ~ 2.14×103 copies/ng和1.98×103~ 2.09 × 105copies/ng,其中nirS显著高于nirK丰度,nirS丰度与湿地出水的pH显著正相关.分析湿地4种设计参数对反硝化功能基因丰度的影响程度,结果显示,对nirS丰度影响程度大小依次为湿地类型>植被类型>水力负荷>基质类型,水平潜流和上行垂直流人工湿地中nirS丰度显著高于下行垂直流人工湿地,无植物人工湿地nirS丰度显著高于有植物人工湿地;对nirK丰度影响程度大小依次为湿地类型>植被类型>基质类型>水力负荷,水平潜流人工湿地nirK丰度显著高于下行垂直流湿地;对nosZ丰度影响程度大小依次为湿地类型>水力负荷>植被类型>基质类型,但影响都不显著. 相似文献
320.
Jeong-Ha Yoo Sung-Woo Shin Jong Soo Kim Chang-Bae Kim Jong-Sung Kim Sung-Cheol Koh 《Journal of environmental science and health. Part. B》2013,48(4):373-379
A new differential display-polymerase chain reaction (PCR) method based on annealing control primers was used to screen and identify potential biomarkers from differentially expressed genes (DEGs) in medaka exposed to sub-lethal concentration of diazinon (100 ppb). Among the differentially expressed genes identified, the majority were in functional categories of protein biosynthesis, transport and metabolism according to the gene ontology classification. The differential expression of ribosomal protein genes was quantified by real time PCR. The genes encoding ribosomal proteins including L3 and S17 were selected as potential biomarkers for diazinon exposure in medaka fish. 相似文献