Synthetic biology promises to simplify the construction of metabolic pathways by assembling the de- tached modules of the whole pathway. This gives new approaches for the microbial production of industrial products su...Synthetic biology promises to simplify the construction of metabolic pathways by assembling the de- tached modules of the whole pathway. This gives new approaches for the microbial production of industrial products such as polyhydroxyalkanoates （PHA）. In this study, to produce poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） （PHBHHx） by Pseudomonas stutzeri 1317 from unrelated carbon sources such as glucose, the phaCl-phaZ-phaC2 operon of P. stutzeri 1317 was knocked out to generate the PHA deficient mutant P. stutzeri 1317LF. Then three modules containing phaCahAReBRe, phaCahBReGep and phaCAhPah were introduced into P. stutzeri 1317LF separately The shake flask results indicated that the precursor supply and PHA synthase activity were the vital factors for the PHBHHx accumulation of P. stutzeri 1317LF. Furthermore, the PHBHHx accumulation of the recombinants from different carbon resources were performed. The highest PHBHHx content was 23.7% （by mass） with 58.6% （by mole） 3HB fraction. These results provide basis for further improving the PHBHHx accumulation of P. stutzeri from unrelated carbon sources.展开更多
It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA （monomer cholesteryl acrylate） and monomer （S...It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA （monomer cholesteryl acrylate） and monomer （S）-（＋）-4-（2-Methyl butanoat-l-butyloxy） phenyl 4-[1-（propenoyloxy） butyloxy] benzoate （MB）. Two monomers were characterized by DSC （differential scanning calorimetry）, POM （polarization optical microscopy） and XRD （X-ray diffraction）. Mesophase temperatures of MA and MB are 81.28 ~C and 54.36~C, respectively. Textures analysis by POM shows that MA was oily streak and MB was schlieren. XRD pattern shows the strongest three peaks of MA at room temperature which are （20, deg）： 2.7153, 5.2992 and 18.8500. The Strongest three peaks of MB at room temperature are （20, deg）： 9.1726, 9.7707 and 12.5389. XRD pattern of MA and MB at mesophase and above mesophase temperature that each peaks disappear.展开更多
Acid functionalized single walled carbon nanotubes （CNTs） were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in ...Acid functionalized single walled carbon nanotubes （CNTs） were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate （TMSPM）, hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy （FTIR）, carbon-13 nuclear magnetic resonance （13C NMR）, Yhermogravimetric Analysis （TGA）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The composite showed improved thermal stability and could be of great potential use in bone tissue engineering.展开更多
In this work, we report the hybrid copolymerization of various cyclic monomers and vinyl monomers. Our studies demonstrate that 1-tert-butyl-4,4,4-tris-（dimethylamino）-2,2-bis[tris（dimethylamino） phophoranyliden-a...In this work, we report the hybrid copolymerization of various cyclic monomers and vinyl monomers. Our studies demonstrate that 1-tert-butyl-4,4,4-tris-（dimethylamino）-2,2-bis[tris（dimethylamino） phophoranyliden-amino]-2A5,A5-catenadi（phosphazene） （t-BuP4） can catalyze the hybrid copolymerization of caprolactone （CL）, lactide （LA） or cyclic carbonate ester with acrylate or methyl acrylate. However, the polymerization of cyclosiloxane with vinyl monomers yields two corresponding homopolymers, and the polymerization of lactone with acrylonitrile （AN） produces only polyacrylonitrile. Clearly, the extent of matching of activity between a monomer and an active center determines whether or not there is hybrid copolymerization.展开更多
基金Supported by the National lqatural Science Foundation of China （31260015）, Natural Science Foundation of Qinghai Province （2012-Z-919Q）, the Extramural Project from State Key Laboratory for Agrobiotechnology （2012SKLAB06-5） and the Research Funds for Young Project of Qinghal University （2011-QYY-1）.
文摘Synthetic biology promises to simplify the construction of metabolic pathways by assembling the de- tached modules of the whole pathway. This gives new approaches for the microbial production of industrial products such as polyhydroxyalkanoates （PHA）. In this study, to produce poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） （PHBHHx） by Pseudomonas stutzeri 1317 from unrelated carbon sources such as glucose, the phaCl-phaZ-phaC2 operon of P. stutzeri 1317 was knocked out to generate the PHA deficient mutant P. stutzeri 1317LF. Then three modules containing phaCahAReBRe, phaCahBReGep and phaCAhPah were introduced into P. stutzeri 1317LF separately The shake flask results indicated that the precursor supply and PHA synthase activity were the vital factors for the PHBHHx accumulation of P. stutzeri 1317LF. Furthermore, the PHBHHx accumulation of the recombinants from different carbon resources were performed. The highest PHBHHx content was 23.7% （by mass） with 58.6% （by mole） 3HB fraction. These results provide basis for further improving the PHBHHx accumulation of P. stutzeri from unrelated carbon sources.
文摘It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA （monomer cholesteryl acrylate） and monomer （S）-（＋）-4-（2-Methyl butanoat-l-butyloxy） phenyl 4-[1-（propenoyloxy） butyloxy] benzoate （MB）. Two monomers were characterized by DSC （differential scanning calorimetry）, POM （polarization optical microscopy） and XRD （X-ray diffraction）. Mesophase temperatures of MA and MB are 81.28 ~C and 54.36~C, respectively. Textures analysis by POM shows that MA was oily streak and MB was schlieren. XRD pattern shows the strongest three peaks of MA at room temperature which are （20, deg）： 2.7153, 5.2992 and 18.8500. The Strongest three peaks of MB at room temperature are （20, deg）： 9.1726, 9.7707 and 12.5389. XRD pattern of MA and MB at mesophase and above mesophase temperature that each peaks disappear.
文摘Acid functionalized single walled carbon nanotubes （CNTs） were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate （TMSPM）, hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy （FTIR）, carbon-13 nuclear magnetic resonance （13C NMR）, Yhermogravimetric Analysis （TGA）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The composite showed improved thermal stability and could be of great potential use in bone tissue engineering.
基金support of the National Basic Research Program of China (2012CB933802) is acknowledged
文摘In this work, we report the hybrid copolymerization of various cyclic monomers and vinyl monomers. Our studies demonstrate that 1-tert-butyl-4,4,4-tris-（dimethylamino）-2,2-bis[tris（dimethylamino） phophoranyliden-amino]-2A5,A5-catenadi（phosphazene） （t-BuP4） can catalyze the hybrid copolymerization of caprolactone （CL）, lactide （LA） or cyclic carbonate ester with acrylate or methyl acrylate. However, the polymerization of cyclosiloxane with vinyl monomers yields two corresponding homopolymers, and the polymerization of lactone with acrylonitrile （AN） produces only polyacrylonitrile. Clearly, the extent of matching of activity between a monomer and an active center determines whether or not there is hybrid copolymerization.
