Roseiflexus castenholzii is a gram-negativefilamentous phototrophic bacterium that carries out anoxygenic photosynthesis through a cyclic electron transport chain(ETC).The ETC is composed of a reaction center(RC)–lig...Roseiflexus castenholzii is a gram-negativefilamentous phototrophic bacterium that carries out anoxygenic photosynthesis through a cyclic electron transport chain(ETC).The ETC is composed of a reaction center(RC)–light-harvesting(LH)complex(rcRC–LH);an alternative complex III(rcACIII),which functionally re-places the cytochrome bc1/b6f complex;and the periplasmic electron acceptor auracyanin(rcAc).Although compositionally and structurally different from the bc1/b6f complex,rcACIII plays similar essential roles in oxidizing menaquinol and transferring electrons to the rcAc.However,rcACIII-mediated electron transfer(which includes both an intraprotein route and a downstream route)has not been clearly elucidated,nor have the details of cyclic ETC.Here,we identify a previously unknown monoheme cytochrome c(cyt c551)as a novel periplasmic electron acceptor of rcACIII.It reduces the light-excited rcRC–LH to complete a cyclic ETC.We also reveal the molecular mechanisms involved in the ETC using electron paramagnetic resonance(EPR),spectroelectrochemistry,and enzymatic and structural analyses.Wefind that electrons released from rcACIII-oxidized menaquinol are transferred to two alternative periplasmic electron acceptors(rcAc and cyt c551),which eventually reduce the rcRC to form the complete cyclic ETC.This work serves as a foundation for further studies of ACIII-mediated electron transfer in anoxygenic photosynthesis and broadens our under-standing of the diversity and molecular evolution of prokaryotic ETCs.展开更多
High response organic ultraviolet photodetectors（UV-PDs） were demonstrated with 4,4＇,4”- tris[3-methyl-pheny（phenyl）amino]triphenylamine（m-MTDATA） and two Re（Ⅰ） complexes, （bathocuproine）- Re（CO）3CI（Re...High response organic ultraviolet photodetectors（UV-PDs） were demonstrated with 4,4＇,4”- tris[3-methyl-pheny（phenyl）amino]triphenylamine（m-MTDATA） and two Re（Ⅰ） complexes, （bathocuproine）- Re（CO）3CI（Re-BCP） and （bathophenanthroline）Re（CO）3Cl（Re-Bphen） to act as the electron donor and acceptor, re- spectively. UV-PDs have the configuration of indium tin oxide（ITO）/m-MTDATA（25 nm）/m-MTDATA：Re-complex （25-35 nm）/Re-complex（20 nm）/LiF（l nm）/Al（200 nm） with different blend layer thicknesses of 25, 30 and 35 nm. The optimized PD based on Re-Bphen offers a corrected-dark photocurrent up to 760μA/cm^2 at -10 V, corresponding to a response of 310 mA/W which is among the best values reported for organic UV-PDs. Excellent electron transport ability makes for such high photo-to-electron conversion.展开更多
The electron-transport machinery in photosynthetic membranes is known to be very sensitive to heat. In this study, the rate of electron transport (ETR) driven by photosystem I (PSI) and photosystem II (PSII) during he...The electron-transport machinery in photosynthetic membranes is known to be very sensitive to heat. In this study, the rate of electron transport (ETR) driven by photosystem I (PSI) and photosystem II (PSII) during heat stress in the wild-type Synechocystis sp. strain PCC 6803 (WT) and its ndh gene inactiva-tion mutants △ndhB (M55) and △ndhD1/ndhD2 (D1/D2) was simultaneously assessed by using the novel Dual-PAM-100 measuring system. The rate of electron transport driven by the photosystems (ETRPSs) in the WT, M55, and D1/D2 cells incubated at 30℃ and at 55℃ for 10 min was compared. Incubation at 55 ℃ for 10 min significantly inhibited PSII-driven ETR (ETRPSII) in the WT, M55 and D1/D2 cells, and the ex-tent of inhibition in both the M55 and D1/D2 cells was greater than that in the WT cells. Further, PSI-driven ETR (ETRPSI) was stimulated in both the WT and D1/D2 cells, and this rate was increased to a greater extent in the D1/D2 than in the WT cells. However, ETRPSI was considerably inhibited in the M55 cells. Analysis of the effect of heat stress on ETRPSs with regard to the alterations in the 2 active NDH-1 complexes in the WT, M55, and D1/D2 cells indicated that the active NDH-1 supercomplex and medi-umcomplex are essential for alleviating the heat-induced inhibition of ETRPSII and for accelerating the heat-induced stimulation of ETRPSI, respectively. Further, it is believed that these effects are most likely brought about by the electron transport mediated by each of these 2 active NDH-1 complexes.展开更多
Charge transport through single molecular neutral mono- and di-cobalt（Ⅱ） complexes with re-conjugated macromolecular wire was investigated. Scanning tunnelling spectroscopy （STS） studies revealed that the mono-co...Charge transport through single molecular neutral mono- and di-cobalt（Ⅱ） complexes with re-conjugated macromolecular wire was investigated. Scanning tunnelling spectroscopy （STS） studies revealed that the mono-cobalt（Ⅱ） complex showed a pronounced rectifying effect with a large rectification ratio and finely featured NDR peaks, while the di-cobalt（Ⅱ） complex showed a relatively symmetric electron transport without clear NDR peaks. The results are explained based on the dipolar and electronic effects.展开更多
目的观察慢性低氧时大鼠线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ、Ⅴ蛋白表达变化并讨论其病理生理学意义。方法成年雄性Wistar大鼠随机分为慢性低氧(4500m,30d)组和对照组,取双侧腓肠肌,分离线粒体,用Clark氧电极法检测线粒体Ⅲ态呼吸(state3,S...目的观察慢性低氧时大鼠线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ、Ⅴ蛋白表达变化并讨论其病理生理学意义。方法成年雄性Wistar大鼠随机分为慢性低氧(4500m,30d)组和对照组,取双侧腓肠肌,分离线粒体,用Clark氧电极法检测线粒体Ⅲ态呼吸(state3,ST3)、Ⅳ态呼吸(state4,ST4)和呼吸控制率(respiratory control ratio,RCR),用Western blot检测线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ、Ⅴ蛋白的表达。结果慢性低氧组大鼠腓肠肌线粒体ST3和RCR显著低于对照组(P<0.05)。慢性低氧组大鼠腓肠肌线粒体复合体Ⅰ30×103亚基、复合体Ⅱ70×103亚基、复合体Ⅴα亚基蛋白表达量显著低对照组(P<0.05)。2组线粒体ST4和复合体Ⅲ核心亚基2蛋白表达无显著性差异(P>0.05)。结论低氧可调节大鼠骨骼机线粒体复合体蛋白非协同性表达,导致线粒体氧化磷酸化功能下降。展开更多
【目的】探讨吗啡后处理对大鼠心肌缺血再灌注损伤的保护机制。【方法】健康成年S-D雄性大鼠40只，随机分成4组，每组10只。假手术组（S组）仅开胸并分离冠状动脉左前降支，但不阻断血流150 min；缺血再灌注组（IR组）行冠状动脉左前降...【目的】探讨吗啡后处理对大鼠心肌缺血再灌注损伤的保护机制。【方法】健康成年S-D雄性大鼠40只，随机分成4组，每组10只。假手术组（S组）仅开胸并分离冠状动脉左前降支，但不阻断血流150 min；缺血再灌注组（IR组）行冠状动脉左前降支阻断30 min ，再灌注120 min；吗啡后处理1组（M1组）于开放左冠状动脉即刻1 min内静推吗啡0．1 mg/kg ，再灌注120 min ，吗啡后处理2组（m^2组）于开放左冠状动脉即刻1 min内静推吗啡0．3 mg/kg ，再灌注120 min。再灌注末测心肌梗死面积，免疫印迹法测心肌细胞色素C氧化酶（CcO）的表达。【结果】和IR组相比，M1组和m^2组心肌梗死面积均减小（ P ＜0．05），m^2组心梗面积降低较M1组更为明显，且差异有显著性（ P ＜0．05）；M1组和m^2组CcO表达均上调（ P ＜0．05）。【结论】吗啡后处理对心肌损伤有保护作用，其机制可能与促进心肌CcO表达有关。展开更多
基金supported by grants from the National Natural Science Foundation of China (32171227,31870740,and 31570738 to X.X.,21825703 and 21927814 to C.T.)the National Key Research and Development Project of China (2019YFA0405600 and 2019YFA0706900 to C.T.)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB37040000)to C.T.,the Youth Innovation Promotion Association CAS (2022455)to L.Y.,the Zhejiang Provincial Natural Science Foundation of China under grant LR22C020002 to X.X.
文摘Roseiflexus castenholzii is a gram-negativefilamentous phototrophic bacterium that carries out anoxygenic photosynthesis through a cyclic electron transport chain(ETC).The ETC is composed of a reaction center(RC)–light-harvesting(LH)complex(rcRC–LH);an alternative complex III(rcACIII),which functionally re-places the cytochrome bc1/b6f complex;and the periplasmic electron acceptor auracyanin(rcAc).Although compositionally and structurally different from the bc1/b6f complex,rcACIII plays similar essential roles in oxidizing menaquinol and transferring electrons to the rcAc.However,rcACIII-mediated electron transfer(which includes both an intraprotein route and a downstream route)has not been clearly elucidated,nor have the details of cyclic ETC.Here,we identify a previously unknown monoheme cytochrome c(cyt c551)as a novel periplasmic electron acceptor of rcACIII.It reduces the light-excited rcRC–LH to complete a cyclic ETC.We also reveal the molecular mechanisms involved in the ETC using electron paramagnetic resonance(EPR),spectroelectrochemistry,and enzymatic and structural analyses.Wefind that electrons released from rcACIII-oxidized menaquinol are transferred to two alternative periplasmic electron acceptors(rcAc and cyt c551),which eventually reduce the rcRC to form the complete cyclic ETC.This work serves as a foundation for further studies of ACIII-mediated electron transfer in anoxygenic photosynthesis and broadens our under-standing of the diversity and molecular evolution of prokaryotic ETCs.
基金Supported by the National Natural Science Foundation of China(No.60978059)the Program for New Century Excellent Talents in Universities of China(No.NCET-10-0176)+1 种基金the Key Project of Ministry of Education of China(No.210053)the Natural Science Foundation of Jilin Province,China(Nos.20101543 and 20100549)
文摘High response organic ultraviolet photodetectors（UV-PDs） were demonstrated with 4,4＇,4”- tris[3-methyl-pheny（phenyl）amino]triphenylamine（m-MTDATA） and two Re（Ⅰ） complexes, （bathocuproine）- Re（CO）3CI（Re-BCP） and （bathophenanthroline）Re（CO）3Cl（Re-Bphen） to act as the electron donor and acceptor, re- spectively. UV-PDs have the configuration of indium tin oxide（ITO）/m-MTDATA（25 nm）/m-MTDATA：Re-complex （25-35 nm）/Re-complex（20 nm）/LiF（l nm）/Al（200 nm） with different blend layer thicknesses of 25, 30 and 35 nm. The optimized PD based on Re-Bphen offers a corrected-dark photocurrent up to 760μA/cm^2 at -10 V, corresponding to a response of 310 mA/W which is among the best values reported for organic UV-PDs. Excellent electron transport ability makes for such high photo-to-electron conversion.
基金Supported by the National Natural Science Foundation of China (Grant No. 30770175)the Natural Science Foundation of Shanghai Muncipality (Grant No. 07ZR14086)+2 种基金the Innovation Program of Shanghai Municipal Education Commission (Grant No. 08ZZ67)the Key Foundation Project of Shanghai (Grant No. 06JC14091)the Leading Academic Discipline Project of Shanghai Municipal Education Commission (Grant No. J50401)
文摘The electron-transport machinery in photosynthetic membranes is known to be very sensitive to heat. In this study, the rate of electron transport (ETR) driven by photosystem I (PSI) and photosystem II (PSII) during heat stress in the wild-type Synechocystis sp. strain PCC 6803 (WT) and its ndh gene inactiva-tion mutants △ndhB (M55) and △ndhD1/ndhD2 (D1/D2) was simultaneously assessed by using the novel Dual-PAM-100 measuring system. The rate of electron transport driven by the photosystems (ETRPSs) in the WT, M55, and D1/D2 cells incubated at 30℃ and at 55℃ for 10 min was compared. Incubation at 55 ℃ for 10 min significantly inhibited PSII-driven ETR (ETRPSII) in the WT, M55 and D1/D2 cells, and the ex-tent of inhibition in both the M55 and D1/D2 cells was greater than that in the WT cells. Further, PSI-driven ETR (ETRPSI) was stimulated in both the WT and D1/D2 cells, and this rate was increased to a greater extent in the D1/D2 than in the WT cells. However, ETRPSI was considerably inhibited in the M55 cells. Analysis of the effect of heat stress on ETRPSs with regard to the alterations in the 2 active NDH-1 complexes in the WT, M55, and D1/D2 cells indicated that the active NDH-1 supercomplex and medi-umcomplex are essential for alleviating the heat-induced inhibition of ETRPSII and for accelerating the heat-induced stimulation of ETRPSI, respectively. Further, it is believed that these effects are most likely brought about by the electron transport mediated by each of these 2 active NDH-1 complexes.
基金the financial supports of the National Science Foundationthe NSF MRSEC program at the University of Chicago
文摘Charge transport through single molecular neutral mono- and di-cobalt（Ⅱ） complexes with re-conjugated macromolecular wire was investigated. Scanning tunnelling spectroscopy （STS） studies revealed that the mono-cobalt（Ⅱ） complex showed a pronounced rectifying effect with a large rectification ratio and finely featured NDR peaks, while the di-cobalt（Ⅱ） complex showed a relatively symmetric electron transport without clear NDR peaks. The results are explained based on the dipolar and electronic effects.
文摘目的观察慢性低氧时大鼠线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ、Ⅴ蛋白表达变化并讨论其病理生理学意义。方法成年雄性Wistar大鼠随机分为慢性低氧(4500m,30d)组和对照组,取双侧腓肠肌,分离线粒体,用Clark氧电极法检测线粒体Ⅲ态呼吸(state3,ST3)、Ⅳ态呼吸(state4,ST4)和呼吸控制率(respiratory control ratio,RCR),用Western blot检测线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ、Ⅴ蛋白的表达。结果慢性低氧组大鼠腓肠肌线粒体ST3和RCR显著低于对照组(P<0.05)。慢性低氧组大鼠腓肠肌线粒体复合体Ⅰ30×103亚基、复合体Ⅱ70×103亚基、复合体Ⅴα亚基蛋白表达量显著低对照组(P<0.05)。2组线粒体ST4和复合体Ⅲ核心亚基2蛋白表达无显著性差异(P>0.05)。结论低氧可调节大鼠骨骼机线粒体复合体蛋白非协同性表达,导致线粒体氧化磷酸化功能下降。
文摘【目的】探讨吗啡后处理对大鼠心肌缺血再灌注损伤的保护机制。【方法】健康成年S-D雄性大鼠40只，随机分成4组，每组10只。假手术组（S组）仅开胸并分离冠状动脉左前降支，但不阻断血流150 min；缺血再灌注组（IR组）行冠状动脉左前降支阻断30 min ，再灌注120 min；吗啡后处理1组（M1组）于开放左冠状动脉即刻1 min内静推吗啡0．1 mg/kg ，再灌注120 min ，吗啡后处理2组（m^2组）于开放左冠状动脉即刻1 min内静推吗啡0．3 mg/kg ，再灌注120 min。再灌注末测心肌梗死面积，免疫印迹法测心肌细胞色素C氧化酶（CcO）的表达。【结果】和IR组相比，M1组和m^2组心肌梗死面积均减小（ P ＜0．05），m^2组心梗面积降低较M1组更为明显，且差异有显著性（ P ＜0．05）；M1组和m^2组CcO表达均上调（ P ＜0．05）。【结论】吗啡后处理对心肌损伤有保护作用，其机制可能与促进心肌CcO表达有关。
