表面等离子体共振技术在分子生物学中的应用

表面等离子体共振(SPR)技术可以实时、原位地测定生物分子间的相互作用而无需任何标记,可以连续监测吸附和解离过程,并可以进行多组分复合物的相互作用的研究。SPR技术在DNA的复制和转录、DNA的修复、核酸与药物的作用以及肽库和抗体库的筛选等分子生物学领域的应用研究取得了令人瞩目的进展,显示了常规技术无法比拟的优越性。     

单分子检测在生物学和药理学研究中的应用

单分子检测可以在单分子水平上原位、实时的获取各种生物化学信息,研究传统分析方法及生物学方法难以解决的问题,在生物学和药理学领域的研究中具有重要的意义.该文综述了荧光单分子检测在细胞生物学、分子生物学、药理学等领域的应用,并对其发展前景进行了展望.     

基于同步辐射技术研究土壤铁氧化物固定重金属分子机制的进展

铁氧化物在土壤中广泛赋存,因其比表面积大,对重金属具有很强的吸附固定能力,深刻影响着土壤重金属的形态转化过程.因此,研究土壤铁氧化物对重金属的固定机制,对于深入理解重金属在土壤系统中的环境化学行为以及评估污染土壤重金属生物有效性具有重要意义.然而,采用传统的吸附模型和化学提取法研究土壤铁氧化物固定重金属的机制具有明显的局限性,无法从分子水平上阐明其固定机制.同步辐射技术在环境土壤学的应用显著推进了在分子水平上认识土壤铁氧化物吸附重金属及其受典型环境因子影响的分子机制.本文主要从同步辐射技术的发展历程、模拟系统和实际土壤系统中铁氧化物在多种因素影响下对重金属固定的分子机制等方面进行了综述,同时对同步辐射技术的未来发展趋势及其在该研究领域的应用进行了展望.     

改性壳聚糖吸附Cu(Ⅱ)及其生物活性研究

壳聚糖具有特殊的生物活性和生理调节机能,其分子的重复单元中富含氨基和羟基,对Cu(Ⅱ)具有良好的络合能力.壳聚糖分子结构的规整性和分子间氢键的存在使其难溶于多数溶剂,对壳聚糖进行改性以增强溶解性和对Cu(Ⅱ)的吸附能力是壳聚糖研究的热点.文章综述了目前壳聚糖的理化改性和对Cu(Ⅱ)的吸附研究,对吸附过程的影响因素做了总结,对壳聚糖吸附体内Cu(Ⅱ)生物学活性的应用作了展望.     

合成生物学及其在生物技术中的应用进展

合成生物学是一门21世纪生物学的新兴学科,它着眼生物科学与工程科学的结合,把生物系统当作工程系统"从下往上"进行处理,由"单元"(unit)到"部件"(device)再到"系统"(system)来设计,修改和组装细胞构件及生物系统.合成生物学是分子和细胞生物学、进化系统学、生物化学、信息学、数学、计算机和工程等多学科交叉的产物.目前研究应用包括两个主要方面:一是通过对现有的、天然存在的生物系统进行重新设计和改造,修改已存在的生物系统,使该系统增添新的功能.二是通过设计和构建新的生物零件、组件和系统,创造自然界中尚不存在的人工生命系统.合成生物学作为一门建立在基因组方法之上的学科,主要强调对创造人工生命形态的计算生物学与实验生物学的协同整合.必须强调的是,用来构建生命系统新结构、产生新功能所使用的组件单元既可以是基因、核酸等生物组件,也可以是化学的、机械的和物理的元件.本文跟踪合成生物学研究及应用,对其在DNA水平编程、分子修饰、代谢途径、调控网络和工业生物技术等方面的进展进行综述.     

糖芯片的制备和检测应用研究进展

近数十年来,糖芯片逐渐成为分析糖介导的识别和结合作用的强有力工具,具有样品检测用量少、特异性强和高通量等优点,可以大大提高糖生物学研究的效率。主要介绍了通过糖库的构建、共价结合和非共价吸附法等方法制备糖芯片的过程,糖芯片的检测方法及其在生物学研究和生物医学领域的应用,以期为糖芯片相关研究提供参考。     

亲和素蛋白与含有生物素的支撑平面膜之间相互作用的研究

生物功能分子的二维有序化组装是分子工程学的重要内容。本文通过构建有生物素受体的人工模型膜,对亲和素与生物素这一具有极强亲和力的系统之间的特异性相互作用的某些制约因素进行了探讨．应用ＬＢ膜技术结合激先椭圆偏振术和表面等离激元谱技术,较深入地研究了蛋白质与脂单层膜发生的非特异性吸附,特异性结合以及结合的侧向空间位阻效应．实验结果表明,膜表面电荷对非特异性吸附的速率有很大的影响,而对最终的蛋白吸附量影响不大;非特异性的吸附可以通过二阶阳离子的脱附而去除;受体蛋白质与配体间的特异性结合受到侧向空间位阻效应的制约．     

胆绿素的激光表面增强拉曼光谱研究

本文中 ,SERS被用来测定胆绿素 ,并对溶液中的 p H和 Na Cl浓度对谱图的影响进行了研究。测定下限可达 1 .2 8× 1 0 -7M,且摄谱时间只需 1 5分钟。另外 ,讨论了胆绿素在银胶表面的吸附状态及质子化状态。研究表明胆绿素在银胶表面是呈近乎平面的环状结构吸附 ,其内酰胺环 A上氧原子和吡咯环上的氮原子可能发生了质子化。     

编者按

在生命科学波澜壮阔的发展进程中,生物研究模型扮演着重要的角色.二维细胞模型和小鼠模型等都极大地促进了生物学基础研究和疾病诊疗应用的进展,可以说,每一个新的研究模型的提出,都为拓展生物学的深度和广度提供了可能.自2009年CLEVERS实验室提出肠道类器官的构建方案以来,类器官培养技术在生物学领域内得到了广泛的认可与应用...     

新产品介绍

超低吸附表面是共价结合的水凝胶表面，具有亲水与中性特性。它具有最小的细胞吸附、蛋白质吸附与酶学活性，这种表面是没有细胞毒性、生物学活性与不可降解性。     

基于双工程菌的“锁扣”生物活材料构建及其体内肠道滞留应用

生物活材料的研究主要集中在利用单一细菌生产生物膜、水塑料等体外应用。由于菌株尺寸较小，当其应用于体内时，容易发生逃逸，导致滞留效果较差。为解决这一难题，本研究借助大肠杆菌(Escherichia coli)表面展示系统(Neae)，在两个菌株表面分别展示SpyTag和SpyCatcher，构建一种双菌“锁扣”型生物活材料生产系统。两菌株之间通过SpyTag和SpyCatcher的结合，发生原位交联，从而长时间滞留在肠道部位。体外实验表明两菌株混合几分钟后，会发生明显的沉降。此外，利用共聚焦成像和微流控平台进一步证明了该系统在流动状态下的粘附效果。最后，为了验证该系统在体内应用的可行性，小鼠连续3d口服A菌(p15A-Neae-SpyTag/sfGFP)和B菌(p15A-Neae-SpyCatcher/mCherry)，收集肠道组织进行冷冻切片染色。结果表明，相较于未结合菌株，该双菌系统能更多滞留在小鼠肠道，为生物活材料进一步的体内应用奠定了基础。     

Tunable nano‐oleosomes derived from engineered Yarrowia lipolytica

Oleosomes are discrete organelles filled with neutral lipids surrounded by a protein‐embedded phospholipid monolayer. Their simple yet robust structure, as well as their amenability to biological, chemical, and physical processing, can be exploited for various biotechnology applications. In this study, we report facile biosynthesis of functionalized oleosomes within oleaginous yeast Yarrowia lipolytica, through expression of oleosin fusion proteins. By fusing a cDNA clone of a sesame oleosin with either the coding sequence of a red fluorescent protein mCherry or a cellulosomal scaffolding protein cohesin from Clostridium cellulolyticum, these oleosin‐fusion proteins were efficiently expressed and specifically targeted to and anchored on the surface of the oleosomes within the Y. lipolytica cells. The engineered oleosomes can be easily separated from the Y. lipolytica cell extract via floating centrifugation and both mCherry and cohesin domains are shown to be functional. Upon sonication, the engineered Yarrowia oleosomes exhibit a mean diameter of 200–300 nm and are found to be highly stable. The feasibility of co‐displaying multiple proteins on the Yarrowia oleosomes was demonstrated by incubating cohesin‐displaying oleosomes with different dockerin‐fusion proteins. Based on this strategy, engineered oleosomes with both cell‐targeting and reporting activities were created and shown to be functional. Taken together, the Yarrowia oleosome surface display system in which oleosin serves as an efficient membrane anchor motif shows great promise as a simple platform for creating tunable nanoparticles. Biotechnol. Bioeng. 2013; 110: 702–710. © 2012 Wiley Periodicals, Inc.     

Control of Pseudophilothrips ichini (Thysanoptera: Phlaeothripidae) with acephate to exclude a biological control agent of Schinus terebinthifolia

Post-release monitoring of biological control agents to determine impact on the target weed has recently received increased priority. Several methods are available to measure the impact of a biological control agent by manipulating the agent population while measuring fitness of the weed. Brazilian peppertree, Schinus terebinthifolia is one of the most damaging weeds in subtropical areas of Florida and Hawaii. A biological control agent, the thrips, Pseudophilothrips ichini is a sap-feeder that shows high levels of specificity and causes severe distortion of leaf tips of the weed. Thrips populations of this species and a generalist thrips, the red banded thrips Selenothrips rubrocinctus were experimentally manipulated by applications of the systemic insecticide acephate by both foliar applications and by an inserted encapsulated formulation. Foliar applications protected plants against red banded thrips for 29 days and against the biological control thrips, P. ichini for 22 days after treatment. Control with inserts were initially low but was achieved after 60 days and this control continued for 182 days after treatment. Manipulation of these biological control thrips populations with foliar or inserted formulations will assist in the determination of biological control agent impact.     

Improved network performance via antagonism: From synthetic rescues to multi‐drug combinations

Recent research shows that a faulty or sub‐optimally operating metabolic network can often be rescued by the targeted removal of enzyme‐coding genes – the exact opposite of what traditional gene therapy would suggest. Predictions go as far as to assert that certain gene knockouts can restore the growth of otherwise nonviable gene‐deficient cells. Many questions follow from this discovery: What are the underlying mechanisms? How generalizable is this effect? What are the potential applications? Here, I approach these questions from the perspective of compensatory perturbations on networks. Relations are drawn between such synthetic rescues and naturally occurring cascades of reaction inactivation, as well as their analogs in physical and other biological networks. I specially discuss how rescue interactions can lead to the rational design of antagonistic drug combinations that select against resistance and how they can illuminate medical research on cancer, antibiotics, and metabolic diseases. Editor's suggested further reading in BioEssays The evolutionary context of robust and redundant cell biological mechanisms Abstract Reprogramming cell fates: reconciling rarity with robustness Abstract     

Environmental and industrial applications of Yarrowia lipolytica

Yarrowia lipolytica is a fungus that degrades hydrophobic substrates very efficiently. The fungus displays several important characteristics that have encouraged researchers to study various basic biological and biotechnological applications in detail. Although the organism has been used as model system for studying dimorphism, salt tolerance, heterologous protein expression, and lipid accumulation, there are no recent reviews on the environmental and industrial applications of this organism. Included here are applications in bioremediation of environments contaminated with aliphatic and aromatic compounds, organic pollutants, 2,4,6-trinitrotoluene, and metals. A variety of industrially important recent processes for the synthesis of β-hydroxy butyrate, l-dopa, and emulsifiers have also been reviewed. Production of unique inherent enzymes (inulinases, α-mannosidases), novel applications of esterases and lipases, and the use of the fungus for heterologous expression of biotechnologically relevant products have also been highlighted. The review while entailing a general overview focuses critically on some of the recent advances on the applications of this yeast. The examples cited here demonstrate the use of wild-type, mutant as well as genetically manipulated strains of Y. lipolytica for the development of different products, processes, and technologies. This also throws light on how a single organism can be versatile with respect to its metabolic abilities and how it can be exploited for a variety of purposes. This review will thus form a base for future developments in this field.     

Gluconobacter in biosensors: applications of whole cells and enzymes isolated from gluconobacter and acetobacter to biosensor construction

Bacteria belonging to the genus Acetobacter and Gluconobacter, and enzymes isolated from them, have been extensively used for biosensor construction in the last decade. Bacteria used as a biocatalyst are easy to prepare and use in amperometric biosensors. They contain multiple enzyme activities otherwise not available commercially. The range of compounds analyzable by Gluconobacter biosensors includes: mono- and poly-alcohols, multiple aldoses and ketoses, several disaccharides, triacylglycerols, and complex parameters like utilizable saccharides or biological O₂ demand. Here, the recent trends in Gluconobacter biosensors and current practical applications are summarized. An erratum to this article can be found at     

Why Nonlinear Biomedical Physics?

The two goals of Nonlinear Biomedical Physics are: firstly to show how nonlinear methods can shed new light on biological phenomena and medical applications and secondly to bridge the technical, mathematical, and cultural divides between the physical disciplines where these methods are being developed and the audience for their use in the biological and medical sciences.     

肽基生物可激活的活体自组装纳米材料及生物医学应用

在生理环境下原位构筑自组装纳米材料,由于其生物体内的可控性、相容性及功能性优势,在临床应用方面具有广泛前景.利用病理条件在体内触发响应,能够在多重弱键相互作用下自发形成高级有序结构.其中内源性组装触发因素,如酶、pH、活性氧和配受体相互作用等,通过生物可激活的体内自组装(bioactivated in vivo ass...     

Environmental safety of biological control: Policy and practice in New Zealand

Introduction of biological control agents into New Zealand is regulated under the Hazardous Substances and New Organisms Act 1996 (HSNO). The legislation is strongly focused on the health and safety of people and the environment. HSNO is implemented by the Environmental Risk Management Authority, a quasi-judicial body of 6–8 people appointed by the Minister for the Environment. The process by which biological control applications are received and processed is described. Two case studies of weed biological control agents which have been through the HSNO process, and the scientific issues that arose in considering the environmental safety of these agents are discussed. The case studies presented are the applications to release the gall fly Procecidochares alani (Diptera: Tephritidae) to control mist flower Ageratina riparia, and three biological control agents, Macrolabis pilosellae (Diptera: Cecidomyiidae), Cheilosia urbana, and Cheilosia psilophthalma (Diptera: Syrphidae) for biological control of hawkweeds (Hieracium spp.). Both applications were approved for agent release into the environment.     

Effects of surface charge and Gibbs surface energy on the settlement behaviour of barnacle cyprids (Balanus amphitrite)

Gibbs surface energy has long been considered to be an important parameter in the design of fouling-resistant surfaces for marine applications. Rigorous testing of the hypothesis that settlement is related to Gibbs surface energy however has never been accomplished, due mainly to practical limitations imposed by the necessary combination of surface engineering and biological evaluation methods. In this article, the effects of surface charge and Gibbs surface energy on the settlement of cyprids of an important fouling barnacle, Balanus amphitrite, were evaluated. Settlement assays were conducted on a range of self-assembled monolayers (SAMs) (CH₃-, OH-, COOH-, N(CH₃)₃ ⁺-, NH₂-terminated), presented in gold-coated polystyrene well plates, varying in terms of their surface charge and Gibbs surface energy. Contrary to contemporary theory, settlement was not increased by high-energy surfaces, rather the opposite was found to be the case with cyprids settling in greater numbers on a low-energy CH₃- SAM compared to a high-energy OH- SAM. Settlement was also greater on negatively-charged SAMs, compared to neutral and positively-charged SAMs. These findings are discussed in the context of data drawn from surfaces that varied in multiple characteristics simultaneously, as have been used previously for such experiments. The finding that surface charge, rather than total surface energy, may be responsible for surface selection by cyprids, will have significant implications for the design of future fouling-resistant materials.