The changes of hydrogen peroxide （H2O2） metabolism and antioxidant enzyme activities in a hybrid poplar （Populus simonii xp. pyramidalis ＇Opera 8277＇） in response to rnechanical damage （MD） and herbivore wound...The changes of hydrogen peroxide （H2O2） metabolism and antioxidant enzyme activities in a hybrid poplar （Populus simonii xp. pyramidalis ＇Opera 8277＇） in response to rnechanical damage （MD） and herbivore wounding （HW） were investigated to determine whether H2O2 could function as the secondary messenger in the signaling of systemic resistance. Results show that H2O2 was generated in wounded leaves through MD and HW treatments and systemically in unwounded leaves around the wounded leaves. The activities of antioxidant enzymes such as superoxide dismutase （SOD）, catalase （CAT） and ascorbate peroxidase （APX） were also enhanced. However, the H2O2 accumulation and antioxidant enzyme activities were inhibited in MD leaves through the pretreatment with DPI （which is a specific inhibitor of NADPH oxidase）. The results of this study suggest that H2O2 could be systemically induced by MD and HW treatments, and H2O2 metabolism was closely related to the change in SOD, APX and CAT activities. A high level of antioxidant enzymes could decrease membrane lipid peroxidation levels and effectively induce plant defense responses.展开更多
Bile acids(BAs)are cholesterol derivatives synthesized in the liver and then secreted into the intestine for lipid absorption.There are numerous scientific reports describing BAs,especially secondary BAs,as strong car...Bile acids(BAs)are cholesterol derivatives synthesized in the liver and then secreted into the intestine for lipid absorption.There are numerous scientific reports describing BAs,especially secondary BAs,as strong carcinogens or promoters of colon cancers.Firstly,BAs act as strong stimulators of colorectal cancer(CRC)initiation by damaging colonic epithelial cells,and inducing reactive oxygen species production,genomic destabilization,apoptosis resistance,and cancer stem cells-like formation.Consequently,BAs promote CRC progression via multiple mechanisms,including inhibiting apoptosis,enhancing cancer cell proliferation,invasion,and angiogenesis.There are diverse signals involved in the carcinogenesis mechanism of BAs,with a major role of epidermal growth factor receptor,and its down-stream signaling,involving mitogen-activated protein kinase,phosphoinositide 3-kinase/Akt,and nuclear factor kappa-light-chain-enhancer of activated B cells.BAs regulate numerous genes including the human leukocyte antigen class I gene,p53,matrix metalloprotease,urokinase plasminogen activator receptor,Cyclin D1,cyclooxygenase-2,interleukin-8,and miRNAs of CRC cells,leading to CRC promotion.These evidence suggests that targeting BAs is an efficacious strategies for CRC prevention and treatment.展开更多
Stabilizing anode for oxygen evolution(OER)in chlorine-containing electrolytes is a significant challenge.Adding corrosion inhibitors in electrolytes can alleviate this problem,but the type and dosage of cor-rosion in...Stabilizing anode for oxygen evolution(OER)in chlorine-containing electrolytes is a significant challenge.Adding corrosion inhibitors in electrolytes can alleviate this problem,but the type and dosage of cor-rosion inhibitors need a lot of exploration,and side reactions may occur to reduce current efficiency.Herein,we prepared a FeCoNiMnMo High entropy alloy(HEA)electrode for OER in simulated seawa-ter without corrosion inhibitors.It exhibits great electrocatalytic activity(overpotential(η)=237 mV at 10 mA cm^(-2))and excellent stability(200 h at 100 mA cm^(-2)).Experiments and Density Functional The-ory(DFT)calculation show that the protective layer containing K_(2)MoO_(4)is the crucial factor for chlorine resistance of FeCoNiMnMo electrode.The tightly adsorbed state of Cl-and K_(2)MoO_(4)ensures that other oxides are not corroded.And the externally added K_(2)MoO_(4)cannot protect the electrode.In addition,the high-entropy effect of HEA reduces the dissolution of the alloy.This work provides an efficient way to prepare a noble-free HEA catalyst that can stabilize oxygen evolution in corrosive electrolytes.展开更多
文摘The changes of hydrogen peroxide （H2O2） metabolism and antioxidant enzyme activities in a hybrid poplar （Populus simonii xp. pyramidalis ＇Opera 8277＇） in response to rnechanical damage （MD） and herbivore wounding （HW） were investigated to determine whether H2O2 could function as the secondary messenger in the signaling of systemic resistance. Results show that H2O2 was generated in wounded leaves through MD and HW treatments and systemically in unwounded leaves around the wounded leaves. The activities of antioxidant enzymes such as superoxide dismutase （SOD）, catalase （CAT） and ascorbate peroxidase （APX） were also enhanced. However, the H2O2 accumulation and antioxidant enzyme activities were inhibited in MD leaves through the pretreatment with DPI （which is a specific inhibitor of NADPH oxidase）. The results of this study suggest that H2O2 could be systemically induced by MD and HW treatments, and H2O2 metabolism was closely related to the change in SOD, APX and CAT activities. A high level of antioxidant enzymes could decrease membrane lipid peroxidation levels and effectively induce plant defense responses.
文摘Bile acids(BAs)are cholesterol derivatives synthesized in the liver and then secreted into the intestine for lipid absorption.There are numerous scientific reports describing BAs,especially secondary BAs,as strong carcinogens or promoters of colon cancers.Firstly,BAs act as strong stimulators of colorectal cancer(CRC)initiation by damaging colonic epithelial cells,and inducing reactive oxygen species production,genomic destabilization,apoptosis resistance,and cancer stem cells-like formation.Consequently,BAs promote CRC progression via multiple mechanisms,including inhibiting apoptosis,enhancing cancer cell proliferation,invasion,and angiogenesis.There are diverse signals involved in the carcinogenesis mechanism of BAs,with a major role of epidermal growth factor receptor,and its down-stream signaling,involving mitogen-activated protein kinase,phosphoinositide 3-kinase/Akt,and nuclear factor kappa-light-chain-enhancer of activated B cells.BAs regulate numerous genes including the human leukocyte antigen class I gene,p53,matrix metalloprotease,urokinase plasminogen activator receptor,Cyclin D1,cyclooxygenase-2,interleukin-8,and miRNAs of CRC cells,leading to CRC promotion.These evidence suggests that targeting BAs is an efficacious strategies for CRC prevention and treatment.
基金This work was supported by the National Natural Science Foundation of China(Nos.52031008,12102307,and 11872284).
文摘Stabilizing anode for oxygen evolution(OER)in chlorine-containing electrolytes is a significant challenge.Adding corrosion inhibitors in electrolytes can alleviate this problem,but the type and dosage of cor-rosion inhibitors need a lot of exploration,and side reactions may occur to reduce current efficiency.Herein,we prepared a FeCoNiMnMo High entropy alloy(HEA)electrode for OER in simulated seawa-ter without corrosion inhibitors.It exhibits great electrocatalytic activity(overpotential(η)=237 mV at 10 mA cm^(-2))and excellent stability(200 h at 100 mA cm^(-2)).Experiments and Density Functional The-ory(DFT)calculation show that the protective layer containing K_(2)MoO_(4)is the crucial factor for chlorine resistance of FeCoNiMnMo electrode.The tightly adsorbed state of Cl-and K_(2)MoO_(4)ensures that other oxides are not corroded.And the externally added K_(2)MoO_(4)cannot protect the electrode.In addition,the high-entropy effect of HEA reduces the dissolution of the alloy.This work provides an efficient way to prepare a noble-free HEA catalyst that can stabilize oxygen evolution in corrosive electrolytes.
基金supported by the National Natural Science Foundation of China(51204208,51374240)National Science&Technology Pillar Program of China(2012BAA03B04)Hunan Provincial Natural Science Foundation,China(13JJ1003)~~
