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Danyelle M Townsend - One of the best experts on this subject based on the ideXlab platform.
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1 A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast ( � 300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1 A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP11 A-, GSTP1-1B-, and GST1-1D-expressing cells
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Kenneth D Tew, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast (~300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP1-1A-, GSTP1-1B-, and GST1-1D-expressing cells ()OH generation resulted (after 36 h) in plasma membrane-permeability-related cell death, whereas GSTP1-1A- and GSTP1-1C-expressing cells had significantly better survival. We used FRET analyses to measure in vitro binding of purified GSTP1-1 allelic variant proteins to purified recombinant Prdx6. The affinities for Prdx6 binding to GSH-loaded GSTP1-1's either mirrored their observed peroxidase activities (using phospholipid hydroperoxide as a substrate), GSTP1-1A>GSTP1-1C (K(D)=51.0 vs 57.0 nM), or corresponded to inactivation, GSTP1-1B (GSTP1-1D) (K(D)=101.0 (94.0) nM). In silico modeling of the GSTP1-1-Prdx6 heterodimer revealed that the sites of GSTP1-1 polymorphism (Ile105 and Ala114) are in close proximity to the binding interface. Thus, there is a hierarchy of effectiveness for polymorphic variants of GSTP1-1 to regulate Prdx6 peroxidase function, a feature that may influence human population susceptibilities to oxidant stress.
Yefim Manevich - One of the best experts on this subject based on the ideXlab platform.
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1 A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast ( � 300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1 A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP11 A-, GSTP1-1B-, and GST1-1D-expressing cells
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Kenneth D Tew, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast (~300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP1-1A-, GSTP1-1B-, and GST1-1D-expressing cells ()OH generation resulted (after 36 h) in plasma membrane-permeability-related cell death, whereas GSTP1-1A- and GSTP1-1C-expressing cells had significantly better survival. We used FRET analyses to measure in vitro binding of purified GSTP1-1 allelic variant proteins to purified recombinant Prdx6. The affinities for Prdx6 binding to GSH-loaded GSTP1-1's either mirrored their observed peroxidase activities (using phospholipid hydroperoxide as a substrate), GSTP1-1A>GSTP1-1C (K(D)=51.0 vs 57.0 nM), or corresponded to inactivation, GSTP1-1B (GSTP1-1D) (K(D)=101.0 (94.0) nM). In silico modeling of the GSTP1-1-Prdx6 heterodimer revealed that the sites of GSTP1-1 polymorphism (Ile105 and Ala114) are in close proximity to the binding interface. Thus, there is a hierarchy of effectiveness for polymorphic variants of GSTP1-1 to regulate Prdx6 peroxidase function, a feature that may influence human population susceptibilities to oxidant stress.
Li Wang - One of the best experts on this subject based on the ideXlab platform.
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graphene oxide wrapped fe3o4 au nanohybrid as sers substrate for aromatic Dye Detection
Sensors and Actuators B-chemical, 2015Co-Authors: Guihong Ding, Shi Xie, Yongmei Zhu, Ying Liu, Li WangAbstract:Abstract An active surface-enhanced Raman scattering (SERS) substrate composed of graphene oxide (GO) wrapped gold nanoparticles (AuNPs) decorated-magnetic sphere Fe3O4 (GO wrapped Fe3O4@Au hybrid) was prepared and used for aromatic Dye Detection. The hybrid was characterized by SEM, EDX, XRD, UV–visible spectroscopy and Raman spectroscopy. This hybrid showed high activity for SERS Detection of aromatic Dye due to the synergistic interaction among GO nanosheet, AuNPs and Fe3O4 sphere. The dosages of AuNPs and GO were optimized to achieve a high sensitivity. The unique GO wrapped Fe3O4@Au hybrid has several advantages (such as high adsorption to target Dye molecules, low noise response and high SERS enhancement ability) as SERS substrate over previously reported Fe3O4 and AuNPs co-decorated GO sheet. Finally, the hybrid was successfully used for SERS Detection of aromatic Dye pollutant malachite green (MG) and nile blue A (NBA) even at concentration down to 1 nM and 0.1 nM, respectively. Potential of this substrate for multiplex Detection of Dye mixture (MG and NBA), and practical Detection of MG in real sample were also evaluated. Our results suggested that the hybrid of GO wrapped Fe3O4@Au can be used as an efficient SERS platform for aromatic Dye Detection.
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graphene oxide silver nanocomposite as sers substrate for Dye Detection effects of silver loading amount and composite dosage
Applied Surface Science, 2015Co-Authors: Guihong Ding, Shi Xie, Ying Liu, Li WangAbstract:Abstract Hybrid of graphene or graphene oxide (GO) with gold or silver nanoparticles (AgNPs) as substrate for SERS Detection often brings large background and low signal to noise ratio, which leads to poor sensitivity. In this study, it is proposed that the silver loading amount on GO and dosage of GO-Ag composite have significant influence on its SERS activity (SERS signal intensity and signal to noise ratio). The adsorption ability and SERS activity of GO-Ag composite for several Dye molecules were investigated in detail. It was found increasing the dosage of GO-Ag or AgNPs loading on GO always enhances its absorption to Dye molecules, while in both cases the SERS signal first increase and then decrease. The reason for this fluctuation of SERS signal was investigated and discussed, which indicate high silver loading amount leads to enhanced background response, while high composite dosage could decrease the signal of target molecule. Finally, an optimized GO-Ag substrate providing strong SERS signal and high signal to noise ratio was used for the Detection of several Dye molecules by SERS with the lowest detectable concentration down to 1 μM. Our results indicated that great caution should be paid on the silver loading amount and dosage of GO-Au/Ag when using GO-Au/Ag as SERS substrate for molecule sensing or comparing different results reported in reference.
Steven Hutchens - One of the best experts on this subject based on the ideXlab platform.
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1 A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast ( � 300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1 A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP11 A-, GSTP1-1B-, and GST1-1D-expressing cells
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allelic variants of glutathione s transferase p1 1 differentially mediate the peroxidase function of peroxiredoxin vi and alter membrane lipid peroxidation
Free Radical Biology and Medicine, 2013Co-Authors: Yefim Manevich, Steven Hutchens, Kenneth D Tew, Danyelle M TownsendAbstract:The dual-functioning antioxidant enzyme peroxiredoxin VI (Prdx6) detoxifies lipid peroxides particularly in biological membranes, and its peroxidase function is activated by glutathione S-transferase Pi (GSTP). The GSTP gene is polymorphic in humans, with the wild-type GSTP1-1A (Ile105, Ala114) and three variants: GSTP1-1B (Ile105Val, Ala114), GSTP1-1C (Ile105Val, Ala114Val), and GSTP1-1D (Ile105, Ala114Val). The focus of this study was to determine the influence of these polymorphisms on Prdx6 peroxidase function. Using extracellular generation of OH radicals and fluorescence (DPPP Dye) Detection, we found a fast (~300 s) onset of lipid peroxidation in membranes of MCF-7 cells transfected with a catalytically inactive Y7F mutant of GSTP1-1 and either GSTP1-1B or GSTP1-1D. However, this effect was not detected in cells expressing either GSTP1-1A or GSTP1-1C. Imaging of DPPP-labeled MCF-7 cells showed fluorescence localized in the plasma membrane, but intensity was substantially diminished in the GSTP1-1A- and GSTP1-1C-expressing cells. Moreover, in the Y7F mutant of GSTP1-1A-, GSTP1-1B-, and GST1-1D-expressing cells ()OH generation resulted (after 36 h) in plasma membrane-permeability-related cell death, whereas GSTP1-1A- and GSTP1-1C-expressing cells had significantly better survival. We used FRET analyses to measure in vitro binding of purified GSTP1-1 allelic variant proteins to purified recombinant Prdx6. The affinities for Prdx6 binding to GSH-loaded GSTP1-1's either mirrored their observed peroxidase activities (using phospholipid hydroperoxide as a substrate), GSTP1-1A>GSTP1-1C (K(D)=51.0 vs 57.0 nM), or corresponded to inactivation, GSTP1-1B (GSTP1-1D) (K(D)=101.0 (94.0) nM). In silico modeling of the GSTP1-1-Prdx6 heterodimer revealed that the sites of GSTP1-1 polymorphism (Ile105 and Ala114) are in close proximity to the binding interface. Thus, there is a hierarchy of effectiveness for polymorphic variants of GSTP1-1 to regulate Prdx6 peroxidase function, a feature that may influence human population susceptibilities to oxidant stress.
Guihong Ding - One of the best experts on this subject based on the ideXlab platform.
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graphene oxide wrapped fe3o4 au nanohybrid as sers substrate for aromatic Dye Detection
Sensors and Actuators B-chemical, 2015Co-Authors: Guihong Ding, Shi Xie, Yongmei Zhu, Ying Liu, Li WangAbstract:Abstract An active surface-enhanced Raman scattering (SERS) substrate composed of graphene oxide (GO) wrapped gold nanoparticles (AuNPs) decorated-magnetic sphere Fe3O4 (GO wrapped Fe3O4@Au hybrid) was prepared and used for aromatic Dye Detection. The hybrid was characterized by SEM, EDX, XRD, UV–visible spectroscopy and Raman spectroscopy. This hybrid showed high activity for SERS Detection of aromatic Dye due to the synergistic interaction among GO nanosheet, AuNPs and Fe3O4 sphere. The dosages of AuNPs and GO were optimized to achieve a high sensitivity. The unique GO wrapped Fe3O4@Au hybrid has several advantages (such as high adsorption to target Dye molecules, low noise response and high SERS enhancement ability) as SERS substrate over previously reported Fe3O4 and AuNPs co-decorated GO sheet. Finally, the hybrid was successfully used for SERS Detection of aromatic Dye pollutant malachite green (MG) and nile blue A (NBA) even at concentration down to 1 nM and 0.1 nM, respectively. Potential of this substrate for multiplex Detection of Dye mixture (MG and NBA), and practical Detection of MG in real sample were also evaluated. Our results suggested that the hybrid of GO wrapped Fe3O4@Au can be used as an efficient SERS platform for aromatic Dye Detection.
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graphene oxide silver nanocomposite as sers substrate for Dye Detection effects of silver loading amount and composite dosage
Applied Surface Science, 2015Co-Authors: Guihong Ding, Shi Xie, Ying Liu, Li WangAbstract:Abstract Hybrid of graphene or graphene oxide (GO) with gold or silver nanoparticles (AgNPs) as substrate for SERS Detection often brings large background and low signal to noise ratio, which leads to poor sensitivity. In this study, it is proposed that the silver loading amount on GO and dosage of GO-Ag composite have significant influence on its SERS activity (SERS signal intensity and signal to noise ratio). The adsorption ability and SERS activity of GO-Ag composite for several Dye molecules were investigated in detail. It was found increasing the dosage of GO-Ag or AgNPs loading on GO always enhances its absorption to Dye molecules, while in both cases the SERS signal first increase and then decrease. The reason for this fluctuation of SERS signal was investigated and discussed, which indicate high silver loading amount leads to enhanced background response, while high composite dosage could decrease the signal of target molecule. Finally, an optimized GO-Ag substrate providing strong SERS signal and high signal to noise ratio was used for the Detection of several Dye molecules by SERS with the lowest detectable concentration down to 1 μM. Our results indicated that great caution should be paid on the silver loading amount and dosage of GO-Au/Ag when using GO-Au/Ag as SERS substrate for molecule sensing or comparing different results reported in reference.
