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Pedosphere 2007年第6期17卷 681-687页

作者： H. KANG C. FREEMAN Department of Civil and Environmental Engineering Yonsei University Seoul 120- 749 （Korea） School of Biological Sciences University of Wales Bangor LL57 2UW （UK）

The nature of the interactions between microbes and roots of plants in a peaty soil were studied in a laboratory- based experiment by measuring activities ofβ-glucosidase,phosphatase,N-acetylglucosaminidase,and *** experiment was based on control(autoclaved),bacteria-inoculated,and plant(transplanted with Dactylorhiza)treatments, and samples were collected over 4 sampling *** enzyme activities were associated with the bacteria-inoculated treatment,suggesting that soil enzyme activities are mainly of microbial *** example,β-glucosidase activity varied between 25-30μmol g^(-1)min^(-1)in the bacteria-inoculated samples whilst the activity of the control ranged between 4-12μmol g^(-1)min^(-1)A similar pattern was found for all other enzymes. At the end of the incubation,the microcosms were destructively sampled and the enzyme activities determined in bulk soil,rhizospheric soil,and on the root *** measurement in different fractions of the peat indicated that higher activities were found in ***,the higher activities ofβ-glucosidase,N-acetylglucosaminidase,and arylsulphatase appeared to be associated with bacterial proliferation on the root surface,whilst a larger proportion of phosphatase appeared to be released from root surface.

关键词： Dactylorhiza extracellular enzyme peat rhizosphere wetland

Trade-off between microbial carbon use efficiency and specific nutrient-acquiring extracellular enzyme activities under reduced oxygen

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Soil Ecology Letters 2023年第2期5卷 43-53页

作者： Ji Chen Irene Cordero Daryl L.Moorhead Jennifer K.Rowntree Lorae T.Simpson Richard D.Bardgett Hayley Craig Department of Agroecology Aarhus University8830 TjeleDenmark Aarhus University Centre for Circular Bioeconomy Aarhus University8830 TjeleDenmark iCLIMATE Interdisciplinary Centre for Climate Change Aarhus University4000 RoskildeDenmark Department of Earth and Environmental Sciences The University of ManchesterOxford RoadManchesterM139PTUK Department of Environmental Sciences University of Toledo2801 W.Bancroft St.ToledoOH 43606-3390USA School of Biological and Marine Sciences University of PlymouthDrake CircusPlymouthPL48AAUK Florida Oceanographic Society 890 NE Ocean BlvdStuartFL 34996USA NatureMetrics Occam CourtSurrey Research ParkGuildfordGU27HJUK

Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)***,mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human ***,both direct and interactive effects of these perturbations on microbially mediated soil C,N and P cycling are poorly ***,we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass,microbial respiration,and extracellular enzyme activities(EEAs)in mangrove *** calculated the microbial metabolic quotient(qCO_(2)),which is regarded as a useful inverse metric of microbial C use efficiency(CUE).Our results show that reduced oxygen significantly increases both qCO_(2) and microbial specific EEAs(enzyme activity per unit of microbial biomass)for C-,N-and P-acquisition regardless of N or P ***,we found that qCO_(2) positively correlated with microbial specific EEAs under reduced oxygen,whereas no clear relationship was detected under ambient *** results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass,indicating higher energy cost per unit enzyme production.

关键词： reduced oxygen extracellular enzyme microbial respiration nutrient acquisition nutrient addition mangrove

Effect of Lanthanum on Growth and extracellular enzyme Acitivty of Erwinia Chrysanthemi in vitro

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Journal of Rare Earths 1999年第2期17卷 64-67页

作者： Liu Qingdu (School of Life Science, University of Science and Technology of China, Hefei 230026, China) Zhang Jian , Cheng Heyuan (Department of Plant Protection, Anhui Agricultural University, Hefei 230036, China)

The effect of lanthanum on the growth and extracellular enzyme activity of Erwinia chrysanthemi(Ech) was studied. Lanthanum inhibited the growth of Ech in solid culture at the concentration of 50, 100, 150, 200, 250, 300 and 350 mgL-1, and the inhibition increased with the increase of the RE concentration. The formation of colony delayed and the diameter of colony decreased. Lanthanum stimulated the growth of Ech within 24h when the lanthanum concentration was less than 200 mgL-1 in liquid medium, but significantly inhibited the growth of Ech with the increase of lanthanum concentration and culture time. When the concentration was higher than 350 mgL-1, the growth of Ech was inhibited completely both in solid and liquid culture. The extracellular enzyme acitivity of Ech was affected by lanthanum at 200 mgL-1. The activity of cellulose was promoted more than that of protease but the activity of pectinase was decreased. The maceration to potato tuber tissue decreased when the cell free filtrate was tr

关键词： Rare earths Lanthanum Erwinia chrysanthemi extracellular enzyme Maceration eated with lanthanum.

extracellular enzyme Activity of Sclerotia-forming and Non-Sclerotia-forming Morchella Strains

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Agricultural Science & Technology 2013年第10期14卷 1392-1396,1408页

作者：陈立佼王芳赵永昌黄兴奇柴红梅云南大学生命科学学院云南昆明650091 云南省农业科学院生物技术与种质资源研究所云南昆明650223 云南省农业科学院教育培训处云南昆明650205

The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica exhibited higher aver- age activities of protease, catalase and xylanase but lower laccase activity than those of sclerotia-forming strains. However, the differences did not reach significance level. The soluble amylases activity of M. crasspies was significantly higher than that of M. conica, while the mean activity of other enzymes had differences between them, but the differences did not reach significance level.

关键词： Morchella conica Morchella crasspies Sclerotia extracellular enzyme

Wildfire severity alters soil microbial exoenzyme production and fungal abundances in the southern Appalachian Mountains

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Pedosphere 2024年第5期34卷 865-878页

作者： Megan L.SCHILL Richard BAIRD Shawn P.BROWN Allison M.VEACH Department of Integrative Biology University of Texas at San Antonio Biochemistry Molecular Biology Entomology and Plant Pathology Department Mississippi State University Department of Biological Sciences The University of Memphis

Climate change has increased drought frequency and duration that are exacerbated by increased temperatures globally. This effect has, and will continue,to increase fire occurrence across many regions of North America. In the southern Appalachian Mountains, wildfires with high burn severity occurred in 2016due to increased drought and human activity. To investigate the effects of burn severity on soil physicochemical properties, microbial extracellular enzyme production, and microbial abundances in a temperate region, surface soils (0–15 cm) were collected from two sites (the Great Smoky Mountains National Park in Tennessee and the Nantahala National Forest in North Carolina, USA) spanning lightly, moderately, and severely burned areas, accompanied by adjacent unburned locations that act as controls. The soil samples were collected at three time points between 2017 and 2019 (i.e., 0.5, 1, and 2.5 years post-fire)among burn severity plots. Total hydrolytic enzyme production varied over time, with severe burn plots having significantly lower enzyme production at 2.5years post-fire. Individual enzymes varied among burn severities and across time post-fire. Light burn plots showed greater carbon-specific (β-glucosidase and β-xylosidase) and phosphorus-specific (acid phosphatase) enzyme activities at 0.5 years post-fire, but this effect was transient. At 2.5 years post-fire, theβ-xylosidase and acid phosphatase activities were lower in severe or moderate burn plots relative to the controls. In contrast, the activity of nitrogen-specific enzyme leucyl aminopeptidase was the lowest in severe burn plots at 0.5 years post-fire, but was the lowest in light burn plots at 2.5 years post-fire. The fungi:bacteria ratio declined with burn severity, indicating that fungi are sensitive or less resilient to high burn severity during recovery. These results suggest that wildfires alter trajectories for soil microbial structure and function within a 2.5-year timeframe, which potentially

关键词： 16S rRNA burn severity extracellular enzyme fungi:bacteria ratio internal transcribed spacer microbial structure

Exogenous nitrogen input skews estimates of microbial nitrogen use efficiency by ecoenzymatic stoichiometry

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Ecological Processes 2023年第1期12卷 625-631页

作者： Lifei Sun Daryl L.Moorhead Yongxing Cui Wolfgang Wanek Shuailin Li Chao Wang CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Environmental Sciences University of ToledoToledo 43606USA Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100871China Division of Terrestrial Ecosystem Research Center of Microbiology and Environmental Systems ScienceUniversity of ViennaDjerassiplatz 11030 ViennaAustria

Background Ecoenzymatic stoichiometry models(EEST)are often used to evaluate microbial nutrient use efficiency,but the validity of these models under exogenous nitrogen(N)input has never been ***,we investigated the effects of long-term N addition(as urea)on microbial N use efficiency(NUE),compared EEST and^(18)O-labeling methods for determining NUE,and evaluated EEST’s theoretical assumption that the ratios of standard ecoenzymatic activities balance resource availability with microbial *** We found that NUE estimated by EEST ranged from 0.94 to *** contrast,estimates of NUE by the^(18)O-labeling method ranged from 0.07 to *** large differences in NUE values estimated by the two methods may be because the sum ofβ-N-acetylglucosaminidase and leucine aminopeptidase activities in the EEST model was not limited to microbial N acquisition under exogenous N inputs,resulting in an overestimation of microbial NUE by *** addition,the acquisition of carbon by N-acquiring enzymes also likely interferes with the evaluation of NUE by *** Our results demonstrate that caution must be exercised when using EEST to evaluate NUE under exogenous N inputs that may skew standard enzyme assays.

关键词： extracellular enzyme Resource allocation Nitrogen addition Microbial metabolism limitation Isotope labeling

Biodrying of municipal solid waste with high water content by combined hydrolytic-aerobic technology

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Journal of Environmental Sciences 2008年第12期20卷 1534-1540页

作者： ZHANG Dongqing HE Pinjing SHAO Liming JIN Taifeng HAN Jingyao State Key Laboratory of Pollution Control and Resources Reuse Key Laboratory of Yangtze River Water Environment College of Environmental Science and Engineering Tongji University Shanghai 200092 China

The high water content of municipal solid waste(MSW)will reduce the effciency of mechanical sorting,consequently unfavorable for beneficial *** this study,a combined hydrolytic-aerobic biodrying technology was introduced to remove water from *** total water removals were proved to depend on the ventilation frequency and the temporal span in the hydrolytic stage. The ventilation frequency of 6 times/d was preferable in the hydrolytic *** hydrolytic span should not be prolonged more than ...

关键词： biodrying high water content hydrolysis aeration municipal solid waste extracellular enzyme

Nitrogen fertilization has minimal influence on rhizosphere effects of smooth crabgrass (Digitaria ischaemum) and bermudagrass (Cynodon dactylon)

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Journal of Plant Ecology 2015年第4期8卷 390-400页

作者： Biao Zhu Kevin Panke-Buisse Jenny Kao-Kniffin Earth Sciences Division Lawrence Berkeley National LaboratoryCyclotron RoadBerkeleyCA 94720USA School of Integrative Plant Science Cornell University134 Plant Sciences BuildingIthacaNY 14853USA

Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil *** quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant *** Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere ***,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic *** component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.

关键词： rhizosphere effect N fertilization belowground carbon allocation microbial biomass extracellular enzyme net N mineralization microbial community composition

Isolation and partial purification of fungal ligninolytic enzymes from the forest soil fungi isolated from Bhadra Wildlife Sanctuary

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Frontiers in Biology 2014年第4期9卷 291-299页

作者： SHIVAKUMAR P. BANAKAR B. THIPPESWAMY Department of Bioseiences Shri J.J. T. University Vidyanagari Chudela-333 001 Jhunjhunu (Dist.) Rajasthan India Department of Studies in Microbiology Bioseience Complex Kuvempu University Jnanasahyadri Shankaraghatta-577 451 Shivamogga (Dist.) Karnataka India

Screening was done for the isolation of effective lignin degraders from the forest soil samples, by providing lignin as a carbon source through the enrichment method, which leads to the isolation of 8 effective fungal isolates among 14 isolates. Submerged fermentation was done for the production of ligninolytic enzymes with the effective microorganisms by providing Guiaicol as a carbon source. The assay of laccase, lignin peroxidise activity and specific activity was done after the incubation intervals of 2, 4, 6, 7, 8, 10 and 12 days at 27±2℃ under shake culture condition. Partially purified protein content was estimated by using Lowry＇s method. Pleurotus sp. and Phanerochaetae chrysosporium are more effective at the 2nd and 7th days of incubation for the production of laccase and lignin peroxidases among the effective isolates.

关键词： laccase lignin peroxidase extracellular enzyme fungi forest soil

Screening of Toxin Mutant of Dickeya zeae and Its Biological Characters

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Agricultural Science & Technology 2013年第10期14卷 1397-1402页

作者： Jingyi ZHANG Yutao WANG Yanchang LI Qiongguang LIU College of Natural Resource&Environment South China Agricultural University

[Objective]This study aimed to screen toxin mutant of Dickeya zeae(Erwinia chrysanthemi ***)and investigate its biological characters.[Method]We obtained a toxin mutant strain *** Ech7-3-42 by using acridine orange as a mutagenic agent and compared their biological characteristics and virulence between the toxin mutant and wild strain.[Result]There was no significant difference in pectin lyase,protease,cellulase and the production of extracellular polysaccharide and lipopolysaccharide,but significant difference in toxin biological activities and ***7-3-42 mutant did not produce toxin,as well as the loss of virulence on rice and HR on tobacco,but did not lose the ability to soft rot on *** strain Ech7-3-42 can infect rice root and then enriched in the root neck and stalk,but it could not cause rice foot *** zeae(wild and mutant strain)could be detected by PCR in the root neck and below the 1-2 cm long stem area,but could not be detected in the leaves.[Conclusion]We believed that toxin may be one of the important factors for *** virulence on rice.

关键词： Dickeya zeae Toxin Virulence extracellular enzyme extracellular polysaccharide