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Seasonal and spatial distribution of ammonia-oxidizing microorganism communities in surface sediments from the East China Sea 被引量:3
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作者 HE Hui ZHEN Yu +2 位作者 MI Tiezhu LU Xinglan YU Zhigang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第8期83-92,共10页
Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea (AOA) and betaproteobacteria (13-AOB) in surface sediments from ... Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea (AOA) and betaproteobacteria (13-AOB) in surface sediments from the East China Sea (ECS) were investigated using ammonia monooxygenase ct subunit (amoA) gene. In order to characterize the community of AOA and 13-AOB, real-time quantitative polymerase chain reaction (qPCR) was carried out in this study, along with environmental parameters. The abundance of 13-AOB amoA gene (2.17x 10^6-4.54x10^7 copy numbers per gram wet weight sediment) was always greater than that ofAOA amoA gene (2.18x 105-9.89x 10^6 copy numbers per gram wet weight sediment) in all sampling stations. The qPCR results were correlated with environmental parameters. AOA amoA gene copy numbers in April were positively related to temperature and nitrite concentration (p〈0.05). 13-AOB amoA gene copy numbers in August correlated negatively with salinity (p〈0.01), and correlated positively with ammonium concentration (p〈0.05). With the increase of salinity, the amoA gene copy ratio of AOB to AOA had a tendency to decrease, which suggested 13-AOB dominated in the area of high level ammonium and AOA preferred high salinity area. 展开更多
关键词 ammonia-oxidizing microorganisms sediment East China Sea
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Compositional Shifts in Ammonia-Oxidizing Microorganism Communities of Eight Geographically Different Paddy Soils —Biogeographical Distribution of Ammonia-Oxidizing Microorganisms 被引量:3
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作者 Lu Lu Huilin Li +3 位作者 Yan He Jing Zhang Juan Xiao Chao Peng 《Agricultural Sciences》 2018年第3期351-373,共23页
Soil nitrification is mediated by ammonia-oxidizing archaea (AOA) and bacteria (AOB), which occupy different specialized ecological niches. However, little is known about the diversification of AOA and AOB communities... Soil nitrification is mediated by ammonia-oxidizing archaea (AOA) and bacteria (AOB), which occupy different specialized ecological niches. However, little is known about the diversification of AOA and AOB communities in a large geographical scale. Here, eight paddy soils collected from different geographic regions in China were selected to investigate the spatial distribution of AOA and AOB, and their potential nitrification activity (PNA). The result showed that the abundance of AOA was predominant over AOB, indicating that the rice fields favor the growth of AOA. PNA highly varied from 0.43 to 3.57 μg NOX-N·g·dry·soil·h-1, and was positively related with soil NH3 content, the abundance of AOA community, and negatively related with the diversity of AOB community (P amoA genes revealed remarkable differences in the compositions of AOA and AOB community. Phylogenetic analyses of amoA genes showed that Nitrosospiracluster-3-like and Nitrosomonas cluster 7-like AOB extensively dominated the AOB communities, and 54d9-like AOA within the soil group 1.1b predominated in AOA communities in paddy soils. Redundancy analysis suggested that the spatial variations of AOA community structure were influenced by soil TN content (P < 0.01), while no significant correlation between AOB community structure and soil properties was found. Findings highlight that ammonia oxidizers exhibit spatial variations in complex paddy fields due to the joint influence of soil variables associated with N availability. 展开更多
关键词 PADDY Soil ammonia-oxidizing microorganism NITRIFICATION Activity Large Geographical Scale Diversification
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Responses of plant diversity and soil microorganism diversity to nitrogen addition in the desert steppe,China
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作者 YE He HONG Mei +4 位作者 XU Xuehui LIANG Zhiwei JIANG Na TU Nare WU Zhendan 《Journal of Arid Land》 SCIE CSCD 2024年第3期447-459,共13页
Nitrogen(N)deposition is a significant aspect of global change and poses a threat to terrestrial biodiversity.The impact of plant-soil microbe relationships to N deposition has recently attracted considerable attentio... Nitrogen(N)deposition is a significant aspect of global change and poses a threat to terrestrial biodiversity.The impact of plant-soil microbe relationships to N deposition has recently attracted considerable attention.Soil microorganisms have been proven to provide nutrients for specific plant growth,especially in nutrient-poor desert steppe ecosystems.However,the effects of N deposition on plant-soil microbial community interactions in such ecosystems remain poorly understood.To investigate these effects,we conducted a 6-year N-addition field experiment in a Stipa breviflora Griseb.desert steppe in Inner Mongolia Autonomous Region,China.Four N treatment levels(N0,N30,N50,and N100,corresponding to 0,30,50,and 100 kg N/(hm2•a),respectively)were applied to simulate atmospheric N deposition.The results showed that N deposition did not significantly affect the aboveground biomass of desert steppe plants.N deposition did not significantly reduce the alfa-diversity of plant and microbial communities in the desert steppe,and low and mediate N additions(N30 and N50)had a promoting effect on them.The variation pattern of plant Shannon index was consistent with that of the soil bacterial Chao1 index.N deposition significantly affected the beta-diversity of plants and soil bacteria,but did not significantly affect fungal communities.In conclusion,N deposition led to co-evolution between desert steppe plants and soil bacterial communities,while fungal communities exhibited strong stability and did not undergo significant changes.These findings help clarify atmospheric N deposition effects on the ecological health and function of the desert steppe. 展开更多
关键词 soil microorganisms plant-microbial community interaction plant diversity nitrogen deposition desert steppe
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The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans
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作者 Rui Zhang Taixiang Chen +4 位作者 Zhenjiang Chen Hao Chen Xuekai Wei Malik Kamran Chunjie Li 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第3期567-580,共14页
In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts f... In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans. 展开更多
关键词 Achnatherum inebrians water immersion liquid aqueous leachate precipitate ALLELOPATHY Elymus nutans soil microorganisms
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Bibliometric analysis of soil phosphate solubilizing microorganisms research using VOSviewer
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作者 Xian-yuan Du Dan-dan Li +2 位作者 Qiang-wei Wang Han-yu Zhang Yang Yang 《Life Research》 2024年第1期10-15,共6页
Phosphorus-solubilizing microbes play key roles in improving phosphorus availability and in alleviating phosphorus nutrient limitation in soils. However, we did not have a comprehensive understanding of the overall re... Phosphorus-solubilizing microbes play key roles in improving phosphorus availability and in alleviating phosphorus nutrient limitation in soils. However, we did not have a comprehensive understanding of the overall research progress and development trend of phosphorus solubilizing microorganisms. In this study, we obtain documents from the Web of Science (WOS) core collection between 2002 and 2022, and a comprehensive review of the progress of global research on soil phosphate solubilizing microorganisms was conducted by using the VOSviewer bibliometric analysis tool. The results showed an increasing trend in the number of published articles from 2002 to 2022. India, accounting for 28% of the total number of published articles, became the most productive country. However, Canada was the country with the highest average citation frequency of articles. Chinese Academy of Sciences (CAS) was the greatest contributor with the most publications. Among the published journals, Frontiers in Microbiology, Applied Soil Ecology and Plant and Soil were the top three core journals in this field. Based on the keyword analysis, the assessment of the mechanisms between phosphorus solubilizing microbes and the soil carbon cycles with the different management practices became the new research trend among the scientific communities. These findings would provide an important reference value for future in-depth research on soil phosphate solubilizing microorganisms. 展开更多
关键词 SOIL phosphate solubilizing microorganisms BIBLIOMETRICS VOSviewe
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Identification of Microorganisms in Poultry Farms in N’djamena and the Border Areas of Hadjer-Lamis and Chari-Baguirmi Chad
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作者 Abakar Abbo Zakaria Bebanto Antipas Ban-Bo +2 位作者 Nadine Terei Bongo Naré Richard Gandolo Abdelsalam Adoum Doutoum 《Journal of Agricultural Chemistry and Environment》 2024年第2期223-234,共12页
Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real... Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real health problems attributable to a lack of monitoring of the vaccination schedule, inadequate compliance with biosecurity measures and poor application of the Ichikawa rule based on the 5 M’s. Objective: The aim of this article is to identify the microorganisms responsible for contamination of poultry farms in the study area. Method: The study was carried out from 28/04/2022 to 31/01/2023 on the basis of 300 samples taken from feed, drinking water, droppings and scrapings from poultry housing surfaces in the 30 farms that served as a framework for our research. Sampling was of the simple random type, and farms were selected on the basis of the farmers’ consent. The data were recorded on pre-established survey forms. Our study was cross-sectional, descriptive and prospective. Bacteria were isolated using the reference method NF EN ISO 6579 for Salmonella spp. and cultured on the specific medium eosin methylene blue (EMB) for Escherichia coli, Pseudomonas and Citrobacter freundii. Results: The following results emerged from this study: Escherichia coli (5.33%), Pseudomonas (1.33%), Citrobacter freundii (12%) and Salmonella paratyphi (21.68%). Conclusion: Of the 300 samples analysed, 121 (40.33%) were contaminated with pathogens. This high level of contamination is a health problem. The study shows that biosecurity is less satisfactory on the farms visited. Nevertheless, farms with a very satisfactory level of biosafety ensure food safety and variety for the population. 展开更多
关键词 microorganisms Identification Poultry Farms N’Djamena Hadjer-Lamis Chari-Baguirmi(Chad)
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Responses of ammonia-oxidizing microorganisms to biochar and compost amendments of heavy metals-polluted soil 被引量:6
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作者 Mingyue Li Jiachao Zhang +5 位作者 Xiao Yang Yaoyu Zhou Lihua Zhang Yuan Yang Lin Luo Qingyun Yan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第4期263-272,共10页
Heavy metal pollution affects soil ecological function.Biochar and compost can effectively remediate heavy metals and increase soil nutrients.The effects and mechanisms of biochar and compost amendments on soil nitrog... Heavy metal pollution affects soil ecological function.Biochar and compost can effectively remediate heavy metals and increase soil nutrients.The effects and mechanisms of biochar and compost amendments on soil nitrogen cycle function in heavy-metal contaminated soils are not fully understood.This study examined how biochar,compost,and their integrated use affected ammonia-oxidizing microorganisms in heavy metal polluted soil.Quantitative PCR was used to determine the abundance of ammonia-oxidizing archaea(AOA)and bacteria(AOB).Ammonia monooxygenase(AMO)activity was evaluated by the enzymelinked immunosorbent assay.Results showed that compost rather than biochar improved nitrogen conversion in soil.Biochar,compost,or their integrated application significantly reduced the effective Zn and Cd speciation.Adding compost obviously increased As and Cu effective speciation,bacterial 16 S rRNA abundance,and AMO activity.AOB,stimulated by compost addition,was significantly more abundant than AOA throughout remediation.Correlation analysis showed that AOB abundance positively correlated with NO_(3)^(-)-N(r=0.830,P<0.01),and that AMO activity had significant correlation with EC(r=-0.908,P<0.01)and water-soluble carbon(r=-0.868,P<0.01).Those seem to be the most vital factors affecting AOB community and their function in heavy metal-polluted soil remediated by biochar and compost. 展开更多
关键词 BIOCHAR COMPOST Heavy metal ammonia-oxidizing community Ammonia monooxygenase activity
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Editorial: Effects of metal contamination on ammonia-oxidizing microorganisms in a freshwater reservoir 被引量:1
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作者 Wei Feng Xiaowen Yan Chris Le 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2019年第5期364-366,共3页
Ammonia-oxidizing microorganisms,including ammoniaoxidizing bacteria(AOB)and archaea(AOA),are important to the global nitrogen cycle.These microbes catalyze the oxidization of ammonia(NH3)to nitrite(NO2-),the ratelimi... Ammonia-oxidizing microorganisms,including ammoniaoxidizing bacteria(AOB)and archaea(AOA),are important to the global nitrogen cycle.These microbes catalyze the oxidization of ammonia(NH3)to nitrite(NO2-),the ratelimiting step in the biogeochemical cycling of nitrogen(Stahl and de la Torre,2012). 展开更多
关键词 ACCIDENTAL metal SPILL ammonia-oxidizing ARCHAEA ammonia-oxidizing bacteria AMOA gene Arsenic cadmium copper lead zinc Lake sediment Nitrogen cycling
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Revisiting “Non-Thermal” Batch Microwave Oven Inactivation of Microorganisms
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作者 Victor John Law Denis Pius Dowling 《American Journal of Analytical Chemistry》 CAS 2023年第1期28-54,共27页
Over the last few decades there has been active discussion concerning the mechanisms involved in “non-thermal” microwave-assisted inactivation of microorganisms. This work presents a novel non-invasive acoustic meas... Over the last few decades there has been active discussion concerning the mechanisms involved in “non-thermal” microwave-assisted inactivation of microorganisms. This work presents a novel non-invasive acoustic measurement of a domestic microwave oven cavity-magnetron operating at f<sub>o</sub> = 2.45 ± 0.05 GHz (λ<sub>o</sub> ~ 12.2 cm) that is modulated in the time-domain (0 to 2 minutes). The measurements reveal the cavity-magnetron cathode filament cold-start warm-up period and the pulse width modulation periods (time-on time-off and base-time period, where time-on minus base-time = duty cycle). The waveform information is used to reconstruct historical microwave “non-thermal” homogeneous microorganism inactivation experiments: where tap-water is used to mimic the microorganism suspension;and ice, crushed ice, and ice slurry mixture are used as the cooling media. The experiments are described using text, diagrams, and photographs. Four key experimental parameters are indentified that influence the suspension time-dependent temperature profile. First, where the selected process time > the time-base, the cavity-magnetron continuous wave rated power should be used for each second of microwave illumination. Second, external crushed ice and ice slurry baths induce different cooling profiles due to difference in their heat absorption rates. In addition external baths may shield the suspension resulting in a retarding of the time-dependent heating profile. Third, internal cooling systems dictate that the suspension is directly exposed to microwave illumination due to the absence of surrounding ice volume. Fourth, four separated water dummy-loads isolate and control thermal heat transfer (conduction) to and from the suspension, thereby diverting a portion of the microwave power away from the suspension. Energy phase-space projections were used to compare the “non-thermal” energy densities of 0.03 to 0.1 kJ·m<sup>-1</sup> at 800 W with reported thermal microwave-assisted microorganism inactivation energy densities of 0.5 to 5 kJ·m<sup>-1</sup> at 1050 ± 50 W. Estimations of the “non-thermal” microwave-assisted root mean square of the electric field strength are found to be in the range of 22 to 41.2 V·m<sup>-1</sup> for 800 W. 展开更多
关键词 Thermal NON-THERMAL MICROWAVE-ASSISTED Microwave Oven Acoustic FOOD microorganismS
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Shape Effect of Nanoparticles on Nanofluid Flow Containing Gyrotactic Microorganisms
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作者 Umair Rashid Azhar Iqbal Abdullah M.Alsharif 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期483-494,共12页
In this paper,we discussed the effect of nanoparticles shape on bioconvection nanofluid flow over the vertical cone in a permeable medium.The nanofluid contains water,Al2O3 nanoparticles with sphere(spherical)and lami... In this paper,we discussed the effect of nanoparticles shape on bioconvection nanofluid flow over the vertical cone in a permeable medium.The nanofluid contains water,Al2O3 nanoparticles with sphere(spherical)and lamina(non-spherical)shapes and motile microorganisms.The phenomena of heat absorption/generation,Joule heating and thermal radiation with chemical reactions have been incorporated.The similarity transformations technique is used to transform a governing system of partial differential equations into ordinary differential equations.The numerical bvp4c MATLAB program is used to find the solution of ordinary differential equations.The interesting aspects of pertinent parameters on mass transfer,energy,concentration,and density of themotilemicroorganisms’profiles are computed and discussed.Our analysis depicts that the performance of sphere shape nanoparticles in the form of velocity distribution,temperature distribution,skin friction,Sherwood number and Motile density number is better than lamina(non-spherical)shapes nanoparticles. 展开更多
关键词 Nanoparticle shape NANOFLUID numerical technique gyrotactic microorganisms MAGNETOHYDRODYNAMICS
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Causative Microorganisms Isolated from Patients with Intra-Abdominal Infections and Their Drug Resistance Profiles:An 11-Year(2011–2021)Single-Center Retrospective Study
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作者 DING Rui MA Rui Rui +10 位作者 LIU Ya Li ZHAO Ying GUO Li Na DOU Hong Tao SUN Hong Li LIU Wen Jing ZHANG Li WANG Yao LI Ding Ding YI Qiao Lian XU Ying Chun 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2023年第8期732-742,共11页
Objective To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections(IAIs).Methods A total of 2,926 bacterial and fungal strain... Objective To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections(IAIs).Methods A total of 2,926 bacterial and fungal strains were identified in samples collected from 1,679 patients with IAIs at the Peking Union Medical College Hospital between 2011 and 2021.Pathogenic bacteria and fungi were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.Antimicrobial susceptibility testing(AST)was performed using the VITEK 2 compact system and the Kirby–Bauer method.AST results were interpreted based on the M100-Ed31 clinical breakpoints of the Clinical and Laboratory Standards Institute.Results Of the 2,926 strains identified,49.2%,40.8%,and 9.5%were gram-negative bacteria,gram-positive bacteria,and fungi,respectively.Escherichia coli was the most prevalent pathogen in intensive care unit(ICU)and non-ICU patients;however,a significant decrease was observed in the isolation of E.coli between 2011 and 2021.Specifically,significant decreases were observed between 2011 and 2021 in the levels of extended-spectrumβ-lactamase(ESBL)-producing E.coli(from 76.9%to 14.3%)and Klebsiella pneumoniae(from 45.8%to 4.8%).Polymicrobial infections,particularly those involving co-infection with gram-positive and gram-negative bacteria,were commonly observed in IAI patients.Moreover,Candida albicans was more commonly isolated from hospital-associated IAI samples,while Staphylococcus epidermidis had a higher ratio in community-associated IAIs.Additionally,AST results revealed that most antimicrobial agents performed better in non-ESBL-producers than in ESBL-producers,while the overall resistance rates(56.9%–76.8%)of Acinetobacter baumanmii were higher against all antimicrobial agents than those of other common gram-negative bacteria.Indeed,Enterococcus faecium,Enterococcus faecalis,S.epidermidis,and S.aureus were consistently found to be susceptible to vancomycin,teicoplanin,and linezolid.Similarly,C.albicans exhibited high susceptibility to all the tested antifungal drugs.Conclusion The distribution and antimicrobial susceptibility of the causative microorganisms from patients with IAls were altered between 2011 and 2021.This finding is valuable for the implementation of evidence-based antimicrobial therapy and provides guidance for the control of hospital infections. 展开更多
关键词 Intra-abdominal infection Causative microorganisms Antimicrobial susceptibility testing Gram-negative bacteria Gram-positive bacteria
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Impact of microorganism degradation on hydrocarbon generation of source rocks:A case study of the Bozhong Sag,Bohai Bay Basin
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作者 Wei Li Yufei Gao Youchuan Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第3期243-253,共11页
The discovery of the Bozhong 19-6 gas field,the largest integrated condensate gas field in the eastern China in 2018,opened up a new field for the natural gas exploration deep strata in the Bohai Bay Basin,demonstrati... The discovery of the Bozhong 19-6 gas field,the largest integrated condensate gas field in the eastern China in 2018,opened up a new field for the natural gas exploration deep strata in the Bohai Bay Basin,demonstrating there is a great potential for natural gas exploration in oil-type basins.The ethane isotope of the Bozhong 19-6 condensate gas is heavy,showing the characteristics of partial humic gas.In this paper,aimed at the source rocks of the Bozhong 19-6 gas field in the Bohai Bay Basin,the characteristics of the source rocks in the Bozhong 19-6 structural belt were clarified and the reason are explained from impact of microorganism degradation on hydrocarbon generation of source rocks why the condensate oil and gas had heavy carbon isotope and why it showed partial humic characteristics was explored based on the research of parent materials.The following conclusions were obtained:The paleontology of the Bozhong 19-6 structural belt and its surrounding sub-sags is dominated by higher plants,such as angiosperm and gymnosperm.During the formation of source rocks,under the intensive transformation of microorganism,the original sedimentary organic matter such as higher plants was degraded and transformed by defunctionalization.Especially,the transformation of anaerobic microorganisms on source rocks causes the degradation and defunctionalization of a large number of humic products such as higher plants and the increase of hydrogen content.The degradation and transformation of microorganism don't transform the terrestrial humic organic matter into newly formed“sapropel”hydrocarbons,the source rocks are mixed partial humic source rocks.As a result,hydrogen content incrased and the quality of source rocks was improved,forming the partial humic source rocks dominated by humic amorphous bodies.The partial humic source rocks are the main source rocks in the Bozhong 19-6 gas field,and it is also the internal reason why the isotope of natural gas is heavy. 展开更多
关键词 Bozhong Sag natural gas types of source rocks microorganism degradation hydrocarbon generation of source rocks
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Heavy metal availability and impact on activity of soil microorganisms along a Cu/Zn contamination gradient 被引量:21
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作者 WANG Yuan-peng SHI Ji-yan +2 位作者 LIN Qi CHEN Xin-cai CHEN Ying-xu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期848-853,共6页
All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciati... All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (Cmic)/organic C (Corg) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient. 展开更多
关键词 heavy metals AVAILABILITY SPECIATION ACTIVITY soil microorganism
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Granulation of filamentous microorganisms in a sequencing batch reactor with saline wastewater 被引量:11
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作者 Zhihua Li Ting Zhang +1 位作者 Na Li Xiaochang Wang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第1期62-67,共6页
Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure wit... Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure with 5% sodium chloride in the substrate. In the early period of experiment, coccoid and rode-like bacteria predominated in the yellowish-brown granules, and later the white and the black granules were developed by filamentous microorganisms. The filamentous granules exhibited low porosity and fast settling velocity, and were more compact even than bacteria granules. It was hypothesized that the elevated pH in the later period might be a possible reason for the compact growth of filamentous granules. However, the bacteria granules showed the high bioactivity in terms of specific oxygen utilizing rate, and comprised of a wider diversity of compounds based on the thermogravimetric evaluation. The findings in this study demonstrated that filamentous microbes could form compact granular structure, which may encourage the utilization of filamentous microorganisms rather than the inhibition of their growth, as the latter is frequently used for sludge bulking control. 展开更多
关键词 aerobic granule sludge bulking filamentous microorganisms thermogravimetric analysis
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Microorganisms Linked to Neoproterozoic Microspar Carbonate Sedimentation in the Jilin-Liaoning Area 被引量:9
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作者 GEMing KUANGHongwei +1 位作者 MENGXianghua GeorgeFURNISS 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期784-789,共6页
Molar-tooth carbonate refers to a sort of rock that has ptygmatical folded structure comparable to the ivory. This kind of carbonate exists in a special time range (from Middle to Neoproterozoic). Its origin and the p... Molar-tooth carbonate refers to a sort of rock that has ptygmatical folded structure comparable to the ivory. This kind of carbonate exists in a special time range (from Middle to Neoproterozoic). Its origin and the possibility to use it in stratigraphic correlation of the paleocontinent is the key task of the IGCP447, a project on Proterozoic molar tooth carbonates and the evolution of the earth (2001-2005). The importance lies in that the molar-tooth structure is the key to solving problems related to Precambrian biological and global geochemical events. The molar-tooth structure is associated with microorganisms. Development and recession of such carbonates have relations with the evolution process of early lives and abrupt changes in sea carbonate geochemistry. In recent years, based on researches on petrology, geochemistry and Sr isotope of molar-tooth carbonate in the Jilin-Liaoning and Xuzhou-Huaiyang area, the authors hold that it can be used as a marker for stratigraphic sequence and sedimentary fades analyses. 展开更多
关键词 molar tooth carbonate NEOPROTEROZOIC sedimentary environment microorganismS ORIGIN
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Damage to DNA of effective microorganisms by heavy metals:Impact on wastewater treatment 被引量:9
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作者 ZHOU, Sheng WEI, Chaohai +1 位作者 LIAO, Chaodeng WU, Haizhen 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第12期1514-1518,共5页
The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their... The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their DNA is damaged.The approach applied in this study is to test with COMET assay the damage of EM DNA in wastewater with different concentrations of heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,Zn2+,as well as the effects of EM treated with As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,and Zn2+ on COD degradin... 展开更多
关键词 effective microorganism heavy metal DNA damage WASTEWATER
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Composting MSW and sewage sludge with effective complex microorganisms 被引量:18
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作者 XiBD LiuHL 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2002年第2期264-268,共5页
The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of... The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus. 展开更多
关键词 effective complex microorganisms(ECM) temperature oxygen consumption organic matter C/N ratio
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Accumulation of Rare Earth Elements in Various Microorganisms 被引量:10
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作者 Takehiko Tsuruta 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第5期526-532,共7页
The removal of rare earth elements (REEs) from solution in various microorganisms was examined. Seventy-six strains from 69 species (22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts) were tested. Initially, ... The removal of rare earth elements (REEs) from solution in various microorganisms was examined. Seventy-six strains from 69 species (22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts) were tested. Initially, Sm was used to test the removal capabilities of the various organisms. Gram-positive bacteria, such as Bacillus licheniformis, B. subtilis, Brevibacterium helovolum, and Rhodococcus elythropolis, exhibited a particularly high capacity for accumulating Sm. In particular, the B. lichemiformis cells accumulated approximately 316 μmol Sm per gram dry wt. of microbial cells. A full suite of screenings was then conducted to compare the abilities of the organisms to remove Se, Y, La, Er, and, Lu from solution. Tests were done with solutions containing one REE at a time. Accumulation was nearly identical for the various metals and organisms. However, when solutions with equimolar amounts of two REEs were used, preferential removal from solution was observed. When an Eu/Gd solution was used, gram-positive bacteria removed more Eu and Gd as compared to actinomycetes. When Eu/Sm combination was used, gram-positive bacteria removed equal mounts of both metals and some actinomycetes removed more Eu. The selective removal was quantified by calculating separation factors (S. F.), which indicated that Streptomyces levoris cells accumulated the greatest proportion of Eu. The removal of REEs from a solution containing five metals (Y, La, Sm, Er, and Lu) was then examined. Mucorjavanicus preferentially accumulated Sm and S. flavoviridis preferentially accumulated Lu. The effects of pH and Sm concentration on the accumulation of Sm by B. licheniformis were also examined. Accumulation increased at higher pH and at greater solution concentrations. 展开更多
关键词 Sm accumulation selective rare earth accumulation microorganism gram-positive bacteria ACTINOMYCETES
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Comparison of Antioxidant Activities in Black Soybean Preparations Fermented with Various Microorganisms 被引量:12
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作者 QIN Yao JIN Xiao-nan Park Heui Dong 《Agricultural Sciences in China》 CSCD 2010年第7期1065-1071,共7页
Black soybeans [Glycine max(L.) Merrill] were fermented with various GRAS(generally recognized as safe) microorganisms,including Aspergillus sp.,Bacillus sp.and yeast(Issatchenkia orientalis) at 30°C for 3 ... Black soybeans [Glycine max(L.) Merrill] were fermented with various GRAS(generally recognized as safe) microorganisms,including Aspergillus sp.,Bacillus sp.and yeast(Issatchenkia orientalis) at 30°C for 3 d.The antioxidant contents,including total phenolics and total flavonoids,and the antioxidant activities of 1,1-diphenyl-2-picrylhydrazine(DPPH),ferric reducing antioxidant power(FRAP) and HO.scavenging were analyzed in preparations of fermented black soybeans.Fermented cultures proved to yield significant levels of antioxidants compared with non-fermented cultures(P 〈 0.05).Fermented black soybean preparations possessed antioxidant activities could be attributed to the total phenolics and flavonoids present. 展开更多
关键词 antioxidant activity black soybean microorganismS FERMENTATION
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Screening on oil-decomposing microorganisms and application in organic waste treatment machine 被引量:9
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作者 LUYi-tong CHENXiao-bin ZHOUPei LIZhen-hong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第3期440-444,共5页
As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing ra... As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment. 展开更多
关键词 oil-decomposing microorganism SCREENING application organic waste treatment machine decomposing rate
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