Green fluorescent protein ( GFP ) gene was expressed transiently in 2-3 d old rice embryos by electroporation with the aid of a specially designed loading net. Under suitable conditions (500 μF capacitance, 300 V/c...Green fluorescent protein ( GFP ) gene was expressed transiently in 2-3 d old rice embryos by electroporation with the aid of a specially designed loading net. Under suitable conditions (500 μF capacitance, 300 V/cm Voltage, 100 μg/mL plasmid DNA), the percentage of embryos expressing GFP was up to 35%. The highest electroporation efficiency (40%) was obtained at pH 5.8 of the electroporation buffer. The GFP gene driven by the Ubi promoter produced the highest efficiency. Thus, on the basis of optimizing electroporation conditions, a transformation system has been developed for young embryos in rice. The electroporated 4-6 d old embryos regenerated plantlets under the controlled cultural conditions. Fluorescence microscopic observations indicated that GFP gene expressed in their calli and R0 plantlets.展开更多
Green fluorescent protein (GFP) gene was successfully transferred into the isolated zygotes and early proembryos of wheat (Triticum aestivum L.) by electroporation. A frequency, as high as 46.7% of GFP gene transient ...Green fluorescent protein (GFP) gene was successfully transferred into the isolated zygotes and early proembryos of wheat (Triticum aestivum L.) by electroporation. A frequency, as high as 46.7% of GFP gene transient expression in early proembryos, was achieved under 150 V/cm electric field strength, 25 muF capacitor, 200 mug/mL of linear plasmid DNA and an electroporation buffer at pH 7.2. Compared with five-day-old proembryos, the zygotes and early proembryos needed lower optimum strength of electric field. After culturing in KM8p medium, the electroporated early proembryos divided and GFP gene expression was observed in daughter cells and subsequent divisions. There was no mosaicism of gene expression in the zygotes and 2-, 4- and 8-celled proembryos.展开更多
Catechol adsorbed on TiO_(2)is one of the simplest models to explore the relevant properties of dye-sensitized solar cells.However,the effects of water and defects on the electronic levels and the excitonic properties...Catechol adsorbed on TiO_(2)is one of the simplest models to explore the relevant properties of dye-sensitized solar cells.However,the effects of water and defects on the electronic levels and the excitonic properties of the catechol/TiO_(2)interface have been rarely explored.Here,we investigate four catechol/TiO_(2)interfaces aiming to study the influence of coverage,water,and defects on the electronic levels and the excitonic properties of the catechol/TiO_(2)interface through the first-principles many-body Green’s function theory.We find that the adsorption of catechol on the rutile(110)surface increases the energies of both the TiO_(2)valence band maximum and conduction band minimum by approximately 0.7 eV.The increasing coverage and the presence of water can reduce the optical absorption of charge-transfer excitons with maximum oscillator strength.Regarding the reduced hydroxylated TiO_(2)substrate,the conduction band minimum decreases greatly,resulting in a sub-bandgap of 2.51 eV.The exciton distributions in the four investigated interfaces can spread across several unit cells,especially for the hydroxylated TiO2substrate.Although the hydroxylated TiO_(2)substrate leads to a lower open-circuit voltage,it may increase the separation between photogenerated electrons and holes and may therefore be beneficial for improving the photovoltaic efficiency by controlling its concentration.Our results may provide guidance for the design of highly efficient solar cells in future.展开更多
The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is ob...The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is observed,which involves two components,^(3)nπ^(∗) and^(3)ππ^(∗) states.The ^(3)ππ^(∗) component contributes more to the^(3)TX^(∗) when increasing the solvent polarity.The self-quenching rate constant ksq of^(3)TX^(∗)is decreased in the order of CH_(3)CN,CH_(3)CN/CH_(3)OH(1:1),and CH_(3)CN/H_(2)O(1:1),which might be caused by the exciplex formed from hydrogen bond interaction.In the presence of diphenylamine(DPA),the quenching of^(3)TX^(∗)happens efficiently via electron transfer,producing the TX^(⋅−) anion and DPA^(⋅+) cation radicals.Because of insignificant solvent effects on the electron transfer,the electron affinity of the ^(3)nπ^(∗) state is proved to be approximately equal to that of the ^(3)ππ^(∗) state.However,a solvent dependence is found in the dynamic decay of TX^(⋅−) anion radical.In the strongly acid aqueous acetonitrile(pH=3.0),a dynamic equilibrium between protonated and unprotonated TX is definitely observed.Once photolysis,^(3)TXH^(+∗) is produced,which contributes to the new band at 520 nm.展开更多
We have conducted a two-color visible-ultraviolet （VIS-UV） resonance-enhanced laser pho- toionization and pulsed field ionization-photoelectron （PFI-PE） study of gaseous vana- dium mononitride （VN） in the total ...We have conducted a two-color visible-ultraviolet （VIS-UV） resonance-enhanced laser pho- toionization and pulsed field ionization-photoelectron （PFI-PE） study of gaseous vana- dium mononitride （VN） in the total energy range of 56900-59020 cm-1. The VN molecules were selectively excited to single rotational levels of the intermediate VN（D3H0, v＇=0） state by using a VIS dye laser prior to photoionization by employing a UV laser. This two-color scheme allows the measurements of rovibronically selected and re- solved PFI-PE spectra for the VN＋（X2A; v＋=0, 1, and 2） ion vibrational bands. By simulating the rotationally resolved PFI-PE spectra, J＋=3/2 is determined to be the lowest rotational level of the ground electronic state, indicating that the symmetry of the ground VN＋ electronic state is 2A3/2. The analysis of the PFI-PE spectra for VN＋ also yields accurate values for the adiabatic ionization energy for the formation of VN＋（X2A3/2）, IE（VN）=56909.5＋0.8 cm-1 （7.05588±0.00010 eV）, the vibrational fre- quency wc＋=1068.0±0.8 cm-1, the anharmonicity constant wc＋Xe＋=5.8±0.8 cm-1, the rotational constants Be＋=0.6563±0.0005 cm-1 and ae＋=0.0069±0.0004 cm-1, and the equi-librium bond length, re＋=1.529A, for VN＋（X2A3/2）; along with the rotational constants Bc＋=0.6578i0.0028 cm-1 and a＋=0.0085±0.0028 cm-1, and the equilibrium bond length re＋=1.527A for VN＋（X2As/2）, and the spin-orbit coupling constant A=153.3±0.8 cm-1 for VN＋（X2/k5/2,3/2）. The highly precise energetic and spectroscopic data obtained in the present study are valuable for benchmarking the predictions based on state-of-the-art ab initio quantum calculations.展开更多
Both activated carbon and magnetite have been reported to promote the syntrophic growth of Geobacter metallireducens and Geobacter sulfurreducens co-cultures, the first model to show direct interspecies electron trans...Both activated carbon and magnetite have been reported to promote the syntrophic growth of Geobacter metallireducens and Geobacter sulfurreducens co-cultures, the first model to show direct interspecies electron transfer (DIET); however, differential transcriptomics of the promotion on co-cultures with these two conductive materials are unknown. Here, the comparative transcriptomic analysis of G. metallireducens and G. sulfurreducens co-cultures with granular activated carbon (GAC) and magnetite was reported. More than 2.6-fold reduced transcript abundances were determined for the uptake hydrogenase genes of G. sulfurreducens as well as other hydrogenases in those co-cultures to which conductive materials had been added. This is consistent with electron transfer in G. metallireducens-G. sulfurreducens co-cultures as evinced by direct interspecies electron transfer (DIET). Transcript abundance for the structural component of electrically conductive pili (e-pili), PilA, was 2.2-fold higher in G. metallireducens, and, in contrast, was 14.9-fold lower in G. sulfurreducens in co-cultures with GAC than in Geobacters co-cultures without GAC. However, it was 9.3-fold higher in G. sulfurreducens in co-cultures with magnetite than in Geobacters co-cultures. Mutation results showed that GAC can be substituted for the e-pili of both strains but magnetite can only compensate for that of G. sulfurreducens, indicating that the e-pili is a more important electron acceptor for the electron donor strain of G. metallireducens than for G. sulfurreducens. Transcript abundance for G. metallireducens c-type cytochrome gene GMET_RS14535, a homologue to c-type cytochrome gene omcE of G. sulfurreducens was 9.8-fold lower in co-cultures with GAC addition, while that for OmcS of G. sulfurreducens was 25.1-fold higher in co-cultures with magnetite, than in that without magnetite. Gene deletion studies showed that neither GAC nor magnetite can completely substitute the cytochrome (OmcE homologous) of G. metallireducens but compensate for the cytochrome (OmcS) of G. sulfurreducens. Moreover, some genes associated with central metabolism were up-regulated in the presence of both GAC and magnetite; however, tricarboxylic acid cycle gene transcripts in G. sulfurreducens were not highly-expressed in each of these amended co-cultures, suggesting that there was considerable redundancy in the pathways utilised by G. sulfurreducens for electron transfer to reduce fumarate with the amendment of GAC or magnetite. These results support the DIET model of G. metallireducens and G. sulfurreducens and suggest that e-pili and cytochromes of the electron donor strain are more important than that of the electron acceptor strain, indicating that comparative transcriptomics may be a promising route by which to reveal different responses of electron donor and acceptor during DIET in co-cultures.展开更多
The mechanisms of reactions between CC13OO? radical and quercetin, rutin and epigallocatechin gallate (EGCG) have been studied using pulse radiolytic technique. It is suggested that the electron transfer reaction is t...The mechanisms of reactions between CC13OO? radical and quercetin, rutin and epigallocatechin gallate (EGCG) have been studied using pulse radiolytic technique. It is suggested that the electron transfer reaction is the main reaction between CC13OO? radical and rutin, EGCG, but there are two main pathways for the reaction of CC13OO? radical with quercetin, one is the electron transfer reaction, the other is addition reaction. The reaction rate constants were determined. It is proved that quercetin and rutin are better CC13OO? radical scavengers than EGCG.展开更多
文摘Green fluorescent protein ( GFP ) gene was expressed transiently in 2-3 d old rice embryos by electroporation with the aid of a specially designed loading net. Under suitable conditions (500 μF capacitance, 300 V/cm Voltage, 100 μg/mL plasmid DNA), the percentage of embryos expressing GFP was up to 35%. The highest electroporation efficiency (40%) was obtained at pH 5.8 of the electroporation buffer. The GFP gene driven by the Ubi promoter produced the highest efficiency. Thus, on the basis of optimizing electroporation conditions, a transformation system has been developed for young embryos in rice. The electroporated 4-6 d old embryos regenerated plantlets under the controlled cultural conditions. Fluorescence microscopic observations indicated that GFP gene expressed in their calli and R0 plantlets.
文摘Green fluorescent protein (GFP) gene was successfully transferred into the isolated zygotes and early proembryos of wheat (Triticum aestivum L.) by electroporation. A frequency, as high as 46.7% of GFP gene transient expression in early proembryos, was achieved under 150 V/cm electric field strength, 25 muF capacitor, 200 mug/mL of linear plasmid DNA and an electroporation buffer at pH 7.2. Compared with five-day-old proembryos, the zygotes and early proembryos needed lower optimum strength of electric field. After culturing in KM8p medium, the electroporated early proembryos divided and GFP gene expression was observed in daughter cells and subsequent divisions. There was no mosaicism of gene expression in the zygotes and 2-, 4- and 8-celled proembryos.
基金supported by the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2020L0609 and No.2020L0556)the Doctoral research funds of Jinzhong University(jzxybsjjxm2019005)the Basic Research Program in Shanxi Province under the Grant No.20210302124345。
文摘Catechol adsorbed on TiO_(2)is one of the simplest models to explore the relevant properties of dye-sensitized solar cells.However,the effects of water and defects on the electronic levels and the excitonic properties of the catechol/TiO_(2)interface have been rarely explored.Here,we investigate four catechol/TiO_(2)interfaces aiming to study the influence of coverage,water,and defects on the electronic levels and the excitonic properties of the catechol/TiO_(2)interface through the first-principles many-body Green’s function theory.We find that the adsorption of catechol on the rutile(110)surface increases the energies of both the TiO_(2)valence band maximum and conduction band minimum by approximately 0.7 eV.The increasing coverage and the presence of water can reduce the optical absorption of charge-transfer excitons with maximum oscillator strength.Regarding the reduced hydroxylated TiO_(2)substrate,the conduction band minimum decreases greatly,resulting in a sub-bandgap of 2.51 eV.The exciton distributions in the four investigated interfaces can spread across several unit cells,especially for the hydroxylated TiO2substrate.Although the hydroxylated TiO_(2)substrate leads to a lower open-circuit voltage,it may increase the separation between photogenerated electrons and holes and may therefore be beneficial for improving the photovoltaic efficiency by controlling its concentration.Our results may provide guidance for the design of highly efficient solar cells in future.
基金supported by the Educational Commission of Anhui Province of China (No.KJ2018A0491)financial support of Anhui Natural Science Foundation (No.1908085MB50)
文摘The photophysical and photochemical behaviors of thioxanthen-9-one(TX)in different solvents have been studied using nanosecond transient absorption spectroscopy.A unique absorption of the triplet state^(3)TX^(∗) is observed,which involves two components,^(3)nπ^(∗) and^(3)ππ^(∗) states.The ^(3)ππ^(∗) component contributes more to the^(3)TX^(∗) when increasing the solvent polarity.The self-quenching rate constant ksq of^(3)TX^(∗)is decreased in the order of CH_(3)CN,CH_(3)CN/CH_(3)OH(1:1),and CH_(3)CN/H_(2)O(1:1),which might be caused by the exciplex formed from hydrogen bond interaction.In the presence of diphenylamine(DPA),the quenching of^(3)TX^(∗)happens efficiently via electron transfer,producing the TX^(⋅−) anion and DPA^(⋅+) cation radicals.Because of insignificant solvent effects on the electron transfer,the electron affinity of the ^(3)nπ^(∗) state is proved to be approximately equal to that of the ^(3)ππ^(∗) state.However,a solvent dependence is found in the dynamic decay of TX^(⋅−) anion radical.In the strongly acid aqueous acetonitrile(pH=3.0),a dynamic equilibrium between protonated and unprotonated TX is definitely observed.Once photolysis,^(3)TXH^(+∗) is produced,which contributes to the new band at 520 nm.
文摘We have conducted a two-color visible-ultraviolet （VIS-UV） resonance-enhanced laser pho- toionization and pulsed field ionization-photoelectron （PFI-PE） study of gaseous vana- dium mononitride （VN） in the total energy range of 56900-59020 cm-1. The VN molecules were selectively excited to single rotational levels of the intermediate VN（D3H0, v＇=0） state by using a VIS dye laser prior to photoionization by employing a UV laser. This two-color scheme allows the measurements of rovibronically selected and re- solved PFI-PE spectra for the VN＋（X2A; v＋=0, 1, and 2） ion vibrational bands. By simulating the rotationally resolved PFI-PE spectra, J＋=3/2 is determined to be the lowest rotational level of the ground electronic state, indicating that the symmetry of the ground VN＋ electronic state is 2A3/2. The analysis of the PFI-PE spectra for VN＋ also yields accurate values for the adiabatic ionization energy for the formation of VN＋（X2A3/2）, IE（VN）=56909.5＋0.8 cm-1 （7.05588±0.00010 eV）, the vibrational fre- quency wc＋=1068.0±0.8 cm-1, the anharmonicity constant wc＋Xe＋=5.8±0.8 cm-1, the rotational constants Be＋=0.6563±0.0005 cm-1 and ae＋=0.0069±0.0004 cm-1, and the equi-librium bond length, re＋=1.529A, for VN＋（X2A3/2）; along with the rotational constants Bc＋=0.6578i0.0028 cm-1 and a＋=0.0085±0.0028 cm-1, and the equilibrium bond length re＋=1.527A for VN＋（X2As/2）, and the spin-orbit coupling constant A=153.3±0.8 cm-1 for VN＋（X2/k5/2,3/2）. The highly precise energetic and spectroscopic data obtained in the present study are valuable for benchmarking the predictions based on state-of-the-art ab initio quantum calculations.
基金supported by the Major Research plan(91751112)the General Programme(41371257,41573071)of the National Natural Science Foundation of China+2 种基金Shandong Natural Science Fund for Distinguished Young Scholars(JQ201608)the Young Taishan Scholars Programme of Shandong Province(tsqn20161054)the Key Research Project for Frontier Science of the Chinese Academy of Sciences(QYZDJ-SSW-DQC015)
文摘Both activated carbon and magnetite have been reported to promote the syntrophic growth of Geobacter metallireducens and Geobacter sulfurreducens co-cultures, the first model to show direct interspecies electron transfer (DIET); however, differential transcriptomics of the promotion on co-cultures with these two conductive materials are unknown. Here, the comparative transcriptomic analysis of G. metallireducens and G. sulfurreducens co-cultures with granular activated carbon (GAC) and magnetite was reported. More than 2.6-fold reduced transcript abundances were determined for the uptake hydrogenase genes of G. sulfurreducens as well as other hydrogenases in those co-cultures to which conductive materials had been added. This is consistent with electron transfer in G. metallireducens-G. sulfurreducens co-cultures as evinced by direct interspecies electron transfer (DIET). Transcript abundance for the structural component of electrically conductive pili (e-pili), PilA, was 2.2-fold higher in G. metallireducens, and, in contrast, was 14.9-fold lower in G. sulfurreducens in co-cultures with GAC than in Geobacters co-cultures without GAC. However, it was 9.3-fold higher in G. sulfurreducens in co-cultures with magnetite than in Geobacters co-cultures. Mutation results showed that GAC can be substituted for the e-pili of both strains but magnetite can only compensate for that of G. sulfurreducens, indicating that the e-pili is a more important electron acceptor for the electron donor strain of G. metallireducens than for G. sulfurreducens. Transcript abundance for G. metallireducens c-type cytochrome gene GMET_RS14535, a homologue to c-type cytochrome gene omcE of G. sulfurreducens was 9.8-fold lower in co-cultures with GAC addition, while that for OmcS of G. sulfurreducens was 25.1-fold higher in co-cultures with magnetite, than in that without magnetite. Gene deletion studies showed that neither GAC nor magnetite can completely substitute the cytochrome (OmcE homologous) of G. metallireducens but compensate for the cytochrome (OmcS) of G. sulfurreducens. Moreover, some genes associated with central metabolism were up-regulated in the presence of both GAC and magnetite; however, tricarboxylic acid cycle gene transcripts in G. sulfurreducens were not highly-expressed in each of these amended co-cultures, suggesting that there was considerable redundancy in the pathways utilised by G. sulfurreducens for electron transfer to reduce fumarate with the amendment of GAC or magnetite. These results support the DIET model of G. metallireducens and G. sulfurreducens and suggest that e-pili and cytochromes of the electron donor strain are more important than that of the electron acceptor strain, indicating that comparative transcriptomics may be a promising route by which to reveal different responses of electron donor and acceptor during DIET in co-cultures.
基金Acknowledgements This work was supported by the Foundation of Qimingxing Program of Shanghai, China (Grant No. 99QA14034).
文摘The mechanisms of reactions between CC13OO? radical and quercetin, rutin and epigallocatechin gallate (EGCG) have been studied using pulse radiolytic technique. It is suggested that the electron transfer reaction is the main reaction between CC13OO? radical and rutin, EGCG, but there are two main pathways for the reaction of CC13OO? radical with quercetin, one is the electron transfer reaction, the other is addition reaction. The reaction rate constants were determined. It is proved that quercetin and rutin are better CC13OO? radical scavengers than EGCG.
