维生素A生物合成的研究进展

维生素A是维持人体代谢的必需维生素,在食品、药品及护肤品等多个领域占有重要地位,是三大维生素支柱产品之一,应用前景广阔。市场上的维生素A主要来源于化学合成和天然提取。近年来,随着绿色生物制造的发展,维生素A的生物合成研究取得了重大的进展。总结了维生素A生物合成的研究现状,并对维生素A生物合成的优化改造方案进行了分析归纳,概述了维生素A发酵生产以及产品组分调控和储存策略,最后对生物合成维生素A的现状进行总结与展望。     

生物可降解高分子材料

介绍了生物可降解材料的降解机理,并概述了生物可降解材料的种类,例如天然可降解高分子材料中的纤维素、淀粉,合成生物可降解高分子材料中的微生物合成类和化学合成类,同时阐述了生物可降解高分子材料合成技术的应用、性能改进,以及这些材料的研究现状、发展方向。并对前景进行了展望。     

木质素-碳水化合物复合体体外合成研究进展

综述了木质素-碳水化合物复合体(LCC)的体外合成方法,对化学合成法和生物合成法涉及的反应机理作了概括总结,并重点阐述了LCC的化学法和生物法合成工艺。其中化学法工艺较为成熟,结构可控性强,具有产物得率高和纯度高的特点,但产物分子量较小;生物法工艺模拟了植物体内木质化过程,研究者对其研究较多,但仅侧重于LCC的结构表征。生物法产品更接近于天然LCC,且分子量较高,在生物活性领域具有一定的研究价值。最后展望了体外合成LCC产品在LCC构效关系领域的研究潜力。     

维生素A合成工艺评述

本文首先介绍了维生素A的Roche和BASF两条合成工艺路线,指出了两条工艺路线的不同技术特征和关键技术难点。阐述了BASF技术路线关键合成步骤的技术开发动态。对国内外工业合成维生素A主要采用的Roche合成工艺的关键中间体的合成进行重点阐述,总结了值得深入研究的合成新工艺、新方法和技术研究开发方向。     

青蒿素生物合成研究进展综述

综述了青蒿素生物合成的研究进展,涉及青蒿素植物组织的培养、生物合成中生理生态因子的影响、生物培养体系的建立及生物合成场所、合成路线、合成关键酶及基因调控等方面的研究,并对青蒿素生物合成的发展前景进行了展望。     

生物表面活性剂介导纳米颗粒的生物合成及其应用进展

生物表面活性剂参与纳米材料合成是一项新兴技术,解决了纳米颗粒易聚集、形态大小不均一等问题,为生物技术大规模合成稳定的纳米颗粒提供了新的思路.简介了生物表面活性剂的特性和种类,综述了生物表面活性剂介导纳米颗粒的生物合成研究进展,总结了生物纳米颗粒在石油工业及生物修复等方面的应用.指出未来的研究重点是:合成具有良好稳定性、...     

曲酸发酵及生物合成途径研究进展

简要介绍了曲酸发酵现状,综述了曲酸生物合成途径的研究手段和成果,包括常规手段同位素标记以及新兴的基因组学研究,总结了可能的曲酸生物合成途径以及相关合成与调节基因。     

生物技术在绿色化学研究中的应用

绿色化学领域的研究导向仍遵循着12条原则:在原料、反应试剂、催化剂、合成路线和产品等节点上以绿色物质取代有毒物质。另一个明显的研究趋势是密切结合或利用生物技术进行化工产品的合成,而对于生物合成的应用关键是找到合适的生物催化剂。     

生物法合成5-氨基乙酰丙酸的研究进展

对国内外生物法合成5-氨基乙酰丙酸(ALA)的进展进行综述,重点比较了诱变育种法和代谢工程技术在ALA生物合成研究中的应用,揭示了新兴的代谢工程技术在ALA的生产开发中极具应用前景,为生物法合成ALA的进一步发展指明了方向,有利于促进ALA生物合成的产业化.     

美国能源部资助开发创新的生物合成途径用于改进生物燃料生产

正美国能源部于2012年5月26日宣布,在2012财年资助约1200万美元用于开发先进生物燃料创新的生物合成途径,对其改进产率和生产力进行验证。合成生物学技术可对重要的先进生物燃料和产品在生物和化学品生产中解决关键障碍的承诺,这些障碍包     

Vitamin A status of healthy children in Manisa,Turkey

Background  

Vitamin A deficiency is a major public health nutrition problem in the developing world. Even subclinical Vitamin A deficiency is associated with increased childhood mortality. Severe maternal vitamin A deficiency may cause increased mortality in the first months of life. There have been a limited number of studies regarding vitamin A status in Turkey. The aim of this study was to assess vitamin A status of healthy children in Manisa, Turkey.     

Vitamin B12 and folate in non-institutionalized urban older people

Vitamin B12 and folate deficiencies are the main nutritional determinants of hyperhomocysteinemia, which is an independent risk factor for cardiovascular diseases. There is scarce information about nutritional status on vitamin B12 and serum levels of folate in Mexican older people. The objective was to evaluate the nutritional status of vitamin B12 and folic acid concentration in non-institutionalized, urban elderly men and women subjects. One hundred volunteers over 60 years were included in this cross-sectional study. Serum levels of vitamin B12 and folate were measured. In addition some biochemical and anthropometric indicators were also evaluated. Considering serum values of vitamin, 30% had vitamin B12 deficiency, 52% normal status and 18% with high levels. None subjects had folic acid deficiency, by the contrary, a high proportion (62%) showed elevated levels in serum. There was an effect of sex on vitamin B12 status. Elderly men showed significantly lower levels of vitamin B12, and it was according with significant higher prevalence of vitamin B12 deficiency in this group as compared with the women group. The high proportion of vitamin B12 deficiency found in this study underline a possible public health problem and guarantee further survey-studies about vitamin B12 status and to explore causes and consequences of the deficiency. Finally, due the sample size and the design of the study, the results must be seen with caution and not try to generalize.     

Der Vitaminbedarf bei Fischen

Vitamin Requirement of Fishes Vitamin requirement of sweet water fishes, especially of carp and trout is dealt with. For fishes in natural water, this requirement is met by the feed. However, if the fishes are held in ponds or traps, vitamins must be incorporated to the feeds (pellets). As in the case with other domestic animals, at low levels of vitamins or in their absence symptoms of deficiency relating to growth, muscle atrophy and nervous disorders are observed. The hitherto known symptoms of deficiency in fishes and their daily vitamin requirement per kilogram weight of fish or per kilogram feed are summarized in a table.     

SeO2对维生素D衍生物烯丙位氧化的概述

维生素D 及其衍生物不仅可以作为治疗疾病的药物,而且也可以成为化学合成的原料.大多数维生素D 衍生物的合成都需要经过烯丙位的氧化,然而维生素D 衍生物烯丙位氧化产率很低,这对维生素D 衍生物的开发和研究带来了困难.因此对近年来以二氧化硒为氧化剂对维生素D 衍生物进行烯丙位氧化—环氧法和Riley 氧化法进行了总结,并对此近年来研究成果进行了分析总结.     

Ergebnis und Auswertung einer Doppelblind-Studie mit Vitamin E und Diclofenac-Natrium sowie der Kombination Vitamin E plus Diclofenac-Natrium bei entzündlich aktivierter Gonarthrose

Results and Evaluation of a Double-Blind Study Concerning Vitamin E/Diclofenac-Sodium and a Combination of Vitamin E Plus Diclofenac-Sodium in the Treatment of Osteoarthritis Antiinflammatory and analgetic effects of vitamin E (300 I.U. per day) and Sodium-Diclofenac (75 mg per day) as well as a combination of the two were compared with eachother in a double-blind prospective clinical trial. Important parameters such as joint-swelling, joint-pain and Keitel-function-test showed significant improvement as compared to the status at the time of admission/uptake in the study. Among the various treatment groups, no significant differences in the degree of swelling, pain at rest and Keitel-function-test could be established. Pressure-pain and pain at movement were clearly much more reduced in the Diclofenac and combination groups as compared to the vitamin E group. Combination of vitamin E with Diclofenac did not show any additional effect which could be due to the relatively small dose of vitamin E used in our study. This study confirms anew that vitamin E, as a low-risk-treatment possibility, is well effective in the rheumatic-group of diseases.     

HPLC von Vitamin A-Estern in Margarine

HPLC of Vitamin A-Esters in Margarine In many countries, margarines are fortified by the addition of fatsoluble vitamins. Vitamin A is usually added in the form of its palmitate or acetate esters or as β-9carotene. The addition of vitamin A-esters to margarines can be controlled by HPLC using silica columns. Various approaches for this analysis are discussed in this paper. The analysis of added vitamin A in the ester form (without saponification) provides a number of advantages which are also discussed. In gradient-elution HPLC the separation of several lipid-soluble vitamins (Vitamin A esters, β-carotene and tocopherols) is possible.     

维生素A1-β-环糊精包合物的制备及其稳定性研究

采用饱和水溶液法制备维生素A1与β-环糊精包合物,通过正交实验确定出最佳工艺条件,即维生素A1与β-环糊精的配比为1∶12,包合温度为55℃,包合时间为3 h。经薄层色谱法和红外光谱法鉴定,表明维生素A1-β-环糊精已形成包合物。维生素A1-β-环糊精包合物可明显提高维生素A1的稳定性。     

高效液相色谱法同时测定牙膏中的维生素B_2、维生素B_3和维生素B_6

建立了同时测定牙膏中维生素B_2、维生素B_3和维生素B_6的检测方法。样品经水分散溶解后,用丙酮沉淀杂质,采用Waters T3色谱柱分离,HPLC测定,实验优化了沉淀剂的选择及用量等条件。结果表明,待测维生素在各自浓度范围内线性良好,相关系数均大于0.999,方法检出限在0.60~1.20 mg/kg之间,在高中低三个添加水平的平均回收率为95.0%~103.7%,相对标准偏差为1.67%~6.96%。该方法具有前处理简单、定量准确、灵敏快速的特点,适用于牙膏中维生素B_2、维生素B_3和维生素B_6的定量分析检测。     

The destruction of vitamin a by rancid cod liver oil

Vitamin A was destroyed in cod liver oil as rancidity developed. Vitamin A was destroyed at lower peroxide values when rancidity developed at room temperature than when it was accelerated by aeration at 100°C. It is suggested that not only vitamin A, but other biological properties of oils are not equally affected by rancidity produced in different ways and at different rates, and that peroxide value may not necessarily be parallel to that of other changes which take place in an oil as rancidity develops.