Peptide composition and arrangement of 4 major light-harvesting complexes LHCP 1-3 and LHCP 3′ isolated from siphonous green algae (Codium fragile (Sur.) Hariot.) were investigated. LHCP 1 showed five main pep...Peptide composition and arrangement of 4 major light-harvesting complexes LHCP 1-3 and LHCP 3′ isolated from siphonous green algae (Codium fragile (Sur.) Hariot.) were investigated. LHCP 1 showed five main peptides, 34.4, 31.5, 29.5, 28.2 and 26.5 kD in SDS-PAGE, the 34.4 and 31.5 kD peptides were never found in higher plants. LHCP 3 contained the other four kinds of LHCP 1 peptides except 34.4 kD, while LHCP 3′ consisted of only 28.2 and 26.5 kD peptides. We found that 34.4, 28.2 and 26.5 kD peptides were easy to decompose from LHCP 1 when subjected to SDS-PAGE without pretreatment. They might be located at the exterior of LHCP 1, while the 31.5 and 29.5 kD peptides were at the central part. The 28.2 and 26.5 kD peptides often occurred in CPa, the center complex of PSⅡ. They are possibly the LHCⅡ peptides tightly associated with CCⅡ. According to the results described above, a peptide map of LHCP 1 was sketched.展开更多
We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same...We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.展开更多
Energy transfer processes between two aggregates in a coupled chromophoric-pigment （protein） system are studied via the standard master equation approach. Each pigment of the two aggregates is modeled as a two-level...Energy transfer processes between two aggregates in a coupled chromophoric-pigment （protein） system are studied via the standard master equation approach. Each pigment of the two aggregates is modeled as a two-level system. The excitation energy is assumed to be transferred from the donor aggregate to the acceptor aggregate. The model can be used to theoretically simulate many aspects of light-harvesting complexes （LHCs）. By applying the real bio-parameters of photosynthesis, we numerically investigate the efficiency of energy transfer （EET） between the two aggregates in terms of some factors, e.g., the initial coherence of the donor aggregate, the coupling strengthes between the two aggregates and between different pigments, and the effects of noise from the environment. Our results provide evidence for that the actual numbers of pigments in the chromophoric tings of LHCs should be the optimum parameters for a high EET. We also give a detailed analysis of the effects of noise on the EET.展开更多
The experimental observation of long-lived quantum coherence in the excitation energy transfer(EET)process of the several photosynthetic light-harvesting complexes at low and room temperatures has aroused hot debate.I...The experimental observation of long-lived quantum coherence in the excitation energy transfer(EET)process of the several photosynthetic light-harvesting complexes at low and room temperatures has aroused hot debate.It challenges the common perception in the field of complicated pigment molecular systems and evokes considerable theoretical efforts to seek reasonable explanations.In this work,we investigate the coherent exciton dynamics of the phycoerythrin 545(PE545)complex.We use the dissipation equation of motion to theoretically investigate the effect of the local pigment vibrations on the population transfer process.The result indicates that the realistic local pigment vibrations do assist the energy transmission.We demonstrate the coherence between different pigment molecules in the PE545 system is an essential ingredient in the EET process among various sites.The coherence makes the excitation energy delocalized,which leads to the redistribution of the excitation among all the chromophores in the steady state.Furthermore,we investigate the effects of the complex high-frequency spectral density function on the exciton dynamics and find that the high-frequency Brownian oscillator model contributes most to the exciton dynamic process.The discussions on the local pigment vibrations of the Brownian oscillator model suggest that the local heterogeneous protein environments and the effects of active vibration modes play a significant role in coherent energy transport.展开更多
According to the WHO histological classification of odontogenic tumours, odontomas originate from odontogenic epithelium and odontogenic ectomesenchyme, with or without hard tissue formation. They are generally classi...According to the WHO histological classification of odontogenic tumours, odontomas originate from odontogenic epithelium and odontogenic ectomesenchyme, with or without hard tissue formation. They are generally classified into two types: complex and compound. Odontomas are usually intraosseous and often associated with delayed eruption of teeth. However, they can be extraosseous and are then referred to as either peripheral complex or compound odontoma. Peripheral odontomas are rare entities. We report a case of an 11 year old boy referred to the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital by the boy’s dentist due to fibrous mass in the marginal gingiva in the anterior lower mandible. Removal of the mass revealed a peripheral complex odontoma and at the final 5-month postoperative inspection there was satisfying healing observed, a small, elevated, hyperplastic fibrous marginal gingiva.展开更多
Under normal conditions, the sympathetic neurotransmitter noradrenaline inhibits the production and release of pro-inflammatory cytokines. However, after peripheral nerve and tissue injury, pro-inflammatory cytokines ...Under normal conditions, the sympathetic neurotransmitter noradrenaline inhibits the production and release of pro-inflammatory cytokines. However, after peripheral nerve and tissue injury, pro-inflammatory cytokines appear to induce the expression of the alphalA-adreno- ceptor subtype on immune cells and perhaps also on other cells in the injured tissue. In turn, noradrenaline may act on up-regulated alphal-adrenoceptors to increase the production of the pro-inflammatory cytokine interleukin-6. In addition, the release of inflammatory mediators and nerve growth factor from keratinocytes and other cells may augment the expression of alphal-adrenoceptors on peripheral nerve fibers. Consequently, nociceptive afferents acquire an abnormal excitability to adrenergic agents, and inflammatory processes build. These mechanisms could contribute to the development of sympathetically maintained pain in conditions such as post-herpetic neuralgia, cutaneous neuromas, amputation stump pain and complex regional pain syndrome.展开更多
An active photosystem(PS)Ⅱparticle and two light-harvesting complexes,as well as their subcomplexes that have not been reported previously,were isolated from a cryptophyte Chroomonas placoidea by Triton X-100 sucrose...An active photosystem(PS)Ⅱparticle and two light-harvesting complexes,as well as their subcomplexes that have not been reported previously,were isolated from a cryptophyte Chroomonas placoidea by Triton X-100 sucrose density gradient centrifugation.The fluorescence spectra revealed that there were efficient energy couplings between phycocyanin(PC645)and chlorophyll(Chl)within both zonesⅢandⅣof the gradient,which were designated respectively as light-harvesting complex and PSⅡparticles whose size was 15-20 nm according to negative staining in electron microscopy.When the two complexes were further resolved into sub-complexes,the energy coupling was retained in the core PSⅡcomplex(named as zoneⅣ-2 of the sucrose gradient),which contained almost no outer antenna pigment Chl c.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that the PC645 components appeared in Chl-containing protein complexes were mainly the β subunit with molecular weight of 20 kDa.These results demonstrate that PC645 in this cryptophyte was structurally but preferentially combined with the light-harvesting complex and PSⅡcore.The excitation energy absorbed by PC645 could be directly transferred to Chl a(especially the long wavelength of Chl a)in the PSⅡreaction center or via the Chl a/c-protein complex.The β subunit corresponded to the terminal fl uorescence emission and might play an important role in transmitting energy from PC645 to the Chl-protein complex.The results will help in elucidating the architecture and function of the energy transfer system comprising phycobiliproteins and Chl-protein complexes in cryptophytes.展开更多
After saturating light illumination for 3 h the potential photochemical efficiency of photosystem Ⅱ （PSII） （FJF,, the ratio of variable to maximal fluorescence） decreased markedly and recovered basically to the l...After saturating light illumination for 3 h the potential photochemical efficiency of photosystem Ⅱ （PSII） （FJF,, the ratio of variable to maximal fluorescence） decreased markedly and recovered basically to the level before saturating light illumination after dark recovery for 3 h in both soybean and wheat leaves, indicating that the decline in FJ/Fm is a reversible down-regulation. Also, the saturating light illumination led to significant decreases in the low temperature （77 K） chlorophyll fluorescence parameters F685 （chlorophyll a fluorescence peaked at 685 nm） and F685/F735 （F735, chlorophyll a fluorescence peaked at 735 nm） in soybean leaves but not in wheat leaves. Moreover, trypsin （a protease） treatment resulted in a remarkable decrease in the amounts of PsbS protein （a nuclear gene psbS-encoded 22 kDa protein） in the thylakoids from saturating light-illuminated （SI）, but not in those from darkadapted （DT） and dark-recovered （DRT） soybean leaves. However, the treatment did not cause such a decrease in amounts of the PsbS protein in the thylakoids from saturating light-illuminated wheat leaves. These results support the conclusion that saturating light illumination induces a reversible dissociation of some light-harvesting complex Ⅱ （LHClI） from PSII reaction center complex in soybean leaf but not in wheat leaf.展开更多
We studied the difference in thermostability of photosystem Ⅱ （PSII） and leaf lipid composition between a T-DNA insertion mutant rice （Oryza sativa L.） VG28 and its wild type Zhonghuau. Native green gel and SDS-P...We studied the difference in thermostability of photosystem Ⅱ （PSII） and leaf lipid composition between a T-DNA insertion mutant rice （Oryza sativa L.） VG28 and its wild type Zhonghuau. Native green gel and SDS-PAGE electrophoreses revealed that the mutant VG28 lacked all light-harvesting chlorophyll a/b protein complexes. Both the mutant and wild type were sensitive to high temperatures, and the maximal efficiency of PSII photochemistry （FJ Fm） and oxygen-evolving activity of PSII in leaves significantly decreased with increasing temperature. However, the PSII activity of the mutant was markedly more sensitive to high temperatures than that of the wild type. Lipid composition analysis showed that the mutant had less phosphatidylglycerol and sulfoquinovosyl diacylglycerol compared with the wild type. Fatty acid analysis revealed that the mutant had an obvious decrease in the content of 16：1t and a marked increase in the content of 18：3 compared with the wild type. The effects of lipid composition and unsaturation of membrane lipids on the thermostability of PSII are discussed.展开更多
The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2 from Rb. sphaeroides 601 were investigated using femtosecond pump-probe technique. Upo...The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2 from Rb. sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls ex-periences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher exci-tonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by inter-conversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.展开更多
We have investigated the dynamics of a protomer coupled to two different decoherent environments,each in a configuration called the spin star configuration.Using the quantum mechanics method,in different situations,we...We have investigated the dynamics of a protomer coupled to two different decoherent environments,each in a configuration called the spin star configuration.Using the quantum mechanics method,in different situations,we obtain the analytical expressions for the transition probability in the protomer system.In thermal equilibrium,there exist well-defined ranges of parameters for which decoherent interaction between the protomer and the environment assists energy transfer in the protomer system,while in pure quantum mechanics states,the decoherent interaction assists energy transfer for an eigenstate but against energy transfer for quantum mechanics averages.In particular,we also find that the dimerization of two bacteriochlorophylls in protomer can always assist energy transfer in certain parameter range,and in the appropriate spin bath energy,the efficiency of energy transport is sensitively depended on the temperature of environments.展开更多
In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic exc...In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center(RC). In this decohering model, the Hamiltonian of the system commutes with the systemenvironment interaction. We take B850 ring of light-harvesting complex II(LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.展开更多
Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,s...Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,sensitizers play a core role due to their responsibility for the generation of the photo carriers resulted from light absorption and the transfer of the photo-generated electrons into semiconductor photoanodes[4].Keywords：Light-harvesting complex Ⅱ; Anthraquinone 2-carboxylic acid; ZnO; TiO2 nanostructure; Solar cell展开更多
Photodynamics of peripheral antenna complexes,light-harvesting complex (LH2) of Rhodobacter (Rb) Sphaeroides 601,was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results ...Photodynamics of peripheral antenna complexes,light-harvesting complex (LH2) of Rhodobacter (Rb) Sphaeroides 601,was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results reveal dramatic dynamical evolutions within B800 and B850 absorption bands of antenna complexes LH2. At excitation wavelength around 835 nm,a sharp photobleaching signal was observed which was assigned to the contribution of the two-exciton state,which was further confirmed by the power dependence measurement. Rate equations with eight-level scheme were used to calculate the population evolution in LH2 and the transient dynamics under femtosecond pulse excitation. The research results prove that not only the transition from ground state to one-exciton state but also that from one-exciton state to two-exciton state contribute to the photodynamics of B850.展开更多
The light-harvesting chlorophyll a/b-protein complex plays an important role in photosynthesis of plants. A full-length cDNA of light-harvesting chlorophyll a/b （cab） gene was cloned from the first strand of Moso （...The light-harvesting chlorophyll a/b-protein complex plays an important role in photosynthesis of plants. A full-length cDNA of light-harvesting chlorophyll a/b （cab） gene was cloned from the first strand of Moso （Phyllostachys edulis） cDNA through RT-PCR and RACE methods, named as cabPhEIO （cab gene 10 from Ph. edulis）. The length of cab- PhEIO （GenBank accession number： EU118754） is 1 151 bp, which contains an open reading frame encoding 283 amino acids from 81st to 932nd position. The bioinformatics analysis indicated that the protein encoded by cab-PhElO had a chlorophll a/b binding domain （83rd -247th position）, two protein kinase C-phosphorylation sites, three Nmyristoylation sites and a yia A/B double helix domain.The amino acid sequence of cab-PhElO showed high similarity with the cab genes of Oryza sativa, Zea mays, Hordeum vulgare, and Vitis vinifera, more than 80%, respectively, which indicated that cab-PhElO gene belongs to lhcb5 gene family.展开更多
文摘Peptide composition and arrangement of 4 major light-harvesting complexes LHCP 1-3 and LHCP 3′ isolated from siphonous green algae (Codium fragile (Sur.) Hariot.) were investigated. LHCP 1 showed five main peptides, 34.4, 31.5, 29.5, 28.2 and 26.5 kD in SDS-PAGE, the 34.4 and 31.5 kD peptides were never found in higher plants. LHCP 3 contained the other four kinds of LHCP 1 peptides except 34.4 kD, while LHCP 3′ consisted of only 28.2 and 26.5 kD peptides. We found that 34.4, 28.2 and 26.5 kD peptides were easy to decompose from LHCP 1 when subjected to SDS-PAGE without pretreatment. They might be located at the exterior of LHCP 1, while the 31.5 and 29.5 kD peptides were at the central part. The 28.2 and 26.5 kD peptides often occurred in CPa, the center complex of PSⅡ. They are possibly the LHCⅡ peptides tightly associated with CCⅡ. According to the results described above, a peptide map of LHCP 1 was sketched.
基金This work was supported by the Zhejiang Provincial Natural Science Foundation of China （No.LY13A040006）, and the K. C. Wong Magna Foundation in Ningbo University.
文摘We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174233)the National Basic Research Program of China(Grant No.2011CB311807)
文摘Energy transfer processes between two aggregates in a coupled chromophoric-pigment （protein） system are studied via the standard master equation approach. Each pigment of the two aggregates is modeled as a two-level system. The excitation energy is assumed to be transferred from the donor aggregate to the acceptor aggregate. The model can be used to theoretically simulate many aspects of light-harvesting complexes （LHCs）. By applying the real bio-parameters of photosynthesis, we numerically investigate the efficiency of energy transfer （EET） between the two aggregates in terms of some factors, e.g., the initial coherence of the donor aggregate, the coupling strengthes between the two aggregates and between different pigments, and the effects of noise from the environment. Our results provide evidence for that the actual numbers of pigments in the chromophoric tings of LHCs should be the optimum parameters for a high EET. We also give a detailed analysis of the effects of noise on the EET.
基金supported by the Natural Science Foundation of China (Grant Nos. 11774418 and 11374363)
文摘The experimental observation of long-lived quantum coherence in the excitation energy transfer(EET)process of the several photosynthetic light-harvesting complexes at low and room temperatures has aroused hot debate.It challenges the common perception in the field of complicated pigment molecular systems and evokes considerable theoretical efforts to seek reasonable explanations.In this work,we investigate the coherent exciton dynamics of the phycoerythrin 545(PE545)complex.We use the dissipation equation of motion to theoretically investigate the effect of the local pigment vibrations on the population transfer process.The result indicates that the realistic local pigment vibrations do assist the energy transmission.We demonstrate the coherence between different pigment molecules in the PE545 system is an essential ingredient in the EET process among various sites.The coherence makes the excitation energy delocalized,which leads to the redistribution of the excitation among all the chromophores in the steady state.Furthermore,we investigate the effects of the complex high-frequency spectral density function on the exciton dynamics and find that the high-frequency Brownian oscillator model contributes most to the exciton dynamic process.The discussions on the local pigment vibrations of the Brownian oscillator model suggest that the local heterogeneous protein environments and the effects of active vibration modes play a significant role in coherent energy transport.
文摘According to the WHO histological classification of odontogenic tumours, odontomas originate from odontogenic epithelium and odontogenic ectomesenchyme, with or without hard tissue formation. They are generally classified into two types: complex and compound. Odontomas are usually intraosseous and often associated with delayed eruption of teeth. However, they can be extraosseous and are then referred to as either peripheral complex or compound odontoma. Peripheral odontomas are rare entities. We report a case of an 11 year old boy referred to the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital by the boy’s dentist due to fibrous mass in the marginal gingiva in the anterior lower mandible. Removal of the mass revealed a peripheral complex odontoma and at the final 5-month postoperative inspection there was satisfying healing observed, a small, elevated, hyperplastic fibrous marginal gingiva.
基金supported by grants from the National Health and Medical Research Council of Australiathe Australian and New Zealand College of Anaesthetists
文摘Under normal conditions, the sympathetic neurotransmitter noradrenaline inhibits the production and release of pro-inflammatory cytokines. However, after peripheral nerve and tissue injury, pro-inflammatory cytokines appear to induce the expression of the alphalA-adreno- ceptor subtype on immune cells and perhaps also on other cells in the injured tissue. In turn, noradrenaline may act on up-regulated alphal-adrenoceptors to increase the production of the pro-inflammatory cytokine interleukin-6. In addition, the release of inflammatory mediators and nerve growth factor from keratinocytes and other cells may augment the expression of alphal-adrenoceptors on peripheral nerve fibers. Consequently, nociceptive afferents acquire an abnormal excitability to adrenergic agents, and inflammatory processes build. These mechanisms could contribute to the development of sympathetically maintained pain in conditions such as post-herpetic neuralgia, cutaneous neuromas, amputation stump pain and complex regional pain syndrome.
基金Supported by the Natural Science Foundation of Shandong Province(No.ZR2018LD009)。
文摘An active photosystem(PS)Ⅱparticle and two light-harvesting complexes,as well as their subcomplexes that have not been reported previously,were isolated from a cryptophyte Chroomonas placoidea by Triton X-100 sucrose density gradient centrifugation.The fluorescence spectra revealed that there were efficient energy couplings between phycocyanin(PC645)and chlorophyll(Chl)within both zonesⅢandⅣof the gradient,which were designated respectively as light-harvesting complex and PSⅡparticles whose size was 15-20 nm according to negative staining in electron microscopy.When the two complexes were further resolved into sub-complexes,the energy coupling was retained in the core PSⅡcomplex(named as zoneⅣ-2 of the sucrose gradient),which contained almost no outer antenna pigment Chl c.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that the PC645 components appeared in Chl-containing protein complexes were mainly the β subunit with molecular weight of 20 kDa.These results demonstrate that PC645 in this cryptophyte was structurally but preferentially combined with the light-harvesting complex and PSⅡcore.The excitation energy absorbed by PC645 could be directly transferred to Chl a(especially the long wavelength of Chl a)in the PSⅡreaction center or via the Chl a/c-protein complex.The β subunit corresponded to the terminal fl uorescence emission and might play an important role in transmitting energy from PC645 to the Chl-protein complex.The results will help in elucidating the architecture and function of the energy transfer system comprising phycobiliproteins and Chl-protein complexes in cryptophytes.
文摘After saturating light illumination for 3 h the potential photochemical efficiency of photosystem Ⅱ （PSII） （FJF,, the ratio of variable to maximal fluorescence） decreased markedly and recovered basically to the level before saturating light illumination after dark recovery for 3 h in both soybean and wheat leaves, indicating that the decline in FJ/Fm is a reversible down-regulation. Also, the saturating light illumination led to significant decreases in the low temperature （77 K） chlorophyll fluorescence parameters F685 （chlorophyll a fluorescence peaked at 685 nm） and F685/F735 （F735, chlorophyll a fluorescence peaked at 735 nm） in soybean leaves but not in wheat leaves. Moreover, trypsin （a protease） treatment resulted in a remarkable decrease in the amounts of PsbS protein （a nuclear gene psbS-encoded 22 kDa protein） in the thylakoids from saturating light-illuminated （SI）, but not in those from darkadapted （DT） and dark-recovered （DRT） soybean leaves. However, the treatment did not cause such a decrease in amounts of the PsbS protein in the thylakoids from saturating light-illuminated wheat leaves. These results support the conclusion that saturating light illumination induces a reversible dissociation of some light-harvesting complex Ⅱ （LHClI） from PSII reaction center complex in soybean leaf but not in wheat leaf.
文摘We studied the difference in thermostability of photosystem Ⅱ （PSII） and leaf lipid composition between a T-DNA insertion mutant rice （Oryza sativa L.） VG28 and its wild type Zhonghuau. Native green gel and SDS-PAGE electrophoreses revealed that the mutant VG28 lacked all light-harvesting chlorophyll a/b protein complexes. Both the mutant and wild type were sensitive to high temperatures, and the maximal efficiency of PSII photochemistry （FJ Fm） and oxygen-evolving activity of PSII in leaves significantly decreased with increasing temperature. However, the PSII activity of the mutant was markedly more sensitive to high temperatures than that of the wild type. Lipid composition analysis showed that the mutant had less phosphatidylglycerol and sulfoquinovosyl diacylglycerol compared with the wild type. Fatty acid analysis revealed that the mutant had an obvious decrease in the content of 16：1t and a marked increase in the content of 18：3 compared with the wild type. The effects of lipid composition and unsaturation of membrane lipids on the thermostability of PSII are discussed.
基金the National Natural Science Foundation of China(Grant No.10274013)State Key Basic Research and Development Plan(Grant No.G1998010100)+1 种基金Natural Science Foundation of Henan Educational Committee(Grant No.20011400003)the Key Natural Science Foundation of Henan University.
文摘The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2 from Rb. sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls ex-periences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher exci-tonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by inter-conversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11274272,11304281,31201001by the Natural Science Foundation of Zhejiang Province under Grant Nos.Y6110250LY14A040001 and Zhejiang Ocean University(X12ZD10)
文摘We have investigated the dynamics of a protomer coupled to two different decoherent environments,each in a configuration called the spin star configuration.Using the quantum mechanics method,in different situations,we obtain the analytical expressions for the transition probability in the protomer system.In thermal equilibrium,there exist well-defined ranges of parameters for which decoherent interaction between the protomer and the environment assists energy transfer in the protomer system,while in pure quantum mechanics states,the decoherent interaction assists energy transfer for an eigenstate but against energy transfer for quantum mechanics averages.In particular,we also find that the dimerization of two bacteriochlorophylls in protomer can always assist energy transfer in certain parameter range,and in the appropriate spin bath energy,the efficiency of energy transport is sensitively depended on the temperature of environments.
基金Supported by the Research Start-up Foundation for Talents of Northwest A&F University of China under Grant Nos.Z111021106 and Z111021307
文摘In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center(RC). In this decohering model, the Hamiltonian of the system commutes with the systemenvironment interaction. We take B850 ring of light-harvesting complex II(LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.
文摘Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,sensitizers play a core role due to their responsibility for the generation of the photo carriers resulted from light absorption and the transfer of the photo-generated electrons into semiconductor photoanodes[4].Keywords：Light-harvesting complex Ⅱ; Anthraquinone 2-carboxylic acid; ZnO; TiO2 nanostructure; Solar cell
基金the National Natural Science Foundation of China (Grant No.10674031)
文摘Photodynamics of peripheral antenna complexes,light-harvesting complex (LH2) of Rhodobacter (Rb) Sphaeroides 601,was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results reveal dramatic dynamical evolutions within B800 and B850 absorption bands of antenna complexes LH2. At excitation wavelength around 835 nm,a sharp photobleaching signal was observed which was assigned to the contribution of the two-exciton state,which was further confirmed by the power dependence measurement. Rate equations with eight-level scheme were used to calculate the population evolution in LH2 and the transient dynamics under femtosecond pulse excitation. The research results prove that not only the transition from ground state to one-exciton state but also that from one-exciton state to two-exciton state contribute to the photodynamics of B850.
基金This project is supported by "948" Introduction Project (2004-4-60, 2005-4-38)
文摘The light-harvesting chlorophyll a/b-protein complex plays an important role in photosynthesis of plants. A full-length cDNA of light-harvesting chlorophyll a/b （cab） gene was cloned from the first strand of Moso （Phyllostachys edulis） cDNA through RT-PCR and RACE methods, named as cabPhEIO （cab gene 10 from Ph. edulis）. The length of cab- PhEIO （GenBank accession number： EU118754） is 1 151 bp, which contains an open reading frame encoding 283 amino acids from 81st to 932nd position. The bioinformatics analysis indicated that the protein encoded by cab-PhElO had a chlorophll a/b binding domain （83rd -247th position）, two protein kinase C-phosphorylation sites, three Nmyristoylation sites and a yia A/B double helix domain.The amino acid sequence of cab-PhElO showed high similarity with the cab genes of Oryza sativa, Zea mays, Hordeum vulgare, and Vitis vinifera, more than 80%, respectively, which indicated that cab-PhElO gene belongs to lhcb5 gene family.
