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11.
Influence of oxytetracycline on the structure and activity of microbial
community in wheat rhizosphere soil 总被引:4,自引:1,他引:3
The microbial community composition in wheat rhizosphere was analyzed by detecting colony forming units (CFUs) in agar plates.
The total CFUs in rhizosphere were 1.04 109/g soil with 9.0 108/g bacteria, 1.37 108/g actinomyces and 3.6 106/g fungi. The 10
dominant bacteria were isolated from wheat rhizosphere and were grouped into genus Bacillus according to their full length 16S rRNA
gene sequences. Although belonging to the same genus, the isolated strains exhibited di erent sensitivities to oxytetracycline. When
a series of the rhizosphere soil was exposed under various concentrations of oxytetracycline, the microbial community structure was
highly a ected with significant decline of CFUs of bacteria and actinomyces (22.2% and 31.7% at 10 mg/kg antibiotic, respectively).
This inhibition was clearly enhanced with the increase exposure dosage of antibiotic and could not be eliminated during 30 d incubation.
There was no obvious influence of this treatment on fungi population. Among the four soil enzymes (alkaline phosphatase, acidic
phosphatase, dehydrogenase and urease), only alkaline phosphatase was sensitive to oxytetracycline exposure with 41.3% decline of
the enzyme activity at 10 mg/kg antibiotic and further decrease of 64.3%–80.8% when the dosage over 30 mg/kg. 相似文献
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13.
Ang Li Rui Cai Di Cui Tian Qiu Changlong Pang Jixian Yang Fang M Nanqi Ren 《环境科学学报(英文版)》2013,25(11):2281-2290
Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature (10℃) from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions: pH 7.0, 10℃, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr^-1 and 32.5 mg/L, respectively. 相似文献
14.
Denitrification characteristics of a marine origin psychrophilic aerobic denitrifying bacterium 总被引:3,自引:0,他引:3
Haiyan Zheng Ying Liu Guangdong Sun Xiyan Gao Qingling Zhang Zhipei Liu 《环境科学学报(英文版)》2011,23(11):1888-1893
A psychrophilic aerobic-denitrifying bacterium was isolated, identified as Psychrobacter sp., and characterized, it performed efficient aerobic-denitrification at low temperature and might be useful in nitrogen removal treatment for low temperature wastewater. 相似文献
15.
ZHANG Xiaoli ZHANG Huiwen LI Xu SU Zhencheng WANG Jingjing ZHANG Chenggang 《环境科学学报(英文版)》2009,21(9):1253-1260
A yeast strain which was capable of degrading sulfonylurea herbicide chlorimuron-ethyl named as LF1 was isolated from a
chlorimuron-ethyl contaminated soil near the warehouse of the factory producing chlorimuron-ethyl in Shenyang City, Northeast China.
The strain was identified as Sporobolomyces sp., based on its morphological and physiological characteristics and the phylogenetic
analysis of 18S rRNA gene sequence. So far, this is the only yeast strain of Sporobolomyces sp. which is able to degrade chlorimuronethyl.
Incubation tests showed that when the initial concentration of chlorimuron-ethyl in culture was 5 mg/L, LF1 could degrade more
than 77% of the herbicide after incubation for 4 d at 30°C. The possible mechanism of chlorimuron-ethyl degradation by LF1 could be
the acidic hydrolysis caused by the acids from the metabolism of the yeast strain. Further study should be conducted to examine the
pathways of chlorimuron-ethyl degradation by LF1 and to approach the feasibility of using LF1 to degrade the chlorimuron-ethyl in
soil system. 相似文献
16.
Changes of microbial community structures and functional genes during
biodegradation of phenolic compounds under high salt condition 总被引:1,自引:1,他引:0
The changes of microbial community structures and functional genes during the biodegradation of single phenol and phenol plus p-cresol under high salt condition were explored.It was found that the phenol-fed system (PFS) exhibited stronger degrading abilities and more stable biomass than that of the phenol plus p-cresol-fed system (PCFS).The microbial community structures were revealed by a modern DNA fingerprint technique,ribosomal intergenic spacer analysis (RISA).The results indicated that the microbial community of PFS changed obviously when gradually increased phenol concentration,while PCFS showed a little change.16S rRNA sequence analysis of the major bands showed that Alcanivorax sp.genus was predominant species during phenolic compounds degradation.Furthermore,amplified functional DNA restriction analysis (AFDRA) on phenol hydroxylase genes showed that the fingerprints were substantially different in the two systems,and the fingerprints were not the same during the different operational periods. 相似文献
17.
Profenofos, a well known organophosphate pesticide, has been in agricultural use over the last two decades for controlling
Lepidopteron pests of cotton and tobacco crops. In this study, a bacterial strain, OW, was isolated from a long term profenofos exposed
soil by an enrichment technique, and its ability to degrade profenofos was determined using gas chromatography. The isolated strain
OW was identified as Pseudomonas aeruginosa according to its physiological and biochemical properties, and the analysis of its 16S
rRNA gene sequence. The strain grew well at pH 5.5–7.2 with a broad temperature profile. Bioremediation of profenofos-contaminated
soil was examined using soil treated with 200 g/g profenofos, which resulted in a higher degradation rate than control soils without
inoculation. In a mineral salt medium (FTW), removal in the level of profenofos of 86.81% was obtained within 48 h of incubation.
The intermediates of profenofos metabolism indicated that the degradation occurred through a hydrolysis mechanism, and one of the
metabolites was found to be 4 bromo-2-cholorophenol (BCP) which in turn was also mineralized by the strain. The results of this study
highlighted the potentiality of P. aeruginosa as a biodegrader which could be used for the bioremediation of profenofos contaminated
soil. 相似文献
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采用PCR法获得不动杆菌Acinetobactor sp.YY-5的一种羟胺氧化酶(Hydroxylamine oxidoreductase,HAO)编码基因序列并进行生物信息学分析.根据自养菌的HAO基因序列保守区设计4对引物,通过RT-PCR获得预期大小的部分序列,再采用Genome walking PCR法向所得的部分序列两侧延伸;对所得序列在NCBI中进行blast分析,并用FGeneSB进行开放滨码框(Open read frame,ORF)预测.结果表明,RT-PCR获得了一段462 bp的序列,通过Genome walking PCR向两侧延伸后,获得了一段3 152 bp长的序列;ORF预测结果显示所得序列可能有4个ORF,RT-PCR获得的462 bp序列所在ORF长555 bp,对应氨基酸序列相对分子质量(M)大小为20.2×103;在Genebank中进行的Blast比对分析显示,除保守区的引物序列外,未发现有与此ORF存在明显相似性的HAO基因,表明这可能是一种新型羟胺氧化酶基因.图5表3参14 相似文献
20.
Polyhydroxyalkanoates(PHAs) are aliphatic polyesters accumulated intracellularly by both Gram-negative and Gram-positive bacteria. However, compared to the PHAs of Gramnegative bacteria, few endotoxins(lipopolysaccharides, LPS), which would be co-purified with PHAs and cause immunogenic reactions, are found in the PHAs produced by Gram-positive bacteria. A thermophilic Gram-positive bacterium K5, which exhibited good growth and polyhydroxybutyrate(PHB)-accumulating ability, has been isolated and characterized from a biotrickling filter designed for the removal of NOx from flue gas in a coal-fired power plant in China. Based on the biochemical characterization and 16 S rRNA gene sequence(Genbank accession no. JX437933), the strain K5 has been identified as Bacillus shackletonii, which has rarely been reported in the literature, and this report is the first time that B. shackletonii has been found to accumulate PHB. The strain K5 was able to utilize glucose as carbon source to synthesize PHB at a broad range of temperatures(from 35 to 50 °C), and the ideal temperature was 45 °C. The strain K5 could effectively yield PHB of up to 69.9% of its cell dry weight(CDW)(2.28 g/L) in flask experiments employing glucose as carbon source at 45 °C, followed by 56.8% and 52.3% of its CDW when using sodium succinate and glycerol as carbon source, respectively. For batch cultivation, the strain K5 was able to produce PHB of up to 72.6% of its cell dry weight(9.76 g/L) employing glucose as carbon source at 45 °C and pH 7.0. 相似文献