Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidas...Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.展开更多
The inactivation of bacterial cells through catalyzed oxidation using hydrogen peroxide as the primary oxidant agent is dependent on a series of factors, such as the concentration of the catalyst, the rate of hydroxyl...The inactivation of bacterial cells through catalyzed oxidation using hydrogen peroxide as the primary oxidant agent is dependent on a series of factors, such as the concentration of the catalyst, the rate of hydroxyl radical formation in the controlled decomposition of the oxidant agent, and the concentration and toxicity of hydrogen peroxide. The objective of this study was to develop a mathematical model able to predict the kinetics of the inactivation Escherichia coli and total coliforms cells present in treated domestic sewage through catalytic peroxidation. The catalyst used was iron oxide supported on mineral coal （called CP）, and the effects of the operational conditions, including hydrogen peroxide concentration and dosage of catalyst, were evaluated. The results showed that the disinfection kinetics of the treated domestic sewage is dependent on the concentrations of hydrogen peroxide and catalyst dosage. The kinetic model was shown to be able to predict the behavior of the inactivation kinetics of the bacterium Escherichia coli ATCC-25922 when different concentrations of hydrogen peroxide （75 and 100 mg·L^-1） were used, regardless of the catalyst dosage.展开更多
文摘Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.
文摘The inactivation of bacterial cells through catalyzed oxidation using hydrogen peroxide as the primary oxidant agent is dependent on a series of factors, such as the concentration of the catalyst, the rate of hydroxyl radical formation in the controlled decomposition of the oxidant agent, and the concentration and toxicity of hydrogen peroxide. The objective of this study was to develop a mathematical model able to predict the kinetics of the inactivation Escherichia coli and total coliforms cells present in treated domestic sewage through catalytic peroxidation. The catalyst used was iron oxide supported on mineral coal （called CP）, and the effects of the operational conditions, including hydrogen peroxide concentration and dosage of catalyst, were evaluated. The results showed that the disinfection kinetics of the treated domestic sewage is dependent on the concentrations of hydrogen peroxide and catalyst dosage. The kinetic model was shown to be able to predict the behavior of the inactivation kinetics of the bacterium Escherichia coli ATCC-25922 when different concentrations of hydrogen peroxide （75 and 100 mg·L^-1） were used, regardless of the catalyst dosage.
