Graphite: a mimic for DNA and other biomolecules in scanning tunneling microscope studies

Highly ordered pyrolytic graphite (HOPG) is the substrate often used in scanning tunneling microscope (STM) studies of biomolecules such as DNA. All of the images presented in this article are of freshly cleaved HOPG surfaces upon which no deposition has occurred. These images illustrate features previously thought to be due to biological molecules, such as periodicity and meandering of "molecules" over steps. These features can no longer be used to distinguish real molecules from features of the native substrate. The feasibility of the continued use of HOPG as a substrate for biological STM studies is discussed.     

紫茎泽兰化学成分及其生物学活性研究进展

 简要评述了紫茎泽兰中的10多种化学成分及其生物学活性的研究进展。     

海洋微生物源生物农药研究进展

综述了海洋微生物源生物农药的最新现状,系统总结了海洋微生物源生物农药种类,展望了海洋微生物源生物农药的应用前景。     

生物入侵机理研究进展

综述生物入侵机理的生态学研究、生理学研究、分子生物学研究,并展望今后的研究方向。     

Calcitonin receptors of kidney and bone

Receptors for calcitonin, determined by activation of adenylate cyclase, were found in a distribution among zones of the kidney distinct from that of receptors for parathyroid hormone or vasopressin. Competitive binding studies showed that the receptors for calcitonin are similar in kidney and bone and that their high apparent affinity for salmon calcitonin accounts in part for the high biological potency in vivo of salmon calcitonin.     

Radiological physics characteristics of the extracted heavy ion beams of the bevatron

Studies of the depth-ionization properties and the biological effects of heavy ion beams produced at the bevatron have extended work previously done with less energetic beams from other sources. Results indicate that heavy ion beams are suitable for tumor therapy, studies relating to space biology, and fundamental radiobiology.     

基因组学在植物病理学中的应用

基因组学研究开创了一个新的生物学世纪,特别是在农业领域。随着遗传模式植物的利用,农业上重要生物的序列测定以及生物信息学和功能基因组学的结合使用促进了农业领域基因组学的发展。笔者就利用基因组学研究方法在植物病理学学科中所取得的一些进展进行了综述。这些研究对深入了解植物-病原菌的互作关系,最终提高植物对有害生物的抗性提供参考。     

植物内生菌研究进展

现有研究表明植物内生菌及其次级代谢产物具有多种生物学功能,是一种潜在的药物开发的新型资源库。该综述针对近年来有关内生菌分离纯化方法及次级代谢产物的生物活性作用等方面的研究进展进行总结概括,以期为植物内生菌资源的开发和利用提供帮助。     

化学固氮的研究

本文讨论了在温和条件下从空气进行化学固氮的问题。在比较了生物固氮和化学固氮的基础上,认识到其间的一些共同特点,这就是为使氮分子活化必须要有过渡金属。随之讨论了有关这方面的机理。为了模拟生物固氮,对固氮酶进行了一系列的研究。本文试就固氮催化剂的化学模型进一步提出一些看法。     

木质素对菲的吸附作用研究

在石油污染土壤生物强化修复技术研究这一实际工程项目前期研究工作的基础上,建立了木质素吸附菲的试验方法,通过木质素对有机污染物吸附作用的多次试验具,考察了各种操作条件对于木质素对菲的吸附特性的影响,得出了木质素可以富集污染物的结论,对石油污染土壤生物强化修复技术研究这一工程项目具有重要的基础意义。     

我国生物冰核研究进展

我国从1986年起开展了冰核活性细菌的研究,已取得一定的进展。查明了我国冰核细菌种类、分布规律、冰核活性强弱程度,明确了影响冰核细菌冰核活性的某些因素和提出了菌种保存方法;验证了冰核细菌是诱发和加重植物霜冻的重要因素,研究揭示冰核细菌、低温强度和植物霜冻害三者的关系,并进行了药剂和生物防霜新技术研究;利用冰核细菌研制成功了冰蛋白降水催化剂,开展了促冻杀虫、克隆了编码冰蛋白的冰核活性基因及有关冰核细菌分子生物学应用技术研究;首次报道了大麦黄矮病毒冰核活性,对揭示未知生物冰核种类有一定意义。     

植物生物防治精准化施药技术的研究进展

为了减少化学农药滥用造成的危害,精准施药技术及相关植保机械发展迅速,实现了化学农药的减施增效,并提高了化学农药的利用率。但在生物防治领域,尤其是利用活体生物的防治措施中,精准化施药技术研发相对滞后,增加了生物农药向市场推广应用的难度。为了更好地了解针对生物防治的精准化施药技术研究现状,分别从植保机械精准施药技术现状、植物病虫害和杂草生物防治的精准施药技术等方面展开综述,并对生物防治精准化施用技术进行了研究展望,旨在为生物防治更加精准高效地推广应用提供发展思路。     

Total eclipses of the sun

Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans.     

珍稀濒危鸡种不同取样方法DNA提取的研究

为了克服珍稀濒危鸡种在分子生物学研究中存在的取样局限性,拓宽取样范围,对鸡的血液、精液、羽毛和死胎蛋的DNA提取进行了研究。结果表明不同取样部位所提DNA浓度均适合于生物学实验要求。该研究中有关方法的应用将为珍稀濒危鸡种的分子生物学研究提供更广阔的DNA来源。     

International research: its role in environmental biology

To determine the role of environmental factors in human health, studies on several population groups are essential, involving the most sophisticated techniques possible. The logistic and political problems associated with such studies, especially in developing countries, and the high cost of modern environmental biological investigations make it particularly desirable to avoid unnecessary duplication and waste of resources. For certain investigations an international research center would appear to have considerable advantages, provided that the organizational difficulties can be overcome. Not only can such an organization provide the human data necessary for calculating the balance between the benefits and harm of a given course of action but also it may stimulate the long-term routine laboratory studies so necessary as a basis for extrapolation from animals to man.     

禽类胚胎生物工程技术研究进展

禽类繁殖力高，饲养成本低；禽蛋干物质含量高，蛋白质含量多，蛋白容易收集保存，不易受外界污染，这些都使禽类胚胎生物工程技术展现出美好的发展前景。本文对禽类胚胎生物工程技术，包括禽类胚胎体外培养技术、禽类嵌合体技术和禽类基因转移技术的研究进行了综述。     

天然楝酰胺类似物的生物活性研究进展

介绍了楝酰胺类化合物的结构和生物活性,从杀虫活性、药物抗癌活性、杀菌活性3方面分析了楝酰胺化合物的生物活性与构效的关系,并对该类化合物今后的研究方向进行了展望。     

Time-resolved x-ray diffraction of biological materials

Instrumental and specimen considerations pertinent to performing time-resolved x-ray diffraction on biological materials are discussed. Existing synchrotron x-ray sources, in conjunction with integrating x-ray detectors, have made millisecond diffraction experiments feasible; exposure times several orders of magnitude shorter than this will be possible with synchrotron sources now on the drawing boards. Experience gained from time-resolved studies together with order-of-magnitude estimates of specimen requirements can be used to determine the instrumental capabilities needed for various time-resolved experiments. Existing instrumental capabilities and methods of dealing with time-resolved specimens are reviewed.     

How obesity causes diabetes: not a tall tale

The epidemic of obesity-associated diabetes is a major crisis in modern societies, in which food is plentiful and exercise is optional. The biological basis of this problem has been explored from evolutionary and mechanistic perspectives. Evolutionary theories, focusing on the potential survival advantages of "thrifty" genes that are now maladaptive, are of great interest but are inherently speculative and difficult to prove. Mechanistic studies have revealed numerous fat-derived molecules and a link to inflammation that, together, are hypothesized to underlie the obesity-diabetes connection and thereby represent prospective targets for therapeutic intervention.