L-羟脯氨酸寡肽混合物的高效液相色谱分离与质谱分析

研究了三氯氧磷辅助下L-羟脯氨酸的成肽反应,建立了采用反相高效液相色谱-质谱/质谱联用技术分离鉴定羟脯氨酸寡肽混合物的方法,优化了L-羟脯氨酸寡肽混合物的色谱分离条件。实验以YWG C8柱(10μm,250mm×10mm)为分离柱,以乙腈-0.06%三氟乙酸水溶液(体积比为2∶98)为流动相进行等度洗脱,在正离子模式下对洗脱物进行了电喷雾电离串联质谱鉴定。结果显示,分离出的各组分分别为L-羟脯氨酸二肽、L-羟脯氨酸环二肽和L-羟脯氨酸三肽

Three-dimensional particle image velocimetry measurement through three-dimensional U-Net neural network

This paper proposes a light field (LF) three-dimensional (3D) particle image velocimetry (PIV) method based on a digital refocused algorithm and 3D U-Net neural network for 3D three-component (3D-3C) velocity measurement. A digital refocused algorithm is used to generate a stack of LF-refocused images of tracer particles for establishing the 3D U-Net. The 3D U-Net is then used for the 3D particle field reconstruction. Based on a pair of 3D particle fields, the 3D-3C velocity field is obtained through a 3D cross correlation algorithm. Numerical simulations and experiments are conducted to analyze the accuracy and efficiency of the proposed method. The simulation results show that the elongation along the depth direction and the efficiency of the 3D particle field reconstruction are improved by the 3D U-Net. The 3D U-Net also provides a better correlation coefficient. The experimental results show that the reconstruction time of the proposed method is ∼220 s which is 10 times faster than the LF tomographic PIV. This further demonstrates that the proposed method improves the reconstruction efficiency without affecting the accuracy of velocity measurement

高粱子粒淀粉表面色素的树脂分离研究

对纯化高粱淀粉过程中所得到的淀粉共生天然色素进行了树脂分离纯化研究。得到了树脂分离高粱淀粉共生色素的吸附动力学结果,3 种大孔吸附树脂 HPD-600、AB-8、H103 对高粱红的吸附为慢速平衡型。通过对树脂分离所得色素成份的红外光谱、紫外光谱、质谱分析得出,高粱籽粒淀粉共生色素与高粱壳中的高粱红主要成份是同样的物质,鉴定出所分离的主要成份之一为 5,7,4′-三羟基黄酮

四川永兴汉墓出土染色绢分析

通过对四川绵阳市东郊永兴汉墓出土染色绢的现代检测分析,对其纤维属性、织物组织、染料品种进行了判定,指出其在研究四川蚕桑丝绸史及中国古代染色史上具有重要意义

Construction of Plant Expression Vector of the proBA Gene from Bacillus subtilis Mutant and Analysis of the Salt Tolerance of Transgenic Arabidopsis thaliana

从枯草芽孢杆菌(Bacillussubtilis)抗脯氨酸结构类似物突变株中克隆得到脯氨酸合成途径中的关键酶基因proB(编码γ-谷氨酰胺激酶)和proA(编码谷氨酰胺-γ-半醛脱氢酶),同时设计引物从拟南芥基因组中扩增得到吡咯啉-5-羧酸合成酶B基因(p5csB)的第一个内含子序列,将其分别与proB和proA基因通过PCR拼接后,酶切连接构建得到植物双元表达载体pBI121pro。以LBA4404为介导,采用真空抽滤的方法转化得到转proBA基因拟南芥;第三代的纯合子(T3)通过半巢式PCR的方法验证外源基因已整合到拟南芥基因组中,GUS活性分析表明外源基因在叶片中表达最强,茎部其次,根部最弱;对600mmol.L-1致死浓度NaCl耐受能力的分析表明,转基因拟南芥的平均存活时间(37.8min)明显高于野生型拟南芥(26min)。The genes proB and proA encoding the two enzymes, -GK (-glutamyl kinase) and -GSADH (Glu-5-semialdehyde dehydrogenase), were amplified from the Bacillus subtilis mutant to the proline analogue.The first intron of p5csB gene was also retrieved from Arabidopsis thaliana and linked with proB and proA respectively through PCR. After the endonuclease digestion and fragment ligation, the recombinant plant binary expression vector (pBI121pro) was obtained. The transformation of Arabidopsis thaliana was mediated by Agrobacterium tumfaciens LBA4404 by using the vacuum infiltration method. Half nested PCR was performed to verify the insertion of exotic genes into the genome of T3 homozygous plants. GUS activity assay indicated that the exotic genes were expressed most highly in the leaves, secondly in the stems and least in the roots. The analysis of tolerance to the deadly salt concentration (600 mmolL~(-1) NaCl) showed that the average survival time of transgenic plants (37.8 min) was obviously higher than that of wild type controls (26 min). In this research, the key gene proBA involved in the proline biosynthesis of highly salt-tolerant microorganism were cloned, and after removal of the feedback inhibition, it was, for the first time, transferred into the model plant Arabidopsis thaliana,which is of highly theoretical and practical significance.教育部十五“211”项目和武汉大学科技创新项目资助

超细SiO_2颗粒的制备及其对α-淀粉酶的吸附固定化

采用TritonX-100反胶团体系法和Stober法分别制备粒径为50nm及1 μm的SiO_2颗粒,用二氯二甲基硅烷(DDS)对其进行表面疏水性修饰,用于α-淀粉酶的固定化.结果表明,经DDS修饰的SiO_2颗粒对α-淀粉酶的吸附能力明显提高,且有效提高了吸附稳定性,经6次洗涤后酶活仅损失30%; 1 μm SiO_2颗粒比50 nm SiO_2颗粒对α-淀粉酶的吸附量大,SiO_2颗粒载体固定的α-淀粉酶的活性为50 nm SiO_2>1 μm SiO_2>50 nm修饰后SiO_2>1 μm修饰后SiO_2

超细SiO_2颗粒的制备及其对α-淀粉酶的吸附固定化

采用TritonX-100反胶团体系法和Stober法分别制备粒径为50nm及1 μm的SiO_2颗粒,用二氯二甲基硅烷(DDS)对其进行表面疏水性修饰,用于α-淀粉酶的固定化.结果表明,经DDS修饰的SiO_2颗粒对α-淀粉酶的吸附能力明显提高,且有效提高了吸附稳定性,经6次洗涤后酶活仅损失30%; 1 μm SiO_2颗粒比50 nm SiO_2颗粒对α-淀粉酶的吸附量大,SiO_2颗粒载体固定的α-淀粉酶的活性为50 nm SiO_2>1 μm SiO_2>50 nm修饰后SiO_2>1 μm修饰后SiO_2

超细SiO_2颗粒的制备及其对α-淀粉酶的吸附固定化

采用TritonX-100反胶团体系法和Stober法分别制备粒径为50nm及1 μm的SiO_2颗粒,用二氯二甲基硅烷(DDS)对其进行表面疏水性修饰,用于α-淀粉酶的固定化.结果表明,经DDS修饰的SiO_2颗粒对α-淀粉酶的吸附能力明显提高,且有效提高了吸附稳定性,经6次洗涤后酶活仅损失30%; 1 μm SiO_2颗粒比50 nm SiO_2颗粒对α-淀粉酶的吸附量大,SiO_2颗粒载体固定的α-淀粉酶的活性为50 nm SiO_2>1 μm SiO_2>50 nm修饰后SiO_2>1 μm修饰后SiO_2