生物比较法教学浅析

生物比较法教学,是指按照事物对立统一规律和人的认识规律,将复杂多样的生命现象和本质,进行分析鉴别和综合比较的教学方法。1生物比较法教学的作用初中生物学,以辩证唯物主义为指导,讲述了各种生命现象和规律。在初中生物教学中,如何帮助学生能举一反三、全面系统准确地认识掌     

小麦幼苗tRNA的提取及其性质

以高等植物作为材料研究核酸,日益引起人们的重视。核酸既是生命的基本物质之一,又是遗传的物质基础。植物的生长、分化、发育和生殖等基本生命现象都与核酸代谢密切相关。为对这些生命现象进行深入的探讨,伴随而来的是要求建立可靠的植物细胞特有的核酸提取、纯化、测定方法。而将动物或微生物的核酸研究中行之有效的分离纯化方法,应用于高等植物材料时,往往不能得到满意的结果。为此,进行以高等植物组织或细胞为对象的核酸研究方法的摸索是     

鱼类细胞自噬研究进展

自噬是广泛存在于真核生物中的生命现象,对于细胞的生长、分化、发育和维持细胞内环境稳态等方面具有重要意义。尽管对于作为低等脊椎动物的鱼类细胞自噬研究起步较晚,但近几年围绕其自噬的诱导、自噬相关基因表达及调控、鱼类病原诱导的自噬,特别是以斑马鱼为试验模型开展的自噬与发育调控关系等研究都取得了一些进展,就此进行综述。     

浅谈比较法在初中生物课堂教学中的应用

生物比较法教学,是指按照事物对立统一规律和人的认识规律,将复杂多样的生命现象和本质,进行分析鉴别和综合比较的教学方法。比较法是研究生物学的重要方法,也是生物教学的重要方法,是生物教学中培养学生能力、开发学生智力的重要手段。     

初中生物教学比较法初探

生物教学比较法是按照事物对立统一规律和人的认识规律,将极其复杂多样的生命现象和本质,进行分析鉴别、综合比较的方法.比较法是研究生物学的重要方法,也是生物教学的重要方法,是生物教学中,培养学生能力,开发学生智力的重要手段。     

试论生物数学的特点与展望

在自然科学发展的历史上,生物学与数学长期以来各自独立、联系甚少。直到20世纪,两门学科才开始相互渗透。由此产生一支新兴的边缘学科——生物数学。 1901年Pearson创办《生物统计学》(Biometrika)杂志,标志着这门学科发展的起点。初期的生物数学研究工作局限于对生命现象作静止的、定量的描述。研究的手段仅仅是统计学、几何、代数和一些初等的解析方法。 30年代以后,生物物理学的发展促进了数学向生物学的进一步渗透。数学在生物学中的应用不再局限于静止地、孤立地描述生命现象,开始分析生命现象复杂的过程,探索其规律性。数学物理方法在生理学、生态学的研究中首先获得成功。以数学物理方法研究生物     

生物学概念教学的有效方法

生物学是一门研究生命现象及其活动规律的自然学科,其基本原理都是建立在生物概念的基础上,因此,生物学概念是生物学领域最基本的语言表达单位,也是思维的基本单位,生物学概念学习是意义学习中最基本的类型,掌握生物学概念是学生学习生物学、了解生命现象及其活动规律、解决问题乃至进行创造的必要前提。     

中学生物教材中对照实验的理论探源

生物学是建立在实验基础上的自然科学。生命现象又往往受到多种因子的影响和制约,并且生物本身又存在着极为鲜明的多样性,因此生物学研究的方法论比其它自然科学更为重要。生物科学史表明:对照实验是确定单因子对生命现象影响的常用而有效的方法。本文试图初探对照实验设计的理论渊源。     

植物学实验教学的探索

植物学是学生进入中学后首先接触到的实验性学科.如何在植物课中贯彻“三个面向”的指示,我们作了一些尝试. 我们认为“三个面向”对智育上的要求,主要是培养有科学的思维方法及具有探求新知识能力的人.针对初一学生及植物学这门学科的特点,我们的教学注意了以下三点: 第一,要充分体现生物学是研究生命现象的科学.生命现象是复杂的,到处都存在.因此,我们每一堂课都应让学生的感官充分地感受到那丰富活跃的生命现象,激发他们对生物、     

糖生物学是研究生命现象的第三个里程碑——糖生物学专刊序言

生命现象的分子基础主要依赖于生物大分子及其相关的一些小分子。生物化学家一直认为：蛋白质和核酸是体现生命现象最重要的生物大分子。20世纪60年代左右,人们才认识到另一类由不同单糖组成的糖链是除蛋白质和核酸外体现生命现象的第三类生物大分子,糖链的研究已公认为继蛋白质和核酸的研究后探索生命奥秘的第三个里程碑。     

几种细胞凋亡检测方法的比较

近年来,凋亡细胞的检测方法从以形态学观察发展到生物化学、免疫化学和分子生物学等定性和定量测定技术,并在细胞、染色质到分子水平日趋完善和成熟。这些方法多用于描述DNA的片段化和细胞死亡过程中许多特定成分的检测。细胞凋亡具有其生物复杂性,检测方法要求灵敏度高、特异性强、准确性好、凋亡与坏死的区分明显等。由于每种方法各有优缺点,故应避免使用单一方法检测。     

真菌内共生细菌研究进展

自真菌内共生细菌在1970年被首次发现以来,各个时期的学者都采用当时流行的研究方法关注宿主真菌及其内共生细菌之间的关联现象。近年来科技手段日益多样,对二者相互作用的探索逐渐成为新的研究热点,随着研究的不断拓展和深入,越来越多的生物学现象和原理被揭示。本文在真菌内共生细菌的研究方法、定殖位置、形态、分类、宿主类群、共生关联的建立、生物学功能、宿主治愈、分离和重新植入等方面进行综述,并在此基础上进行展望,以期为真菌内共生细菌的广泛深入研究提供借鉴。     

生物聚集体中群体感应作用的研究进展

群体感应是微生物利用信号分子感知环境条件并进行特定基因表达调控.近年来,随着群体感应在微生物信息交流中的作用日益凸显,其在生物聚集体(生物膜和颗粒)形成过程中的作用受到广泛关注.本文综述了自体诱导信号分子AI的分类和相应的群体感应调控方式,以及群体感应信号分子对生物聚集体形成和结构稳定的调控,并对群体感应研究新领域进行了展望.     

Microarray missing data imputation based on a set theoretic framework and biological knowledge

Gene expressions measured using microarrays usually suffer from the missing value problem. However, in many data analysis methods, a complete data matrix is required. Although existing missing value imputation algorithms have shown good performance to deal with missing values, they also have their limitations. For example, some algorithms have good performance only when strong local correlation exists in data while some provide the best estimate when data is dominated by global structure. In addition, these algorithms do not take into account any biological constraint in their imputation. In this paper, we propose a set theoretic framework based on projection onto convex sets (POCS) for missing data imputation. POCS allows us to incorporate different types of a priori knowledge about missing values into the estimation process. The main idea of POCS is to formulate every piece of prior knowledge into a corresponding convex set and then use a convergence-guaranteed iterative procedure to obtain a solution in the intersection of all these sets. In this work, we design several convex sets, taking into consideration the biological characteristic of the data: the first set mainly exploit the local correlation structure among genes in microarray data, while the second set captures the global correlation structure among arrays. The third set (actually a series of sets) exploits the biological phenomenon of synchronization loss in microarray experiments. In cyclic systems, synchronization loss is a common phenomenon and we construct a series of sets based on this phenomenon for our POCS imputation algorithm. Experiments show that our algorithm can achieve a significant reduction of error compared to the KNNimpute, SVDimpute and LSimpute methods.     

Data Deposition and Annotation at the Worldwide Protein Data Bank

The Protein Data Bank (PDB) is the repository for three-dimensional structures of biological macromolecules, determined by experimental methods. The data in the archive is free and easily available via the Internet from any of the worldwide centers managing this global archive. These data are used by scientists, researchers, bioinformatics specialists, educators, students, and general audiences to understand biological phenomenon at a molecular level. Analysis of this structural data also inspires and facilitates new discoveries in science. This chapter describes the tools and methods currently used for deposition, processing, and release of data in the PDB. References to future enhancements are also included. Shuchismita Dutta, Kyle Burkhardt, and Ganesh J. Swaminathan have contributed equally to this work.     

Application of theoretical group methods in the modeling of complex systems

It has been shown that theoretical group methods can be applied in studies of complex physical and biological systems in which the phenomenon of self-organization takes place. The problem of calculating the parameters of climatic sensitivity with allowance for the cyclone-anticyclone structure of the atmosphere optically dense in the infrared region is considered as an example.     

Quantitative analysis of formate in solutions containing phosphate

Standard colorimetric methods based on the initial reduction of formate to formaldehyde were found to yield erratic results when applied to the analysis of millimolar concentrations of formate in a microbial culture medium. The source of interference was identified as inorganic orthophosphate inhibition of the magnesium/hydrochloric acid reduction stage. Passivation of magnesium by millimolar concentrations of phosphate is known to occur at low pH and it is proposed that this phenomenon is responsible for the inhibition of the reduction process. The presence of orthophosphate in biological extracts is almost universal and would lead to acceptance of spuriously low values for formate concentration if the previously unreported inhibitory effect is not recognized. The colorimetric method of Barker and Somers in which formate is reacted directly with 2-thiobarbituric acid to form the chromophore was evaluated and proved to be entirely free from interference by orthophosphate and other medium components. This method although less sensitive than the formate reduction methods is therefore suggested as the method of choice for the determination of formate in biological or other solutions containing phosphate.     

History of development of evolutionary methods in St. Petersburg school of computer simulation in biology

The work presents a short history of development of evolutionary methods in the St. Petersburg school of computer simulation of biological processes. Several moments confirm priority of this school in modeling of micro- and macroevolutionary processes. A peculiarity of the school is a combination of the applied and theoretical study, penetration into the biological essence of phenomenon, consideration of real interrelationships of ecological and physiological parameters. The natural tendency for transition to modeling at the level of single individuals and then-to imitation of evolutionary processes on computer is traced. Paradoxically, such detalization sometimes does not worsen, but improves prognostic properties of models of populations, communities, and ecosystems, and besides, makes unnecessary monitoring of some variable characteristics, because the individual-based approach allows to direct account for adaptive processes and hidden evolutionary relationships between the life history parameters. Problems and perspectives of development of evolutionary methods of modeling are analyzed.     

密码子偏性的分析方法及相关研究进展

密码子偏性是指生物体中编码同一种氨基酸的同义密码子的非均衡使用的现象,由于这一现象与遗传信息的载体分子DNA和生物功能分子蛋白质相关联,所以具有重要的生物学意义;本文概述了密码子偏性研究方面的基本理论和常用分析方法,归纳了密码子使用分析的常用软件和提供在线分析网站,介绍了与密码子偏性相关的生物学领域及最新的研究进展,并对深入研究进行展望。