The sense and antisense fragments of the soluble starch synthase （SSII1） gene and the intron fragment of somatic embryogenesis receptor-like kinase （SERK1） gene were cloned from potato using PCR techniques. The RN...The sense and antisense fragments of the soluble starch synthase （SSII1） gene and the intron fragment of somatic embryogenesis receptor-like kinase （SERK1） gene were cloned from potato using PCR techniques. The RNAi plant expression vectors pBI-SSIII-RNAi and pBIC-SSIII-RNAi were constructed which containing fusion fragment of ＂sense fragment-intron-antisense fragment＂ driven by the constitutive expression promoter CaMV 35S and the tuber-specific expression promoter CIPP, respectively. The putative transgenic plants of potato cultivars Kexin-1 and Kexin-4 were obtained using Agrobacterium-mediated transformation method. PCR assay showed that the interference fragment of SSlll gene was integrated into potato genome. The RT-PCR analysis showed that the expression of SSlll gene was repressed apparently on the transcription level. Starch granules of the transgenic potato plants were different in morphology and became cracked in starch granule centre compared with the non-transgenic control plants. The amylose content of starch was increased by 2.68-29.05%, amylopectin to amylose ratio of starch had declined significantly, and the phosphorus content of the starch of the transgenic plants was reduced 9.94-58.36% compared with control plants. The results could provide certain foundation for improvement of potato starch quality.展开更多
The starches were isolated by alkaline extraction from white and red sorghum, predominant cultivars in the Sahara of Algeria. Morphological, thermal properties and amylose content of isolated starches were examined. T...The starches were isolated by alkaline extraction from white and red sorghum, predominant cultivars in the Sahara of Algeria. Morphological, thermal properties and amylose content of isolated starches were examined. The starches of two sorghum landraces of white and pigmented kernels growing in hyper arid environmental conditions showed significant differences in granule size, amylose content and thermal behavior which ultimately affect the physicochemical and functional properties. When observed using environmental scanning electron microscopy （ESEM）. The starch granules showed polyhedral shape. Some of them showed pinholes. The granular size ranged between 6.325-39.905 μm and 7.096-44.774 μm, respectively for white and red sorghum starches. The granule size distribution was unimodal. The amylose content in white sorghum starch （27.1%） was higher than that in red sorghum （24.8%）. Differential scanning calorimetry （DSC） analysis revealed that sorghum starches present higher temperatures at the peak （70.60℃ and 72.28℃ for white and red sorghum starches, respectively） and lower gelatinization enthalpies （9.087 J/g and 8.270 J/g for white and red sorghum starches, respectively） than other cereal starches. The determination of these properties is relevant to the comprehension of starch and starch-based foods digestibility in order to direct them towards the specific applications in food and nonfood sectors.展开更多
The development of noble-metal-free electrocatalysts for water splitting is indispensable for the efficient production of hydrogen fuel.Herein,a Co-doped Ni-Mo phosphide nanorod arrays fabricated on porous Ni foam was...The development of noble-metal-free electrocatalysts for water splitting is indispensable for the efficient production of hydrogen fuel.Herein,a Co-doped Ni-Mo phosphide nanorod arrays fabricated on porous Ni foam was shown to be an efficient binder-free electrocatalyst for water splitting.This catalyst featured exceptional activity,exhibiting an overpotential of 29 mV at a current density of 10 mA·cm−2 for the hydrogen evolution reaction,whereas the corresponding precatalyst exhibited an overpotential of 314 mV at a current density of 50 mA·cm^−2 for the oxygen evolution reaction.The achieved electrocatalytic performance provided access to a simple water splitting system,affording a current density of 10 mA·cm^−2 at 1.47 V in 1 M KOH electrolyte.Density functional theory results indicated that Co doping and phosphorization were responsible for the high electrocatalytic performance.Thus,this work paves the way for the development of novel noble-metal-free electrocatalysts for practical H2 production via water splitting.展开更多
基金supported by the National High-Technology R&D Program of China(2006AA100107)the National Natural Science Foundation of China(30871573, 31160298)
文摘The sense and antisense fragments of the soluble starch synthase （SSII1） gene and the intron fragment of somatic embryogenesis receptor-like kinase （SERK1） gene were cloned from potato using PCR techniques. The RNAi plant expression vectors pBI-SSIII-RNAi and pBIC-SSIII-RNAi were constructed which containing fusion fragment of ＂sense fragment-intron-antisense fragment＂ driven by the constitutive expression promoter CaMV 35S and the tuber-specific expression promoter CIPP, respectively. The putative transgenic plants of potato cultivars Kexin-1 and Kexin-4 were obtained using Agrobacterium-mediated transformation method. PCR assay showed that the interference fragment of SSlll gene was integrated into potato genome. The RT-PCR analysis showed that the expression of SSlll gene was repressed apparently on the transcription level. Starch granules of the transgenic potato plants were different in morphology and became cracked in starch granule centre compared with the non-transgenic control plants. The amylose content of starch was increased by 2.68-29.05%, amylopectin to amylose ratio of starch had declined significantly, and the phosphorus content of the starch of the transgenic plants was reduced 9.94-58.36% compared with control plants. The results could provide certain foundation for improvement of potato starch quality.
文摘The starches were isolated by alkaline extraction from white and red sorghum, predominant cultivars in the Sahara of Algeria. Morphological, thermal properties and amylose content of isolated starches were examined. The starches of two sorghum landraces of white and pigmented kernels growing in hyper arid environmental conditions showed significant differences in granule size, amylose content and thermal behavior which ultimately affect the physicochemical and functional properties. When observed using environmental scanning electron microscopy （ESEM）. The starch granules showed polyhedral shape. Some of them showed pinholes. The granular size ranged between 6.325-39.905 μm and 7.096-44.774 μm, respectively for white and red sorghum starches. The granule size distribution was unimodal. The amylose content in white sorghum starch （27.1%） was higher than that in red sorghum （24.8%）. Differential scanning calorimetry （DSC） analysis revealed that sorghum starches present higher temperatures at the peak （70.60℃ and 72.28℃ for white and red sorghum starches, respectively） and lower gelatinization enthalpies （9.087 J/g and 8.270 J/g for white and red sorghum starches, respectively） than other cereal starches. The determination of these properties is relevant to the comprehension of starch and starch-based foods digestibility in order to direct them towards the specific applications in food and nonfood sectors.
基金This work was supported by the National Natural Science Foundation of China(No.51827901).
文摘The development of noble-metal-free electrocatalysts for water splitting is indispensable for the efficient production of hydrogen fuel.Herein,a Co-doped Ni-Mo phosphide nanorod arrays fabricated on porous Ni foam was shown to be an efficient binder-free electrocatalyst for water splitting.This catalyst featured exceptional activity,exhibiting an overpotential of 29 mV at a current density of 10 mA·cm−2 for the hydrogen evolution reaction,whereas the corresponding precatalyst exhibited an overpotential of 314 mV at a current density of 50 mA·cm^−2 for the oxygen evolution reaction.The achieved electrocatalytic performance provided access to a simple water splitting system,affording a current density of 10 mA·cm^−2 at 1.47 V in 1 M KOH electrolyte.Density functional theory results indicated that Co doping and phosphorization were responsible for the high electrocatalytic performance.Thus,this work paves the way for the development of novel noble-metal-free electrocatalysts for practical H2 production via water splitting.
