The Experts below are selected from a list of 15033 Experts worldwide ranked by ideXlab platform
Sylvie Begin-colin - One of the best experts on this subject based on the ideXlab platform.
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Development and applications of a DNA labeling method with magnetic nanoparticles to study the role of horizontal gene transfer events between bacteria in Soil Pollutant bioremediation processes
Environmental Science and Pollution Research, 2015Co-Authors: Jérémy Pivetal, C. Vézy, N M Dempsey, Luiz Fernando Zanini, Georgeta Ciuta, Marie Frenea-robin, Frédéric Dumas-bouchiat, Gilbert Reyne, Naoufel Haddour, Sylvie Begin-colinAbstract:Horizontal gene transfers are critical mechanisms of bacterial evolution and adaptation that are involved to a significant level in the degradation of toxic molecules such as xenobiotic pesticides. However, understanding how these mechanisms are regulated in situ and how they could be used by man to increase the degradation potential of Soil microbes is compromised by conceptual and technical limitations. This includes the physical and chemical complexity and heterogeneity in such environments leading to an extreme bacterial taxonomical diversity and a strong redundancy of genes and functions. In addition, more than 99 % of Soil bacteria fail to develop colonies in vitro, and even new DNA-based investigation methods (metagenomics) are not specific and sensitive enough to consider lysis recalcitrant bacteria and those belonging to the rare biosphere. The objective of the ANR funded project “Emergent” was to develop a new culture independent approach to monitor gene transfer among Soil bacteria by labeling plasmid DNA with magnetic nanoparticles in order to specifically capture and isolate recombinant cells using magnetic microfluidic devices. We showed the feasibility of the approach by using electrotransformation to transform a suspension of Escherichia coli cells with biotin-functionalized plasmid DNA molecules linked to streptavidin-coated superparamagnetic nanoparticles. Our results have demonstrated that magnetically labeled cells could be specifically retained on micromagnets integrated in a microfluidic channel and that an efficient selective separation can be achieved with the microfluidic device. Altogether, the project offers a promising alternative to traditional culture-based approaches for deciphering the extent of horizontal gene transfer events mediated by electro or natural genetic transformation mechanisms in complex environments such as Soil.
Jérémy Pivetal - One of the best experts on this subject based on the ideXlab platform.
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Development and applications of a DNA labeling method with magnetic nanoparticles to study the role of horizontal gene transfer events between bacteria in Soil Pollutant bioremediation processes
Environmental Science and Pollution Research, 2015Co-Authors: Jérémy Pivetal, C. Vézy, N M Dempsey, Luiz Fernando Zanini, Georgeta Ciuta, Marie Frenea-robin, Frédéric Dumas-bouchiat, Gilbert Reyne, Naoufel Haddour, Sylvie Begin-colinAbstract:Horizontal gene transfers are critical mechanisms of bacterial evolution and adaptation that are involved to a significant level in the degradation of toxic molecules such as xenobiotic pesticides. However, understanding how these mechanisms are regulated in situ and how they could be used by man to increase the degradation potential of Soil microbes is compromised by conceptual and technical limitations. This includes the physical and chemical complexity and heterogeneity in such environments leading to an extreme bacterial taxonomical diversity and a strong redundancy of genes and functions. In addition, more than 99 % of Soil bacteria fail to develop colonies in vitro, and even new DNA-based investigation methods (metagenomics) are not specific and sensitive enough to consider lysis recalcitrant bacteria and those belonging to the rare biosphere. The objective of the ANR funded project “Emergent” was to develop a new culture independent approach to monitor gene transfer among Soil bacteria by labeling plasmid DNA with magnetic nanoparticles in order to specifically capture and isolate recombinant cells using magnetic microfluidic devices. We showed the feasibility of the approach by using electrotransformation to transform a suspension of Escherichia coli cells with biotin-functionalized plasmid DNA molecules linked to streptavidin-coated superparamagnetic nanoparticles. Our results have demonstrated that magnetically labeled cells could be specifically retained on micromagnets integrated in a microfluidic channel and that an efficient selective separation can be achieved with the microfluidic device. Altogether, the project offers a promising alternative to traditional culture-based approaches for deciphering the extent of horizontal gene transfer events mediated by electro or natural genetic transformation mechanisms in complex environments such as Soil.
Rita Földényi - One of the best experts on this subject based on the ideXlab platform.
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Acetochlor as a Soil Pollutant
Environmental Science and Pollution Research, 2003Co-Authors: Zsófia Lengyel, Rita FöldényiAbstract:Acetochlor is a widely used herbicide all over the world. Similarly to other organic Pollutants, the environmental fate of the acetochlor is strongly related to its adsorption properties. Static adsorption equilibrium measurements were carried out at 25°C on different types of Hungarian Soils characterized by varying amounts of organic matter and pH values. Isotherms obtained under different conditions, as well as on various Soils, exhibit a similar shape, thus indicating a two-step adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles. The adsorption coefficients (K) were estimated from the initial slope of the curves. These values were determined not only by the type of the Soil, but also by the composition of the aqueous media. The organic matter adsorption coefficients (K_om) were also calculated and they were approximately identical for Soils of high organic matter. Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile Pollutant of the Soil posing a potential danger to the aquatic environment. For Soils with high organic content, the K_om values are similar to each other and, due to the significant coverage of the inorganic surfaces, the adsorption is controlled by the solute-organic substance interactions. The adsorption of weakly polar compounds, however, is remarkable even on those Soils where the organic content is low. In this case, the binding is governed by the soluteinorganic surface interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz. According to our hypothesis, the second part of the adsorption step is controlled by the solute-adsorbed solute interactions. The role of the organic matter in this region of the isotherm is probably negligible. As the organic matter content of the Soils plays an important role in the acetochlor adsorption, humic substances must have a strong influence upon the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and the development of a quantitative model are in progress.
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Acetochlor as a Soil Pollutant
Journal of Soils and Sediments, 2002Co-Authors: Zsófia Lengyel, Rita FöldényiAbstract:The agricultural use of pesticides leads to diffuse pollution whereby the various contaminants of the Soil infiltrate into the groundwater reaching lakes and drinking water aquifers. Due to the extensive application of these chemicals, their leaching presents a high environmental risk. Since the adsorption coefficient (K) characterizes the Soil / water partitioning [1] and is also representative for leaching, the first step in understanding of the environmental fate of a Pollutant is to study its adsorption properties. Weak binding to the Soil constituents (low K) leads to groundwater pollution, while a strong binding (high K) results in surface water pollution through the erosion of the Soil. Acetochlor is a widely used herbicide all over the world. Similar to other organic Pollutants, the environmental fate of this chemical is strongly related to its adsorption properties. Static adsorption equilibrium measurements were carried out at 25°C on different types of Hungarian Soils (chernozem, brown forest and sandy Soil) characterized by varying amounts of organic matter and pH values. Acetochlor solutions were prepared in the presence of nitrate and phosphate ions (0.1 mol/L sodium nitrate and 0.1 mol/L phosphate uffer, pH=7) which are constituents of fertilizers occurring in high concentrations in the environment. In order to appreciate their effect, adsorption studies were also performed in pure aqueous medium. The equilibrated liquid was analyzed after centrifugation by two different methods (Total Organic Carbon measurement, High Performance Liquid Chromatography). Isotherms obtained under different conditions, as well as on various Soils, exhibit a similar shape, thus indicating a two-step adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles (H-, L- and C-type, [2]). The adsorption coefficients were estimated from the initial slope of the curves. These values were determined not only by the type of the Soil, but also by the composition of the aqueous media. Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile Pollutant of the Soil posing a potential danger to the aquatic environment. The organic matter adsorption coefficients (K_om) [3] were also calculated and they were approximately identical for Soils of high organic matter. For the chernozem and brown forest Soils, the values of the K and K_om parameters are increasing in the order from water < phosphate buffer < sodium nitrate. For Soils of low organic content, the similarity of the K_om values cannot be expected (due to the hyperbolic nature of the equation) as the data really indicate it for the adsorption behavior of the sandy Soil. Here, the organic matter plays a less important role and the adsorption is controlled by the solute / inorganic substance interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz resulting thereby in a similar plot being obtained for the Soils. According to the hypothesis presented here, the first step of the isotherms is controlled by the solute / surface interactions while the solute / adsorbed solute interactions are operating in the second step of the isotherm. The role of the organic matter in this region of the isotherm is probably negligible. The comparison of the adsorption coefficients leads to the conclusion that the presence of nitrate and phosphate ions enhances the adsorption of acetochlor on the Soils containing a high percentage of organic matter. As these ions are present in the environment due to the extensive use of fertilizers, they may increase the acetochlor pollution of water by erosion. This conclusion corroborates those earlier observations that reported frequent acetochlor contamination of the surface waters [4–5]. As the organic matter content of the Soils plays an important role in the acetochlor adsorption, humic substances must have a strong influence on the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and the development of a quantitative model are in progress.
Naoufel Haddour - One of the best experts on this subject based on the ideXlab platform.
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Development and applications of a DNA labeling method with magnetic nanoparticles to study the role of horizontal gene transfer events between bacteria in Soil Pollutant bioremediation processes
Environmental Science and Pollution Research, 2015Co-Authors: Jérémy Pivetal, C. Vézy, N M Dempsey, Luiz Fernando Zanini, Georgeta Ciuta, Marie Frenea-robin, Frédéric Dumas-bouchiat, Gilbert Reyne, Naoufel Haddour, Sylvie Begin-colinAbstract:Horizontal gene transfers are critical mechanisms of bacterial evolution and adaptation that are involved to a significant level in the degradation of toxic molecules such as xenobiotic pesticides. However, understanding how these mechanisms are regulated in situ and how they could be used by man to increase the degradation potential of Soil microbes is compromised by conceptual and technical limitations. This includes the physical and chemical complexity and heterogeneity in such environments leading to an extreme bacterial taxonomical diversity and a strong redundancy of genes and functions. In addition, more than 99 % of Soil bacteria fail to develop colonies in vitro, and even new DNA-based investigation methods (metagenomics) are not specific and sensitive enough to consider lysis recalcitrant bacteria and those belonging to the rare biosphere. The objective of the ANR funded project “Emergent” was to develop a new culture independent approach to monitor gene transfer among Soil bacteria by labeling plasmid DNA with magnetic nanoparticles in order to specifically capture and isolate recombinant cells using magnetic microfluidic devices. We showed the feasibility of the approach by using electrotransformation to transform a suspension of Escherichia coli cells with biotin-functionalized plasmid DNA molecules linked to streptavidin-coated superparamagnetic nanoparticles. Our results have demonstrated that magnetically labeled cells could be specifically retained on micromagnets integrated in a microfluidic channel and that an efficient selective separation can be achieved with the microfluidic device. Altogether, the project offers a promising alternative to traditional culture-based approaches for deciphering the extent of horizontal gene transfer events mediated by electro or natural genetic transformation mechanisms in complex environments such as Soil.
Gilbert Reyne - One of the best experts on this subject based on the ideXlab platform.
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Development and applications of a DNA labeling method with magnetic nanoparticles to study the role of horizontal gene transfer events between bacteria in Soil Pollutant bioremediation processes
Environmental Science and Pollution Research, 2015Co-Authors: Jérémy Pivetal, C. Vézy, N M Dempsey, Luiz Fernando Zanini, Georgeta Ciuta, Marie Frenea-robin, Frédéric Dumas-bouchiat, Gilbert Reyne, Naoufel Haddour, Sylvie Begin-colinAbstract:Horizontal gene transfers are critical mechanisms of bacterial evolution and adaptation that are involved to a significant level in the degradation of toxic molecules such as xenobiotic pesticides. However, understanding how these mechanisms are regulated in situ and how they could be used by man to increase the degradation potential of Soil microbes is compromised by conceptual and technical limitations. This includes the physical and chemical complexity and heterogeneity in such environments leading to an extreme bacterial taxonomical diversity and a strong redundancy of genes and functions. In addition, more than 99 % of Soil bacteria fail to develop colonies in vitro, and even new DNA-based investigation methods (metagenomics) are not specific and sensitive enough to consider lysis recalcitrant bacteria and those belonging to the rare biosphere. The objective of the ANR funded project “Emergent” was to develop a new culture independent approach to monitor gene transfer among Soil bacteria by labeling plasmid DNA with magnetic nanoparticles in order to specifically capture and isolate recombinant cells using magnetic microfluidic devices. We showed the feasibility of the approach by using electrotransformation to transform a suspension of Escherichia coli cells with biotin-functionalized plasmid DNA molecules linked to streptavidin-coated superparamagnetic nanoparticles. Our results have demonstrated that magnetically labeled cells could be specifically retained on micromagnets integrated in a microfluidic channel and that an efficient selective separation can be achieved with the microfluidic device. Altogether, the project offers a promising alternative to traditional culture-based approaches for deciphering the extent of horizontal gene transfer events mediated by electro or natural genetic transformation mechanisms in complex environments such as Soil.
