The Experts below are selected from a list of 14388 Experts worldwide ranked by ideXlab platform
Yakov Kuzyakov - One of the best experts on this subject based on the ideXlab platform.
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spatial distribution and catalytic mechanisms of β glucosidase activity at the root soil interface
Biology and Fertility of Soils, 2016Co-Authors: Muhammad Sanaullah, Bahar S Razavi, Evgenia Blagodatskaya, Yakov KuzyakovAbstract:We compared modifications of soil zymography, a new in situ technique to visualize enzyme activities, based on contact of fluorgenic substrate-saturated membranes with soil either through the gel layer (gel zymography) or without gel application (direct zymography). We coupled zymography with quantitative measurements of enzyme kinetics to characterize catalytic mechanisms of β-glucosidase activity at the plant-soil interface including root surface (rhizoplane), rhizosphere, and bulk soil. Direct zymography refined and focused image resolution. The Area of Hotspots (i.e., spots with most intensive enzyme activity) as well as color intensity ratios estimated using direct zymography exceeded by a factor of 2 the corresponding values obtained with gel zymography. As determined by direct zymography, the percentage of Hotspots associated to root surfaces was 58–68 % of total Hotspot Area. Hotspot Area comprised only 6.8 ± 0.1 % of the total Area of an image and 9.0 ± 3 % of the root surface Area. The intensity of β-glucosidase activity, however, was up to 20 times higher in the Hotspots versus bulk soil. The contribution of rhizosphere to β-glucosidase activity of the whole image (77–82 %) was four times higher than the contribution of the root surface. Enzyme kinetic parameters indicated different enzyme systems in bulk and rhizosphere soil. Higher substrate affinity and catalytic efficiency in bulk than in rhizosphere soil suggested relative domination of microorganisms with more efficient enzyme systems in the former. Coupling direct zymography and kinetic assays enabled mapping the two-dimensional (2D) distribution of enzyme activity at the root-soil interface and estimating the catalytic properties of root-associated and soil-associated enzymes.
Evgenia Blagodatskaya - One of the best experts on this subject based on the ideXlab platform.
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microbial growth and enzyme kinetics in rhizosphere Hotspots are modulated by soil organics and nutrient availability
Soil Biology & Biochemistry, 2020Co-Authors: Peng Tian, Bahar S Razavi, Evgenia Blagodatskaya, Xuechen Zhang, Qingkui WangAbstract:Abstract The input of labile organics by plant roots stimulates microbial activity and therefore facilitates biochemical process rates in the rhizosphere compared to bulk soil, forming microbial Hotspots. However, the extent to which the functional properties of soil microorganisms are different in the Hotspots formed in soils with contrasting fertility remains unclear. We identified the Hotspots related to different levels of Zea mays L. root architecture by zymography of leucine aminopeptidase in two soils with contrasting fertility. The Hotspots localized by tiny wet-needle approach around first- and second-order roots were compared for parameters of microbial growth and enzyme kinetics. The pattern of Hotspot distribution was more dispersed and the Hotspot Area was one order of magnitude smaller around first-versus second-order roots. The specific microbial growth rate (μm) and biomass of active microorganisms were soil-specific, with no difference between the Hotspots and bulk soil in the fertile soil. In contrast, in the soil poor in organic matter and nutrients, 1.2-fold higher μm and greater growing biomass were found in the Hotspots versus bulk soil. Lower enzyme affinity (1.3–2.2 times higher Km value) of β-glucosidase and leucine aminopeptidase to the substrate was detected in the Hotspots versus bulk soil, whereas only β-glucosidase showed higher potential enzyme activity (Vmax) in the Hotspots, being 1.7–2.1 times greater than that in bulk soil. Notably, the activity of C-acquiring enzyme, β-glucosidase positively correlated with the biomass of actively growing microorganisms. The fertile soil, on the whole, showed greater Vmax and catalytic efficiency (Vmax/Km) and an approximately 2.5 times shorter substrate turnover time as compared to the poor soil. Therefore, we conclude that i) the differences in microbial growth strategy between rhizosphere Hotspots and bulk soil were dependent on soil fertility; ii) affinity of hydrolytic enzyme systems to substrate was mainly modulated by plant, whereas potential enzymatic activity was driven by both plant and soil quality.
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spatial distribution and catalytic mechanisms of β glucosidase activity at the root soil interface
Biology and Fertility of Soils, 2016Co-Authors: Muhammad Sanaullah, Bahar S Razavi, Evgenia Blagodatskaya, Yakov KuzyakovAbstract:We compared modifications of soil zymography, a new in situ technique to visualize enzyme activities, based on contact of fluorgenic substrate-saturated membranes with soil either through the gel layer (gel zymography) or without gel application (direct zymography). We coupled zymography with quantitative measurements of enzyme kinetics to characterize catalytic mechanisms of β-glucosidase activity at the plant-soil interface including root surface (rhizoplane), rhizosphere, and bulk soil. Direct zymography refined and focused image resolution. The Area of Hotspots (i.e., spots with most intensive enzyme activity) as well as color intensity ratios estimated using direct zymography exceeded by a factor of 2 the corresponding values obtained with gel zymography. As determined by direct zymography, the percentage of Hotspots associated to root surfaces was 58–68 % of total Hotspot Area. Hotspot Area comprised only 6.8 ± 0.1 % of the total Area of an image and 9.0 ± 3 % of the root surface Area. The intensity of β-glucosidase activity, however, was up to 20 times higher in the Hotspots versus bulk soil. The contribution of rhizosphere to β-glucosidase activity of the whole image (77–82 %) was four times higher than the contribution of the root surface. Enzyme kinetic parameters indicated different enzyme systems in bulk and rhizosphere soil. Higher substrate affinity and catalytic efficiency in bulk than in rhizosphere soil suggested relative domination of microorganisms with more efficient enzyme systems in the former. Coupling direct zymography and kinetic assays enabled mapping the two-dimensional (2D) distribution of enzyme activity at the root-soil interface and estimating the catalytic properties of root-associated and soil-associated enzymes.
Muhammad Sanaullah - One of the best experts on this subject based on the ideXlab platform.
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spatial distribution and catalytic mechanisms of β glucosidase activity at the root soil interface
Biology and Fertility of Soils, 2016Co-Authors: Muhammad Sanaullah, Bahar S Razavi, Evgenia Blagodatskaya, Yakov KuzyakovAbstract:We compared modifications of soil zymography, a new in situ technique to visualize enzyme activities, based on contact of fluorgenic substrate-saturated membranes with soil either through the gel layer (gel zymography) or without gel application (direct zymography). We coupled zymography with quantitative measurements of enzyme kinetics to characterize catalytic mechanisms of β-glucosidase activity at the plant-soil interface including root surface (rhizoplane), rhizosphere, and bulk soil. Direct zymography refined and focused image resolution. The Area of Hotspots (i.e., spots with most intensive enzyme activity) as well as color intensity ratios estimated using direct zymography exceeded by a factor of 2 the corresponding values obtained with gel zymography. As determined by direct zymography, the percentage of Hotspots associated to root surfaces was 58–68 % of total Hotspot Area. Hotspot Area comprised only 6.8 ± 0.1 % of the total Area of an image and 9.0 ± 3 % of the root surface Area. The intensity of β-glucosidase activity, however, was up to 20 times higher in the Hotspots versus bulk soil. The contribution of rhizosphere to β-glucosidase activity of the whole image (77–82 %) was four times higher than the contribution of the root surface. Enzyme kinetic parameters indicated different enzyme systems in bulk and rhizosphere soil. Higher substrate affinity and catalytic efficiency in bulk than in rhizosphere soil suggested relative domination of microorganisms with more efficient enzyme systems in the former. Coupling direct zymography and kinetic assays enabled mapping the two-dimensional (2D) distribution of enzyme activity at the root-soil interface and estimating the catalytic properties of root-associated and soil-associated enzymes.
Bai Zhang - One of the best experts on this subject based on the ideXlab platform.
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what did china s national wetland conservation program achieve observations of changes in land cover and ecosystem services in the sanjiang plain
Journal of Environmental Management, 2020Co-Authors: Hengxing Xiang, Zongming Wang, J. Zhang, Dehua Mao, Bai ZhangAbstract:Abstract China implemented the National Wetland Conservation Program (NWCP) from 2002 to protect and rehabilitate wetlands. Under the background of sustainable development, assessment on the effectiveness of the NWCP is important to ecosystem management, especially in the Sanjiang Plain, the largest marsh distribution Area and Hotspot Area with wetland loss. To achieve this aim, this study examined the changes in land cover and ecosystem services (ESs) from 1990 to 2000 and from 2000 to 2015 in the Sanjiang Plain as well as the nine national nature reserves for wetlands (NNRWs) by means of Landsat series images and the InVEST model. Results reveal that the NWCP played critical roles in reducing wetland loss and improving regional ESs. The shrinkage rate of wetlands in the Sanjiang Plain has been decreased remarkably, with a declined rate of wetland loss from 750 km2 yr−1 to 189 km2 yr−1. The reduction rate of habitat Area in good suitable grade and ecosystem carbon stock declined notably during the period 2000–2015 compared to the period 1990–2000. The amount of water retention increased by 5.4%, while the grain production capacity was enhanced by nine times from 1990 to 2015. Specifically, since 2000, the reduction rate of wetland Area in NNRWs (33 km2 yr−1) was obviously lower than that in the entire Sanjiang Plain, whilst various ESs in NNRWs were better than that in the whole Sanjiang Plain. This study is expected to provide an example for evaluating the effectiveness of the NWCP at other regions and support regional wetland conservation management.
Bahar S Razavi - One of the best experts on this subject based on the ideXlab platform.
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microbial growth and enzyme kinetics in rhizosphere Hotspots are modulated by soil organics and nutrient availability
Soil Biology & Biochemistry, 2020Co-Authors: Peng Tian, Bahar S Razavi, Evgenia Blagodatskaya, Xuechen Zhang, Qingkui WangAbstract:Abstract The input of labile organics by plant roots stimulates microbial activity and therefore facilitates biochemical process rates in the rhizosphere compared to bulk soil, forming microbial Hotspots. However, the extent to which the functional properties of soil microorganisms are different in the Hotspots formed in soils with contrasting fertility remains unclear. We identified the Hotspots related to different levels of Zea mays L. root architecture by zymography of leucine aminopeptidase in two soils with contrasting fertility. The Hotspots localized by tiny wet-needle approach around first- and second-order roots were compared for parameters of microbial growth and enzyme kinetics. The pattern of Hotspot distribution was more dispersed and the Hotspot Area was one order of magnitude smaller around first-versus second-order roots. The specific microbial growth rate (μm) and biomass of active microorganisms were soil-specific, with no difference between the Hotspots and bulk soil in the fertile soil. In contrast, in the soil poor in organic matter and nutrients, 1.2-fold higher μm and greater growing biomass were found in the Hotspots versus bulk soil. Lower enzyme affinity (1.3–2.2 times higher Km value) of β-glucosidase and leucine aminopeptidase to the substrate was detected in the Hotspots versus bulk soil, whereas only β-glucosidase showed higher potential enzyme activity (Vmax) in the Hotspots, being 1.7–2.1 times greater than that in bulk soil. Notably, the activity of C-acquiring enzyme, β-glucosidase positively correlated with the biomass of actively growing microorganisms. The fertile soil, on the whole, showed greater Vmax and catalytic efficiency (Vmax/Km) and an approximately 2.5 times shorter substrate turnover time as compared to the poor soil. Therefore, we conclude that i) the differences in microbial growth strategy between rhizosphere Hotspots and bulk soil were dependent on soil fertility; ii) affinity of hydrolytic enzyme systems to substrate was mainly modulated by plant, whereas potential enzymatic activity was driven by both plant and soil quality.
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spatial distribution and catalytic mechanisms of β glucosidase activity at the root soil interface
Biology and Fertility of Soils, 2016Co-Authors: Muhammad Sanaullah, Bahar S Razavi, Evgenia Blagodatskaya, Yakov KuzyakovAbstract:We compared modifications of soil zymography, a new in situ technique to visualize enzyme activities, based on contact of fluorgenic substrate-saturated membranes with soil either through the gel layer (gel zymography) or without gel application (direct zymography). We coupled zymography with quantitative measurements of enzyme kinetics to characterize catalytic mechanisms of β-glucosidase activity at the plant-soil interface including root surface (rhizoplane), rhizosphere, and bulk soil. Direct zymography refined and focused image resolution. The Area of Hotspots (i.e., spots with most intensive enzyme activity) as well as color intensity ratios estimated using direct zymography exceeded by a factor of 2 the corresponding values obtained with gel zymography. As determined by direct zymography, the percentage of Hotspots associated to root surfaces was 58–68 % of total Hotspot Area. Hotspot Area comprised only 6.8 ± 0.1 % of the total Area of an image and 9.0 ± 3 % of the root surface Area. The intensity of β-glucosidase activity, however, was up to 20 times higher in the Hotspots versus bulk soil. The contribution of rhizosphere to β-glucosidase activity of the whole image (77–82 %) was four times higher than the contribution of the root surface. Enzyme kinetic parameters indicated different enzyme systems in bulk and rhizosphere soil. Higher substrate affinity and catalytic efficiency in bulk than in rhizosphere soil suggested relative domination of microorganisms with more efficient enzyme systems in the former. Coupling direct zymography and kinetic assays enabled mapping the two-dimensional (2D) distribution of enzyme activity at the root-soil interface and estimating the catalytic properties of root-associated and soil-associated enzymes.