搜索到1845篇“ THREONINE“的相关文章
Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine
2024年
The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.
Lamzira PharulavaLevani EliashviliVakhtang BetlemidzeBachana Sulava
关键词:ASPARAGINETHREONINEMETHIONINE
Increasing concentrations of dietary threonine,tryptophan,and glycine improve growth performance and intestinal health with decreasing stress responses in broiler chickens raised under multiple stress conditions
2024年
The current study aimed to compare the effects of increasing concentrations of dietary threonine(Thr),tryptophan(Trp),and glycine(Gly)on growth performance,stress biomarkers,and intestinal function in broiler chickens under multiple stress conditions.Five hundred sixty broiler chickens at 21 d old were randomly allotted to 5 treatments with 8 replicates.Birds in a positive control(PC)treatment were raised under low stock density(16.9 birds/m^(2) per cage)with recommended environmental conditions,whereas birds in 4 treatments were subjected to multiple stress conditions:a cyclic heat stress of 30±0.3℃ for 10 h and 23±0.2℃ for 14 h per day with high stock density(25.3 birds/m^(2) per cage).A basal diet was assigned to both PC and negative control(NC)treatments.Three additional diets were individually formulated to contain double concentrations of digestible Thr,Trp,or Gly+Ser compared with their concentrations in the basal diet.The experiment lasted for 14 d.Results showed that NC treatment had less growth performance(P<0.001),jejunal goblet cell counts(P=0.018),and trans-epithelial electrical resistance(TEER;P<0.001),but greater(P=0.026)feather corticosterone(CORT)concentrations than PC treatment.Thr treatment showed the least(P<0.001)feed conversion ratio(FCR)among treatments under multiple stress conditions.Thr,Trp,and Gly treatments had less(P=0.026)feather CORT concentrations,but had greater(P<0.001)TEER than NC treatment.In conclusion,increasing concentrations of dietary Thr,Trp,or Gly improve the growth performance and intestinal health in broiler chickens with decreasing stress response under multiple stress conditions.
Hyun Woo KimJong Hyuk KimGi Ppeum HanDong Yong Kil
关键词:GLYCINETHREONINETRYPTOPHAN
苏氨酸二次母液的脱色工艺优化
2024年
以苏氨酸二次母液为研究对象,采用氨基酸分析仪对母液中的氨基酸进行定量分析。结果表明,苏氨酸质量浓度为7.82 g/100 mL。以苏氨酸二次母液脱色率和苏氨酸损失率为评价指标,通过对比活性炭、大孔吸附树脂、阴、阳离子交换树脂共9种脱色剂对苏氨酸二次母液的脱色效果,确定最佳脱色剂种类,并通过设计单因素试验与响应面试验对苏氨酸二次母液的脱色工艺进行优化。结果表明,粉末活性炭对苏氨酸二次母液的脱色效果优于其他脱色剂,选用粉末活性炭作为苏氨酸二次母液的脱色剂;通过响应面优化,得到最佳脱色工艺条件为自然pH值、脱色温度35℃、脱色时间40 min、活性炭添加量25%,在此条件下,得到的苏氨酸二次母液脱色率为97.69%,苏氨酸损失率为5.02%。
胡鑫王维浩全志刚全志刚魏明智曹龙奎
关键词:活性炭树脂脱色
代谢工程改造大肠杆菌合成L-苏氨酸研究进展
2024年
L-苏氨酸是一种人体自身无法合成,必须从食物中摄取的8种必需氨基酸之一,是蛋白质合成的重要组成成分,广泛应用于食品、饲料、医药等多个领域。目前,利用大肠杆菌发酵可获得更理想的苏氨酸产量,是工业上用于苏氨酸生产的主要菌株。随着代谢工程技术的发展,对菌株的改造不再局限于传统诱变育种,菌株的定向改造极大地提高了菌株L-苏氨酸的合成能力,促进了L-苏氨酸工业的发展。本文主要从L-苏氨酸的理化性质、合成途径以及利用代谢工程技术在提高L-苏氨酸产量研究中取得的一系列成果进行综述,旨在为改造大肠杆菌高效合成苏氨酸的研究提供更全面的认识。
罗筱萍苏卜利邓名荣徐晓龙朱红惠
关键词:L-苏氨酸大肠杆菌代谢调控前体辅因子
补喂赖氨酸和苏氨酸对放牧条件下泌乳母马血液生化指标的影响
2024年
通过给放牧条件下泌乳母马补饲赖氨酸和苏氨酸,探究其对泌乳母马血液生化指标的影响,为氨基酸调控泌乳期母马的健康提供参考依据。选择产驹日期相近(5月份),年龄7~9岁,胎次4~5胎,平均体重(428.00±33.42)kg,泌乳30 d的伊犁马母马24匹,随机分为4个组,每组6匹,分别为对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组。在相同的放牧条件下(放牧时间、饮水时间、挤奶时间和放牧草场完全相同),对照组不进行任何氨基酸补喂,试验Ⅰ组每匹马补饲赖氨酸40 g/d+苏氨酸20 g/d,试验Ⅱ组每匹马补饲赖氨酸60 g/d+苏氨酸40 g/d,试验Ⅲ组每匹马补饲赖氨酸80 g/d+苏氨酸60 g/d。整个补饲期为120 d,定期采集母马血液,测定相关生化指标。结果:在蛋白质代谢方面,试验Ⅰ~Ⅲ组母马血液中总蛋白和白蛋白含量均显著低于对照组(P<0.05),尿酸含量分别比对照组提高16.33%、37.20%和17.58%;在糖脂代谢方面,试验Ⅰ~Ⅲ组的总胆红素均极显著高于对照组(P<0.01),葡萄糖和甘油三酯含量均低于对照组;在酶活力方面,试验Ⅰ~Ⅲ组的谷丙转氨酶和谷草转氨酶活力均极显著低于对照组(P<0.01),碱性磷酸酶和肌酸激酶的活力随着赖氨酸和苏氨酸剂量的增加而呈上升趋势;在矿物质方面,Ca^(2+)、无机磷和Mg^(2+)的含量各组之间均无显著差异(P>0.05),但试验Ⅱ组Fe^(2+)含量最高,与其他3组有显著或极显著差异。综上,在放牧条件下给泌乳母马补饲赖氨酸和苏氨酸可降低其血液中葡萄糖、甘油三酯含量以及谷草转氨酶和谷丙转氨酶的活力,提高总胆红素、无机磷、Mg^(2+)和Fe^(2+)的含量,促进泌乳母马的健康,以每匹泌乳母马摄入60 g/d的赖氨酸和40 g/d的苏氨酸效果最佳。
钟明彬经宏鑫袁景成梁润飞高博坤张城铭马壮阿布都沙拉木·艾合麦提夏津巴特李晓斌
关键词:赖氨酸苏氨酸血液生化指标
结核分枝杆菌丝氨酸/苏氨酸蛋白激酶PknE胞外感受器结构域的晶体学初步研究
2024年
结核分枝杆菌中的丝氨酸/苏氨酸蛋白激酶E(PknE)可以抑制宿主巨噬细胞的凋亡,从而使该病原菌得以在宿主中生存.PknE是由N端胞内激酶结构域与C端胞外感受器结构域组成,2个结构域通过单次跨膜螺旋连接.本实验在大肠杆菌表达系统中表达了PknE的胞外感受器结构域,将其纯化后对蛋白结晶条件进行了筛选,最终得到了形状较好的晶体.在上海同步辐射光源收集到分辨率达到0.175 nm的衍射数据,并对数据进行了初步的处理.这些实验和数据为PknE感受器结构域的结构解析奠定基础,并为基于结构的药物研发提供了重要信息.
范琳琳刘祥周卫红
关键词:结核分枝杆菌表达纯化
HPLC法同时测定N-芴甲氧羰基-O-叔丁基-L-苏氨酸中的6个杂质
2024年
目的:建立高效液相色谱同时测定N-芴甲氧羰基-O-叔丁基-L-苏氨酸中6个特定杂质的方法。方法:采用YMC Triart C18(250 mm×4.6 mm,3μm)色谱柱,以0.1%三氟乙酸水溶液为流动相A,以0.1%三氟乙酸乙腈溶液为流动相B,流速1.0 mL·min^(-1),梯度洗脱,检测波长265 nm,柱温30℃,进样体积10μL。结果:N-芴甲氧羰基-O-叔丁基-L-苏氨酸与相邻杂质峰的分离良好;6个杂质分离度均大于1.5;且在相应质量浓度范围内呈现良好的线性关系(r≥0.999);6个杂质检测限和定量限分别约为0.03μg·mL^(-1)和0.06μg·mL^(-1);6个杂质的平均回收率(n=9)在97.6%~98.8%范围内。3批N-芴甲氧羰基-O-叔丁基-L-苏氨酸测定结果显示,杂质1的含量<0.2%,杂质4的含量<0.1%,其他4种杂质未检出,总杂含量<1%。结论:本方法分离度好,灵敏度高,专属性强,适用于N-芴甲氧羰基-O-叔丁基-L-苏氨酸中有关物质的检测。
杨欣茹李铁健胡发红韩忠丽张贵民
关键词:梯度洗脱
低蛋白日粮补充苏氨酸对肉鸭生长性能、肌肉发育及经济效益的影响
2024年
文中旨在探究低蛋白日粮补充苏氨酸对肉鸭生长性能、肌肉发育及经济效益的影响。试验将1000羽1日龄的健康肉鸭分为4组,每组10个重复,每重复25羽,对照组(Ⅰ组)饲喂正常蛋白质水平日粮,试验组Ⅱ、Ⅲ和Ⅳ在基础日粮基础上降低约2%的粗蛋白质水平的同时补充蛋氨酸(Met)和赖氨酸(Lys)以使各组间Met和Lys水平保持一致。并分别额外补充0%、0.10%和0.20%苏氨酸(Thr)的试验日粮。与对照组相比,降低2%的粗蛋白质水平组肉鸭FBW显著降低5.76%(P<0.05);与低蛋白日粮组相比,添加0.20的Thr组肉鸭末体重(FBW)显著提高2.70%(P<0.05),但仍低于对照组3.21%(P<0.05);低蛋白日粮组,添加0%~0.20%Thr组肉鸭平均日增重(ADG)分别显著降低5.89%、4.52%和3.29%(P<0.05)料重比(F/G)分别显著提高7.65%、5.09%和3.91%(P<0.05)。与对照组相比,低蛋白日粮组补充0%~0.20%的Thr组肉鸭的胸肌率显著降低(P<0.05);低蛋白日粮组补充0%~0.20%的Thr组肉鸭的腿肌率显著降低(P<0.05),与0%和0.10%的Thr组相比,0.20%的Thr组肉鸭腿肌率显著提高(P<0.05);低蛋白日粮组补充0%~0.20%的Thr组肉鸭的肌肉粗蛋白含量显著降低(P<0.05),与0%的Thr组相比,0.10和0.20%的Thr组肉鸭肌肉粗蛋白含量显著提高(P<0.05)本试验各组饲料价格分别为3.2701、3.1783、3.1855和3.1927元/kg;低蛋白日粮添加0%~0.0820%的Thr组饲料总成本较对照组显著降低,且组内差异不显著(P>0.05);综合计算后,本试验各组毛利润分别为15.33、13.51、14.15和14.51元,低蛋白日粮添加0%~0.0820%的Thr组毛利润较对照组显著降低(P<0.05)。总之,日粮蛋白质水平对肉鸭生长影响显著,补充0.10%的Thr能部分恢复低蛋白质水平导致的生长发育迟缓。
张志平王兆麟
关键词:肉鸭低蛋白苏氨酸肌肉发育
Higher intakes of lysine,threonine and valine are inversely associated with non-alcoholic fatty liver disease risk:a community-based case-control study in the Chinese elderly
2024年
The associations of individual amino acid with non-alcoholic fatty liver disease(NAFLD)risk remained unclear.The present study aimed to investigate the associations between the two in the Chinese elderly.Methods:A community-based health check-up program was conducted in Qingdao,China.NAFLD was diagnosed by ultrasonography accompanied by epidemiological investigation.The dietary intakes of amino acids were investigated with 3-day,24-h dietary records and calculated by Nutrition Calculator software.Restricted cubic spline model was used to evaluate a nonlinear relationship between amino acid intake and NAFLD risk.Results:400 NAFLD subjects were identified,and 400 participants were randomly selected as controls and matched by gender and age(±3 years)Dose-response analysis showed that 1000 mg increment of aromatic amino acids(AAAs)was associated with reduced 16%risk of NAFLD.Dietary increments of 750 mg/d threonine,950 mg/d valine,or 1700 mg/d lysine were associated with a 20%reduction in the NAFLD risk(all P for linearity<0.05).Conclusion:The present study demonstrated that the dietary increases in milk,eggs and deep-sea fish,which are rich in the amino acids,might contribute to protecting against NAFLD in the elderly.
Xueqi LiWenjun MaTing YangChong WangWei ZhangHui LiTing ZhaoXiaofei Guo
美国不良事件报告系统中丝氨酸/苏氨酸蛋白激酶/丝裂原活化蛋白激酶联合抑制剂不良反应信号数据挖掘与分析
2024年
目的:本研究旨在比较维莫非尼联合考比替尼、达拉非尼联合曲美替尼和康奈非尼联合贝美替尼3种丝氨酸/苏氨酸蛋白激酶(serine/threonine-protein kinase B-raf,BRAF)/丝裂原活化蛋白激酶(mitogen-activated protein kinases,MEK)联合抑制剂间药品不良反应(adverse drug reaction,ADR)的差异,以期指导临床安全用药。方法:收集2011年第1季度—2023年第2季度美国FDA不良事件报告系统中的ADR报告,使用报告比值比法和贝叶斯可信区间递进神经网络法进行数据分析,同时采用Chi-square统计方法对组间数据进行分析。结果:研究共纳入17982份ADR报告,其中达拉非尼联合曲美替尼报告数最多,为12746份,且报告死亡结局的比例(26.62%)也高于其他方案组。3种治疗方案主要累及系统器官分别为皮肤及皮下组织类疾病、全身性疾病及给药部位各种反应和胃肠系统疾病。在维莫非尼联合考比替尼和康奈非尼联合贝美替尼方案中,浆液性视网膜病关联性最强,维莫非尼联合考比替尼方案发生器质性脑综合征ADR致死概率为100.00%。结论:临床上应关注维莫非尼联合考比替尼方案发生器质性脑综合征ADR致死风险,不同BRAF/MEK联合抑制剂与特定系统器官的ADR关联强度存在差异,临床医生可根据患者的具体需求合理选择药物,并对ADR进行有效监测。
刘红王文娟白羽张关敏张艳华
关键词:药物警戒药品不良反应丝裂原活化蛋白激酶抑制剂

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