螺旋藻中藻蓝蛋白的生理功能及其提取纯化研究进展

藻蓝蛋白是螺旋藻的主要组成成分,它的生理功能已经得到多方面的证实.对藻蓝蛋白的结构、抗氧化、抗炎等生理活性及其提取纯化工艺作了较为系统的综述,以期为藻蓝蛋白的进一步研究与开发利用积累完善的资料.     

克氏原螯虾新型过敏原血蓝蛋白的鉴定及性质研究

以克氏原螯虾为研究对象,鉴定血蓝蛋白的理化性质及其过敏原性。酶联免疫吸附试验结果表明:6份甲壳类过敏患者血清与克氏原螯虾血淋巴发生特异性IgE反应,利用离心和柱层析方法从血淋巴中分离纯化到目的蛋白。SDS-PAGE分析显示纯化的目的蛋白由6个亚基(依次为68,72,76,82,84和88 ku)组成,采用兔抗凡纳滨对虾血蓝蛋白多克隆抗体的免疫印迹试验证实目的蛋白为血蓝蛋白。免疫印迹试验结果显示,纯化的血蓝蛋白与甲壳类过敏患者血清出现了特异的杂交显色条带,表明血蓝蛋白具有IgE结合活性。与克氏原螯虾主要过敏原(原肌球蛋白)相比,血蓝蛋白的糖含量为1.99%,热稳定性好,pH稳定性及对胃蛋白酶的耐受性不如原肌球蛋白,但比原肌球蛋白更耐胰液消化。综合血清学及理化性质分析结果,提示血蓝蛋白是克氏原螯虾的1种新型过敏原。     

聚球藻PCC7002藻蓝蛋白提取纯化及热致褪色机理研究

本文旨在研究聚球藻PCC7002（Synechococcus sp. PCC7002,简称“聚球藻”）藻蓝蛋白（Phycocyanin,PC）的提取纯化及热致褪色机理,通过高压均质、壳聚糖絮凝和硫酸铵盐析提取纯化藻蓝蛋白,并采用色泽指标、UV-Vis光谱、荧光发射光谱、粒径电位、FTIR光谱、SDS-PAGE电泳研究其在热处理（50、60、70、80、90 ℃,30 min）过程中褪色的机理。结果表明:藻蓝蛋白的最适提取条件是将藻粉溶于0.04 mol/L的NaCl溶液中使其浓度达到2 mg/mL并在80 MPa下均质7 min,此时藻蓝蛋白得率为10.5081% ± 0.0936%;经0.15 mg/mL壳聚糖絮凝、50%饱和硫酸铵盐析后,藻蓝蛋白纯度可由0.6950 ± 0.0043提高至1.9084 ± 0.2621。进一步研究藻蓝蛋白的热致褪色机理发现:从60 ℃开始,脱辅基蛋白空间结构的破坏使蛋白骨架维持的藻蓝胆素天然构象发生转变、藻蓝蛋白紫外吸收和特征荧光大幅下降,藻蓝蛋白的蓝色色泽因此大幅消褪;粒径结果表明,藻蓝蛋白在60 ℃时开始聚集,而80 ℃下形成的更大聚集体可能将四吡咯发色团包埋于其内,使得藻蓝蛋白色泽消褪程度加深;此外,FTIR光谱和SDS-PAGE表明热处理过程中藻蓝蛋白β亚基的破坏程度可能远高于α亚基,且被破坏的结构主要是α-螺旋。综上,维持藻蓝蛋白脱辅基蛋白结构或者发色团依托蛋白结构的稳定,是藻蓝蛋白热处理过程中呈色稳定的关键。本研究结果为藻蓝蛋白在热处理过程中护色措施的研究提供了一定的理论依据。     

表面等离子体共振生物芯片无标记实时检测虾血蓝蛋白

利用自行研制的便携式表面等离子体共振生物芯片检测系统,在生物芯片表面分别固定虾血蓝蛋白、虾血蓝蛋白的单克隆抗体、虾血蓝蛋白的单克隆抗体腹水作为生物探针,利用免疫反应的特异性,研究虾血蓝蛋白与其单克隆抗体的相互作用,分析动力学反应过程,建立标准曲线。用同一个生物芯片检测了8个抗体样品、7个未纯化的抗体腹水,为现场检测大量食品中过敏原、检测临床血清中过敏原特异性抗体进行基础研究。表面等离子体共振生物芯片检测过敏原,仪器便携、操作简便、无需标记、无污染、成本低,可进行现场大量样品的实时连续检测和快速筛选,适用于超市、集市、工厂等需要实时快速检测和质量监控的场所,也可以应用于临床上患者血清样品的过敏原抗体检测。     

功能食品藻蓝蛋白的生理活性研究进展

藻蓝蛋白是一种存在于蓝藻、螺旋藻细胞中的色素蛋白复合体,除了能够捕获光能为藻类细胞提供能量外,藻蓝蛋白还具有抗炎性、抗肿瘤、抗氧化等多种生理功能,全面了解和掌握藻蓝蛋白的生理调控功能以及作用机制对藻蓝蛋白的开发与利用有着重要的指导意义。作者以藻蓝蛋白的研究现状出发,分别从抗肿瘤、抗炎、抗氧化以及免疫调节活性几个方面对藻蓝蛋白的生理功能和作用机制进行了阐述,对藻蓝蛋白提取过程中关键瓶颈——藻毒素的去除方法进行了总结和分析,并进一步提出了研究藻蓝蛋白调控机制的新筛选方法。作者为深入研究藻蓝蛋白的调控机理以及进一步开发安全性药物提供参考。     

藻蓝蛋白制备关键技术研究

藻蓝蛋白是从螺旋藻中分离出的一种深蓝色水溶性蛋白质,是荧光色素与蛋白质的络合物.藻蓝蛋白作为纯天然的色素,其色泽鲜亮,可用于食品、化妆品和医药等工业.2020年,国家卫生健康委员会发布了藻蓝蛋白作为食品添加剂的食品安全标准(GB1886.309-2020).藻蓝蛋白具有抗肿瘤、抗氧化、抗炎、增强免疫力等功能活性,作为一...     

胃蛋白酶酶法改性藻蓝蛋白及其稳定性研究

目的 探究胃蛋白酶酶法改性藻蓝蛋白在不同温度和pH条件下的呈色和结构稳定性。方法 通过比较藻蓝蛋白在胃蛋白酶改性前后的分子量变化和色度色差, 确定最佳的改性条件; 利用紫外-可见吸收光谱和圆二色谱分析改性对藻蓝蛋白结构的影响; 并通过液相色谱-质谱技术分析改性藻蓝蛋白的肽段序列; 最终以色度和色差、色素保留率、紫外-可见吸收光谱和圆二色谱等指标, 评价改性藻蓝蛋白在不同温度和pH下的呈色和结构稳定性。结果 藻蓝蛋白的最佳改性条件为酶解pH 2.0, 灭酶方式煮沸6 min, 酶解时间2 h。此条件下改性藻蓝蛋白与未改性藻蓝蛋白相比, 紫外-可见吸收光谱显示藻蓝蛋白分子结构发生变化, 圆二色谱结果说明酸性和酶解条件会导致藻蓝蛋白从典型的α-螺旋结构向无序结构转变。通过液相色谱-质谱联用技术, 本研究鉴定到7条含有藻蓝胆素的肽段序列, 这些肽段与藻蓝胆素的稳定结合对维持改性藻蓝蛋白的呈色稳定性起关键作用。稳定性评价结果表明, 改性藻蓝蛋白在高温和酸性环境显示出优异的呈色和结构稳定性。70℃以下的温度范围内, 色素保留率大于(91.25±0.08)%, 关键色度b*和二级结构占比无显著变化; 在pH 2.0附近时改性藻蓝蛋白呈色和结构最稳定。结论 本研究所得改性藻蓝蛋白较未改性藻蓝蛋白在高温和酸性环境的呈色和结构稳定性显著提升, 为藻蓝蛋白在食品加工过程中应用于不同食品基质、应对不同加工处理条件提供理论基础和技术支持。     

藻蓝蛋白对非小细胞肺癌H1299生长、迁移和凋亡的功能影响

藻蓝蛋白(C-phycocyanin,C-PC)是一种从顿顶螺旋藻中提取的天然水溶性无毒的活性蛋白。采用MTT法、克隆形成实验、流式细胞术、划痕实验等探究不同浓度的藻蓝蛋白对人类非小细胞肺癌H1299细胞活力、凋亡、迁移等的影响。结果表明:藻蓝蛋白能显著(p<0.05)降低H1299细胞存活率,通过下调周期蛋白cyclinA、CDK2,上调周期抑制因子P21使细胞周期阻滞在S期;藻蓝蛋白处理使细胞形态发生改变,同时通过调控bad、bax、bcl-xL、bcl-2等凋亡相关基因的表达促进细胞凋亡;体外划痕实验表明藻蓝蛋白通过调控基质金属蛋白酶9(matrix metalloproteinase-9,MMP-9)和基质金属蛋白酶2(matrix metalloproteinase-2,MMP-2)抑制细胞迁移。研究结果表明藻蓝蛋白能够通过细胞周期S期阻滞,调控细胞周期、凋亡和迁移相关基因的表达而抑制非小细胞肺癌H1299细胞的生长和迁移,进而诱导细胞凋亡,为进一步开发功能食品奠定坚实的理论基础。     

螺旋藻中藻蓝蛋白提取、纯化及稳态化研究进展

藻蓝蛋白是螺旋藻中一种主要功能性蛋白质,能占到螺旋藻（干基）的20%,也是一种天然着色剂（CNS：08.137）。根据纯度（Purity,P）藻蓝蛋白分为食品级（P>0.7）、试剂级（0.74.0）等多种规格,可以广泛应用于食品、化妆品及医药等领域;但藻蓝蛋白的光、热易敏性,以及不耐受酸碱的特性,造成藻蓝蛋白的产业化应用尚未普及。本文对近5年来螺旋藻中藻蓝蛋白的提取纯化研究进展进行了回顾总结,系统分析、比较了藻蓝蛋白分离、纯化的影响因素;同时对藻蓝蛋白稳态化的研究进展进行了概述,藻蓝蛋白稳态化应用比较多的是加入海藻糖或麦芽糊精等制作藻蓝蛋白微胶囊,旨在为藻蓝蛋白的精深加工、应用推广提供系统性认识。     

藻蓝蛋白稳定性及稳态化的研究进展

藻蓝蛋白是一种存在于蓝藻、红藻和隐藻中的具有光捕获功能的天然水溶性色素蛋白,具有抗氧化、抗炎、抗癌、保肝和增强免疫力的特性.目前,藻蓝蛋白广泛用作食品着色剂、化妆品添加剂、临床诊断和免疫化学荧光试剂.然而,因藻蓝蛋白易受pH、光、温度、外源性物质等因素的影响而变性、沉淀和变色,使其在生产应用中受到限制,影响了其应用范围...     

琥珀与仿琥珀塑料的放大检查

目前市场上仿琥珀产品很多,对其鉴别较困难.通过放大检查琥珀与仿琥珀塑料样品的包裹体与外部特征,结果发现,两者存在较多的差异,如蜜蜡与仿蜜蜡塑料的条纹、爆花琥珀与仿爆花琥珀塑料的裂隙盘、植物珀与仿植物珀塑料的植物枝节特征、虫珀与仿虫珀塑料的昆虫特征等,这些均可用于鉴别琥珀与仿琥珀塑料.     

Characterisation and tissue distribution of polyphenol oxidase of deepwater pink shrimp (Parapenaeus longirostris)

Characterisation and tissue distribution of polyphenol oxidase (PPO) was studied in deepwater pink shrimp (Parapenaeus longirostris) post mortem. PPO activity was the highest in the carapace, followed by that in the abdomen exoskeleton, cephalotorax, pleopods and telson. No PPO activity was found in the abdomen muscle and in the pereopods and maxillipeds using the enzymatic assay. Storage of whole shrimps and of the different organs showed that melanosis (blackening) required the presence of the cephalotorax to be initiated, indicating that its development depends on other factors in addition to the PPO levels. Further characterisation was carried out in extracts partly purified using 40–70% ammonium sulfate fractionation. The enzyme had the highest activity at pH 4.5 and was most stable at pH 4.5 and 9.0. No clear maximum was observed in the 15–60 °C range but the higher stability was achieved at 30–35 °C. Apparent kinetic constants in the partly purified PPO from carapace were K_M = 1.85 mM and V_max = 38.5 U/mg of protein, pointing to a high affinity and reactivity of the enzyme when assayed with DOPA. Electrophoretic mobility was studied in native PAGE and non-reducing SDS–PAGE followed by staining with DOPA. Approximate MW of 500 kDa and 200 kDa were observed, respectively. These two forms could correspond to aggregates of minor PPO subunits that could not be resolved in these electrophoretic systems. The peptide mass fingerprinting obtained by MALDI-TOF analysis showed some peptides whose homology with hemocyanins and different PPO subunit precursors has already been demonstrated in the same species.     

The statistical properties of a stepwise procedure for testing the purity of fruit juice

In many cases no fixed standards are available and a sample from a target population is used to provide the necessary quality-control norms. Furthermore, many products possess several correlated attributes that are relevant to the authenticity question. This article addresses some issues related to statistical tests used in such cases, focussing in particular on a procedure that has been lately proposed for differentiating between pure and adulterated fruit juice. The quality control of fruit juice is usually performed by comparing the values of several characteristics in the tested sample against some prespecified standards. In many cases those standards are based on the values found in a sample of a presumably pure juice, which is used as a "reference sample" or a "base sample". Several detection methods were recently proposed that use universal "base samples" and are supposed to be valid when applied to juices from different sources or different varieties. We compare the results yielded by the use of various "base samples" and show that the application of such a method to Israeli citrus juice leads to too many rejections of pure juices. We suggest that the main drawbacks of the method is the use of improper "base sample" that is not specific to the sample being tested.     

Pharmacogenomics: the genomics of drug response

Pharmacogenomics is defined as the study of the association between genetics and drug response. This is a rapidly expanding field with the hope that, within a few years, prospective genotyping will lead to patients being prescribed drugs which are both safer and more effective ('the right drug for the right patient', or personalized medicine). There are many existing examples in the literature of strong associations between genetic variation and drug response, and some of these even form the basis of accepted clinical tests. The molecular basis for some of these associations is described, and includes examples of variation in genes responsible for absorption and metabolism of the drug, and in target and disease genes. However, there are many issues surrounding the legal, regulatory and ethical framework to these studies that remain unanswered, and a huge amount of education both for the public and healthcare professionals will be needed before the results of this new medicine can be widely accepted.     

川、滇小曲酒比较

川、滇固态小曲酒,从生产工艺到微量成份都有许多共同点,但因控制点和发酵设备等不同,造成风味上的差异,通过相互学习,取长补短,共同促进我国小曲酒的发展和进步。     

Trends and affordability of cigarette prices: ample room for tax increases and related health gains

BACKGROUND: Increasing the price of tobacco products is arguably the most effective method of curbing the prevalence and consumption of tobacco products. Price increases would reduce the global burden of disease brought about by tobacco consumption. OBJECTIVES: To compare cigarette price data from more than 80 countries using varying methods, examine trends in prices and affordability during the 1990s, and explore various policy implications pertaining to tobacco prices. DESIGN: March 2001 cigarette price data from the Economist Intelligence Unit are used to compare cigarette prices across countries. To facilitate comparison and to assess affordability, prices are presented in US dollars, purchasing power parity (PPP) units using the Big Mac index as an indicator of PPP and in terms of minutes of labour required to purchase a pack of cigarettes. Annual real percentage changes in cigarette prices between 1990 and 2000 and annual changes in the minutes of labour required to buy cigarettes between 1991 and 2000 are also calculated to examine trends. RESULTS: Cigarette prices tend to be higher in wealthier countries and in countries that have strong tobacco control programmes. On the other hand, minutes of labour required to purchase cigarettes vary vastly between countries. Trends between 1990 and 2000 in real prices and minutes of labour indicate, with some exceptions, that cigarettes have become more expensive in most developed countries but more affordable in many developing countries. However, in the UK, despite recent increases in price, cigarettes are still more affordable than they were in the 1960s. CONCLUSIONS: The results suggest that there is ample room to increase tobacco prices through taxation. In too many countries, cigarette prices have failed to keep up with increases in the general price level of goods and services, rendering them more affordable in 2000 than they were at the beginning of the decade. Opportunities to increase government revenue and improve health through reduced consumption brought about by higher prices have been overlooked in many countries.     

关于膳食脂肪与健康的几个问题(Ⅰ)

膳食脂肪和人体健康的关系是人们十分关心的一个问题,也是目前学术研究的一个重要课题。近年来学术界在这方面已进行了大量的和深入的研究,并取得了很大的进展。对有些问题已得到了一致的结论,但还有些问题还存在着一些分歧和争论,尚待进一步深入研究。本文综述了近年来这方面的研究进展和见解,讨论了我国膳食结构的状况,全文分六个部分:必需脂肪酸;反式脂肪酸;芥酸;膳食脂肪与心血管疾病;膳食脂肪与肿瘤;合理地控制膳食脂肪的数量和质量,保持身体代谢平衡。     

Budding yeast as a model organism for population genetics

Population genetics is a highly theoretical field in which many models and theories of broad significance have received little experimental testing. Microbes are well-suited for empirical population genetics since populations of almost any size may be studied genetically, and because many have easily controlled life cycles. Saccharomyces cerevisiae is almost ideal for such studies as the growing body of knowledge and techniques that have made it the best characterized eukaryote genome also allow the experimental manipulation and analysis of its population genetics. In experiments to date, the evolution of laboratory yeast populations has been observed for up to 1000 generations. In several cases, adaptation has occurred by gene duplications. The interaction between mutation, selection and genetic drift at varying population sizes is a major area of theoretical study in which yeast experiments can provide particularly valuable data. Conflicts between gene-level and among-cell selection, and co-evolution between genes within a genome, are additional topics in which a population genetics perspective may be particularly helpful. The growing field of genomics is increasingly complementary with that of population genetics. The characterization of the yeast genome presents unprecedented opportunities for the detailed study of evolutionary and population genetics. Conversely, the redundancy of the yeast genome means that, for many open reading frames, deletion has only a quantitative effect that is most readily observed in competitions with a wild-type strain.     

Surface roughness of uncoated particleboards and its relation with the raw material, adhesive and climatic conditions

The effect of raw material, adhesive and climatic conditions on the surface roughness and moisture content of uncoated particleboards was determined. Particleboards made with recycled particles in the surface layer had the roughest surfaces irrespective of the adhesive used. The relationship between equilibrium moisture content and roughness are a complex function of interactions between many variables.     

云门洞藏酒工艺初探

介绍了云门洞藏酒的贮酒容器、贮酒时间和环境,并通过多年的跟踪监测,发现了洞藏酒在白酒感官质量和微量成分变化上同库房贮存酒的不同。证明了洞藏工艺是白酒贮存工艺中最优的。