绿豆幼苗的超弱发光规律及盐胁迫下的变化

为了研究绿豆幼苗的超弱发光规律及盐胁迫对其的影响和改变,本研究首次采用以EMCCD(电子倍增式CCD)为主的、自行搭建的超弱光图像探测系统,以豫绿2号绿豆为实验材料,检测了绿豆幼苗的自发超弱发光以及在盐胁迫下的改变情况。结果发现:绿豆幼苗自发发光的强度远小于延迟发光的强度,不同的盐胁迫时间对延迟发光强度和自发发光强度的影响各不相同,故可以用延迟发光强度的变化来表征盐胁迫对植物的伤害程度。实验数据的统计结果表明:盐胁迫下绿豆幼苗的发光强度-时间曲线遵循指数衰减规律,说明生物光子具有一定的相干性。本文结果将为农田实时监测植物盐胁迫生理状况提供一种新的光子学手段。     

种子辐射诱导发光与辐射敏感性关系的研究

种子辐射诱导发光随时间的延长,发光强度及发光强度的衰减速度逐渐降低．发光强度的衰减规律接近二级动力学反应规律．每粒种子吸收单位剂量辐射所产生的诱导发光强度及浸种初期的发光强度与幼苗的相对苗高之间具有显著的相关关系,这说明辐射敏感性高的种子吸收单位剂量在单粒种子内产生的诱导发光强度也高．辐照种子发芽后的发光强度比未辐照种子低．     

免标记光学纳米生物传感器的研究

利用发光稳定的多孔硅,当蛋白质溶液固定到多孔硅表面时,其发光强度和反射光谱的峰位会随着被测物质量浓度的变化而发生变化的特性。制备免标记光学纳米生物传感器来检测牛血清白蛋白（BSA）,把不同质量浓度的BSA溶液固定到多孔硅上测量反射光谱的峰位和荧光强度的变化。实验结果表明：反射光谱的峰位与牛血清白蛋白的浓度呈线性关系：y=1．4189x＋366．31,R^2=0．9898;荧光强度的降低量与BSA溶液的浓度呈线性关系,检测限为8×10^-9 mol／L。     

绿豆和花生的超弱发光

对黄化绿豆幼苗先形态建成过程的超弱发光图象（延迟发光）的初步观察发现：见光培养40min后的绿豆幼苗即可探测到明显的延迟发光;见光时间越长,光诱导的延迟发光强度也越强。从绿豆和花生幼苗的趋弱发光图象来看,生长健壮的幼苗发光较强。其中茎尖和新生幼叶的延迟发光最强,上胚轴、子叶和下胚轴弯钩较强,下胚轴伸长部分次之,根部发光最弱。从不同发育阶段叶片的超弱发光图象来看,光合作用较强、新陈代谢旺盛的成熟叶片的超弱发光较强;光合作用和其它代谢过程相对较弱的叶片（伸展叶、老叶和幼叶）,其超弱发光强度相应较弱。而叶绿素提取液和失活绿叶观测不到超弱发光。此外,对超弱发光光谱的初步研究表明它很可能来自光合作用中叶绿素的发光。这些都暗示,植物的（诱导）超弱发光与光形态建成和光合作用等生长代谢过程密切相关。     

浅谈糖蛋白

糖蛋白是指糖和蛋白质间,以蛋白质为主,其一定部位以共价键与若干糖分子链相连而构成的分子。糖蛋白广泛存在于生物体内,包括许多酶、大分子蛋白质、激素、血浆蛋白、全部抗体、血型物质和粘液组分以及许多膜蛋白,是细胞质膜、细胞间质、血浆、粘液等的重要组成成     

植物耐盐性的分子生物学研究进展

研究证明了植物的耐盐机制十分复杂,安与植物的小分子物质的积累,离子摄入和区域化,以及基因表达和大分子蛋白质的合成有关,如调渗蛋白、通道蛋白、晚期胚胎发生富集蛋白。同时,利用克隆技术分离到了一些盐诱导基因。现将这部分工作做一综述。     

绿豆和花生的超弱发光

对黄化绿豆幼苗光形态建成过程的超弱发光图象的初步观察发现：见光培养４０ｍｉｎ后绿豆幼苗即可探测到明显的延迟发光;见光时间越长,光诱导的延迟发光强度也越强。从绿豆和花生幼苗的超弱发光图象来看,生长健壮的幼苗发光较强。其中茎尖和新生幼叶的延迟发光最强,上胚轴,子叶和一胚轴钩较强,下胚轴伸长部分次之,根部发光最弱。     

黄粉甲幼虫抗菌物质的诱导及其抗菌活性

采用饥饿法、紫外线照射法和针刺法处理黄粉甲Tenebriomolitor 6龄幼虫后均能诱导其 产生抗菌物质,收集的血淋巴上清液对真菌有抑制作用,对细菌无抑制作用;经热处理后的血 淋巴上清液则对细菌有抑制作用,而对真菌无抑制作用。SDS-PAGE检测结果发现,与未诱导的 对照相比经诱导的黄粉甲幼虫血淋巴中,原有的一类大分子蛋白质如分子量分别为97kD、44 kD和37 kD左右的蛋白质缺失;而ESI-MS分析结果显示诱导后比诱导前黄粉甲幼虫血淋巴中有 小分子物质产生,推测可能是此类缺失蛋白质分解为小分子量的抗菌肽,从而表现出抗菌活性 。     

CO2激光照射对青椒、茄子种子及幼苗生长点超弱发光影响的研究

本文利用ＣＯ２激光照射青椒、茄子干种子后,观察刺激剂量、半致死剂量对种子及幼苗生长点超弱发光的影响,从而探索超弱发光是否可作为激光照射后衡量种子活力综合反应的一项指标。其结果表明：１．青椒、茄子干种子超弱发光的动态变化随着照射间隔期的延长,其不同剂量之间超弱发光强度的差异也相应变小,照射时间最长的半致死剂量组２５″、３５″,其超弱发光由最高降为最低;激光刺激剂量组３″、１３″的超弱发光强度始终高于ＣＫ。２．青椒、茄子种子发芽过程中超弱发光表现为激光刺激剂量组均极显著高于ＣＫ;半致死剂量２５″、３５″均极显著低于ＣＫ。３．激光组的活体生长点和提取液的超弱发光均极显著高于ＣＫ;活体生长点的超弱发光低于提取液的超弱发光。     

发光细菌JMU07的分离鉴定及其在生物毒性测定的初步研究

从乌贼表皮通过分离纯化得到一株发光细菌JMU07。该菌的菌落形态呈典型细菌菌落特征;显微镜下观察其为球杆状菌,革兰氏染色阴性。用荧光分光光度计测定其发光波长在420-650 nm之间,最大发光波长为477 nm。16S rDNA法测序,构建系统进化树,初步鉴定发光细菌JMU07为鳆发光杆菌(Photobacterium leiog-nathi)。生长发光曲线测定表明,发光细菌JMU07发光强度最高出现在对数中后期,相比明亮发光杆菌,JMU07具有发光强度高,持续发光时间长的特点。根据国标GB/T15441-1995研究HgCl2浓度与发光细菌JMU07发光强度抑制率的关系得到:HgCl2浓度与发光细菌JMU07发光强度抑制呈良好线性关系;JMU07 EC50为0.11 mg/L,略低于明亮发光杆菌的0.14 mg/L,表明JMU07对HgCl2的毒性更敏感。因此新分离得到的发光细菌JMU07有希望用于环境检测、食品卫生与安全等领域综合毒性的快速检测。     

氨基酸的置换与生物大分子进化的保守性的评析

以蛋白质分子的核氨基酸或核酸分子的核苷酸置换 ,阐明功能上重要的大分子在进化速率上低于那些功能上不重要的大分子———即生物大分子进化的保守性     

Biomacromolecular localization in bacterial cells by the diffusion and capture mechanism

Subcellular localization of biomacromolecules (nucleotides and proteins) is the base for their proper function in bacterial cells. One model to explain the localization of biomacromolecules, particularly proteins, is “diffusion and capture”. In this model, proteins are localized by diffusion through the cytoplasm or the membrane until binding to another protein or proteins that were already previously sequestered in cells. The use of fusions with fluorescent proteins to follow the fate of biomacromolecules has given new insight into the molecular localization mechanisms in living cells. Here, several proteins following a diffusion and capture mechanism to reach their proper location in the cells are presented. Some RNAs also seem to localize by this mechanism. It is an intrinsic feature that the information for molecular localization should exist in the sequences of protein itself. However, very little information has been available in this field to date.     

香草酸与多酚氧化酶相互作用机制研究及新型指纹谱构建

生物大分子与小分子之间的相互作用机制研究是当今各个学科领域的前沿和热点,不仅有利于进一步认识大分子的结构和功能,还能进一步获得检测生物大分子或小分子的新途径．本研究将中药材特征指纹图谱应用于植物多酚氧化酶(polyphenol oxidase, PPO)与植物体内活性成分香草酸(vanillic acid, VA)的具体相互作用机制的研究,采用光谱实验法结合分子模拟技术,分析VA与PPO的相互作用机制,并构建其三维相互作用指纹谱．光谱实验结果显示,VA增强了PPO的荧光强度. 维持VA-PPO体系的相互作用力主要为疏水作用,VA与PPO的结合距离r值为2.48 nm,发生了非辐射能量转移．由光谱实验数据构建的λ-UV-F新型指纹图谱,系统地反映了活性分子VA与PPO之间相互作用特征．分子模拟结果精确显示了VA与PPO的结合位域与结合作用力,表明维持VA与PPO的相互作用力主要为疏水作用和氢键(位于氨基酸残基 Met258, His88, His109, His240, His244和His274位)．计算机模拟与光谱学实验结果一致,并成功构建了VA-PPO相互作用特征关系的新型指纹图谱．     

Real-time monitoring of cell surface protein arrival with split luciferases

Each cell in a multicellular organism permanently adjusts the concentration of its cell surface proteins. In particular, epithelial cells tightly control the number of carriers, transporters and cell adhesion proteins at their plasma membrane. However, sensitively measuring the cell surface concentration of a particular protein of interest in live cells and in real time represents a considerable challenge. Here, we introduce a novel approach based on split luciferases, which uses one luciferase fragment as a tag on the protein of interest and the second fragment as a supplement to the extracellular medium. Once the protein of interest arrives at the cell surface, the luciferase fragments complement and generate luminescence. We compared the performance of split Gaussia luciferase and split Nanoluciferase by using a system to synchronize biosynthetic trafficking with conditional aggregation domains. The best results were achieved with split Nanoluciferase, for which luminescence increased more than 6000-fold upon recombination. Furthermore, we showed that our approach can separately detect and quantify the arrival of membrane proteins at the apical and basolateral plasma membrane in single polarized epithelial cells by detecting the luminescence signals with a microscope, thus opening novel avenues for characterizing the variations in trafficking in individual epithelial cells.     

Biochemical effects of molecular crowding

Cell cytoplasm contains high concentrations of high-molecular-weight components that occupy a substantial part of the volume of the medium (crowding conditions). The effect of crowding on biochemical processes proceeding in the cell (conformational transitions of biomacromolecules, assembling of macromolecular structures, protein folding, protein aggregation, etc.) is discussed in this review. The excluded volume concept, which allows the effects of crowding on biochemical reactions to be quantitatively described, is considered. Experimental data demonstrating the biochemical effects of crowding imitated by both low-molecular-weight and high-molecular-weight crowding agents are summarized.Translated from Biokhimiya, Vol. 69, No. 11, 2004, pp. 1522–1536.Original Russian Text Copyright © 2004 by Chebotareva, Kurganov, Livanova.     

Time-gated luminescence assay using nonmetal probes for determination of protein kinase activity-based disease markers

A novel nonmetal optical probe ARC-1063 whose long-lifetime luminescence is induced by association with the target protein kinase is used for the measurement of the concentration of catalytic subunit of protein kinase A (PKAc) in complicated biological solutions. High affinity (K(D) = 10 pM toward PKAc) and unique optical properties of the probe enable its application for the measurement of picomolar concentrations of PKAc in the presence of high concentrations of other proteins. The described assay is applicable in the high-throughput format with the instrument setups designed for lanthanide-based time-gated (time-resolved) luminescence methods. The assay is used for demonstration that extracellular PKAc (ECPKA) is present in plasma samples of all healthy persons and cancer patients but great care must be taken for procedures of treatment of blood samples to avoid disruption, damage, or activation of platelets in the course of plasma (or serum) preparation and conservation.     

Designed protein multimerization and polymerization for functionalization of proteins

Biotechnology Letters - Multimeric and polymeric proteins are large biomacromolecules consisting of multiple protein molecules as their monomeric units, connected through covalent or non-covalent...     

生物大分子从头合成和设计的研究进展

生物大分子指生物体内存在的DNA、蛋白质、多糖等物质,其对生物体正常生命活动至关重要.从头合成和设计技术在生物大分子的合成和结构设计上具有自由度高、前体简单等特点,能够按照特定研究目的对生物大分子进行全新设计和高效合成.近年来,从头合成与设计技术在人造基因组合成、新型蛋白质类药物设计、糖缀合物合成等领域已开始受到重视.基于生物大分子从头合成和设计技术,可以定向制备全新设计的DNA或全新的基因表达产物,以及具有识别功能的糖链或糖缀合物,将大大推进诸如细胞因子模拟物、基因治疗递送载体等生物活性物质的开发,为人工生物系统的构建、罕见疾病的治疗等提供新的解决方法.本文就DNA、蛋白质和多糖的从头合成和设计进行了综述,阐述了相关方法及应用,最后概括分析了三者之间的关系.     

Protein oxidation and turnover

All biomacromolecules are faced with oxidative stress. Oxidation of a protein molecule always induces inactivation of the molecule and introduces a tag to that molecule. These modified protein molecules are prone to degradation in vivo by the proteasome system. Coupling of protein modification and degradation of chemically modified proteins is one of the normal protein turnover pathways in vivo. We call this a 'chemical apoptosis' process, which is one of the early manifestations of programmed cell death. Impairment of the proteasome system leads to accumulation of modified nonfunctional proteins or 'aged proteins' that might cause various clinical syndromes including cataractogenesis, premature aging, neurological degeneration and rheumatoid disease. The metal-catalyzed oxidation of biomacromolecules provides an excellent artificial aging system in vitro. The system is very useful in the characterization of structure and function relationships of proteins (enzymes), especially in those containing metal binding domain(s), because the oxidation is always followed by an affinity cleavage at the metal binding site(s) that allows easy identification and further characterization.     

Protein S binding in relation to the subunit composition of human C4b-binding protein

The human regulatory complement component C4b-binding protein (C4BP) circulates in plasma either as a free protein or in a bimolecular complex with the vitamin K-dependent protein S. The major form of C4BP is composed of 7 identical, disulfide-linked 70 kDa subunits (alpha-chains), the arrangement of which gives the C4BP molecule a spider-like appearance. Recently, we identified a unique 45 kDa subunit (beta-chain) in C4BP. We have now isolated a subpopulation of C4BP, which does not bind protein S. This C4BP species, which had a molecular weight slightly lower than that of the predominant form, was found to lack the beta-chain. Another lower molecular weight form of C4BP was also purified. It contained the beta-chain and was efficient in binding protein S. Its subunit composition was judged to comprise six alpha-chains and one beta-chain. These results indicate C4BP in plasma to be heterogeneous at a molecular level vis-a-vis subunit composition and/or protein S binding ability and provide support for the concept that the beta-chain of C4BP contains the single protein S binding site.