Transcriptional activation of the human CYP1A1 gene (coding for cytochrome P450 1A1) is mediated ... more Transcriptional activation of the human CYP1A1 gene (coding for cytochrome P450 1A1) is mediated by the aryl hydrocarbon receptor. In the present study we have examined interaction of the ginsenoside Rg1 and Rb1 with the carcinogen activation pathway mediated by the aryl hydrocarbon receptor in HepG2 cells. RT-PCR was used to determine the CYP1A1 mRNA levels. The results showed that in HepG2 cells CYP1A1 mRNA expression was significantly increased in a concentration-and time-dependent manner by ginsenoside Rg1 and Rb1. Ginsenoside Rg1 and Rb1 activated the DNA-binding capacity of the aryl hydrocarbon receptor for the xenobiotic responsive element of CYP1A1 as measured by the electrophoretic-mobility shift assay (EMSA). Rg1 and Rb1 were able to activate the ability of the aryl hydrocarbon receptor to bind to an oligonucleotide containing the xenobiotic-responsive element (XRE) of the cyp1a1 promoter. These results indicate that Rg1 and Rb1's effects on CYP1A1 induction are mediated by the aryl hydrocarbon receptor. Since CYP1A1 and aryl hydrocarbon receptor play important roles in carcinogenesis, development, differentiation and many other essential physiological functions, these results suggest that the chemopreventive effect of Panax ginseng may be due, in part, to ginsenoside Rg1 and Rb1's ability to compete with aryl hydrocarbons for both the aryl hydrocarbon receptor and CYP1A1. Rg1 and Rb1 may thus be natural ligands and substrates of the aryl hydrocarbon receptor or have relationship with aryl hydrocarbon receptor pathway. These properties might be of help for future studies in P. ginseng and chemoprevention in chemical-induced cancer.
Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2006
Aconitine, a major Aconitum alkaloid, is well known for its high toxicity that induces severe arr... more Aconitine, a major Aconitum alkaloid, is well known for its high toxicity that induces severe arrhythmias leading to death. The current study investigated the metabolism of aconitine and the effects of selective cytochrome P450 (CYP) inhibitors on the metabolism of aconitine in rat liver microsomes. The metabolites were separated and assayed by liquid chromatography-ion trap mass spectrometry (LC/MS(n)) and further identified by comparison of their mass spectra and chromatographic behaviors with reference substances. Various selective inhibitors of CYP were used to identify the isoforms of CYP, that involved in the metabolism of aconitine. A total of at least six metabolites were found and characterized in rat liver microsomal incubations. Result showed that the inhibitor of CYP 3A had an inhibitory effect on aconitine metabolism in a concentration-dependant manner, the inhibitor of CYP1A1/2 had a modest inhibitory effect, whereas inhibitors of CYP2B1/2, 2D and 2E1 had no obvious inhibitory effects on aconitine metabolism. Aconitine might be metabolized by CYP 3A and CYP1A1/2 isoforms in rat liver microsome.
Ferroplasma spp. are widely distributed in acid mine drainage (AMD) and biomining environments at... more Ferroplasma spp. are widely distributed in acid mine drainage (AMD) and biomining environments at mesophilic and moderately elevated temperatures, at low pH and high concentrations of iron and other metal ions. Microbial attachment and biofilm formation on metal sulfides is of great importance during bioleaching. In this work, several cultivation and microscopical techniques were applied to investigate the biofilm development of Ferroplasma acidiphilum. Biofilms were heterogeneously distributed on filters over time, and varied within the different growth conditions such as supplementation with glucose. Additionally, cell distribution, biofilm formation as well as EPS production of F. acidiphilum cells forming biofilms on pyrite were observed by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) combined with epifluorescence microscopy (EFM). Cells formed a monolayered biofilm and were preferably attached to the cracks/defects of pyrite surfaces. Biofilm and planktonic cells exhibited significant morphological differences. Capsular EPS were observed in both biofilm and planktonic cells.
Transcriptional activation of the human CYP1A1 gene (coding for cytochrome P450 1A1) is mediated ... more Transcriptional activation of the human CYP1A1 gene (coding for cytochrome P450 1A1) is mediated by the aryl hydrocarbon receptor. In the present study we have examined interaction of the ginsenoside Rg1 and Rb1 with the carcinogen activation pathway mediated by the aryl hydrocarbon receptor in HepG2 cells. RT-PCR was used to determine the CYP1A1 mRNA levels. The results showed that in HepG2 cells CYP1A1 mRNA expression was significantly increased in a concentration-and time-dependent manner by ginsenoside Rg1 and Rb1. Ginsenoside Rg1 and Rb1 activated the DNA-binding capacity of the aryl hydrocarbon receptor for the xenobiotic responsive element of CYP1A1 as measured by the electrophoretic-mobility shift assay (EMSA). Rg1 and Rb1 were able to activate the ability of the aryl hydrocarbon receptor to bind to an oligonucleotide containing the xenobiotic-responsive element (XRE) of the cyp1a1 promoter. These results indicate that Rg1 and Rb1's effects on CYP1A1 induction are mediated by the aryl hydrocarbon receptor. Since CYP1A1 and aryl hydrocarbon receptor play important roles in carcinogenesis, development, differentiation and many other essential physiological functions, these results suggest that the chemopreventive effect of Panax ginseng may be due, in part, to ginsenoside Rg1 and Rb1's ability to compete with aryl hydrocarbons for both the aryl hydrocarbon receptor and CYP1A1. Rg1 and Rb1 may thus be natural ligands and substrates of the aryl hydrocarbon receptor or have relationship with aryl hydrocarbon receptor pathway. These properties might be of help for future studies in P. ginseng and chemoprevention in chemical-induced cancer.
Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2006
Aconitine, a major Aconitum alkaloid, is well known for its high toxicity that induces severe arr... more Aconitine, a major Aconitum alkaloid, is well known for its high toxicity that induces severe arrhythmias leading to death. The current study investigated the metabolism of aconitine and the effects of selective cytochrome P450 (CYP) inhibitors on the metabolism of aconitine in rat liver microsomes. The metabolites were separated and assayed by liquid chromatography-ion trap mass spectrometry (LC/MS(n)) and further identified by comparison of their mass spectra and chromatographic behaviors with reference substances. Various selective inhibitors of CYP were used to identify the isoforms of CYP, that involved in the metabolism of aconitine. A total of at least six metabolites were found and characterized in rat liver microsomal incubations. Result showed that the inhibitor of CYP 3A had an inhibitory effect on aconitine metabolism in a concentration-dependant manner, the inhibitor of CYP1A1/2 had a modest inhibitory effect, whereas inhibitors of CYP2B1/2, 2D and 2E1 had no obvious inhibitory effects on aconitine metabolism. Aconitine might be metabolized by CYP 3A and CYP1A1/2 isoforms in rat liver microsome.
Ferroplasma spp. are widely distributed in acid mine drainage (AMD) and biomining environments at... more Ferroplasma spp. are widely distributed in acid mine drainage (AMD) and biomining environments at mesophilic and moderately elevated temperatures, at low pH and high concentrations of iron and other metal ions. Microbial attachment and biofilm formation on metal sulfides is of great importance during bioleaching. In this work, several cultivation and microscopical techniques were applied to investigate the biofilm development of Ferroplasma acidiphilum. Biofilms were heterogeneously distributed on filters over time, and varied within the different growth conditions such as supplementation with glucose. Additionally, cell distribution, biofilm formation as well as EPS production of F. acidiphilum cells forming biofilms on pyrite were observed by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) combined with epifluorescence microscopy (EFM). Cells formed a monolayered biofilm and were preferably attached to the cracks/defects of pyrite surfaces. Biofilm and planktonic cells exhibited significant morphological differences. Capsular EPS were observed in both biofilm and planktonic cells.
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Papers by Yuguang Wang