1.Sequence analysis of 16S rDNA and pmoCAB gene cluster of trichloroethylene-degrading methanotroph.
Yunru ZHANG ; Huaqing CHEN ; Yanhui GAO ; Zhilin XING ; Tiantao ZHAO
Chinese Journal of Biotechnology 2014;30(12):1912-1923
Methanotrophs could degrade methane and various chlorinated hydrocarbons. The analysis on methane monooxygenase gene cluster sequence would help to understand its catalytic mechanism and enhance the application in pollutants biodegradation. The methanotrophs was enriched and isolated with methane as the sole carbon source in the nitrate mineral salt medium. Then, five chlorinated hydrocarbons were selected as cometabolic substrates to study the biodegradation. The phylogenetic tree of 16S rDNA using MEGE5.05 software was constructed to identify the methanotroph strain. The pmoCAB gene cluster encoding particulate methane monooxygenase (pMMO) was amplified by semi-nested PCR in segments. ExPASy was performed to analyze theoretical molecular weight of the three pMMO subunits. As a result, a strain of methanotroph was isolated. The phylogenetic analysis indicated that the strain belongs to a species of Methylocystis, and it was named as Methylocystis sp. JTC3. The degradation rate of trichloroethylene (TCE) reached 93.79% when its initial concentration was 15.64 μmol/L after 5 days. We obtained the pmoCAB gene cluster of 3 227 bp including pmoC gene of 771 bp, pmoA gene of 759 bp, pmoB gene of 1 260 bp and two noncoding sequences in the middle by semi-nested PCR, T-A cloning and sequencing. The theoretical molecular weight of their corresponding gamma, beta and alpha subunit were 29.1 kDa, 28.6 kDa and 45.6 kDa respectively analyzed using ExPASy tool. The pmoCAB gene cluster of JTC3 was highly identical with that of Methylocystis sp. strain M analyzed by Blast, and pmoA sequences is more conservative than pmoC and pmoB. Finally, Methylocystis sp. JTC3 could degrade TCE efficiently. And the detailed analysis of pmoCAB from Methylocystis sp. JTC3 laid a solid foundation to further study its active sites features and its selectivity to chlorinated hydrocarbon.
Methylocystaceae
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classification
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metabolism
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Multigene Family
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Oxygenases
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genetics
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Phylogeny
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Polymerase Chain Reaction
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RNA, Ribosomal, 16S
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genetics
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Sequence Analysis, DNA
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Trichloroethylene
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metabolism
2.Comparison of Criminal Characteristics in Depression Patients and Schizophrenics with Homicide Behavior
Jing WANG ; Peixin FU ; Yanli GAO ; Mingxia ZHU ; Tiantao SHI
Journal of Forensic Medicine 2017;33(3):244-246
Objective T o explore the crim inal characteristics of forensic psychiatry expertise in depression patients and schizophrenics w ith hom icide behavior. Methods A total of 40 depression (depressive episode) patients and 50 schizophrenics w ith hom icide behavior w ere random ly assigned into the study group and control group, respectively. D ata of dem ographic and crim inal characteristic of the tw o groups w ere collected by a self-designed questionnaire, and then w ere com pared. Results T here w ere no statis-tical differences in age, education level and career betw een study and control groups (P>0.05). C om pared w ith the control group, the victim s in the study group w ere m ainly the patient's children and parents, and m ost offenders had suicidal behavior after hom icide (70% ). In study group, the m otives of crim e w ere m ainly extended suicide and indirect suicide, and m ost offenders had attem pted suicide (85% ) and dim inished capacity of crim inal responsibility (70% ), w hich in control group had no capacity of crim inal responsibility (56% ). E xcept for crim inal site, there w ere statistical differences in other crim inal charac-teristics betw een tw o groups (P<0.05). Conclusion T here are different crim inal characteristics betw een de-pression patients and schizophrenics w ith hom icide behavior in forensic psychiatry, and these characteris-tics should be considered w hen these tw o diagnoses are distinguished in forensic psychiatry expertise.
3.Effects of copper on biodegradation mechanism of trichloroethylene by mixed microorganisms.
Yanhui GAO ; Tiantao ZHAO ; Zhilin XING ; Zhi HE ; Lijie ZHANG ; Xuya PENG
Chinese Journal of Biotechnology 2016;32(5):621-634
We isolated and enriched mixed microorganisms SWA1 from landfill cover soils supplemented with trichloroethylene (TCE). The microbial mixture could degrade TCE effectively under aerobic conditions. Then, we investigated the effect of copper ion (0 to 15 μmol/L) on TCE biodegradation. Results show that the maximum TCE degradation speed was 29.60 nmol/min with 95.75% degradation when copper ion was at 0.03 μmol/L. In addition, genes encoding key enzymes during biodegradation were analyzed by Real-time quantitative reverse transcription PCR (RT-qPCR). The relative expression abundance of pmoA gene (4.22E-03) and mmoX gene (9.30E-06) was the highest when copper ion was at 0.03 μmol/L. Finally, we also used MiSeq pyrosequencing to investigate the diversity of microbial community. Methylocystaceae that can co-metabolic degrade TCE were the dominant microorganisms; other microorganisms with the function of direct oxidation of TCE were also included in SWA1 and the microbial diversity decreased significantly along with increasing of copper ion concentration. Based on the above results, variation of copper ion concentration affected the composition of SWA1 and degradation mechanism of TCE. The degradation mechanism of TCE included co-metabolism degradation of methanotrophs and oxidation metabolism directly at copper ion of 0.03 μmol/L. When copper ion at 5 μmol/L (biodegradation was 84.75%), the degradation mechanism of TCE included direct-degradation and co-metabolism degradation of methanotrophs and microorganisms containing phenol hydroxylase. Therefore, biodegradation of TCE by microorganisms was a complicated process, the degradation mechanism included co-metabolism degradation of methanotrophs and bio-oxidation of non-methanotrophs.
Biodegradation, Environmental
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Copper
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chemistry
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Methylocystaceae
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metabolism
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Oxidation-Reduction
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Soil Microbiology
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Trichloroethylene
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metabolism