To mutagenize two conserved CCCT and PTK motifs in the central domain of Chinese strain of potato Y potyvirus (PVY-C) helper component proteinase (HC-Pro), four mutants of HC-Pro gene were obtained by PCR and site-dir...To mutagenize two conserved CCCT and PTK motifs in the central domain of Chinese strain of potato Y potyvirus (PVY-C) helper component proteinase (HC-Pro), four mutants of HC-Pro gene were obtained by PCR and site-directed mutagenesis, and then were inserted into the constitutive expression vector pBin438. Leaves from tobacco (Nicotiana tabacum L. cv. K326) were transformed with these four plant expression plasmids by Agrobacterium-mediated transformation, respectively. Southern and Western blotting analyses showed that these four mutants were integrated into tobacco genomic DNA and could express the corresponding proteins in most of die transgenic plants. The challenge of transgenic plants with potato X potexvirus (PVX) revealed that the expression products of PVY-C HC-Pro mutants in transgenic plants greatly abolished functions of HC-Pro in enhancing the accumulation and pathogenicity of PVX, indicating that CCCT and PTK motifs of HC-Pro were required for PVX/PVY synergism. Meanwhile, the results demonstrated that PVY-C HC-Pro had a function in accelerating the long-distance movement of PVX in these transgenic plants for the first time.展开更多
Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability...Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.展开更多
In this study, silver nano-particles have been anchored in the surface of Bi OBr photocatalysts by a citric acid-assisted photoreduction method. The citric acid was served as a chelating and reductive agent for the pr...In this study, silver nano-particles have been anchored in the surface of Bi OBr photocatalysts by a citric acid-assisted photoreduction method. The citric acid was served as a chelating and reductive agent for the preparation of Ag-decorated Bi OBr photocatalysts(named as Ag/Bi OBr-2). The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and UV-Vis diffuse reflection spectroscopy(DRS). The Ag/Bi OBr-2 photocatalyst exhibited excellent and stable photocatalytic activities on MO and phenol degradation under simulated sunlight irradiation. The enhanced photocatalytic activity could be ascribed to the smaller size, rough surface, and the surface plasma resonance(SPR) effect of Ag. Also, the Schottky junction, between the surface of the Bi OBr and silver nanoparticles, accelerated the efficient transfer and separation of photoinduced electron-hole pairs and promoted the photocatalytic performance. The active species tests indicated that the superoxide radical(·O-2) was responsible for the enhanced photocatalytic performance of Ag/Bi OBr-2. Finally, a possible photocatalytic mechanism was proposed.展开更多
文摘To mutagenize two conserved CCCT and PTK motifs in the central domain of Chinese strain of potato Y potyvirus (PVY-C) helper component proteinase (HC-Pro), four mutants of HC-Pro gene were obtained by PCR and site-directed mutagenesis, and then were inserted into the constitutive expression vector pBin438. Leaves from tobacco (Nicotiana tabacum L. cv. K326) were transformed with these four plant expression plasmids by Agrobacterium-mediated transformation, respectively. Southern and Western blotting analyses showed that these four mutants were integrated into tobacco genomic DNA and could express the corresponding proteins in most of die transgenic plants. The challenge of transgenic plants with potato X potexvirus (PVX) revealed that the expression products of PVY-C HC-Pro mutants in transgenic plants greatly abolished functions of HC-Pro in enhancing the accumulation and pathogenicity of PVX, indicating that CCCT and PTK motifs of HC-Pro were required for PVX/PVY synergism. Meanwhile, the results demonstrated that PVY-C HC-Pro had a function in accelerating the long-distance movement of PVX in these transgenic plants for the first time.
文摘Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.
基金supported by the National Natural Science Foundation of China(21176168,21206105)the International Cooperation Project of Shanxi Province(2012081017)
文摘In this study, silver nano-particles have been anchored in the surface of Bi OBr photocatalysts by a citric acid-assisted photoreduction method. The citric acid was served as a chelating and reductive agent for the preparation of Ag-decorated Bi OBr photocatalysts(named as Ag/Bi OBr-2). The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and UV-Vis diffuse reflection spectroscopy(DRS). The Ag/Bi OBr-2 photocatalyst exhibited excellent and stable photocatalytic activities on MO and phenol degradation under simulated sunlight irradiation. The enhanced photocatalytic activity could be ascribed to the smaller size, rough surface, and the surface plasma resonance(SPR) effect of Ag. Also, the Schottky junction, between the surface of the Bi OBr and silver nanoparticles, accelerated the efficient transfer and separation of photoinduced electron-hole pairs and promoted the photocatalytic performance. The active species tests indicated that the superoxide radical(·O-2) was responsible for the enhanced photocatalytic performance of Ag/Bi OBr-2. Finally, a possible photocatalytic mechanism was proposed.
