The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
C K Stover - One of the best experts on this subject based on the ideXlab platform.
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development of a liquid chromatography mass spectrometry based drug Accumulation Assay in pseudomonas aeruginosa
Analytical Biochemistry, 2009Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonasaeruginosa, rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [3H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
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Development of a liquid chromatography/mass spectrometry-based drug Accumulation Assay in Pseudomonas aeruginosa.
Analytical Biochemistry, 2008Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonas aeruginosa , rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC 50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3 H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [ 3 H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
Kelly A Rose - One of the best experts on this subject based on the ideXlab platform.
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development of a liquid chromatography mass spectrometry based drug Accumulation Assay in pseudomonas aeruginosa
Analytical Biochemistry, 2009Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonasaeruginosa, rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [3H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
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Development of a liquid chromatography/mass spectrometry-based drug Accumulation Assay in Pseudomonas aeruginosa.
Analytical Biochemistry, 2008Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonas aeruginosa , rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC 50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3 H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [ 3 H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
Steve Dunham - One of the best experts on this subject based on the ideXlab platform.
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development of a liquid chromatography mass spectrometry based drug Accumulation Assay in pseudomonas aeruginosa
Analytical Biochemistry, 2009Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonasaeruginosa, rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [3H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
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Development of a liquid chromatography/mass spectrometry-based drug Accumulation Assay in Pseudomonas aeruginosa.
Analytical Biochemistry, 2008Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonas aeruginosa , rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC 50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3 H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [ 3 H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
Lanhsin Liang - One of the best experts on this subject based on the ideXlab platform.
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development of a liquid chromatography mass spectrometry based drug Accumulation Assay in pseudomonas aeruginosa
Analytical Biochemistry, 2009Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonasaeruginosa, rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [3H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
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Development of a liquid chromatography/mass spectrometry-based drug Accumulation Assay in Pseudomonas aeruginosa.
Analytical Biochemistry, 2008Co-Authors: Kelly A Rose, Lanhsin Liang, Steve Dunham, C K StoverAbstract:Abstract Bacterial resistance to antibiotic therapy remains a worldwide problem. In Pseudomonas aeruginosa , rates of efflux confer inherent resistance to many antimicrobial agents, including fluoroquinolones, due to a high level of expression and a relatively high turnover number of the efflux pumps in gram-negative bacteria. To understand the roles of efflux pumps in both the influx and efflux of compounds in P. aeruginosa and to aid the chemistry compound design by bridging in vitro enzymatic binding data (IC 50 values) with whole cell results (MIC numbers), a collaborative effort was put forward to validate a series of bacterial penetration/Accumulation Assays for assessment of intracellular drug concentration. Initially, using 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP) as the tracer, a 96-well fluorescence Assay was established to measure the time-dependent Accumulation of DMP in wild-type (PAO1), MexABOprM deletion (PAO200), and MexABOprM–MexCDOprJ–MexJKL:FRT deletion mutants (PAO314). At steady state, the order of DMP Accumulation was PAO314 > PAO200 > PAO1. Subsequently, the established Assay conditions were applied to a radiolabeled Assay format using 3 H-labeled ciprofloxacin. At the concentration tested, the Accumulation of [ 3 H]ciprofloxacin approached a plateau after 15 min and the amount of Accumulation in PAO314 was higher (∼2- to 10-fold) than that in PAO1. Finally, with an additional step of cell lysis, a liquid chromatography/mass spectrometry-based Assay was established with ciprofloxacin with (i) superior sensitivity (the detection limit can be as low as 0.24 ng/ml for ciprofloxacin) and (ii) the ability to monitor cold or nonfluorescent compounds in a drug discovery setting.
Haimou Zhang - One of the best experts on this subject based on the ideXlab platform.
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organic uv filters inhibit multixenobiotic resistance mxr activity in tetrahymena thermophila investigations by the rhodamine 123 Accumulation Assay and molecular docking
Ecotoxicology, 2016Co-Authors: Tao Yuan, Peng Cheng, Chuanqi Zhou, Junjie Ao, Wenhua Wang, Haimou ZhangAbstract:Multixenobiotic resistance (MXR) transporters, which belong to ATP-binding cassette (ABC) family proteins, are present in living organisms as a first line of defense system against xenobiotics and environmental contaminants. The effects of six organic UV filters (4-methyl -benzylidene camphor, 4-MBC; benzophenone-3, BP-3; butyl methoxydibenzoyl-methane, BM-DBM; ethylhexyl methoxy cinnamate, EHMC; octocrylene, OC and homosalate, HMS) on multixenobiotic resistance (MXR) in Tetrahymena thermophila were investigated in this study. It was found that 4-MBC, BP-3 and BM-DBM could significantly inhibit activity of the MXR system, causing concentration dependent Accumulation of rhodamine 123; while EHMC, OC and HMS had weak MXR inhibition. The IC50 (50 % inhibition concentration) values of 4-MBC, BP-3 and BM-DBM were 23.54, 40.59 and 26.37 μM, respectively, with inhibitory potentials of 23.1, 13.4 and 20.6 % relative to verapamil (VER, a model inhibitor of P-glycoprotein). Our results firstly provide the evidence for UV filters inhibition effect on MXR in aquatic organisms. In addition, it was revealed by molecular docking analysis that the selected six UV filters can occupy the same binding site on T. thermophila P-gp as VER does; and form H-bonds with residues Ser 328 and/or Asn 281. This study raises the awareness of aquatic ecological risk from the organic UV filters exposure, as they would be involved in potentiating toxic effects by chemosensitizing.
