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PROTON PUMPING AND ELECTRON-TRANSfER IN THE CYTOCHROME B/f COMPLEX Of ALGAE

BIOCHIMICA ET BIOPHYSICA ACTA 1986年第2期849卷 211-222页

作者： JOLIOT, P JOLIOT, A Institut de Biologie Physico-Chimique 13 rue Pierre et Marie Curie 75005 Paris France

The electron-transfer reactions and the slow transmembrane electrogenic phase (phase b) have been studied in Photosystem-II-depleted mutant strains of Chlorella sorokiniana under anaerobic conditions. The dark reduction of cytochrome b previously oxidized by a strong illumination is a biphasic process. The first phase, completed in about 20 s, is associated with the reduction of the high-potential form of cytochrome b;a slower phase, completed in about 10 min, is associated with the reduction of the low-potential form of cytochrome b. The .alpha.-bands of these two forms differ slightly. Under repetitive weak flash illumination, i.e., when a fraction of cytochrome b is oxidized prior to each flash, phase b is associated with minor changes in cytochrome b redox changes. In the presence of 2-n-nonyl-4-hydroxyquinoline N-oxide (NQNO), a large reduction of cytochrome b (t1/2 .apprxeq. 2 ms) is followed by a slow reoxidation. Under these conditions, phase b becomes biphasic, a first phase, insensitive to the inhibitor, is associated with cytochrome b reduction while the second phase, dependent upon the inhibitor concentration, is related to cytochrome b oxidation. These results are interpreted in terms of a modified Q-cycle model. A single weak flash given to dark-adapted algae, i.e., when the two b cytochromes are in their reduced state, induces a large cytochrome b oxidation with which is associated a phase b of longer duration but larger amplitude than the one observed under repetitive-flash illumination. Addition of 2-n-nonyl-4-hydroxyquinoline N-oxide inhibits neither the oxidation of cytochrome b nor phase b. These results suggest that a proton pump is coupled to the redox changes of plastoquinone occurring at a site, Z, close to the inner face of the membrane. This model implies that site Z is connected to the outer face of the thylakoid by a proton channel. Thus, depending upon the experiment conditions, two different mechanisms might be involved in the process o

关键词： Proton pump Electron transfer Cytochrome b f complex Plastoquinone Cytochrome b (Chlorella) PS Photosystem PQ plastoquinone PQH 2 plastoquinol PQ − plastosemiquinone cytochrome b or Cyt b cytochrome b 6 Cyt f cytochrome f HQNO 2- n -heptyl-4-hydroxyquinoline N -oxide NQNO 2- n -nonyl-4-hydroxyquinoline N -oxide

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Efficacy and safety of Tripterygium wilfordii Hook. f. for oral lichen planus: Evidence from 18 randomized controlled trials

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PHYTOTHERAPY RESEARCH 2020年第9期34卷 2180-2191页

作者： Luo, Yue Kuai, Le Chen, Jia Sun, Xiaoying Liu, Liu Luo, Ying Ru, Yi Xing, Meng Ding, Xiaojie Zhou, Mi Li, Bin Li, Xin Shanghai Univ Tradit Chinese Med Yueyang Hosp Integrated Tradit Chinese & Western Dept Dermatol Shanghai 200437 Peoples R China Shanghai Acad Tradit Chinese Med Inst Dermatol Shanghai Peoples R China Tongji Univ Shanghai Dermatol Hosp Dept Dermatopathol Shanghai Peoples R China Shanxi TCM Hosp Dept Dermatol Xian Peoples R China

Glycosides from the roots of Tripterygium wilfordii Hook. f. are used for the treatment of oral lichen planus (OLP), a chronic inflammatory disease affecting the oral mucosa. To investigate the effectiveness and safety of Tripterygium glycosides (TGs) for OLP treatment, we conducted a systematic review of 18 randomized controlled trials, comprising 1,339 participants, from international and Chinese databases. We evaluated outcomes of TGs alone or in combination with conventional treatments. In combination with topical glucocorticoids (TGCs), including triamcinolone acetonide and prednisone, the total effectiveness rate (risk ratio [RR], 1.17;95% confidence interval [CI], 1.09-1.25;p < .00001), symptom score reducing index (mean difference [MD], -2.44;95% CI, -3.12 to -1.77;p < .0001), and visual analog scale score (MD, -1.61;95% CI, -2.22 to -1.00;p < .0001) were significantly improved. Patients treated with TGs combined with TGCs experienced lower recurrence rates (RR, 0.37;95% CI, 0.18-0.76;p = 0.007). The occurrence of adverse events was not significantly different between the TGs groups and controls. The combination of TG and TGCs improved clinical efficacy and reduced recurrence without increasing the risk of adverse events. A high-quality multicenter clinical study is needed to corroborate these findings.

关键词： combination therapy glycosides meta-analysis oral lichen planus topical glucocorticoids Tripterygium wilfordii Hook f

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ELECTRON-MICROSCOPY Of BEEf-HEART MITOCHONDRIAL f1-ATPASE

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fEBS LETTERS 1984年第2期167卷 285-290页

作者： TSUPRUN, VL MESYANZHINOVA, IV KOZLOV, IA ORLOVA, EV MV LOMONOSOV STATE UNIV BELOZERSKII MOLEC & BIOORGAN CHEM LAB MOSCOW 117234 USSR

The quaternary structure of isolated and membrane-bound f1-ATPase (submitochondrial particles) has been studied by electron microscopy. A model of the molecule has been proposed: six protein masses are arranged in two layers approximately at the vertices of a triangular antiprism. Computer averaging of the images showed that the frontal view of the molecule can be approximately characterized by mirror plane symmetry.

关键词： f 1 -ATPase Enzyme structure Electron microscopy

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THE LOW-POTENTIAL ELECTRON-TRANSfER CHAIN IN THE CYTOCHROME B/f COMPLEX

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BIOCHIMICA ET BIOPHYSICA ACTA 1988年第2期933卷 319-333页

作者： JOLIOT, P JOLIOT, A Institut de Biologie Physico-Chimique Paris France

The oxidized-minus-reduced spectra of the low- and high-potential cytochromes b6 were measured from 380 to 590 nm under anaerobic conditions in a mutant of Chlorella sorokiniana lacking of Photosystem II (PS II). The two spectra are similar in the Soret band;in the .alpha.-band, cytochrome b1 and cytochrome bh peak at 563.4 and 564 nm, respectively. The spectrum of a third component, G, located on the outer face of the membrane and able to exchange electrons with cytochrome bh (Lavergne, J. (1983) Biochim. Biophys. Acta 725, 25-33) was characterized. The oxidized minus-reduced spectrum of G displays a negative band peaking around 424 nm (probably a double peak) and a broad and small negative band in the green region. This spectrum resembles that of a soluble high-spin cytochrome c'', as characterized in several classes of photosynthetic bacteria. As other cytochromes c'', G binds CO with a low affinity, which inhibits electron exchange with cytochrome bh. The kinetics of reduction of cytochrome bh and cytochrome b1 were measured in algae under conditions, following illumination by weak continuous light or saturating flashes. from the kinetic behaviour, the difference between the midpoint potentials of cytochrome bh and cytochrome b1 was estimated at approx. 140 mV. Two populations can be distinguished among cytochrome b/f complexes. In a first fraction, the complexes are associated with the carrier G, which very likely takes part in an electron-transfer chain mediating cytochrome b reduction by a stromal reductant. This chain could be involved in cyclic electron flow around Photosystem I. In the second fraction, where G is not attached to the complex, the reduction of the b-cytochromes is a much slower process. Cytochrome bh and G are in equilibrium, the midpoint potential G being approx. 20 mV higher than that of cytochrome bh. from the study of the PS II-driven photoreduction of cytochrome bh and G (under aerobic conditions) in a mutant which lacks of PS I, we con

关键词： Electron transfer Cytochrome b f complex Cytochrome b Cytochrome c ′ Plastoquinone ( Chlorella ) PS Photosystem PQ plastoquinone PQH 2 plastoquinol PQ − plastosemiquinone DNP-INT dinitrophenylether iodonitrothymol DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea cytochrome b cytochrome b 6 PMS N -methylphenazonium methosulphate

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Effect of N and f content on structural, optical and photocatalytic methylene blue degradation properties of TiO2

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JOURNAL Of CHEMICAL RESEARCH 2016年第12期40卷 729-734页

作者： Elena, fakhrutdinova Anastasiia, Shabalina Valery, Svetlichnyi Alexei, Salanov Tomsk State Univ Siberian Phys Tech Inst 1 Novosobornaya Sq Tomsk 634050 Russia Boreskov Inst Catalysis SB RAS 5 Lavrenteva St Novosibirsk 630090 Russia

Photocatalytic systems based on fluorine- and nitrogen-doped titanium dioxide were obtained via the sol-gel method. Titanium tetraisopropoxide and ammonium fluoride were used as precursors. Transmission electron microscopy and measurement of Brunauer-Emmett-Teller surface area and porosity were used to establish that the concentration of ammonium fluoride has an impact on the structural parameters of titanium dioxide produced in the sol-gel process. X-ray photoelectron spectroscopy and fourier transform infrared spectroscopy revealed that the dopants (f and N) are not incorporated into the crystal lattice of titanium dioxide, but affect the optical properties of titanium dioxide due to the emergence of additional bands in the absorption spectra in the range of 380-450 nm. Sorption and photoactivity were found using methylene blue photodecomposition under visible light. It was found that dopant introduction increases both sorption ability and photoactivity of the materials.

关键词： photocatalysis sensitisation to visible light titania doping f N co-doping

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THE INTERACTION Of NUCLEOTIDES WITH f1-ATPASE INACTIVATED WITH 4-CHLORO-7-NITROBENZOfURAZAN

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BIOCHIMICA ET BIOPHYSICA ACTA 1981年第2期635卷 284-294页

作者： GREGORY, R RECKTENWALD, D HESS, B Max-Planck-Institut für Ernährungsphysiologie Rheinlanddamm 201 D-4600 Dortmund F.R.G.

In common with the f1-ATPase from other sources, yeast mitochondrial f1-ATPase was inhibited by 4-chloro-7-nitrobenzofurazan. Total inhibition of the f1-ATPase activity was compatible with the modification of a single tyrosine residue per f1-ATPase molecule. Radioactive labeling experiments localized this modification on a .beta.-subunit. The inactive modified enzyme retained the capacity to bind the photoaffinity label 8-azido-1,N6-etheno-ATP, which was previously shown to bind nucleotide sites of low affinity. The inactive modified enzyme bound Mg-ATP with high affinity, yielding a Kd of 14 .mu.M. The hypothesis of alternating, or cooperative, site catalysis by f1-ATPase was confirmed.

关键词： f 1 -ATPase Nucleotide binding 4-Chloro-7-nitrobenzofurazan (Yeast) Tricine N -tris(hydroxymethyl)methylglycine Hepps 4-(2-hydroxyethyl)-1-piperazinepropanesulphonic acid Pipes piperazine- N , N ′-bis(2-ethanesulphonic acid) Taps 3-[tris(hydroxymethyl)methyl[aminopropanesulphonic acid ϵ-N 3 -ATP 8-azido-1, N 6 -etheno-ATP NbfCl 7-chloro-4-nitrobenzo-2-oxa-1, 3-diazole, or 4-chloro-7-nitrobenzofurazan SDS sodium dodecyl sulphate

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A new furan derivative from an endophytic Aspergillus tubingensis of Decaisnea insignis (Griff.) Hook.f. & Thomson

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NATURAL PRODUCT RESEARCH 2019年第19期33卷 2777-2783页

作者： Yang, Xiu-fang Wang, Ning-ning Kang, Yi-fan Ma, Yang-min Shaanxi Univ Sci & Technol Minist Educ Key Lab Auxiliary Chem & Technol Chem Ind Xian 710021 Shaanxi Peoples R China

A new furan derivative named 3-(5-oxo-2,5-dihydrofuran-3-yl) propanoic acid (1) was isolated for the first time. Its structure was elucidated by UV, IR, NMR, HR-ESI-MS and the single-crystal X-ray diffraction spectroscopic data. Meanwhile, the antifungal and antibacterial activities of compound 1 was tested, it exhibited potent antifungal activity against fusarium graminearum with MIC value of 16 mu g/mL and medium antibacterial activity against Streptococcus lactis with MIC value of 32 mu g/mL.

关键词： furan derivative 3-(5-oxo-2 5-dihydrofuran-3-yl) propanoic acid Aspergillus tubingensis Decaisnea insignis (Griff ) Hook f & Thomson

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Assessment of cobalt accumulation effect on growth and antioxidant responses in aquatic macrophyte Hydrilla verticillata (L.f.) Royle

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BIOLOGIA 2020年第11期75卷 2001-2008页

作者： Sridhar, Arun Khader, Parvez Ahmed Ramasamy, Thirumurugan Bharathidasan Univ Sch Life Sci Lab Aquabiot Nanosci Dept Anim Sci Tiruchirappalli 620024 Tamil Nadu India Bharathidasan Univ Dept Biotechnol & Genet Engn Tiruchirappalli 620024 Tamil Nadu India

Cobalt is an essential trace metal and plays a pivotal role in the growth of all living organisms. The exposure of cobalt in the aquatic environment is ubiquitous via both natural and anthropogenic activities. The present study was carried out to investigate the accumulation response of macrophyte Hydrilla verticillata (L.f.) Royle towards the cobalt exposure at different concentrations (1, 25, 50, 75 and 100 mu M) for seven days. The results showed that the cobalt accumulation increased in treated H. verticillata (L.f.) Royle with increase in concentration. The Bioconcentration factor (BCf) values were high in plants exposed to higher concentration of cobalt. Increase in growth (shoot length) and pigments (chlorophyll a, b and total chlorophyll) were detected at 25 mu M cobalt concentration, whereas the growth and pigments were declined in 50, 75 and 100 mu M. There was no significant difference in the carotenoid content between control and treated plant. Antioxidant enzymes (superoxide dismutase, catalase, and peroxidase) were increased at higher concentrations of cobalt. The results indicated that the decline in growth and pigments, and an increase in antioxidant enzyme activities, were triggered by the accumulation of cobalt in the plant. These observations suggest that H. verticillata (L.f.) Royle is well equipped to accumulate low concentration of cobalt in tissues to increase its growth and detoxify ROS generation. The BCf results indicate the efficiency of using H. verticillata (L.f.) Royle as a phytostabilizer.

关键词： Cobalt Hydrilla verticillata (L f ) Royle Antioxidant enzymes Bioconcentration factor

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A model of the quaternary structure of the Escherichia coli f₁ ATPase from X-ray solution scattering and evidence for structural changes in the delta subunit during ATP hydrolysis

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BIOPHYSICAL JOURNAL 1998年第5期75卷 2212-2219页

作者： Svergun, DI Aldag, I Sieck, T Altendorf, K Koch, MHJ Kane, DJ Kozin, MB Grüber, G Univ Osnabruck Fachbereich Biol Chem D-49069 Osnabruck Germany European Mol Biol Lab Hamburg Outstn D-22603 Hamburg Germany Russian Acad Sci Inst Crystallog Moscow 117333 Russia Max Planck Inst Biophys Dept Biophys Chem D-60596 Frankfurt Germany GKSS WS Res Ctr D-21502 Geesthacht Germany

The shape and subunit arrangement of the Escherichia coli f-1 ATPase (ECf1 ATPase) was investigated by synchrotron radiation x-ray solution scattering. The radius of gyration and the maximum dimension of the enzyme complex are 4.61 +/- 0.03 nm and 15.5 +/- 0.05 nm, respectively. The shape of the complex was determined ab initio from the scattering data at a resolution of 3 nm, which allowed unequivocal identification of the volume occupied by the alpha(3)beta(3) subassembly and further positioning of the atomic models of the smaller subunits. The delta subunit was positioned near the bottom of the alpha(3)beta(3) hexamer in a location consistent with a beta-delta disulfide formation in the mutant ECf1 ATPase, beta Y331W:beta Y381C:epsilon S108C, when MgADP is bound to the enzyme. The position and orientation of the epsilon subunit were found by interactively fitting the solution scattering data to maintain connection of the two-helix hairpin with the alpha(3)beta(3) complex and binding of the beta-sandwich domain to the gamma subunit. Nucleotide-dependent changes of the delta subunit were investigated by stopped-flow fluorescence technique at 12 degrees C using N-[4-[7-(dimethylamino)-4-methyl]coumarin-3-yl]maleimide (CM) as a label. fluorescence quenching monitored after addition of MgATP was rapid [k = 6.6 s(-1)] and then remained constant. Binding of MgADP and the noncleavable nucleotide analog AMP . PNP caused an initial fluorescent quenching followed by a slower decay back to the original level. This suggests that the delta subunit undergoes conformational changes and/or rearrangements in the ECf1 ATPase during ATP hydrolysis.

关键词： EC f 1 f O Escherichia coli f 1 f O ATP synthase CM N -[4-[7-(dimethylamino)-4-methyl]coumarin-3-yl)]maleimide EC f 1 soluble portion of the Escherichia coli f 1 f O ATP synthase PAGE polyacrylamide gel electrophoresis

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ELECTROGENIC PROTON TRANSLOCATION BY THE CHLOROPLAST CYTOCHROME-B6/f COMPLEX RECONSTITUTED INTO PHOSPHOLIPID-VESICLES

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fEBS LETTERS 1982年第2期149卷 211-216页

作者： HURT, EC HAUSKA, G SHAHAK, Y UNIV REGENSBURG INST BOT D-8400 REGENSBURG FED REP GER WEIZMANN INST SCI DEPT BIOCHEM IL-76100 REHOVOT ISRAEL

When the cytochrome b 6 / f complex from chloroplasts is incorporated into liposomes, reduction of external plastocyanin by plastoquinol is stimulated under uncoupling conditions. An extra H + /e − is ejected from the vesicles during the reaction, in addition to the scalar proton liberated from plastoquinol. This is stimulated by valinomycin/K + and abolished under uncoupling conditions. furthermore, the formation of a membrane potential during the reaction, negative inside the vesicles, is observed with the help of carbocyanine dyes. We conclude that the cytochrome b 6 / f complex, like the cytochrome bc 1 from mitochondria, functions as an electrogenic proton translocator.

关键词： Cytochrome b 6 / f complex Chloroplast Electron transport Proton translocation Membrane potential Carbocyanine Antimycin A diO-C 5 -(3) 3,3'-dipentyloxacarbocyanine diS-(C 3 -(5) 3,3'-dipropylthiadicarbocyanine DNP-INT 2-iodo-6-isopropyl-3-methyl-2', 4,4'-trinitrodiphenyl ether fCCP carbonyl cyanide p -trifluoromethoxy-phenylhydrazone HEPES N -2-hydroxyethylpiperazine- N '-ethanesulfonic acid

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