Alcohol-induced changes of {beta}-lactoglobulin - retinol-binding stoichiometry

It has been demonstrated using CD that ethanol induces importantsecondary structure changes of ß-lactoglobulin. CDspectra indicate that ß-lactoglobulin secondary structure,which is mainly composed of ß-strands, becomes mostly-helical under the influence of the solvent polarity changes.The midpoint of ß-strand/-helix transition in ß-lactoglobulinis observed at dielectric constant {small tilde}60 (35% ethanol;v/v). According to CD measurements, the ethanol-dependent secondarystructure changes are reversible. The alkylation of lysines-NH₂ in ß-lactoglobulin weakens the central ß-barrelstructure, since the ß-strand/-helix transition midpointof alkylated ß-lactoglobulin is shifted to lower ethanolconcentration (25% ethanol; v/v). ß-Lactoglobulinstructural changes are triggering the dissociation of the ß-lactoglobulin- retinol complex as judged from complete quenching of its fluorescencein ethanol concentration >30% (v/v). However, in 20% ethanol(v/v), ß-lactoglobulin still retains most of its nativesecondary structure as shown by CD and, in this condition, oneß-lactoglobulin molecule binds an additional secondretinol molecule. This suggests that the highly populated speciesobserved around 20% ethanol (v/v) might represent an intermediatestate able to bind two molecules of retinol.     

老年高血压患者脉压指数与尿微量白蛋白/尿肌酐、血清视黄醇结合蛋白的关系

目的 探讨老年原发性高血压（EH）患者脉压指数（PPI）与尿微量白蛋白/尿肌酐（尿mAlb/尿Cr）、血清视黄醇结合蛋白（RBP）的关系.方法 选取血肌酐（Cr）正常的老年EH患者50例（EH组,根据PPI分为PPI＆lt;0.5组及≥0.5组）及健康体检的老年人20例（对照组）.比较各组尿mAlb/尿Cr比值、血清RBP的变化及与PPI的相关性.结果 尿mAlb/尿Cr比值、血清RBP值比较：EH组高于对照组,PPI≥0.5组高于PPI＆lt;0.5组（均P＆lt;0.05）;尿mAlb/尿Cr比值联合血清RBP值阳性率比较：PPI≥0.5组高于PPI＆lt;0.5组（63.64%比28.57%,P＆lt;0.05）;PPI与尿mAlb/尿Cr比值、血清RBP值呈正相关（r=0.425,P=0.019;r=0.401,P=0.032）.结论 老年EH患者PPI与尿mAlb/尿Cr、血清RBP密切相关,联合检测可作为老年EH患者早期肾功能损害的一个评估指标.     

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。     

Comparison of clinical efficacies of sodium ascorbyl phosphate, retinol and their combination in acne treatment

Acne vulgaris impairs the appearance of an individual and causes psychological irritation. Inflammatory acne lesion is caused by multifactor incorporates in each step of acne pathogenesis. In an attempt to archive inflammatory lesion treatment with the promise of prevention of acne vulgaris, randomized and double-blind studies on the comparison of the efficacies of topical formulations containing 5% sodium ascorbyl phosphate (SAP) and 0.2% retinol, separately as well as in combination application, were conducted. The resulting data showed that SAP reduced the inflammatory lesion by 20.14% and 48.82% within 4 and 8 weeks respectively. Application of the formulation containing retinol slightly improved the treatment efficacy as the lesion reduced by 21.79% and 49.50% after 4 and 8 weeks respectively. The combination treatment significantly reduced the inflammatory lesion by 29.28% after 4 weeks and 63.10% after 8 weeks of application. The most effective treatment was by using the combination of 5% SAP and 0.2% retinol, which incorporated the synergistic effects on lipid peroxidation and sebaceous gland function in addition to the enhancement of SAP permeability by the desquamation of stratum corneum influenced by retinol, keratin plug removal and anti-inflammatory effect of retinol. This study promises for the development of cosmetic products to overcome aesthetic and psychological problems caused by acne vulgaris.     

Provitamin‐A and xanthophyll carotenoids in vegetables and food grains of nutritional and medicinal importance

This study reports carotenoid composition of vegetables (n = 56), cereals (n = 12), pulses and legumes (n = 12), analysed by HPLC. It was hypothesised that food grains, like vegetables may be good sources of carotenoids. Amongst vegetables, higher level (mg/100 g dry weight) of lutein (210–419) was detected in green/red/capsicum and yellow zucchini, whilst zeaxanthin was dominant in kenaf (4.59). β‐Carotene (mg/100 g dry weight) was higher in green capsicum and kenaf (48,159) whilst carrot, ivy gourd and green capsicum contain α‐carotene (22–110). Amongst food grains, chickpea, split red gram and flaxseed contain higher levels (μg/100 g dry weight) of lutein (185–200) whilst zeaxanthin level was highest in puffed chickpea (1.8). Red unpolished parboiled rice was richest (μg/100 g dry weight) in β‐carotene (67.6) whilst whole black gram contained higher levels of α‐carotene (52.7). Thus, results indicate that chickpea and red unpolished parboiled rice are good sources of carotenoids. These carotenoid‐rich vegetables and grains may be exploited to meet the lutein and β‐carotene requirement.     

4-甲氧基-1-氧代-2,2,6,6-四甲基哌啶催化氧化维生素A醇制备维生素A醛

以维生素A醇为原料，用4-甲氧基-1-氧代-2，2，6，6-四甲基哌啶为主催化剂，氯化亚铜为辅催化剂，通氧气制备了维生素A醛。     

Molecular dynamics simulations of the whey protein {beta}-lactoglobulin

Molecular dynamics simulations have been used to model the motionsand conformational behavior of the whey protein bovine ß-lactoglobulin.Simulations were performed for the protein by itself and complexedto a single retinol ligand located in a putative interior bindingpocket. In the absence of the retinol ligand, the backbone loopsaround the opening of this ulterior pocket shifted inward topartially close off this cavity, similar to the shifts observedin previously reported molecular dynamics simulations of theuncomplexed form of the homologous retinol binding protein.The protein complexed with retinol does not exhibit the sameconformational shifts. Conformational changes of this type couldserve as a recognition signal allowing in vivo discriminationbetween the free and retinol complexed forms of the 3-lactoglobulinmolecule. The unusual bending of the single a-helix observedin the simulations of retinol binding protein were not observedin the present calculations     

Human Cellular Retinol Binding Protein II Forms a Domain-Swapped Trimer Representing a Novel Fold and a New Template for Protein Engineering

Domain-swapping is a mechanism for evolving new protein structure from extant scaffolds, and has been an efficient protein-engineering strategy for tailoring functional diversity. However, domain swapping can only be exploited if it can be controlled, especially in cases where various folds can coexist. Herein, we describe the structure of a domain-swapped trimer of the iLBP family member hCRBPII, and suggest a mechanism for domain-swapped trimerization. It is further shown that domain-swapped trimerization can be favored by strategic installation of a disulfide bond, thus demonstrating a strategy for fold control. We further show the domain-swapped trimer to be a useful protein design template by installing a high-affinity metal binding site through the introduction of a single mutation, taking advantage of its threefold symmetry. Together, these studies show how nature can promote oligomerization, stabilize a specific oligomer, and generate new function with minimal changes to the protein sequence.     

替诺福韦酯治疗对慢性乙型肝炎患者血清FGF-23、β2-MG、Cys-C及RBP水平的影响

目的: 研究替诺福韦酯治疗对慢性乙型肝炎患者血清成纤维细胞生长因子-23（FGF-23）、β2-微球蛋白（β2-MG）、胱抑素-C（Cys-C）及视黄醇结合蛋白（RBP）水平的影响。方法: 抽取2015年1月至2016年1月在本院治疗的80例慢性乙型肝炎患者作为研究对象,予服用替诺福韦酯,300 mg/次,1次/d,治疗12个月,抽取40例健康体检者作为对照组。观察患者在不同时间点HBV-DNA水平、HBV-DNA不可检测率、HBeAg转阴率及血清中FGF-23、β2-MG、Cys-C及RBP浓度水平变化情况。结果: 与治疗前相比较,经过替诺福韦酯治疗后,患者HBV-DNA水平明显下降（P<0.05）,HBV-DNA不可检测率明显上升（P<0.05）,HBeAg转阴率明显升高（P<0.05）;治疗后6个月、12个月,病例组患者血清中FGF-23、β2-MG、Cys-C及RBP浓度水平明显高于对照组（均P<0.05）;病例组患者血清中FGF-23浓度水平与β2-MG、Cys-C及RBP浓度水平呈正相关（r：0.566,0.643,0.604,P<0.05）,β2-MG、Cys-C、RBP指标之间也呈正相关（P<0.05）。FGF-23、β2-MG、Cys-C及RBP指标异常组和对照组比较,BNU、Ccr、GFR、P水平差异具有统计学意义（t值分别为：5.581,6.947,3.330,4.921,均P<0.05）,Scr比较差异无统计学意义（P>0.05）。结论: 替诺福韦酯对乙型肝炎患者FGF-23、β2-MG、Cys-C及RBP水平具有升高作用,通过监测这些指标的变化,有助于调整替诺福韦酯治疗方案,预防或减少肾功能不全和低磷性骨病的发生。