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排序方式: 共有561条查询结果,搜索用时 15 毫秒
41.
Change of bacterial communities in sediments along Songhua River in Northeastern China after a nitrobenzene pollution event 总被引:1,自引:0,他引:1
More than 100 tons of nitrobenzene and related compounds were released into Songhua River due to the explosion of an aniline production factory in November, 2005. Sediment samples were taken from the heavily polluted drainage canal, one upstream and three downstream river sites. The change of bacterial community structures along the river was studied by denaturing gradient gel electrophoresis (DGGE) and cloning and sequencing of 16S rRNA genes with five clone libraries constructed and 101 sequences acquired representing 172 clones. Both DGGE profiles and sequences of 16S rRNA genes from clone libraries demonstrated that the contaminated drainage canal and three downstream river sites were similar in that all had Betaproteobacteria , mainly grouped into Comamonadaceae , as the dominant group of bacteria, and all had Firmicutes , primarily as Clostridium spp. These results suggest that these latter two groups of bacteria may play potential roles in degradation and detoxification of nitrobenzene in the present contaminated river environments. 相似文献
42.
Hanene Cherif Hadda Ouzari Massimo Marzorati Lorenzo Brusetti Naceur Jedidi Abdennaceur Hassen Daniele Daffonchio 《World journal of microbiology & biotechnology》2008,24(7):1159-1167
Bacterial community structure and diversity of Tunisian agricultural soil treated with different amounts of municipal solid
waste compost (MSWC) and other fertilizers were studied using DGGE and ARISA fingerprinting methods. Sequence analysis of
dominant DGGE bands revealed the presence of three major clusters, Cytophaga/Flexibacter/Bacteroides (CFB) group, Proteobacteria and Acidobacteria group. Using ARISA profiles, dominant populations were assigned to low and high GC Gram positive bacteria, Cyanobacteria, Spirochetes and Cytophagales. The two methods revealed the absence of significant bacterial community shifts related to the different MSWC applications.
Moreover, indigenous bacterial population of the used loam-clayey soil was observed to limit proliferation and survival of
Proteobacteria, initially dominant in MSWC and farmyard manure. Effectiveness of the two methods for soil bacterial community studying was
shown. While DGGE was more accurate for bacterial identification, ARISA was more practical for handling and rapid estimation
of dominant bacteria. 相似文献
43.
van Leerdam RC Bonilla-Salinas M de Bok FA Bruning H Lens PN Stams AJ Janssen AJ 《Biotechnology and bioengineering》2008,101(4):691-701
Anaerobic methanethiol (MT) degradation by mesophilic (30 degrees C) alkaliphilic (pH 10) communities was studied in a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor inoculated with a mixture of sediments from the Wadden Sea (The Netherlands), Soap Lake (Central Washington), and Russian soda lakes. MT degradation started after 32 days of incubation. During the first 252 days, complete degradation was achieved till a volumetric loading rate of 7.5 mmol MT/L/day, and sulfide, methane, and carbon dioxide were the main reaction products. Temporary inhibition of MT degradation occurred after MT peak loads and in the presence of dimethyl disulfide (DMDS), which is the autooxidation product of MT. From day 252 onwards, methanol was dosed to the reactor as co-substrate at a loading rate of 3-6 mmol/L/day to stimulate growth of methylotrophic methanogens. Methanol was completely degraded and also a complete MT degradation was achieved till a volumetric loading rate of 13 mmol MT/L/day (0.77 mmol MT/gVSS/day). However, from day 354 till the end of the experimental run (day 365), acetate was formed and MT was not completely degraded anymore, indicating that methanol-degrading homoacetogenic bacteria had partially outcompeted the methanogenic MT-degrading archea. The archeal community in the reactor sludge was analyzed by DGGE and sequencing of 16S rRNA genes. The methanogenic archea responsible for the degradation of MT in the reactor were related to Methanolobus oregonensis. A pure culture, named strain SODA, was obtained by serial dilutions in medium containing both trimethyl amine and dimethyl sulfide (DMS). Strain SODA degraded MT, DMS, trimethyl amine, and methanol. Flow sheet simulations revealed that for sufficient MT removal from liquefied petroleum gas, the extraction and biological degradation process should be operated above pH 9. 相似文献
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46.
John R. Haines Ronald Herrmann Kenneth Lee Susan Cobanli Christian Blaise 《Bioremediation Journal》2002,6(3):283-296
During a controlled oil spill study in a freshwater wetland, four methods were used to track changes in microbial populations in response to in situ remediation treatments, including nutrient amendments and the removal of surface vegetation. Most probable number (MPN) estimates of alkane and aromatic hydrocarbon degraders showed divergence of the alkane and aromatic degrading populations during the first summer of the experiment. Alkane degraders increased in all plots by 1.5 orders of magnitude and aromatic degraders increased in oiled plots by 3.5 orders of magnitude. Phospholipid fatty acid (PLFA) analysis of biomass and community composition showed no essential differences among treatments. Denaturing gradient gel electrophoresis (DGGE) analysis of the sediment microbial community showed some differences in specific populations of organisms with respect to oiled and unoiled plots. Some organisms were only found in the oiled plots. Sediment toxicity measured against single celled algae showed that the oiled sediments were toxic into the second year of the study, but that nutrient addition relieved the toxicity more rapidly than natural attenuation of the oil. 相似文献
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48.
Phenylketonuria (PKU) is a widespread autosome recessive hereditary disease caused by a deficiency of the liver enzyme phenylalanine
hydroxylase, which results in distortion of metabolism of phenylalanine and accumulation of toxic metabolites. The knowledge
of molecular bases of PKU is of a high social importance as it enables phenotypic correction of the disease in the case of
its early diagnostics. This disease is known to be associated with mutations in the phenylalanine hydroxylase gene, the distribution
and mutation spectrum having pronounced ethnic and regional features. We studied the spectrum of mutations in the phenylalanine
hydroxylase gene in a group of patients with PKU from the Novosibirsk region to reveal 10 missense point mutations, 1 mutation
in the splice donor site, and 1 microdeletion. For these mutations, most widely distributed in the region, we used straightforward
detection methods basing on the restriction fragment length polymorphism (RFLP), artificial constructed restriction sites
(ACRS) PCR, and denaturing gradient gel electrophoresis (DGGE). 相似文献
49.
This study was aimed to authenticate and present phylogenetic relationship among 19 species of genus Chlorophytum using DNA barcoding. In all, 107 accessions were analyzed with eight plastid (matK, rbcL, trnH-psbA, rpoC1, ycf5, rpoB, atp and psbK-psbI) and six nuclear (ITS) markers. The matK and rbcL were found to be ideal markers for identification and discrimination of Chlorophytum species. Phylogenetic analysis based on matK and rbcL sequences resolved the species in two major clades. All markers, except matK and rbcL, showed ambiguous reads and paralogy in analysis. DGGE analysis showed the presence of pseudogenes and/or co-amplification in these markers, which caused poor sequence quality. Phylogeny and probable evolution of genus Chlorophytum was proposed on the basis of cytological, morphological and genetic information. 相似文献
50.
Prakaimuk Saraithong Yihong Li Kanokporn Saenphet Zhou Chen Panuwan Chantawannakul 《Insect Science》2017,24(1):81-92
Bacterial communities are known to play important roles during the developmental stages of insects, but current knowledge of bacteria associated with the midgut of Apis dorsata, the giant Asian honeybee, is limited. Using polymerase chain reaction‐denaturing gradient gel electrophoresis analysis (PCR‐DGGE) and 16S rRNA sequencing, the aim of this study was to determine the dynamics of bacterial community structure across four A. dorsata life stages in different geographical locations. The results reveal that bacterial diversity increased as the bee progressed through larval stage to newly emerged worker and old worker. However, in the pupal stage, no bands identified as bacteria could be observed. Overall, 2 bacterial phyla (Proteobacteria and Firmicutes) and 4 classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Bacilli) were identified, but the frequency varied among the different stages and locations. The classes of Gammaproteobacteria and Bacilli dominated among larval, newly emerged worker and old worker developmental stages. 相似文献