假根羽藻主要捕光叶绿素a/b-蛋白复合体的特性

应用阴离子交换和凝胶过滤层析技术,从假根羽藻(Bryopsis corticulans Setch.)类囊体膜中直接分离、纯化获得了主要叶绿素a/b-蛋白复合体(LHCⅡ).经蔗糖密度梯度超速离心获得了该色素蛋白复合体的单体和三聚体.反相液相色谱的色素分析结果显示,假根羽藻LHCⅡ的色素组成含有叶绿素a、叶绿素b、新黄质、紫黄质和管藻素等.其单体的电子跃迁能谱与三聚体的相似.园二色光谱分析显示,在LHCⅡ脱辅基蛋白质上分别存在着很强的叶绿素a偶极子之间和叶绿素b偶极子之间的分子内相互作用,然而这些偶极子之间的分子间的相互作用在三聚体中得到明显增强.在能量传递方面,LHCⅡ单体有着与三聚体相似的从叶绿素b到叶绿素a以及从管藻素到叶绿素a的高效传能能力.实验结果表明,假根羽藻中LHCⅡ单体具有像三聚体那样可以高效发挥吸能和传能生理功能的色素组成形式.因此,这些单体可能是假根羽藻类囊体膜上具有功能作用的LHCⅡ的结构形式.     

假根羽藻外周天线色素分子间能量传递

假根羽藻外周天线捕光色素蛋白复合物(L ight-harvesting Comp lex II,LHC II)在不同聚集态的情况下,它所包含色素分子间的能量传递是不同的。采用荧光发射光谱和激发光谱技术对不同聚集态(单体、三聚体和寡聚体)的LHC II进行研究,发现三聚体中色素分子间的能量传递效率比较高,单体要小一些。520 nm激发下,类胡萝卜素分子向叶绿素a分子的能量传递效率:三聚体约为64%、单体约为56%;650 nm激发下,叶绿素b分子向叶绿素a分子的能量传递效率:三聚体约为89%、单体约为78%。寡聚体的能量传递要复杂些,从光谱分析出它包含两种不同吸收光谱特性的叶绿素b分子,吸收峰分别为480 nm和468 nm,其中蓝区吸收峰为480 nm的叶绿素b分子向发射685 nm荧光的叶绿素a分子的能量传递效率要小于75%。     

从假根羽藻类囊体膜直接分离纯化主要捕光叶绿素a/b蛋白复合体

应用液相色谱层析技术从海生绿藻,即假根羽藻(Bryopsis corticulans Setch.)的类囊体膜直接分离纯化获得了主要捕光叶绿素a/b蛋白质复合体(LHCⅡ).类囊体膜提取物经3％n-Octyl-b-D-glucopyranoside去垢剂处理后,其中的LHCⅡ蛋白质获得与Q型阴离子交换层析柱的特异亲和力,因此LHCⅡ从类囊体膜中被高选择性分离出来.经过蔗糖密度梯度离心,获得了LHCⅡ单体、三聚体和聚集体.多肽组分的SDS-PAGE分析证明纯化获得的LHCⅡ单体、三聚体和寡聚体具有很高的纯度.该LHCⅡ制备物的吸收光谱也说明了其结构的完整性.首次提出了通过少数简单步骤从类囊体膜直接分离、纯化LHCⅡ是可以实现的.     

从假根羽藻类囊体膜直接分离纯化主要捕光叶绿素a／b蛋白复合体

应用液相色谱层析技术从海生绿藻,即假根羽藻(Bryopsis corticulans Setch.)的类囊体膜直接分离纯化获得了主要捕光叶绿素a/b蛋白质复合体(LHC II)。类囊体膜提取物经3% n-Octyl-b-D-glucopyranoside去垢剂处理后,其中的LHC II蛋白质获得与Q型阴离子交换层析柱的特异亲和力,因此LHC II从类囊体膜中被高选择性分离出来。经过蔗糖密度梯度离心,获得了LHC II单体、三聚体和聚集体。多肽组分的SDS-PAGE分析证明纯化获得的LHC II单体、三聚体和寡聚体具有很高的纯度。该LHC II制备物的吸收光谱也说明了其结构的完整性。首次提出了通过少数简单步骤从类囊体膜直接分离、纯化LHC II是可以实现的。     

捕光天线LHCⅡ的膜脂组成及PG在LHCⅡ 聚集中的作用

用去垢剂增溶及高速离心的方法,从菠菜类囊体膜中提取并纯化了光系统Ⅱ的捕光天线LHCⅡ异质三聚体。分析其膜脂组成和脂肪酸含量,发现其中磷脂酰甘油（PG）的含量特别高,是PSⅡ的两倍,而PG中含高达31.1%的反式十六碳一烯酸,采用特异作用于十六碳一烯酸链的磷脂酶A2（PLA2）消化PG和体外回加PG重组的方法证明,PLA2消化PG会引起LHCⅡ三聚体解聚为单体,使叶绿素b(Chlb）的吸收峰（475nm,655nm）和荧光激发峰（480nm）下降非常明显,而回加PG重组后,部分LHCⅡ单体又可重新聚集成三聚体。以上实验结果证明,PG及其反式十六碳一烯酸不仅在LHCⅡ三聚体的形成中具重要作用,而且还影响色素色子在LHCⅡ三聚体中的结合状态以及叶绿素b到叶绿素α的正常能量传递。     

不同聚集态LHCⅡ的组成及其光谱性质分析

不同聚集态的LHCⅡ在调节植物光能的吸收和传递上有重要意义. 用蔗糖密度梯度离心的方法从菠菜类囊体膜中分离出了LHCⅡ三聚体、二聚体和单体, 并分析了三者的多肽和色素组成, 以及吸收和荧光光谱特性. 结果表明, 它们都由分子量分别为29, 28和26 kD的3种多肽组成, 且结合有叶绿素a, 叶绿素b, 黄体素, 新黄素和紫黄素等5种色素, 但色素的含量各不相同. 三聚体中各色素的含量最多, 二聚体和单体中依次减少. 结构和组成的不同导致了功能的差异. 吸收及荧光光谱的分析结果显示, 三者在光能的吸收和传递效率上存在明显不同, 表现为三聚体 > 二聚体 > 单体, 推测植物体内3种聚集态LHCⅡ处在相互转换的动态平衡中, 并以此调节植物光能的吸收和传递, 从而适应光环境的变化.     

管藻目绿藻刺松藻LHCII复合物的分离

采用TritoX-100增溶刺松藻类囊体膜,经初离心,蔗糖密度梯度离心和Mg^2 聚集作用后再离心,纯化到一种只含有分子质量为28000u脱辅基蛋白的LHCⅡ复合物,证实此种多肽为同时结合有Chla、Chlb和管藻黄素及管藻素的色素蛋白复合物,Chla/b=0.91。吸收和荧光光谱显示分离物中各种色素之间保持着良好的能量传递关系。其中管藻黄素及管藻素吸收的光能可直接传递给Chla,而无需Chlb作为中介。     

叶绿体膜的结构与功能——ⅩⅦ.LHCP的蛋白磷酸化及其在膜上的横向移动

捕光叶绿素a/b蛋白复合体的蛋白磷酸化使叶绿体低温荧光(77K)在735 nm处的发射增强,间质片层膜的叶绿素a/b比值降低。聚丙烯酰胺凝胶电泳分析表明:LHCP蛋白磷酸化引起部分LHCP在膜上不仅以单体,而且以二聚体、三聚体的形式从富含PSⅡ的基粒膜横向移动到富含PS Ⅰ的间质膜,并与PS Ⅰ相结合,作为它的外周天线,扩大了PS Ⅰ的捕光面积,从而使激发能分配有利于PS Ⅰ。     

菠菜类囊体LHC的叶绿素-蛋白中的叶绿素排列和方向的研究

用蔗糖梯度离心的方法,从胰蛋白酶处理叶绿体和对照叶绿体膜分离LHC。比较研究了它们的吸收光谱、荧光光谱、圆二色光谱和荧光偏振度的变化。观测到消化叶绿体LHC的吸收光谱除位于652nm的肩消失外,其它特征性吸收均无明显改变,荧光发射峰位和在670nm的C.D.信号峰位与对照相比发生偏移,叶绿素b和吸收≤670 Nm叶绿素a的荧光偏振度降低。结果说明含叶绿素b的蛋白和短波长叶绿素a的蛋白位于类囊体膜的外侧,胰蛋白酶消化引起LHC的构型改变,从而使色素与色素、色素与蛋白的相互关系及叶绿素分子排列和方向发生改变。讨论了LHC上蛋白构型、叶绿素分子机构和叶绿素分子间能量传递的相互关系。提出了蛋白质在色素能量传递过程中的作用。     

冷害对黄瓜叶绿体类囊体膜的影响

研究了冷害温度(0℃,16h)对黄瓜(Cucumis sativus L.)叶绿体类囊体膜膜脂、膜蛋白成分的影响。在没有可见伤害症状的低温处理条件下,黄瓜叶片叶绿体类囊体膜膜脂成分已有变化,主要是磷脂酰甘油(PG)含量明显降低,但主要脂类成分单半乳糖基甘油二酯(MGDG)、双半乳糖基甘油二酯(DGDG)、硫代异鼠李糖甘油二酯(SQDC)和PG的脂肪酸组分没有明显的变化;类囊体膜上色素蛋白质复合体的变化以光系统Ⅱ捕光叶绿素a/b蛋白质(LHCⅡ)单体及寡聚体含量的变化最明显,低温处理使LHCⅡ单体比例增加。对提纯的LHCⅡ结合脂的分析表明,低温处理改变了LHCⅡ结合脂及其脂肪酸的组成,使PG含量降低。以上结果表明,LHCⅡ结合脂成分变化以及LHCⅡ寡聚体解聚可能是叶绿体类囊体膜受冷害的最初反应。     

辣椒红色素稳定性研究

本文对辣椒红色素的稳定性进行了研究。结果表明,色素样品的耐热、耐酸碱性较好;室内光线下,放置四周不褪色。但置于室外强阳光下曝晒,两小时后即褪色;常见金属离子中,Ｃｕ２＋可使色素立即褪色,而Ｆｅ３＋、Ａｌ３＋、Ｓｎ２＋对色素影响较小     

A novel system for separation and purification of egg pigments from the nondiapause red-egg mutant Re-nd in the silkworm,Bombyx mori

Re-nd, which was induced from the wild-type C108 by the chemical mutagen N-methane-N-methylnitrourea, is a nondiapause red-egg mutant of silkworm Bombyx mori. The special significance of the Re-nd mutant is that it is an independent dominant mutant. The aim of this study was to establish the type of pigment responsible for the red coloration in the Re-nd mutant eggs in silkworm. We compared the eggs of Re-nd mutants with those of the other B. mori egg color strains and confirmed that the Re-nd mutant is the only strain with red color and red pigment granules in nondiapause, showing this mutant belongs to the pigmentation in the serosa. We speculated that the red substance, which contributed to the bright red pigmentation for nondiapause eggs of the Re-nd mutant, could potentially be a novel pigment according to its solubility, optimum absorption peak, and oxidation–reduction reaction. Moreover, we have successfully constituted the system for enrichment, extraction, and purification of the red substance responsible for the Re-nd mutant, providing a new method for the separation and purification of other known and unknown pigments or substances.     

我国植物食用色素资源开发利用评价

古代人们使用的着色剂都是天然产品,除少数矿物颜料外,主要是植物源色素。我国古代就有以红曲米作为着色剂利用的习惯;在高等植物方面,生产蓝色、黄色、绿色的颜料的高等植物种类不少,大多沿用至今。自19世纪中叶以后,人工合成色素以着色牢固、鲜艳、成本低廉等特点,迅速占领了印染、食品等许多行业,但20世纪60年代以后,许多研究表明,一般合成色素都有程度不等的毒性,特别是化学结构含偶氮型的色素有可能在人体内成为致癌物。同时,在色素合成的过程中,还有可能污染有重金属及其他有害物质。因此,合成色素越来越使人们感到不安全。从20世纪50年代的100多种人工合成色素用于食品着色,到20世纪末,已有60~70余种被禁用了,而植物食用色素在食品行业中成为主要着色剂。近年来又涌现出多种有价值的高等植物源色素,我们选择其主要一些植物种类做些介绍,供有关方面参考。     

Copepod feeding behavior and the measurement of grazing rates in vivo and in vitro

In this paper some aspects of the use of the gut fluorescence method for estimating ingestion rates have been, examined. One assumption is that gut turnover time in feeding copepods is equal to the gut clearance time in filtered seawater. When arctic Pseudocalanus were pre-fed on Thalassiosira weisflogii, and then given a trace addition of the same C¹⁴-labelled culture, or were transferred to filtered seawater, results suggested that this assumption was probably justified. In another experiment in which Pseudocalanus were fed at the same concentration of either melted ice algae, or pelagic under ice algae, there were significant differences in both gut clearance times and gut pigment levels in the two cases.Pigment: biogenic silica ratios in epontic algae were higher than those in faecal pellets produced by Pseudocalanus feeding on the algae, suggesting that pigment destruction was occurring during grazing. In a 28 hr time course experiment ingestion rates determined by rate of disappearance of particulate chlorophyll were higher than those simultaneously determined by the gut fluorescence method, which also supports the idea of pigment destruction in copepods guts.     

禽类蛋壳颜色及其基因的遗传研究进展

禽类的蛋壳具有白色、青色及褐色３种颜色, 特别是鸡和鸭的青壳蛋因外观美观, 口感好, 营养价值高, 蛋壳硬度和强度高于白壳蛋而具有较好的市场前景。但依据表型培育青壳鸡或鸭品系存在误选, 因而研究蛋壳颜色的形成及控制机理具有重要的理论及现实意义。文章主要介绍了禽类蛋壳颜色的种类、色素组成及其合成, 它的可遗传性、遗传力大小、遗传模式, 控制蛋壳颜色的基因数量及其相互之间的显隐性关系, 以期为揭示蛋壳颜色的形成机理提供参考。     

栀子色素研究的进展

从栀子果中可提制出黄色、蓝色、天蓝色、红色等色素。本文详尽评述了栀子黄和栀子蓝的提制和纯化分离的各种技术,并指出了今后的发展方向。     

山蓝色素前体的分子组成和化学变化

山蓝色素前体是很不稳定的化合物。用液相色谱-核磁共振谱联用的技术,结合紫外光谱的变化,研究山蓝色素前体的分子组成及化学变化。表明山蓝色素前体分子有由2个紫蓝氨酸残基和1个氨基酚残基键合而成的片段,在室温下放置后,氨基酚结构转变为醌结构。研究结果为山蓝色素前体、山蓝色素及其相关化合物的结构测定提供了重要数据,为山蓝色素的化学、山蓝色素形成机理的阐明起到了关键作用。     

天然棕色棉色素提取、纯化及其UV光谱研究

选用16种溶剂对天然棕色棉色素进行溶解性试验,发现蒸馏水和pH=9的氢氧化钠溶液是最为经济有效的色素提取溶剂(60℃)。在此基础上,对棕色素进行粗提、纯化、UV光谱测定和化学性质初步鉴定,其中5种纯化方法效果显著,分别是：乙醇沉淀法、重结晶法、铅盐法或铜盐法、纸层析法和柱层析法,并设计了几种纯化方法综合应用的工艺流程。对色素进行UV光谱检测,以218nm附近强吸收、264nm附近弱吸收。根据溶解性试验和化学性质鉴定,推断棕色素化学结构含有双键和酚羟基的存在。     

Isolation of two novel purple naphthoquinone pigments concomitant with the bioactive red bikaverin and derivates thereof produced by Fusarium oxysporum

Filamentous fungi have gained growing interest as sources of diverse pigmented secondary metabolites. Some specific polyketides from Ascomycetous species have demonstrated a wide range of industrial applications in food, cosmetic, textile, and in the design of pharmaceutical products. The formulation of recipes containing fungal polyketides has increased over recent years. Fusarium strains were proven useful to mankind in a variety of technologies. Nevertheless, there is still need of new isolates of Fusarium for use in emerging and already existing fields. In this article, we report the concomitant production of the bioactive red bikaverin along with two novel purple pigments by the phytopathogenic Fusarium oxysporum LCP531 strain isolated from soil. In literature, the production of purple pigment had only been described in cultures of Fusarium Fujikuroi, Fusarium verticillioides, and Fusarium graminearum. The production of these naphthoquinonic pigments, their distribution (either produced in mycelia or excreted in liquid medium) and their chemical profiles were investigated with respect to nutrient composition. The pigments were extracted by using a pressurized liquid extraction method, monitored by colorimetric analysis and characterized by HPLC-DAD chromatography. To our knowledge, this is the first report of these two novel wild-type purple naphtoquinones pigments along with bikaverin, where additionally, the culture conditions were put into perspective to optimize fermentation cultures and extraction process accordingly to the pigment/biomolecule desired. These colored naphthoquinones should be promising fungal functional compounds which could be expected to have a place of choice, along with other antibacterial, antifungal, antiviral, anticancer, and antineoplastic derivatives. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2738, 2019     

Phototrophic pigment production with microalgae: biological constraints and opportunities

There is increasing interest in naturally produced colorants, and microalgae represent a bio‐technologically interesting source due to their wide range of colored pigments, including chlorophylls (green), carotenoids (red, orange and yellow), and phycobiliproteins (red and blue). However, the concentration of these pigments, under optimal growth conditions, is often too low to make microalgal‐based pigment production economically feasible. In some Chlorophyta (green algae), specific process conditions such as oversaturating light intensities or a high salt concentration induce the overproduction of secondary carotenoids (β‐carotene in Dunaliella salina (Dunal) Teodoresco and astaxanthin in Haematococcus pluvialis (Flotow)). Overproduction of all other pigments (including lutein, fucoxanthin, and phycocyanin) requires modification in gene expression or enzyme activity, most likely combined with the creation of storage space outside of the photosystems. The success of such modification strategies depends on an adequate understanding of the metabolic pathways and the functional roles of all the pigments involved. In this review, the distribution of commercially interesting pigments across the most common microalgal groups, the roles of these pigments in vivo and their biosynthesis routes are reviewed, and constraints and opportunities for overproduction of both primary and secondary pigments are presented.