Olive leaves have an antioxidant capacity,and olive leaf extract can protect the blood,spleen and hippocampus in lead-poisoned mice.However,little is known about the effects of olive leaf extract on lead-induced brain...Olive leaves have an antioxidant capacity,and olive leaf extract can protect the blood,spleen and hippocampus in lead-poisoned mice.However,little is known about the effects of olive leaf extract on lead-induced brain injury.This study was designed to determine whether olive leaf extract can inhibit lead-induced brain injury,and whether this effect is associated with antioxidant capacity.First,we established a mouse model of lead poisoning by continuous intragastric administration of lead acetate for 30 days.Two hours after successful model establishment,lead-poisoned mice were given olive leaf extract at doses of 250,500 or 1000 mg/kg daily by intragastric administration for 50 days.Under the transmission electron microscope,olive leaf extract attenuated neuronal and capillary injury and reduced damage to organelles and the matrix around the capillaries in the frontal lobe of the cerebral cortex in the lead-poisoned mice.Olive leaf extract at a dose of 1000 mg/kg had the greatest protective effect.Spectrophotometry showed that olive leaf extract significantly increased the activities of superoxide dismutase,catalase,alkaline phosphatase and acid phosphatase,while it reduced malondialdehyde content,in a dose-dependent manner.Furthermore,immunohistochemical staining revealed that olive leaf extract dose-dependently decreased Bax protein expression in the cerebral cortex of lead-poisoned mice.Our findings indicate that olive leaf extract can inhibit lead-induced brain injury by increasing antioxidant capacity and reducing apoptosis.展开更多
The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID...The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID(Aux/IAA)family of transcriptional repressors.Notably,many auxin-modulated physiological processes are also regulated by nitric oxide(NO)that executes its biological effects predominantly through protein S-nitrosylation at specific cysteine residues.However,little is known about the molecular mechanisms in regulating the interactive NO and auxin networks.Here,we show that NO represses auxin signaling by inhibiting IAA17 protein degradation.NO induces the S-nitrosylation of Cys-70 located in the intrinsically disordered region of IAA17,which inhibits the TIR1-IAA17 interaction and consequently the proteasomal degradation of IAA17.The accumulation of a higher level of IAA17 attenuates auxin response.Moreover,an IAA17^(C70W)nitrosomimetic mutation renders the accumulation of a higher level of the mutated protein,thereby causing partial resistance to auxin and defective lateral root development.Taken together,these results suggest that S-nitrosylation of IAA17 at Cys-70 inhibits its interaction with TIR1,thereby negatively regulating auxin signaling.This study provides unique molecular insights into the redox-based auxin signaling in regulating plant growth and development.展开更多
Optically transparent microwave absorbing metasurfaces have shown great potential and are needed in multiple applications environments containing optical windows owing to their ability to reduce backscattering electro...Optically transparent microwave absorbing metasurfaces have shown great potential and are needed in multiple applications environments containing optical windows owing to their ability to reduce backscattering electromagnetic(EM)signals while keeping continuous optical observation.Meanwhile,they are also required to have adaptive EM manipulation capability to cope with complex and capricious EM environments.As a general approach,distributed circuit components,including positive-intrinsic-negative diodes and varactors and sensing components,are integrated with passive absorbing metasurfaces to realize adaptive control of microwave absorption.However,these circuit elements generally require bulky electrical wires and complex control circuits to regulate the operating state,resulting in the absorbing structures being optically opaque.Hence,it is a great challenge to realize self-operating absorbers while maintaining optical transparency.Here,we report an optically transparent cognitive metasurface made of patterned graphene sandwich structures and a radio frequency detector,which can achieve adaptive frequency manipulation to match incident EM waves.As a proof-of-principle application example,we realize a closed-loop automatic absorber system prototype of the proposed graphene metasurface with self-adaptive frequency variation,without any human intervention.The approach may facilitate other adaptive metadevices in microwave regime with high-level recognition and manipulation and,more generally,promote the development of intelligent stealth technologies.展开更多
Apoptotic regulation is critical to organismal homeostasis and protection against many human disease processes such as cancer.Significant research efforts over the past several decades have illuminated many signaling ...Apoptotic regulation is critical to organismal homeostasis and protection against many human disease processes such as cancer.Significant research efforts over the past several decades have illuminated many signaling molecules and effecter proteins responsible for this form of programmed cell death.Recent evidence suggests that transfer RNA(tRNA)regulates apoptotic sensitivity at the level of cytochrome c-mediated apoptosome formation.This finding unexpectedly places tRNA at the nexus of cellular biosynthesis and survival.Here we review the current understanding of both the apoptotic machinery and tRNA biology.We describe the evidence linking tRNA and cytochrome c in depth,and speculate on the implications of this link in cell biology.展开更多
The reaction of alkenes with ozone has great effect on atmospheric oxidation,its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols(SOA).In the present study,the re...The reaction of alkenes with ozone has great effect on atmospheric oxidation,its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols(SOA).In the present study,the reaction of tetramethylethene(TME) with ozone was investigated using self-assembled low temperature matrix isolation system.The TME and ozone were co-deposited on a salt plate at 15 K,and then slowly warmed up the plate.The first transient species primary ozonide(POZ) was detected,indicating that the reaction followed Criegee mechanism.Then POZ began to decompose at 180 K.However,secondary ozonide(SOZ) was not observed according to Criegee mechanism.Probably,Criegee Intermediate(CI) did not react with inert carbonyl of acetone,but with remaining TME formed tetra-methyl epoxide(EPO).展开更多
基金supported by the Natural Science Foundation of Gansu Province,No.1107RJZK243a grant from Gansu Provincial Education Committee,No.1128B-01
文摘Olive leaves have an antioxidant capacity,and olive leaf extract can protect the blood,spleen and hippocampus in lead-poisoned mice.However,little is known about the effects of olive leaf extract on lead-induced brain injury.This study was designed to determine whether olive leaf extract can inhibit lead-induced brain injury,and whether this effect is associated with antioxidant capacity.First,we established a mouse model of lead poisoning by continuous intragastric administration of lead acetate for 30 days.Two hours after successful model establishment,lead-poisoned mice were given olive leaf extract at doses of 250,500 or 1000 mg/kg daily by intragastric administration for 50 days.Under the transmission electron microscope,olive leaf extract attenuated neuronal and capillary injury and reduced damage to organelles and the matrix around the capillaries in the frontal lobe of the cerebral cortex in the lead-poisoned mice.Olive leaf extract at a dose of 1000 mg/kg had the greatest protective effect.Spectrophotometry showed that olive leaf extract significantly increased the activities of superoxide dismutase,catalase,alkaline phosphatase and acid phosphatase,while it reduced malondialdehyde content,in a dose-dependent manner.Furthermore,immunohistochemical staining revealed that olive leaf extract dose-dependently decreased Bax protein expression in the cerebral cortex of lead-poisoned mice.Our findings indicate that olive leaf extract can inhibit lead-induced brain injury by increasing antioxidant capacity and reducing apoptosis.
基金supported by grants from the National Natural Science Foundation of China (31830017)Chinese Academy of Sciences (XDB27030207)+1 种基金the Hainan Excellent Talent TeamState Key Laboratory of Plant Genomics (SKLPG2023-22)
文摘The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID(Aux/IAA)family of transcriptional repressors.Notably,many auxin-modulated physiological processes are also regulated by nitric oxide(NO)that executes its biological effects predominantly through protein S-nitrosylation at specific cysteine residues.However,little is known about the molecular mechanisms in regulating the interactive NO and auxin networks.Here,we show that NO represses auxin signaling by inhibiting IAA17 protein degradation.NO induces the S-nitrosylation of Cys-70 located in the intrinsically disordered region of IAA17,which inhibits the TIR1-IAA17 interaction and consequently the proteasomal degradation of IAA17.The accumulation of a higher level of IAA17 attenuates auxin response.Moreover,an IAA17^(C70W)nitrosomimetic mutation renders the accumulation of a higher level of the mutated protein,thereby causing partial resistance to auxin and defective lateral root development.Taken together,these results suggest that S-nitrosylation of IAA17 at Cys-70 inhibits its interaction with TIR1,thereby negatively regulating auxin signaling.This study provides unique molecular insights into the redox-based auxin signaling in regulating plant growth and development.
基金China Postdoctoral Science Foundation(2022M710670)Fundamental Research Funds for the Central Universities(2242022k30008,2242022R20018)+1 种基金National Natural Science Foundation of China(62101115)China National Funds for Distinguished Young Scientists(61925103)。
文摘Optically transparent microwave absorbing metasurfaces have shown great potential and are needed in multiple applications environments containing optical windows owing to their ability to reduce backscattering electromagnetic(EM)signals while keeping continuous optical observation.Meanwhile,they are also required to have adaptive EM manipulation capability to cope with complex and capricious EM environments.As a general approach,distributed circuit components,including positive-intrinsic-negative diodes and varactors and sensing components,are integrated with passive absorbing metasurfaces to realize adaptive control of microwave absorption.However,these circuit elements generally require bulky electrical wires and complex control circuits to regulate the operating state,resulting in the absorbing structures being optically opaque.Hence,it is a great challenge to realize self-operating absorbers while maintaining optical transparency.Here,we report an optically transparent cognitive metasurface made of patterned graphene sandwich structures and a radio frequency detector,which can achieve adaptive frequency manipulation to match incident EM waves.As a proof-of-principle application example,we realize a closed-loop automatic absorber system prototype of the proposed graphene metasurface with self-adaptive frequency variation,without any human intervention.The approach may facilitate other adaptive metadevices in microwave regime with high-level recognition and manipulation and,more generally,promote the development of intelligent stealth technologies.
基金National Natural Science Foundation of China(Grant No.81473352)Guangdong Province Innovation Training Project(Grant No.201610573040)Guangzhou Science and Technology Bureau Foundation(Grant No.201707010170)
基金supported by NIH grants GM60911 and CA088868 to X.Y.and GM68561 and GM81601 to Y.-M.H.
文摘Apoptotic regulation is critical to organismal homeostasis and protection against many human disease processes such as cancer.Significant research efforts over the past several decades have illuminated many signaling molecules and effecter proteins responsible for this form of programmed cell death.Recent evidence suggests that transfer RNA(tRNA)regulates apoptotic sensitivity at the level of cytochrome c-mediated apoptosome formation.This finding unexpectedly places tRNA at the nexus of cellular biosynthesis and survival.Here we review the current understanding of both the apoptotic machinery and tRNA biology.We describe the evidence linking tRNA and cytochrome c in depth,and speculate on the implications of this link in cell biology.
基金primarily supported by National Key R&D Program of China(No.2019YFC0214200)National Environmental Protection Public Welfare Industry Research Project(No.201509010)+1 种基金National Basic Science Research Program of Chinese Research Academy of Environmental Sciences(No.JY-21277132-201309406)the National Natural Science Foundation of China(No.21277132)
文摘The reaction of alkenes with ozone has great effect on atmospheric oxidation,its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols(SOA).In the present study,the reaction of tetramethylethene(TME) with ozone was investigated using self-assembled low temperature matrix isolation system.The TME and ozone were co-deposited on a salt plate at 15 K,and then slowly warmed up the plate.The first transient species primary ozonide(POZ) was detected,indicating that the reaction followed Criegee mechanism.Then POZ began to decompose at 180 K.However,secondary ozonide(SOZ) was not observed according to Criegee mechanism.Probably,Criegee Intermediate(CI) did not react with inert carbonyl of acetone,but with remaining TME formed tetra-methyl epoxide(EPO).
