The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal mo...The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments. H2O2 can modulate the activities of many components in signaling, such as protein phosphatases, protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.展开更多
Objective： To evaluate the effects and possible mechanisms of rutaecarpine on angiotensin Ⅱ （Ang Ⅱ ）-induced proliferation in cultured rat vascular smooth muscle cells （VSMCs）. Methods： VSMCs were isolated fro...Objective： To evaluate the effects and possible mechanisms of rutaecarpine on angiotensin Ⅱ （Ang Ⅱ ）-induced proliferation in cultured rat vascular smooth muscle cells （VSMCs）. Methods： VSMCs were isolated from Male Sprague-Dawley rat aorta, and cultured by enzymic dispersion method. Experiments were performed with cells from passages 3-8. The cultured VSMCs were randomly divided into control, model （Ang Ⅱ 0.1 μ moVL）, and rutaecarpine （0.3-3.0μmol/L） groups. VMSC proliferation was induced by Ang Ⅱ, and was evaluated by the 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide assay and cell counting. To examine the mechanisms involved in anti-proliferative effects of rutaecarpine, nitric oxide （NO） levels and NO synthetase （NOS） activity were determined. Expressions of VSMC proliferation-related genes including endothelial nitric oxide synthase （eNOS）, and c-myc hypertension related gene-1 （HRG-1） were determined by real-time reverse chain reaction （RT-PCR）. Results： Rutaecarpine （0.3-3.0μmol/l_） inhibited Ang R-induced VSMC proliferation and the best effects were achieved at 3.0 μmol/L. The Ang Ⅱ-induced decreases in cellular NO contents and NOS activities were antagonized by rutaecarpine （P〈0.05）. Ang Ⅱ administration suppressed the expressions of eNOS and HRG-1, while increased c-myc expression （P〈0.05）. All these effects were attenuated by 3.0μmol/L rutaecarpine （P〈0.05）. Conclusion： Rutaecarpine is effective against Ang Ⅱ-induced rat VSMC proliferation, and this effect is due, at least in part, to NO production and the modulation of VMSC proliferation-related gene expressions.展开更多
AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by...AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by lipid-mediated transfection, including transient and stable transfection. Positive clones were screened by incubating in the selective medium with 600 μg/mL G418 and named HL-7702/HBV-encoded X protein （HBx） cells. The expressions of Fas/FasL, Bax/Bcl-2, and c-myc mRNA were measured by semi-quantitative RT-PCR in HL-7702/HBx and control group, respectively.RESULTS： RT-PCR analysis confirmed that HBV X gene was transfected into HL-7702 cells successfully. By semiquantitative RT-PCR analysis, Bax and c-myc mRNA levels in HL-7702/HBx cells of transient transfection were significantly higher than those in control, FasL and c-myc mRNA levels in HL-7702/HBx cells of stable transfection were significantly higher than those in control, whereas the Bcl-2 mRNA levels in HL-7702/HBx cells of transient and stable transfection were significantly lower than thosein control.CONCLUSION： HBV X gene may promote the apoptosis of hepatocytes by regulating the expressions of Fas/FasL, Bax/Bcl-2, and c-myc gene in a dose-dependent manner.展开更多
Heat and acid treatments were reported to be a promising substitute for SO2 fumigation in color protection of postharvest lychee （Litchi chinensis） fruits, but the mechanism was not clear. In the present study, hot ...Heat and acid treatments were reported to be a promising substitute for SO2 fumigation in color protection of postharvest lychee （Litchi chinensis） fruits, but the mechanism was not clear. In the present study, hot water （70℃） dipping followed by immersion in 2% HC1 （heat-acid） substantially protected the red color of the fruit during storage at 25℃ and inhibited anthocyanin degradation while hot water dipping alone （heat） led to rapidly browning and about 90% loss in anthocyanin content. The pH values in the pericarp of the heat-acid treated fruit dropped to 3.2, while the values maintained around 5.0 in the heat-treated and control fruit. No significantly different pH values were detected among the arils of heat-acid, heat treated and control fruit. Heat-acid treatment dramatically reduced the activities of anthocyanin degradation enzyme （ADE）, peroxidase （POD） and polyphenol oxidase in the pericarp. A marked reduction in LcPOD gene expression was also detected in heat-acid treated fruit, in contrast, induction was found in heat treated fruit. The pericarp of heat-acid treated fruit exhibited significantly lower respiration rate but faster water loss than that of the untreated or heat treated fruit. Taken together, heat treatment triggered quick browning and anthocyanin loss in lychee fruit, while heat-acid treatment protected the fruit color by a great reduction in the activities/gene expression of anthocyanin degradation enzymes and acidification of lychee pericarp.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.39870372,30370765&30440079)the National Key Basic Special Funds(Grant No.2003CB114305).
文摘The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments. H2O2 can modulate the activities of many components in signaling, such as protein phosphatases, protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.
基金Supported by the National Natural Science Foundation of China(No.81160528)the Governor Foundation of Guizhou Province(No.2006-07)Administration of Traditional Chinese Medicine of Guizhou Province Foundation(No.2009-79)
文摘Objective： To evaluate the effects and possible mechanisms of rutaecarpine on angiotensin Ⅱ （Ang Ⅱ ）-induced proliferation in cultured rat vascular smooth muscle cells （VSMCs）. Methods： VSMCs were isolated from Male Sprague-Dawley rat aorta, and cultured by enzymic dispersion method. Experiments were performed with cells from passages 3-8. The cultured VSMCs were randomly divided into control, model （Ang Ⅱ 0.1 μ moVL）, and rutaecarpine （0.3-3.0μmol/L） groups. VMSC proliferation was induced by Ang Ⅱ, and was evaluated by the 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide assay and cell counting. To examine the mechanisms involved in anti-proliferative effects of rutaecarpine, nitric oxide （NO） levels and NO synthetase （NOS） activity were determined. Expressions of VSMC proliferation-related genes including endothelial nitric oxide synthase （eNOS）, and c-myc hypertension related gene-1 （HRG-1） were determined by real-time reverse chain reaction （RT-PCR）. Results： Rutaecarpine （0.3-3.0μmol/l_） inhibited Ang R-induced VSMC proliferation and the best effects were achieved at 3.0 μmol/L. The Ang Ⅱ-induced decreases in cellular NO contents and NOS activities were antagonized by rutaecarpine （P〈0.05）. Ang Ⅱ administration suppressed the expressions of eNOS and HRG-1, while increased c-myc expression （P〈0.05）. All these effects were attenuated by 3.0μmol/L rutaecarpine （P〈0.05）. Conclusion： Rutaecarpine is effective against Ang Ⅱ-induced rat VSMC proliferation, and this effect is due, at least in part, to NO production and the modulation of VMSC proliferation-related gene expressions.
基金Supported by the Science and Technology Fund of Fujian Province, No. 99-Z-162
文摘AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by lipid-mediated transfection, including transient and stable transfection. Positive clones were screened by incubating in the selective medium with 600 μg/mL G418 and named HL-7702/HBV-encoded X protein （HBx） cells. The expressions of Fas/FasL, Bax/Bcl-2, and c-myc mRNA were measured by semi-quantitative RT-PCR in HL-7702/HBx and control group, respectively.RESULTS： RT-PCR analysis confirmed that HBV X gene was transfected into HL-7702 cells successfully. By semiquantitative RT-PCR analysis, Bax and c-myc mRNA levels in HL-7702/HBx cells of transient transfection were significantly higher than those in control, FasL and c-myc mRNA levels in HL-7702/HBx cells of stable transfection were significantly higher than those in control, whereas the Bcl-2 mRNA levels in HL-7702/HBx cells of transient and stable transfection were significantly lower than thosein control.CONCLUSION： HBV X gene may promote the apoptosis of hepatocytes by regulating the expressions of Fas/FasL, Bax/Bcl-2, and c-myc gene in a dose-dependent manner.
基金supported by the National Key Basic Research Program of China (2013CB127105)the National Natural Science Foundation of China (30671466)+1 种基金China Litchi and Logan Research System (CARS-33-14)Guangdong Fruit Research System,China (2009-356)
文摘Heat and acid treatments were reported to be a promising substitute for SO2 fumigation in color protection of postharvest lychee （Litchi chinensis） fruits, but the mechanism was not clear. In the present study, hot water （70℃） dipping followed by immersion in 2% HC1 （heat-acid） substantially protected the red color of the fruit during storage at 25℃ and inhibited anthocyanin degradation while hot water dipping alone （heat） led to rapidly browning and about 90% loss in anthocyanin content. The pH values in the pericarp of the heat-acid treated fruit dropped to 3.2, while the values maintained around 5.0 in the heat-treated and control fruit. No significantly different pH values were detected among the arils of heat-acid, heat treated and control fruit. Heat-acid treatment dramatically reduced the activities of anthocyanin degradation enzyme （ADE）, peroxidase （POD） and polyphenol oxidase in the pericarp. A marked reduction in LcPOD gene expression was also detected in heat-acid treated fruit, in contrast, induction was found in heat treated fruit. The pericarp of heat-acid treated fruit exhibited significantly lower respiration rate but faster water loss than that of the untreated or heat treated fruit. Taken together, heat treatment triggered quick browning and anthocyanin loss in lychee fruit, while heat-acid treatment protected the fruit color by a great reduction in the activities/gene expression of anthocyanin degradation enzymes and acidification of lychee pericarp.
