目的采用高效液相色谱-四极杆飞行时间串联质谱法(high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry,HPLC-Q-TOF-MS/MS)结合主成分分析(principal component analysis,PCA)揭示不同糖苷键...目的采用高效液相色谱-四极杆飞行时间串联质谱法(high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry,HPLC-Q-TOF-MS/MS)结合主成分分析(principal component analysis,PCA)揭示不同糖苷键二糖的质谱裂解特征,以用于实际样品中二糖糖苷键的鉴定。方法采用HPLC-Q-TOF-MS/MS对含有不同糖苷键的二糖标准品进行检测,采集二糖标准品的MS/MS谱图中离子峰数据,采用PCA建立二糖糖苷键的预测模型,并将该模型用于实际低聚半乳糖样品中二糖糖苷键的鉴定分析。结果PCA结果显示第二主成分(PC2)可区分α和β构型二糖,α构型二糖相比β构型二糖具有较高的[C_(12)H_(22)O_(11)+Na-C_(6)H_(10)O_(5)]^(+)(m/z 203),以糖苷键裂解为主;第一主成分(PC1)可区分α构型二糖中的1→6、1→2糖苷键和1→3、1→4糖苷键,以及β构型二糖中的1→2糖苷键和1→3、1→4、1→6糖苷键,β(1→2)、α(1→2)、α(1→6)二糖较其他糖苷键二糖在MS/MS谱图上的m/z<185范围内含有较高的碎片离子峰。基于PCA模型可鉴定两种低聚半乳糖样品中的二糖含β(1→3)、β(1→4)、β(1→6)和α(1→3)或α(1→4)键。结论HPLC-Q-TOF-MS/MS与PCA相结合为实际样品的二糖糖苷键鉴定分析提供了一种简便快速的方法,可为含低聚糖产品的质量控制和开发提供思路和方法。展开更多
为了获得产新型纤维二糖磷酸化酶(CBP)的菌株,利用选择性培养基从牛瘤胃液中逐步分离纯化,筛选能以纤维二糖为唯一碳源生长的菌株,分别检测所筛选菌株的β-葡萄糖苷酶(βG)和CBP活力,并对其纤维二糖的利用方式(水解途径或磷解途径)进行...为了获得产新型纤维二糖磷酸化酶(CBP)的菌株,利用选择性培养基从牛瘤胃液中逐步分离纯化,筛选能以纤维二糖为唯一碳源生长的菌株,分别检测所筛选菌株的β-葡萄糖苷酶(βG)和CBP活力,并对其纤维二糖的利用方式(水解途径或磷解途径)进行鉴定,获得产CBP的菌株,命名为BY-a。采用形态学观察、生理生化试验,结合16S r DNA序列分析,鉴定菌株BY-a为克雷伯氏菌属(Klebsiella)。对菌种产CBP的温度、时间、最适装液量和溶氧量进行初步优化,结果显示,BY-a菌株在装液量为30mL(250mL)、37℃振荡培养24 h时,产CBP活力最高。展开更多
The production of chemicals or fuels from renewable biomass resources especially cellulose has attracted much attention because of the worldwide demand for less dependence on fossil resources.However,the direct utiliz...The production of chemicals or fuels from renewable biomass resources especially cellulose has attracted much attention because of the worldwide demand for less dependence on fossil resources.However,the direct utilization of cellulose is still a challenge because of its robust crystalline structure.Herein,the hydrogenation of cellobiose,a typical cellulose,over carbon nanotube supported ruthenium catalyst (Ru/CNT) was reported.The mechanism of cellobiose conversion was proposed and the kinetic equation was obtained.Based on the kinetic experiments carried out in the range 120—185℃ under 5.0 MPa H2,the reaction rate constants and activation energies of each reaction step in cellobiose hydrogenation were obtained with MATLAB,in which the activation energy for hydrolysis and hydrogenolysis of cellobiose was estimated as 147.1 kJ·mol-1 and 71.2 kJ·mol-1,respectively.The obtained kinetic model and some general rules on the catalytic hydrogenation of cellobiose may provide important data for efficient utilization of cellulose.展开更多
Experiments to investigate the effects of daidzein on membrane digestion of disaccharide in suckling and weanling piglet were carried in vitro. 12 piglets were randomly assigned two groups, either supplemented with 20...Experiments to investigate the effects of daidzein on membrane digestion of disaccharide in suckling and weanling piglet were carried in vitro. 12 piglets were randomly assigned two groups, either supplemented with 20mg/kg·BW daidzein or skim milk powder once per two days after birth one week. 14 and 35 days old piglets were killed, jejunum and colon were collected for further study.The result showed that supplemented with daidzein can improve the activities of maltase and lactase in jejunum mucosa and colon mucosa in the lactational period of piglet, the activities of maltase and lactase in jejunum mucosa increased by 63.30%(P<0.01)and 49.98%(P<0.01), and those in the colon increased by 56.78%(P<0.01)and 24.05%(P<0.01)respectively. However, in weanling piglets the activity of lactase was decreased by 41.40%(P<0.05),whereas the activity of maltase increased by 22.31%(P<0.01) in jejunum, the activity of maltase increased by 21.14%(P<0.05)in colon. This result indicates that feeding daidzein can improve the using of disaccharide in piglets.展开更多
文摘目的采用高效液相色谱-四极杆飞行时间串联质谱法(high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry,HPLC-Q-TOF-MS/MS)结合主成分分析(principal component analysis,PCA)揭示不同糖苷键二糖的质谱裂解特征,以用于实际样品中二糖糖苷键的鉴定。方法采用HPLC-Q-TOF-MS/MS对含有不同糖苷键的二糖标准品进行检测,采集二糖标准品的MS/MS谱图中离子峰数据,采用PCA建立二糖糖苷键的预测模型,并将该模型用于实际低聚半乳糖样品中二糖糖苷键的鉴定分析。结果PCA结果显示第二主成分(PC2)可区分α和β构型二糖,α构型二糖相比β构型二糖具有较高的[C_(12)H_(22)O_(11)+Na-C_(6)H_(10)O_(5)]^(+)(m/z 203),以糖苷键裂解为主;第一主成分(PC1)可区分α构型二糖中的1→6、1→2糖苷键和1→3、1→4糖苷键,以及β构型二糖中的1→2糖苷键和1→3、1→4、1→6糖苷键,β(1→2)、α(1→2)、α(1→6)二糖较其他糖苷键二糖在MS/MS谱图上的m/z<185范围内含有较高的碎片离子峰。基于PCA模型可鉴定两种低聚半乳糖样品中的二糖含β(1→3)、β(1→4)、β(1→6)和α(1→3)或α(1→4)键。结论HPLC-Q-TOF-MS/MS与PCA相结合为实际样品的二糖糖苷键鉴定分析提供了一种简便快速的方法,可为含低聚糖产品的质量控制和开发提供思路和方法。
文摘为了获得产新型纤维二糖磷酸化酶(CBP)的菌株,利用选择性培养基从牛瘤胃液中逐步分离纯化,筛选能以纤维二糖为唯一碳源生长的菌株,分别检测所筛选菌株的β-葡萄糖苷酶(βG)和CBP活力,并对其纤维二糖的利用方式(水解途径或磷解途径)进行鉴定,获得产CBP的菌株,命名为BY-a。采用形态学观察、生理生化试验,结合16S r DNA序列分析,鉴定菌株BY-a为克雷伯氏菌属(Klebsiella)。对菌种产CBP的温度、时间、最适装液量和溶氧量进行初步优化,结果显示,BY-a菌株在装液量为30mL(250mL)、37℃振荡培养24 h时,产CBP活力最高。
文摘The production of chemicals or fuels from renewable biomass resources especially cellulose has attracted much attention because of the worldwide demand for less dependence on fossil resources.However,the direct utilization of cellulose is still a challenge because of its robust crystalline structure.Herein,the hydrogenation of cellobiose,a typical cellulose,over carbon nanotube supported ruthenium catalyst (Ru/CNT) was reported.The mechanism of cellobiose conversion was proposed and the kinetic equation was obtained.Based on the kinetic experiments carried out in the range 120—185℃ under 5.0 MPa H2,the reaction rate constants and activation energies of each reaction step in cellobiose hydrogenation were obtained with MATLAB,in which the activation energy for hydrolysis and hydrogenolysis of cellobiose was estimated as 147.1 kJ·mol-1 and 71.2 kJ·mol-1,respectively.The obtained kinetic model and some general rules on the catalytic hydrogenation of cellobiose may provide important data for efficient utilization of cellulose.
文摘Experiments to investigate the effects of daidzein on membrane digestion of disaccharide in suckling and weanling piglet were carried in vitro. 12 piglets were randomly assigned two groups, either supplemented with 20mg/kg·BW daidzein or skim milk powder once per two days after birth one week. 14 and 35 days old piglets were killed, jejunum and colon were collected for further study.The result showed that supplemented with daidzein can improve the activities of maltase and lactase in jejunum mucosa and colon mucosa in the lactational period of piglet, the activities of maltase and lactase in jejunum mucosa increased by 63.30%(P<0.01)and 49.98%(P<0.01), and those in the colon increased by 56.78%(P<0.01)and 24.05%(P<0.01)respectively. However, in weanling piglets the activity of lactase was decreased by 41.40%(P<0.05),whereas the activity of maltase increased by 22.31%(P<0.01) in jejunum, the activity of maltase increased by 21.14%(P<0.05)in colon. This result indicates that feeding daidzein can improve the using of disaccharide in piglets.
