玫瑰茄红色素的研制与应用Ⅲ.三种金属离子的效应

以热带经济植物玫瑰茄(Hibiscus sabdariffa L.)的成熟花萼为原料提制而成的玫瑰茄红色素,是一种新的食用天然色素^{[3,10,11,18,19]}。我们已经简要报道过这种色素的提制工艺、理化性质、安全性和着色试验的研究结果^[2],尔后又详细报道了玫瑰茄红色素最优提取条件的选择^[4]和热效应试验^[5]。本文拟报道玫瑰茄红色素对三种金属离子的效应。     

玫瑰茄种子油成分、营养和毒性评价(译述)

玫瑰茄(Hibiscus sabdariffa)为锦葵科木槿属一年生直立草本植物。原产非洲,广布于全世界热带和亚热带地区。根据国外文献报道和国内的试用结果,利用玫瑰茄花萼提取的红色素,可作为红色着色剂,应用在果酱、果冻、琼脂软糖、水果软糖、汽水、果汁、配制低度酒、蜜饯、冰棒等食品上。在南亚,还可用作织品的染色剂。此外,由     

响应面法优化玫瑰茄粗多糖提取工艺及其抗氧化活性的研究

利用响应面法优化玫瑰茄粗多糖的提取工艺条件,测定粗多糖的抗氧化活性。按照Box-Behnken中心组合试验设计原理,以玫瑰茄粗多糖的得率为响应值,在单因素试验的基础上,进行响应面分析试验,考察料液比、提取时间和提取温度对得率的影响。玫瑰茄粗多糖最佳提取工艺条件为：料液比1∶26 (g/mL)、提取时间3.1 h、提取温度90℃,在该最优条件下所得玫瑰茄粗多糖的得率为14.41%,与预测值接近;玫瑰茄粗多糖对DPPH、羟基、超氧阴离子自由基具有一定的清除作用。研究结果为玫瑰茄粗多糖的研究、开发和利用提供了理论基础。     

有机膜在谷氨酸发酵液分离中的应用研究

目的：采用有机微滤膜和超滤膜连续过滤谷氨酸发酵液,去除菌体蛋白,以利于后续的提取操作。方法：利用微滤膜去除菌体及大分子蛋白等杂质,微滤透过液进入超滤膜系统,进一步去除小分子蛋白及色素等,再利用浓缩连续等电法进行提取,得到谷氨酸。结果：发酵液经过滤后,可溶性蛋白、色素去除率分别可达到86.7%和63.2%,谷氨酸的损失率仅为0.6%;谷氨酸的提取收率和纯度分别可达到95%和99%。结论：利用有机膜系统处理谷氨酸发酵液,可高效去除发酵液中的菌体蛋白和色素等,明显地提高了谷氨酸的提取收率及纯度。     

玫瑰茄发酵酸乳生产工艺研究

目的：将具有抗氧化活力的玫瑰茄与酸乳发酵结合起来,开发玫瑰茄发酵酸乳。方法：玫瑰茄活性物质采用温水浸提法,获得玫瑰茄花茶并将pH调整至6.0后进行酸乳的发酵。玫瑰茄活性物质通过测定540nm和280 nm吸光度值,分别对应玫瑰茄色素与精油的含量;玫瑰茄发酵酸乳的生产工艺以感官评价分数为响应值,通过单因素试验与响应面优化,最终获得玫瑰茄发酵酸乳的最佳生产工艺。结果：玫瑰茄浸液会对乳酸菌的生长造成一定的影响,玫瑰茄用量要小于0.5%;玫瑰茄浸提活性物质最佳条件为40℃温水浸提40 min。结论：最终确定的玫瑰茄发酵酸乳最佳生产工艺为玫瑰茄用量0.3%、奶粉用量5%、发酵时间24 h。     

玫瑰茄醇提物的抑菌活性及其作用机制

玫瑰茄具有多种药理活性,包括抗肿瘤、抗氧化和抑菌作用等,但目前关于玫瑰茄的抑菌作用研究较少,有关抑菌机制方面的研究尚未见报道. 本文通过测定玫瑰茄醇提物对大肠杆菌和金黄色葡萄球菌细胞膜、蛋白质和核酸的影响,及其与DNA的作用方式等,系统阐述玫瑰茄的抑菌作用机制. 电导率和大分子物质的测定结果显示,玫瑰茄醇提物只对菌体的细胞膜造成微小损伤,其抑菌作用的靶点不在细胞膜. SDS-PAGE和DAPI结果显示,玫瑰茄醇提物可抑制大肠杆菌和金黄色葡萄球菌蛋白质和核酸的合成. 琼脂糖凝胶电泳和紫外吸收光谱结果显示,玫瑰茄醇提物可与DNA结合,当DNA与药物的浓度比较低时,玫瑰茄醇提物与DNA以嵌入结合为主,当二者的浓度较高时,两者间发生的是氢键结合. 上述结果证明,玫瑰茄醇提物对大肠杆菌和金黄色葡萄球菌抑菌机制,主要是药物通过与DNA发生嵌入结合和氢键结合,使DNA不能进行正常的复制和转录,降低核酸的含量,进而影响蛋白质的合成,最终导致菌体生物学功能的丧失.     

根癌农杆菌介导的玫瑰茄愈伤组织的遗传转化

以根癌农杆菌LBA4404和EHA105为供体菌株,对玫瑰茄愈伤组织进行了转化条件的研究,建立了一套玫瑰茄愈伤组织遗传转化体系。利用该转化体系获得了2个稳定表达新霉素磷酸转移酶活性的玫瑰茄转化细胞系。GUS活性组织化学检测和PCR扩增鉴定的结果表明,愈伤组织的转化率为4%。说明采用农杆菌介导法将外源基因经愈伤组织导入玫瑰茄细胞是可行的。     

拟南芥植物硫肽激素基因在玫瑰茄细胞中的表达

利用玫瑰茄愈伤组织遗传转化体系,通过根癌农杆菌将AtPSK2基因导入玫瑰茄细胞,并获得了功能性表达。研究结果表明,所获得的转基因玫瑰茄细胞系的临界植板细胞密度和临界起始细胞密度分别降低了60%和50%,悬浮细胞培养周期由16d缩短到12d,转化愈伤组织的比生长速率比对照提高了75%,转基因玫瑰茄细胞和愈伤组织中的花黄素含量与对照相比没有发生明显变化。本研究所获得的转基因玫瑰茄细胞系不仅为花青苷和花黄素等次生代谢产物高产细胞株的选育提供出发材料,而且为PSK-α作用机理的深入研究提供一个有用的模型。     

玫瑰茄中营养元素的分析研究

通过原子吸收火焰光度法对玫瑰茄中的营养元素进行测定分析,结果表明：玫瑰茄中富含钙、镁营养元素,富含铁、锰、锌微量元素,从而为玫瑰茄的食用、医用价值及保健功能提供科学理论依据。     

玫瑰茄中营养元素的分析研究

通过原子吸收火焰光度法对玫瑰茄中的营养元素进行测定分析,结果表明玫瑰茄中富含钙、镁营养元素,富含铁、锰、锌微量元素,从而为玫瑰茄的食用、医用价值及保健功能提供科学理论依据.     

A new method for liposome preparation using a membrane contactor

In this article, we present a novel, scalable liposomal preparation technique suitable for the entrapment of pharmaceutical agents into liposomes. This new method is based on the ethanol-injection technique and uses a membrane contactor module, specifically designed for colloidal system preparation. In order to investigate the process, the influence of key parameters on liposome characteristics was studied. It has been established that vesicle-size distribution decreased with a decrease of the organic-phase pressure, an increase of the aqueous-phase flow rate, and a decrease of the phospholipid concentration. Additionally, special attention was paid on reproducibility and long-term stability of lipid vesicles, confirming the robustness of the membrane contactor-based technique. On the other hand, drug-loaded liposomes were prepared and filled with two hydrophobic drug models. High entrapment-efficiency values were successfully achieved for indomethacin (63%) and beclomethasone dipropionate (98%). Transmission electron microscopy images revealed nanometric quasispherical-shaped multilamellar vesicles (size ranging from 50 to 160?nm).     

Triton X-100 as an effective surfactant for the isolation and purification of photosystem I from Arthrospira platensis

Surfactants play important roles in the preparation, structural, and functional research of membrane proteins, and solubilizing and isolating membrane protein, while keeping their structural integrity and activity intact is complicated. The commercial n-Dodecyl-β-D-maltoside (DDM) and Triton X-100 (TX) were used as solubilizers to extract and purify trimeric photosystem I (PSI) complex, an important photosynthetic membrane protein complex attracting broad interests. With an optimized procedure, TX can be used as an effective surfactant to isolate and purify PSI, as a replace of the much more expensive DDM. A mechanism was proposed to interpret the solubilization process at surfactant concentrations lower than the critical solubilization concentration. PSI-TX and PSI-DDM had identical polypeptide bands, pigment compositions, oxygen consumption, and photocurrent activities. This provides an alternative procedure and paves a way for economical and large-scale trimeric PSI preparation.     

Contribution of Müller cells toward the regulation of photoreceptor outer segment assembly

The assembly of photoreceptor outer segments into stacked discs is a complicated process, the precise regulation of which remains a mystery. It is known that the integrity of the outer segment is heavily dependent upon surrounding cell types including the retinal pigment epithelium and Müller cells; however the role played by Müller cells within this photoreceptor-specific process has not been fully explored. Using an RPE-deprived but otherwise intact Xenopus laevis eye rudiment preparation, we reveal that Müller cell involvement in outer segment assembly is dependent upon the stimulus provided to the retina. Pigment epithelium-derived factor is able to support proper membrane folding after inhibition of Müller cell metabolism by alpha-aminoadipic acid, while isopropyl beta-D-thiogalactoside, a permissive glycan, requires intact Müller cell function. These results demonstrate that both intrinsic and extrinsic redundant mechanisms exist to support the ability of photoreceptors to properly assemble their outer segments. Our study further suggests that the receptor for pigment epithelium-derived factor resides in photoreceptors themselves while that for permissive glycans is likely localized to Müller cells, which in turn communicate with photoreceptors to promote proper membrane assembly.     

Measurements of Light Transmission Through Single Melanophores

A photometrical method has been developed that allows assessment of subcellular pigment migration in melanophores of the fish cockoo wrasse (Labrus ossifagus L.). The pigment migration was studied with local light spot transmission measurements. Depending on where the light beam is placed on the melanophores it is possible to study events within an area of approximately 75 μm². Measuring pigment translocation in different parts of a melanophore gives new possibilities to study how cell membrane receptor-mediated signals are spread within a single cell, which will increase our understanding of how receptor activating drugs exert their cellular effect. The technique can be used in pharmacological and biophysical studies and in biosensors, pharmaceutical screens, environmental detectors, etc. The method clearly has the ability to study local and small changes in light transmission due to displacement of melanophore pigment granules. Since one melanophore on the tip of an optical fibre would be enough to obtain a measurable effect, the presented technique provides the basis for future development of biosensors small enough for in vivo applications, e.g., to monitor the catecholamine levels of circulating blood.     

脂质体重组和脂蛋白体在植物生物膜研究中的应用

脂质体是磷脂在一定条件下在水中形成的由脂质双分子层组成的内部为水相的闭合囊泡。在推动生物膜的研究进展中,它作为模式系统起着非常重要的作用,能用于研究膜蛋白的性质和功能;膜脂和膜蛋白的相互关系;膜的电化学性质等。近年来脂质体重组技术开始引入到植物学研究领域,用于对植物膜蛋白的研究。本文简要介绍了脂质体的制备和脂酶体重组的方法及其在植物生物膜研究中的应用。     

脂质体重组和脂蛋白体在植物生物膜研究中的应用

脂质体是磷脂在一定条件下在水中形成的由脂质双分子层组成的内部为水相的闭合囊泡。在推动生物膜的研究进展中,它作为模式系统起着非常重要的作用,能用于研究膜蛋白的性质和功能;膜脂和膜蛋白的相互关系;膜的电化学性质等。近年来脂质体重组技术开始引入到植物学研究领域,用于对植物膜蛋白的研究。本文简要介绍了脂质体的制备和脂酶体重组的方法及其在植物生物膜研究中的应用。     

紫草素的分离制备方法研究

采取CO2超临界萃取的方法从辽宁硬紫草中提取总紫草色素,用紫外分光光度法测定其含量。分别采用有机溶剂溶解碱液萃取法,直接碱水解法,以及Cu^2 络合法制备紫草素。通过三种紫草素制备方法的比较,确定先经Cu^2 络合纯化处理后再经水解法制备紫草素,收率较高,是实验室中简单、快速、高收率的由天然紫草分离制备紫草素的有效方法。     

An electron microscopic study of retinal degeneration in Sprague-Dawley rats

Retinal degeneration in untreated, female Sprague-Dawley rats was studied by electron microscopy and horseradish peroxidase tracer technique. The degeneration appeared to have started at a very young age. The severity of the defect varied from a decrease of photoreceptor nuclei to total loss of receptor cells and the pigment epithelium. In mild degeneration some regions of the retinal pigment epithelium became bilayered and the basal plasma membrane became flattened or formed elaborate infoldings. Breaks in Bruch's membrane occurred in severe degeneration. Degeneration of the pigment epithelium allowed permeation of tracer material from the choroid into the retina.     

Purification and characterization of chick intestine brush border membrane. Effects of 1alpha(OH) vitamin D3 treatment

A new technique has been developed for the isolation of membrane vesicles from the vitamin D-deficient and vitamin D-treated chick intestinal brush border membrane. The technique involves removal of nuclei from a low speed pellet by discontinuous sucrose gradient centrifugation. The resulting intact brush borders are then homogenized in 0.5 M Tris and the membrane fragments purified on a glycerol gradient. This preparation represents a 20-fold purification of the brush border marker sucrase. After 1alpha-hydroxyvitamin D3 treatment there is a significant increase in membrane phospholipid phosphorous, an alteration in the fatty acid composition of the phosphatidylcholine fraction of membrane phospholipid, and a decrease in sucrase specific activity.