我国核酸和核酸保健品抗衰保健研究进展

本文综述核酸及外源性核酸作为保健品的开发研究进展。从外源性核酸对动物自身DNA损伤保护,对动物生长发育及生存质量的改善,对机体的免疫功能的提高和对抗氧化酶系活性的提高,对动物老年色素形成产生的影响、DNA添加于化妆品中的临床试验、DNA在案例分析中的应用,核酸保健品的生产以及对核酸营养的异议等多方面进行探讨。     

反义RNA网络──一种新假说

根据核酸的基本特性和最新研究成果,提出了一种新的假说──反义RNA网络：生物体内存在着许许多多小分子的基因组反义RNA以及与之互补的反反义RNA片段,由于机体的自身修饰作用（或其它机理）,它们彼此不发生复性或杂交.这种反义RNA网络一方面参与调控特定基因在特定部位、特定时间的启动和关闭,维持机体各种功能活动的相对稳定,另一方面对体内突变核酸和体外侵入核酸发挥特异性识别和排斥作用.     

功能核酸概念的内涵与外延

对功能核酸概念的分析需要建立在对功能核酸研究的基础上,从内涵和外延两个方面来进行探析。从内涵来看,它是对具有特殊结构、执行特定生物功能的核酸分子的统称;从外延来看,它包括适体、核酸核酶、核糖开关、发光核酸、修饰核酸、功能核酸裁剪、核酸自组装、功能核酸纳米材料、核酸纳米酶、核酸药物、核酸补充剂以及DNA存储技术等。目前功能核酸已成功地应用于生物传感、生物成像、生物医学等诸多领域。对功能核酸这一概念进行了探讨,并尝试对其范畴、特点进行归纳总结,以期梳理和完善功能核酸的基本概念,促进该领域的进一步发展。     

珍奥酵母核酸对环磷酰胺致小鼠免疫功能低下的影响

目的 通过环磷酰胺致小鼠免疫功能低下,建立BALB/C小鼠免疫功能低下模型,评价珍奥酵母核酸对小鼠免疫功能低下的作用.方法 选用BALB/C小鼠,随机分组,分别给予相应的处理,选择T淋巴细胞亚群CD69+/CD3+比值、NK细胞亚群CD69+/NKG2D+比值、淋巴细胞转化率及血清IL-2含量作为细胞免疫的指标.结果 核酸各剂量组和添加剂组均可使免疫低下小鼠外周血和脾的T淋巴细胞亚群CD69+/CD3+比值、NK细胞亚群CD69+/NKG2D+比值提高,同时可提高免疫低下小鼠淋巴细胞转化率及IL-2水平,尤以高、中剂量核酸组和添加剂组明显(P＜0.05).结论 珍奥酵母核酸可以提高免疫低下小鼠的免疫功能,以其为珍奥酵母核酸的临床应用及提高机体免疫力提供了实验依据.     

异种DNA对受照小鼠体细胞染色体的保护效应

核酸代谢是机体内对射线较敏感的一个重要环节。在急性放射病时,体内一些重要生命物质代谢,尤其是核酸代谢遭到破坏,并导致其他一系列物质代谢的紊乱,从而影响整个细胞代谢过程,造成组织和脏器的功能障碍,成为急性放射损伤重要发病机理之一。因此,机体在受急性外照射时,若能阻断和抑制其代谢紊乱进一步发展,或能修复体内核酸大分子的辐射损伤,并加速核酸的合成代谢等,就成为     

核酸疫苗的特点、组成及在动物免疫中的应用

核酸疫苗是一种新型的基因工程疫苗,它将含有编码某种抗原蛋白基因序列的重组质粒作为疫苗直接导入机体细胞内,通过宿主细胞的转录系统合成抗原蛋白,诱导机体产生体液免疫和细胞免疫．从而使被接种机体获得相应的免疫保护而达到防病治病的目的。就核酸疫苗的特点、组成、免疫方式、目前存在的主要问题及在动物免疫中的应用情况进行综述。     

食药用真菌: 天然抗氧化剂的重要来源

生物体在新陈代谢过程中不断产生自由基。自由基在机体内的生成和去除通常处于平衡状态,不会对机体造成严重损伤,但当机体内的自由基过剩时,常引起生物大分子如脂类、蛋白质和核酸的氧化损伤,进而引发机体衰老以及癌症、动脉粥样硬化、风湿性关节炎、肺气肿等疾病。过去20年中,自由基在细胞损     

功能核酸DNA水凝胶的制备与组装

功能核酸DNA水凝胶是一种以DNA为构建单元通过化学反应或物理缠结自组装而成的新型柔性材料,其构建单元中包含1种或多种能够形成功能核酸的特定序列。功能核酸是通过碱基修饰和DNA分子之间的相互作用力组合的一类特定核酸结构,包括核酸适配体、DNA核酶、G-四联体(G-quadruplex,G4)和i-motif结构等。传统上,高浓度的长DNA链是制备DNA水凝胶的必要条件,而核酸扩增方法的引入为DNA水凝胶的组装方式提供了新的可能。因此,对常用于制备DNA水凝胶的多种功能核酸以及核酸的提取、合成和扩增手段进行了详细的介绍。在此基础上,综述了通过化学或物理交联方式组装功能核酸DNA水凝胶的制备方法。最后,提出了DNA纳米材料的组装所面临的挑战和潜在的发展方向,以期为开发高效组装的功能核酸DNA水凝胶提供参考。     

家蝇飞翔肌线粒体超氧化物歧化酶活性及荧光衰老色素含量的年龄变化的研究

超氧阴离子(O_2~-)是生物体内的主要自由基。自由基与很多大分子如脂质、蛋白质及核酸等反应,破坏细胞的结构,干扰细胞的功能,根据Harman 的自由基理论,最终导致有机体的衰老和死亡。超氧化物歧化酶(SOD)促进O_2~-的歧化反应,对机体起保护作用,因此认为它与寿命有关。荧光哀老色素(FAP)又叫脂褐素,被认为是自由基诱导的不饱和脂肪酸和其他大分子如:蛋白质、核酸等氧化的终产物。它的含量被看成是发     

恒温技术介导的功能核酸生物传感器研究进展

随着社会不断发展,消费者对食品安全的关注度日渐上升,食品多样性日益增加,食品流通量日益增长,对食品安全检测技术的要求不断提升。功能核酸通过形成特定的空间结构,能够发挥除了储存遗传信息以外的多种功能,在检测领域起到重要作用。功能核酸生物传感器是一类利用功能核酸进行信号识别、信号放大或者信号输出的传感器,具有高灵敏度、高特异性、检测时间短、成本低等优势。为了避免对变温仪器设备的依赖,实现现场检测,恒温技术介导的功能核酸生物传感器发展迅速。相对于变温技术,恒温技术无需变温设备,有些在室温条件下即可进行,能够降低检测成本,在一定程度上缩短检测时间。根据恒温技术在功能核酸生物传感器中的功能不同,可以分为恒温介导的信号识别技术、信号放大技术和信号输出技术。就这3个方面对恒温技术介导的功能核酸生物传感器展开论述,并从理论层面、应用层面和学科交叉方面提出展望。     

Experiments with lysis of living cells of Eremothecium ashbyii and of Methanomonas by microbial enzymes

The possibility to use microorganisms as human food is limited by several factors. The intact cell is resistant to digestion, the cell wall is unbalanced in essential amino acids, and the nucleic acids are said to be harmful. For using single cell protein as food it may thus be necessary to disrupt the cell wall and separate the protein from nucleic acid. This paper is concerned with the production and properties of extracellular enzymes able to lyse cell walls of microorganisms. Soil bacteria and actinomycetes have been cultivated and lytic enzymes from these organisms have been used to lyse living cells of the yeast like organism E. ashbyii. Efforts were also made to use these enzymes for lysing cell of a Methanomonas sp.     

Libraries for genomic SELEX.

An increasing number of proteins are being identified that regulate gene expression by binding specific nucleic acidsin vivo. A method termed genomic SELEX facilitates the rapid identification of networks of protein-nucleic acid interactions by identifying within the genomic sequences of an organism the highest affinity sites for any protein of the organism. As with its progenitor, SELEX of random-sequence nucleic acids, genomic SELEX involves iterative binding, partitioning, and amplification of nucleic acids. The two methods differ in that the variable region of the nucleic acid library for genomic SELEX is derived from the genome of an organism. We have used a quick and simple method to construct Escherichia coli, Saccharomyces cerevisiae, and human genomic DNA PCR libraries that can be transcribed with T7 RNA polymerase. We present evidence that the libraries contain overlapping inserts starting at most of the positions within the genome, making these libraries suitable for genomic SELEX.     

细菌CRISPR-Cas系统的研究进展

获得性免疫长期以来被视为真核生物所独有,而CRISPR-Cas系统的发现则打破了这一定论。它是广泛存在于细菌和古菌中的一种获得性免疫系统,通过捕获整合初次感染的外源核酸片段,在Cas蛋白与cr RNA(CRISPR RNAs)的共同作用下抵御相同核酸的再次入侵,以保护宿主免受侵扰。近些年,CRISPR-Cas系统得到广泛的关注和研究。本文主要从细菌微生物角度,对系统分类、作用机制及原核领域应用等取得重要突破的研究进行扼要阐述,为CRISPR-Cas系统的深入探究和应用拓展提供有价值的参考信息。     

Nucleic acid hybridization: from research tool to routine diagnostic method

The nucleic acid hybridization reaction is extremely specific and thus a valuable tool for the identification of genes or organism of interest. The increasing use of nucleic acid hybridization in applied fields like diagnostic medicine has led to the development of more convenient hybridization assays than those originally used in basic research. In conventional nucleic acid hybridization methods immobilized nucleic acids are detected on a filter by a radiolabelled probe. Sandwich hybridization is a simple test format for the analysis of unpurified biological material, but has the disadvantage of a slow reaction rate. Solution hybridization methods are fast and easy to perform provided that a method to separate the formed hybrids from the reaction mixture is available. In non-isotopic detection the nucleic acid probe is modified with a chemical group, which is identified with a labelled detector molecule after hybridization. The low sensitivity of detection is the main problem in nucleic acid hybridization methods. Procedures to amplify the detectable signal or the amount of detectable nucleic acid sequences are potential solutions to this problem. The new hybridization methods have successfully been used for some applications, but still need to be combined into well performing tests to be applicable to any desired purpose.     

Optical fiber-based sensors: application to chemical biology

Optical fibers have been used to develop sensors based on nucleic acids and cells. Sensors employing DNA probes have been developed for various genomics applications and microbial pathogen detection. Live cell-based sensors have enabled the monitoring of environmental toxins, and have been used for fundamental studies on populations of individual cells. Both single-core optical fiber sensors and optical fiber sensor arrays have been used for sensing based on nucleic acids and live cells.     

Helicase translocation assay method using avidin and biotinylated nucleotides

Helicase involves many cellular processes that separate double-stranded nucleic acid into single strands. Although it is believed that helicase translocates nucleic acids, it is difficult to show the direct evidence of translocation on nucleic acids. In this study, an avidin-biotinylated nucleotides-based method for helicase translocation assay has been described, and the biochemical assay results have been demonstrated.     

Comparison of nucleic acid extraction platforms for detection of select biothreat agents for use in clinical resource limited settings

High-quality nucleic acids are critical for optimal PCR-based diagnostics and pathogen detection. Rapid sample processing time is important for the earliest administration of therapeutic and containment measures, especially in the case of biothreat agents. In this context, we compared the Fujifilm QuickGene-Mini80 to Qiagen's QIAamp Mini Purification kits for extraction of DNA and RNA for potential use in austere settings. Qiagen (QIAamp) column-based extraction is the currently recommended purification platform by United States Army Medical Research Institute for Infectious Diseases for both DNA and RNA extraction. However, this sample processing system requires dedicated laboratory equipment including a centrifuge. In this study, we investigated the QuickGene-Mini80, which does not require centrifugation, as a suitable platform for nucleic acid extraction for use in resource-limited locations. Quality of the sample extraction was evaluated using pathogen-specific, real-time PCR assays for nucleic acids extracted from viable and γ-irradiated Bacillus anthracis, Yersinia pestis, vaccinia virus, Venezuelan equine encephalitis virus, or B. anthracis spores in buffer or human whole blood. QuickGene-Mini80 and QIAamp performed similarly for DNA extraction regardless of organism viability. It was noteworthy that γ-irradiation did not have a significant impact on real-time PCR for organism detection. Comparison with QIAamp showed a less than adequate performance of the Fujifilm instrument for RNA extraction. However, QuickGene-Mini80 remains a viable alternative to QIAamp for DNA extraction for use in remote settings due to extraction quality, time efficiency, reduced instrument requirements, and ease of use.     

Circulating nucleic acids: possible inherited effects

The presence of circulating nucleic acids in man, animals and plants is well documented. It is clear that such nucleic acids can not only circulate freely within an organism, but can also enter cells when their biology may be changed either epigenetically or genetically. Evidence is presented concerning a possible influence of these nucleic acid fragments on the genetics of the F1 generation of man, animals and plants. The data presented also offer a mechanism by which the incorporation of horizontally transferred genes between organisms may be achieved. The role that circulating nucleic acids might play in modifying the F1 generation and possibly the evolutionary process is considered. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 931–948.     

Extracellular nucleic acids

Extracellular nucleic acids are found in different biological fluids in the organism and in the environment: DNA is a ubiquitous component of the organic matter pool in the soil and in all marine and freshwater habitats. Data from recent studies strongly suggest that extracellular DNA and RNA play important biological roles in microbial communities and in higher organisms. DNA is an important component of bacterial biofilms and is involved in horizontal gene transfer. In recent years, the circulating extracellular nucleic acids were shown to be associated with some diseases. Attempts are being made to develop noninvasive methods of early tumor diagnostics based on analysis of circulating DNA and RNA. Recent observations demonstrated the possibility of nucleic acids exchange between eukaryotic cells and extracellular space suggesting their participation in so far unidentified biological processes.