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Manuel Salvador - One of the best experts on this subject based on the ideXlab platform.
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Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens
Frontiers Media S.A., 2018Co-Authors: Manuel Salvador, Montserrat Argandona, Laszlo N Csonka, Joaquin J Nieto, Emilia Naranjo, Francine Piubeli, Carmen VargasAbstract:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by Temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by Temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of Temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting Disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and Temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and Temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and Temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by Temperature. However, salt-induced cell motility was reduced at high Temperature, possibly caused by an alteration of Na+ permeability by Temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high Temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens
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Presentation_1_Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens.PDF
2018Co-Authors: Manuel Salvador, Montserrat Argandona, Laszlo N Csonka, Joaquin J Nieto, Emilia Naranjo, Francine Piubeli, Carmen VargasAbstract:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by Temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by Temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of Temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting Disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and Temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and Temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and Temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by Temperature. However, salt-induced cell motility was reduced at high Temperature, possibly caused by an alteration of Na+ permeability by Temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high Temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens.
Carmen Vargas - One of the best experts on this subject based on the ideXlab platform.
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Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens
Frontiers Media S.A., 2018Co-Authors: Manuel Salvador, Montserrat Argandona, Laszlo N Csonka, Joaquin J Nieto, Emilia Naranjo, Francine Piubeli, Carmen VargasAbstract:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by Temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by Temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of Temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting Disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and Temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and Temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and Temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by Temperature. However, salt-induced cell motility was reduced at high Temperature, possibly caused by an alteration of Na+ permeability by Temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high Temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens
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Presentation_1_Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens.PDF
2018Co-Authors: Manuel Salvador, Montserrat Argandona, Laszlo N Csonka, Joaquin J Nieto, Emilia Naranjo, Francine Piubeli, Carmen VargasAbstract:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by Temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by Temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of Temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting Disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and Temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and Temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and Temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by Temperature. However, salt-induced cell motility was reduced at high Temperature, possibly caused by an alteration of Na+ permeability by Temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high Temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens.
Seyyed Rashid Khazeiynasab - One of the best experts on this subject based on the ideXlab platform.
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resilience analysis and cascading failure modeling of power systems under extreme Temperatures
Journal of Modern Power Systems and Clean Energy, 2020Co-Authors: Seyyed Rashid KhazeiynasabAbstract:In this paper, we propose an AC power flow based cascading failure model that explicitly considers external weather conditions, extreme Temperatures in particular, and evaluates the impact of extreme Temperature on the initiation and propagation of cascading blackouts. Based on this model, careful analysis is performed on the resilience of the power system under extreme Temperatures. Specifically, load and dynamic line rating changes are modeled due to Temperature Disturbance, the probabilities for transmission line and generator outages are evaluated, and the timing for each type of events is carefully calculated to decide the actual event sequence. It should be emphasized that the correlated events, in the advent of external Temperature changes, could together contribute to voltage instability. Besides, we model undervoltage load shedding and operator re-dispatch as control strategies for preventing the propagation of cascading failures. The effectiveness of the proposed model is verified by simulation results on the RTS-96 3-area system and it is found that Temperature Disturbances can lead to correlated load change and line/generator tripping, which together will greatly increase the risk of cascading and voltage instability. Critical Temperature change, critical area with Temperature Disturbance, identification of most vulnerable buses, and comparison of different control strategies are also carefully investigated.
Thomas, Hywel R. - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of dual porosity coupled thermo-hydro-mechanical behaviour during CO2 sequestration in coal
'Elsevier BV', 2020Co-Authors: Hosking, Lee J., Chen Min, Thomas, Hywel R.Abstract:This study presents a coupled dual porosity thermal-hydraulic-mechanical (THM) model of non-isothermal gas flow during CO2 sequestration in coal seams. Thermal behaviour is part of the disturbed physical and chemical condition of a coal seam caused by CO2 injection, and must be understood for accurate prediction of CO2 flow and storage. A new porosity-permeability model is included for consideration of the fracture-matrix compartment interaction. The new model is verified against an analytical solution and validated against experimental measurements, before being used to analyse coupled THM effects during CO2 sequestration in coal. A simulation of CO2 injection at a fixed rate shows the development of a cooling region within the coal seam due to the Joule-Thomson effect, with the Temperature in the vicinity of the well declining sharply before recovering slowly. The Temperature Disturbance further from the well is more gradual by comparison. Under the simulation conditions studied, CO2 injection increases coal matrix porosity and decreases the porosity and permeability of the natural fracture network, especially in the vicinity of the injection well, due to adsorption-induced coal swelling. Compared with the effects of gas pressure and Temperature, the matrix-fracture compartment interaction plays an important role in changes of porosity and permeability. Considering the Temperature Disturbance caused by CO2 injection under the set of representative conditions studied, the coupled model can provide an insight into the associated effects on CO2 flow and storage during its sequestration in coal seams
Hr Thomas - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of dual porosity coupled thermo-hydro-mechanical behaviour during CO2 sequestration in coal
'Elsevier BV', 2020Co-Authors: Lj Hosking, Chen M, Hr ThomasAbstract:This study presents a coupled dual porosity thermal-hydraulic-mechanical (THM) model of non-isothermal gas flow during CO2 sequestration in coal seams. Thermal behaviour is part of the disturbed physical and chemical condition of a coal seam caused by CO2 injection, and must be understood for accurate prediction of CO2 flow and storage. A new porosity-permeability model is included for consideration of the fracture-matrix compartment interaction. The new model is verified against an analytical solution and validated against experimental measurements, before being used to analyse coupled THM effects during CO2 sequestration in coal. A simulation of CO2 injection at a fixed rate shows the development of a cooling region within the coal seam due to the Joule-Thomson effect, with the Temperature in the vicinity of the well declining sharply before recovering slowly. The Temperature Disturbance further from the well is more gradual by comparison. Under the simulation conditions studied, CO2 injection increases coal matrix porosity and decreases the porosity and permeability of the natural fracture network, especially in the vicinity of the injection well, due to adsorption-induced coal swelling. Compared with the effects of gas pressure and Temperature, the matrix-fracture compartment interaction plays an important role in changes of porosity and permeability. Considering the Temperature Disturbance caused by CO2 injection under the set of representative conditions studied, the coupled model can provide an insight into the associated effects on CO2 flow and storage during its sequestration in coal seams.The first author gratefully acknowledges the financial support provided by the Welsh European Funding Office (WEFO), through the FLEXIS project. The financial support from the China Scholarship Council for the PhD studentship of the second author is also gratefully acknowledged
