共查询到20条相似文献,搜索用时 218 毫秒
1.
2.
以解木糖赖氨酸芽孢杆菌XX-2为出发菌株,110mmol/L L-赖氨酸单盐酸盐为发酵前体,144h发酵后L-2-氨基己二酸浓度达到10.4mmol/L,产率9.5%。以解木糖赖氨酸芽孢杆菌XX-2全细胞为生物催化剂,利用共生的L-赖氨酸 6-脱氢酶和?-1-哌啶啉-6-羧酸脱氢酶催化L-赖氨酸单盐酸盐转化为L-2-氨基己二酸。最优条件为:细胞浓度45g(干重)/L,L-赖氨酸单盐酸盐浓度100mmol/L,pH7.0,温度30℃,反应时间144h。在最优条件下,从100mmol/LL-赖氨酸单盐酸盐产生90mmol/L L-2-氨基己二酸,产率90%。推测了生物催化过程中L-2-氨基己二酸产生的反应机理。 相似文献
3.
4.
研究了以非离子表面活性剂聚乙二醇辛基苯基醚(OP)作增敏剂,火焰原子吸收光谱法测定微量铜和锌的方法.结果表明:表面活性剂OP的加入可使铜吸光度增加70%,锌吸光度增加25%.测定铜和锌的线性范围分别在1.2 mg·L-1及0.6 mg·L-1以内;应用此方法分析了5种植物样品,测定结果的相对标准偏差均小于6%,加标回收率在96.8%~103.0%之间. 相似文献
5.
6.
利用亲水性超支化聚酰胺酯通过化学键合的方法对聚甲基丙烯酸甲酯(PMMA)微流控芯片的表面进行改性。对改性后PMMA微流控芯片的表面进行了接触角的测定,利用扫描电子显微镜(SEM)和体视显微镜观察了改性后芯片的表面形貌。结果表明,改性后的PMMA微流控芯片表面形成了一层均匀、致密、连续的亲水性涂层,芯片表面的亲水性得到了明显提高,接触角由未改性时的89.9°降低到29.5°。改性后芯片的电渗流较之改性前明显降低。利用芯片对腺苷和L-赖氨酸两种生物分子进行了分离检测。两种生物分子实现了完全分离,所得到的检测峰峰形尖锐,分离清晰。对腺苷和L-赖氨酸的分离柱效(理论塔板数)分别高达8.44×104 塔板/m和9.82×104 塔板/m,分离度(Rs)达到5.31,均远远高于未改性的芯片。改性后的芯片具有良好的分离时间重现性。本研究为提高PMMA微流控芯片的亲水性和应用范围提供了一种新的有效方法。 相似文献
7.
8.
用发射光谱法测定了55倒广州地区居民患肾小球疾病时血清和头发申锌、铜、铁、钴、铬、锰含量,观察对象包括肾病综合征组17例,肾炎组17例,尿毒症组21例.对照组为30例健康人。其年龄、性别构成比、地区与观察组无显著性差异.结果经统计学检验发现肾病综合征组病人血清锌、铜、钴及头发锌、钴含量均明显下降,头发铜无明显变化,肾炎组血清钴、头发钴明显下降,血清锌、铜及头发锌、铜无明显变化。尿毒症组病人血清锌、头发锌、钴显著下降,血清钴、铜及头发铜无明显变化.肾炎组、肾病综合征组及尿毒症组病人血清及头发申铁、铬、锰均无明显变化。 相似文献
9.
10.
利用钙置换Zn EGTA中锌 ,镁置换Zn EDTA中锌 ,采用计时电位溶出法间接地测定血清中钙镁含量。血清用量仅为 2 0 μl,且不必消化 ,钙的线性范围为 0~ 4 80 μg·L- 1,检出限为 2 μg·L- 1,相关系数为 0 .9976 (n =6 ) ,镁的线性范围为 0~ 2 88μg·L- 1,检出限为 1μg·L- 1,相关系数为0 .9984 (n =6 )。用模拟血清测定钙的平均回收率为 99.4 % ,镁的平均回收率为 10 0 .1%。 相似文献
11.
L-赖氨酸锌配合物致惊厥实验研究 总被引:1,自引:0,他引:1
为观察L-赖氨酸锌配合物是否具有致惊厥作用,选出了阈下剂量的化学致惊剂和电刺激强度,用小鼠进行了实验研究,结果表明,L-赖氨酸锌配合物无明显增强阈下剂量回苏灵和阈下电刺激小鼠致惊厥作用。 相似文献
12.
13.
Determination of activable isotopic tracers of zinc by neutron activation analysis for study of bioavailability of zinc 总被引:1,自引:0,他引:1
Bang-Fa Ni Pingsheng Wang Yingjun Luo Shouyang Yu 《Journal of Radioanalytical and Nuclear Chemistry》1991,151(2):255-260
A procedure of pre-irradiation concentration of zinc in fecal samples using anion exchanger was developed for the study of the bioavailability of zinc by neutron activation analysis. The mass ratios between70Zn and68Zn, or64Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc when the abundance of the isotope70Zn is not high ehough. 相似文献
14.
M. Antonia Maj Abdelilah Alla Jordi J. Bou Concepcin Herranz Sebastin Muoz-Guerra 《European Polymer Journal》2004,40(12):2699-2708
Two sets of AA · BB-type polyamides (PLyTA) were synthesized from natural compounds L-lysine and D- or L-tartaric acid via the active ester polycondensation method. The carboxyl and hydroxyl side groups were orthogonally protected as methyl ester and methyl ether, respectively. Direct reaction of methyl L-lysinate dihydrochloride with bis(pentachlorophenyl) di-O-methyl tartaric acid led to the aregic polyamide ar-PLyTA, whereas isoregic (ir-PLyTA) and syndioregic (sr-PLyTA) polyamides were obtained by polycondensation of specifically designed amide–aminoacid and amide–diamine monomeric precursors, respectively. These polyamides have intrinsic viscosities in the 0.50–0.76 dl g−1 range, display optical activity, and are readily soluble in chloroform. They start to decompose well above 200 °C and display glass-transition temperatures at 100–105 °C. DSC and X-ray diffraction results indicated that these polyamides are not crystalline but they seem to adopt a partially ordered phase. No differences in properties other than optical rotation were observed between PLyTA made of D- and L-tartaric acid. 相似文献
15.
Anna Rogaska Julita Regua Joanna Suliburska Zbigniew Krejpcio 《Molecules (Basel, Switzerland)》2021,26(7)
Introduction: Despite the constant efforts of scientists to improve the texture, sensory properties, and nutritional value of gluten-free bread, obtaining high bioavailability of minerals is still a huge challenge. Gluten-free bakery products are characterized by a low bioavailability of minerals. The aim of this study was to design gluten-free bread with high bioavailability of minerals commonly found in deficiencies in people struggling with gluten intolerance. Material and methods: The material consisted of gluten-free breads designed to obtain the highest possible content of minerals in the bread while maintaining a good structure and taste. Results: Higher contents of all the analyzed minerals were obtained in breads with natural and synthetic additives, both in rice and buckwheat bread, compared to basic bread. There was also a higher content of the analyzed minerals in buckwheat bread in comparison to rice bread for each type of additive. Higher bioavailability of iron, copper, calcium, and magnesium was noted in rice bread, while the bioavailability of zinc was higher in buckwheat bread. Conclusion: The additives used increased the bioavailability of the analyzed minerals from the gluten-free breads. The use of various variants of flour (rice, buckwheat) influenced the bioavailability of iron, zinc, copper, calcium, and magnesium. The release of minerals from gluten-free bread depends on the element and added components (seeds or synthetic additives). 相似文献
16.
Poly (methacrylic acid) gels (PMAA gels) of various degrees of crosslinking were prepared and the dissociation behavior of these gels was examined; the swelling behavior was investigated as a function of the solution pH values. A reentrant phenomenon of swelling was observed and interpreted based on the Flory-Huggins equation and the Donnan equilibrium formula. Moreover, adsorption of L-lysine, oligo(L-lysine)s (Lys-n,n=3, 9, and 19) and poly(L-lysine) onto PMAA gels from aqueous solutions was investigated under different conditions of pH and concentration of adsorbate. The adsorption ratio of L-lysine onto PMAA gel is dependent on both the pH of solution and the degree of crosslinking. In a pH range between 8 and 9, the protonated form of L-lysine is strongly adsorbed on the PMAA gel by electrostatic interactions. Oligomers and polymer of L-lysine are adsorbed in a somewhat different way from the monomeric L-lysine. In addition, the desorption behavior of L-lysine from PMAA gels by a change in pH was also investigated. 相似文献
17.
对白血病患儿体内血清锌、血清铜浓度以及血清铜/锌比值作了初步的观测.在41例白血病患儿和33例正常对照儿童中,观察到在明确诊断化疗前,41例白血病患儿中有20例患儿的血清锌浓度低于正常低限,他们的平均血清锌浓度为12.3±3.4 μmol/L,明显低于对照组18.3±4.0 μmol/L.白血病患儿的血清铜/锌比值为1.40±0.38,明显高于正常儿童1.19±0.25.经治疗后,有12例患儿获缓解并继续随访至发病后6~8周,平均血清锌浓度由11.4±2.2μmol/L,提高到13.7±2.1μmol/L,血清铜/锌比值由1.51±0.36,下降到1.29±0.23.说明白血病患儿体内存在着锌代谢的异常. 相似文献
18.
观察了慢性肾功能衰竭大鼠经中药“慢肾康”治疗后血清锌铜的变化,研究发现“慢肾康”能明显改善肾衰动物低血锌状况,并且慢性肾衰动物低血锌与血浆白蛋白呈正相关,而与尿蛋白呈负相关。研究提示,“慢肾康”通过改善肾功能,减轻蛋白尿和升高血浆白蛋白而使血清锌升高,同时药物本身所含的锌元素也有一定的补充作用。“慢肾康”的治疗,对肾衰动物的血清铜无明显影响。 相似文献
19.
剌梨利康饮对汞中毒大鼠汞铜锌含量的影响 总被引:1,自引:1,他引:0
用高汞水喂养大鼠8周,复制出慢性汞中毒模型,再分别自由饮用利康饮饮料和腹腔注射二巯基丙磺酸钠3周,探讨剌梨利康饮和二巯基丙磺酸钠对慢性汞中毒大鼠体内汞、铜、锌含量的影响。结果显示:慢性汞中毒引起血清、肝、脑和肾中汞含量升高的同时,引起血清、脑和肾中铜、锌含量及肝中锌含量降低;利康饮可降低血清和肾中汞含量,并可提高血清、脑和肾中铜、锌含量及肝含量;二巯基丙磺酸钠虽可降低血清、肝和肾中汞含量,升高血清 相似文献
20.
锌从土壤向食物链的迁移 总被引:19,自引:1,他引:19
锌是生物必需微量元素,但过多时对动植物都有毒害。本文对锌在人类食物链中的行为及在土壤--植物--人类和动物系统中的迁移,决定农业系统中锌动力学的关键过程,锌在作物可食部位的丰度,影响锌生物有效性的土壤环境,植物因子及锌在食物中的需要量等作了综述了论述。 相似文献