Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (R...Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (Root-inducing) plasmid was transferred to the plant genome by A. rhizo-genes and has been maintained in all 291 hexaploid sweet potato cultivars of the world. The maintenance in the sweet potato genome and expression of two T-DNA genes for tryptophan-2-monooxygenease (iaaM) and for indole-3-acetamide hydrolase (iaaH) are likely to be physiologically significant since these enzymes convert tryptophan to indole-3-acetic acid, a major plant growth hormone auxin. Sweet potato (Ipomoea batatas (L.) Lam) is ranked the third most important root crop after potato and cassava, and the seventh in global food crop production with more than 126 million metric tons. Although sweet potato originated in Central or South America, China currently produces over 86% of world production with 109 million metric tons. In the United States, North Carolina is the leading producer with 38.5% of the 2007 sweet potato production, followed by California, Mississippi, and Louisiana with 23%, 19%, and 15.9%, respectively. Leaf curl virus diseases have been reported in sweet potato throughout the world. One of the causal agents is Sweet potato leaf curl virus (SPLCV) belonging to the genus Begomovirus (family Geminiviridae). Although SPLCV does not cause symptoms on Beauregard, one of the most predominant sweet potato cultivars in the US, it can reduce the yield up to 26%. Serological detection of SPLCV is not currently available due to the difficulties in obtaining purified virions that can be used as antigen for antiserum production. In attempts to obtain the coat protein (CP) of SPLCV for antibody production, primers were designed to amplify the CP gene. This gene was cloned into the expression vector pMAL-c2E as a fusion protein with maltose-binding protein, and transformed into Escherichia coli strain XL1-Blue. After gene induction, a fusion protein of 72 kDa was purified by amylose affinity chromatography. The yield of the purified fusion protein was approximately 200 μg/liter of bacterial culture. Digestion with enterokinase cleaved the fusion protein into a 42.5 kDa maltosebinding protein and a 29.4 kDa protein. The latter protein was identified by mass spectrometry analysis as the coat protein of SPLCV based on the fact that the mass spectrometry elucidated the sequences corresponding to 37% of amino acid positions of the SPLCV coat protein.展开更多
A new method was developed based on the electron beam vacuum dispersion（EBVD） technology to prepare the PTFE polymer coating of the new polymer quartz piezoelectric crystal sensor for testing liquor products. The ne...A new method was developed based on the electron beam vacuum dispersion（EBVD） technology to prepare the PTFE polymer coating of the new polymer quartz piezoelectric crystal sensor for testing liquor products. The new method was applied in the new EBVD equipment which we designed. A real-time system monitoring the polymer coating＇s thickness was designed for the new EBVD equipment according to the quartz crystal microbalance（QCM） principle, playing an important role in preparing stable and uniform PTFE polymer coatings of the same thickness. 30 pieces of PTFE polymer coatings on the surface of the quartz crystal basis were prepared with the PTFE polymer ultrafine powder（purity ≥ 99.99%）as the starting material. We obtained 30 pieces of new PTFE polymer sensors. By using scanning electron microscopy（SEM）, the structure of the PTFE polymer coating＇s column clusters was studied. One sample from the 30 pieces of new PTFE polymer sensors was analysed by SEM in four scales, i.e., 400×, 1000×, 10000×, and 25000×. It was shown that under the condition of high bias voltage and low bias current, uniformly PTFE polymer coating could be achieved, which indicates that the new EBVD equipment is suitable for mass production of stable and uniform polymer coating.展开更多
酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液...酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF/MS)技术,从种皮、种仁中共鉴定出57个化学成分。结合主成分分析(PCA)和正交偏最小二乘法判别分析(OPLS-DA)对两者进行差异成分研究,以变量投影重要度(VIP)值>5为标准,筛选了差异成分17个,其中白桦脂酸、桦木酮酸、麦珠子酸和酸枣仁皂苷Ⅰ主要存在于种皮部位,斯皮诺素、酸枣仁皂苷A和6-阿魏酰斯皮诺素等13个化合物主要存在于种仁部位。通过超高效液相色谱-电雾式检测器(UPLC-CAD)结合反梯度补偿技术,建立半定量液相色谱指纹图谱,考察了6个不同结构类型的代表成分的响应一致性,其不同浓度下平均响应因子间的RSD值为7.04%,各化合物响应一致性良好,可用于酸枣仁的半定量表征分析;结果表明:种皮部位主要成分为白桦脂酸和油酸,其中白桦脂酸的含量约是种仁的7倍;种仁部位主要成分为斯皮诺素、酸枣仁皂苷A、亚油酸、白桦脂酸和油酸,其中斯皮诺素、酸枣仁皂苷A的含量分别是种皮的18倍和24倍。综上,本研究阐明了酸枣仁种皮、种仁的化学成分差异,明确了酸枣仁两个部位中各自的主要成分及其相对含量,为酸枣仁不同部位合理开发和利用奠定了基础。展开更多
Sofosbuvir is one of the new direct-acting antiviral drugs against hepatitis C virus(HCV) infection. This drug has recently been launched into the market, and generic versions of the medication are expected to be prod...Sofosbuvir is one of the new direct-acting antiviral drugs against hepatitis C virus(HCV) infection. This drug has recently been launched into the market, and generic versions of the medication are expected to be produced by local drug producers in some countries. Therefore, new methods are required to control sofosbuvir in pharmaceuticals. In the present study, a new method based on reversed phase(RP)-ultra-high performance liquid chromatography(UHPLC) coupled to diode array detection(DAD) and mass spectrometry(MS) was developed to facilitate the qualitative and quantitative analysis of sofosbuvir in film coated tablets. A wavelength of 260 nm was selected to perform a cost-effective quantification and the method showed adequate linearity,with an R^2 value of 0.9998, and acceptable values of accuracy(75%–102%) and precision(residual standard deviation < 5%). The detection and quantification limits were 0.07 μg/mL and 0.36 μg/mL, respectively.Furthermore, the use of high-resolution MS enabled us to ensure the specificity, check impurities and better sensitivity. Therefore, this methodology promises to be suitable not only for the routine analysis of sofosbuvir in pharmaceutical dosage forms, but also for potential degradants.展开更多
文摘Sweet potato is one of the first natural GMOs, genetically modified 8000 years ago by Agrobacterium rhizogenes as reported recently by Kyndt et al. A section of 10 kbp long DNA (Transferred- DNA or T-DNA) of the Ri (Root-inducing) plasmid was transferred to the plant genome by A. rhizo-genes and has been maintained in all 291 hexaploid sweet potato cultivars of the world. The maintenance in the sweet potato genome and expression of two T-DNA genes for tryptophan-2-monooxygenease (iaaM) and for indole-3-acetamide hydrolase (iaaH) are likely to be physiologically significant since these enzymes convert tryptophan to indole-3-acetic acid, a major plant growth hormone auxin. Sweet potato (Ipomoea batatas (L.) Lam) is ranked the third most important root crop after potato and cassava, and the seventh in global food crop production with more than 126 million metric tons. Although sweet potato originated in Central or South America, China currently produces over 86% of world production with 109 million metric tons. In the United States, North Carolina is the leading producer with 38.5% of the 2007 sweet potato production, followed by California, Mississippi, and Louisiana with 23%, 19%, and 15.9%, respectively. Leaf curl virus diseases have been reported in sweet potato throughout the world. One of the causal agents is Sweet potato leaf curl virus (SPLCV) belonging to the genus Begomovirus (family Geminiviridae). Although SPLCV does not cause symptoms on Beauregard, one of the most predominant sweet potato cultivars in the US, it can reduce the yield up to 26%. Serological detection of SPLCV is not currently available due to the difficulties in obtaining purified virions that can be used as antigen for antiserum production. In attempts to obtain the coat protein (CP) of SPLCV for antibody production, primers were designed to amplify the CP gene. This gene was cloned into the expression vector pMAL-c2E as a fusion protein with maltose-binding protein, and transformed into Escherichia coli strain XL1-Blue. After gene induction, a fusion protein of 72 kDa was purified by amylose affinity chromatography. The yield of the purified fusion protein was approximately 200 μg/liter of bacterial culture. Digestion with enterokinase cleaved the fusion protein into a 42.5 kDa maltosebinding protein and a 29.4 kDa protein. The latter protein was identified by mass spectrometry analysis as the coat protein of SPLCV based on the fact that the mass spectrometry elucidated the sequences corresponding to 37% of amino acid positions of the SPLCV coat protein.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2013AA030901)
文摘A new method was developed based on the electron beam vacuum dispersion（EBVD） technology to prepare the PTFE polymer coating of the new polymer quartz piezoelectric crystal sensor for testing liquor products. The new method was applied in the new EBVD equipment which we designed. A real-time system monitoring the polymer coating＇s thickness was designed for the new EBVD equipment according to the quartz crystal microbalance（QCM） principle, playing an important role in preparing stable and uniform PTFE polymer coatings of the same thickness. 30 pieces of PTFE polymer coatings on the surface of the quartz crystal basis were prepared with the PTFE polymer ultrafine powder（purity ≥ 99.99%）as the starting material. We obtained 30 pieces of new PTFE polymer sensors. By using scanning electron microscopy（SEM）, the structure of the PTFE polymer coating＇s column clusters was studied. One sample from the 30 pieces of new PTFE polymer sensors was analysed by SEM in four scales, i.e., 400×, 1000×, 10000×, and 25000×. It was shown that under the condition of high bias voltage and low bias current, uniformly PTFE polymer coating could be achieved, which indicates that the new EBVD equipment is suitable for mass production of stable and uniform polymer coating.
文摘酸枣仁为鼠李科植物酸枣Ziziphus jujuba Mill.var.spinosa(Bunge)Hu ex H.F.Chou的干燥成熟种子,其分为种皮、种仁两个部位,比较研究酸枣仁不同部位化学成分组成及相对含量可为合理开发利用中药酸枣仁资源提供理论依据。基于超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF/MS)技术,从种皮、种仁中共鉴定出57个化学成分。结合主成分分析(PCA)和正交偏最小二乘法判别分析(OPLS-DA)对两者进行差异成分研究,以变量投影重要度(VIP)值>5为标准,筛选了差异成分17个,其中白桦脂酸、桦木酮酸、麦珠子酸和酸枣仁皂苷Ⅰ主要存在于种皮部位,斯皮诺素、酸枣仁皂苷A和6-阿魏酰斯皮诺素等13个化合物主要存在于种仁部位。通过超高效液相色谱-电雾式检测器(UPLC-CAD)结合反梯度补偿技术,建立半定量液相色谱指纹图谱,考察了6个不同结构类型的代表成分的响应一致性,其不同浓度下平均响应因子间的RSD值为7.04%,各化合物响应一致性良好,可用于酸枣仁的半定量表征分析;结果表明:种皮部位主要成分为白桦脂酸和油酸,其中白桦脂酸的含量约是种仁的7倍;种仁部位主要成分为斯皮诺素、酸枣仁皂苷A、亚油酸、白桦脂酸和油酸,其中斯皮诺素、酸枣仁皂苷A的含量分别是种皮的18倍和24倍。综上,本研究阐明了酸枣仁种皮、种仁的化学成分差异,明确了酸枣仁两个部位中各自的主要成分及其相对含量,为酸枣仁不同部位合理开发和利用奠定了基础。
基金the postdoctoral grant associated to the Excellence Project P11-CTS-7625, which was also financed by the previous entity
文摘Sofosbuvir is one of the new direct-acting antiviral drugs against hepatitis C virus(HCV) infection. This drug has recently been launched into the market, and generic versions of the medication are expected to be produced by local drug producers in some countries. Therefore, new methods are required to control sofosbuvir in pharmaceuticals. In the present study, a new method based on reversed phase(RP)-ultra-high performance liquid chromatography(UHPLC) coupled to diode array detection(DAD) and mass spectrometry(MS) was developed to facilitate the qualitative and quantitative analysis of sofosbuvir in film coated tablets. A wavelength of 260 nm was selected to perform a cost-effective quantification and the method showed adequate linearity,with an R^2 value of 0.9998, and acceptable values of accuracy(75%–102%) and precision(residual standard deviation < 5%). The detection and quantification limits were 0.07 μg/mL and 0.36 μg/mL, respectively.Furthermore, the use of high-resolution MS enabled us to ensure the specificity, check impurities and better sensitivity. Therefore, this methodology promises to be suitable not only for the routine analysis of sofosbuvir in pharmaceutical dosage forms, but also for potential degradants.
