对"扩散"和"渗透"的讨论

自由扩散和协助扩散都是可自由运动的微粒通过热运动而发生的2种过膜扩散．生物体内的渗透是自由水通过生物膜的协助扩散。     

<生态旅游>一书评介

近年来生态旅游一词频频见于宣传媒体 ,它代表一种时尚 ,更是反映人类自我教育、自我完善的一种行动。旅游活动从来都是作为个人的行为 ,作为某种精神和物质的消费。然而 ,随着全球性生态危机的出现 ,人们的环境意识不断增强。从关心自身到关心环境 ,从追求当前利益到追求长远的可持续发展 ,一种新的生态观正在形成。这就是生态旅游出现的时代背景。生态旅游被认为是旅游可持续发展的最佳模式 ,成为当代世界旅游业的新时尚 ,代表了 2 1世纪旅游业发展的方向和潮流。我国幅员辽阔 ,地貌、气候类型复杂 ,生物多样性丰富 ,有着开展生态旅游活动…     

生态学的“教”与“做”的教学模式探讨

根据高等师范院校培养具有创新知识和创新能力的新型人才的办学宗旨．从本校生态学课程开设理论教学学时数少、实验教学刚起步的实情出发,结合生态学基础性强、研究范围广、应用范围宽的学科特点,阐述了在生态学教学中,为了营造良好的生态学学习情境、激发学生的学习兴趣,教师为“教”所进行的筛选课程内容、改进教学方法和构建新的实验体系与培养学生探究应用能力即“做”的教学模式探讨与体会。     

Reflections on the problem of "discreteness" and "steady state" in living processes

A survey is given over the different meaning of the dialectic pair of terms continuity and discontinuity in philosophy contrasting with sciences. In mathematics, the term continuum is defined by Cantor in set theory as the innumerable multitude of the real numbers especially in the interval [0, 1]. The discontinuum means in Cantor's definition the rational fractions in [0, 1] which in triadic development do not contain the figure 1 [written I). In a more general sense, continuum is used in the mechanics of continuous fluids and gases in physics as well as in physiology. Here, the use of this term neglects the reality of intermolecular spaces intentionally. To employ in the life sciences, the pair of terms steady state and discreteness is clearer. Processes of life mostly are steady in the sense of balanced proceedings but numbers of individuals, cells, molecules, sexes etc, are discrete only. For example, the difference or the dimorphism between males and females is a distinct one between two different conditions but cannot be projected on "discontinuity". Discreteness as a term comprehends Boole an variables as are male-female, living-dead, as well as crowds of measure points.     

Special Issue on‘‘Metagenomics of Marine Environments’’

<正>We are pleased to announce a special issue on‘‘Metagenomics of Marine Environments’’of the journal Genomics,ProteomicsBioinformatics(GPB),aiming to provide a platform for high-quality papers focusing on the topic and we invite submissions for this special issue(to be published in the fall of 2015).With most microbes being difficult or impossible to culture     

Highlights on the capacities of "Gel-based" proteomics

Gel-based proteomic is the most popular and versatile method of global protein separation and quantification. This is a mature approach to screen the protein expression at the large scale, and a cheaper approach as compared with gel-free proteomics. Based on two independent biochemical characteristics of proteins, two-dimensional electrophoresis combines isoelectric focusing, which separates proteins according to their isoelectric point, and SDS-PAGE, which separates them further according to their molecular mass. The next typical steps of the flow of gel-based proteomics are spots visualization and evaluation, expression analysis and finally protein identification by mass spectrometry. For the study of differentially expressed proteins, two-dimensional electrophoresis allows simultaneously to detect, quantify and compare up to thousand protein spots isoforms, including post-translational modifications, in the same gel and in a wide range of biological systems. In this review article, the limits, benefits, and perspectives of gel-based proteomic approaches are discussed using concrete examples.     

Effect of "helper lipid" on lipoplex electrostatics

Lipoplexes, which are complexes between cationic liposomes (L+) and nucleic acids, are commonly used as a nucleic acid delivery system in vitro and in vivo. This study aimed to better characterize cationic liposome and lipoplex electrostatics, which seems to play a major role in the formation and the performance of lipoplexes in vitro and in vivo. We characterized lipoplexes based on two commonly used monocationic lipids, DOTAP and DMRIE, and one polycationic lipid, DOSPA--each with and without helper lipid (cholesterol or DOPE). Electrical surface potential (Psi0) and surface pH were determined using several surface pH-sensitive fluorophores attached either to a one-chain lipid (4-heptadecyl hydroxycoumarin (C17HC)) or to the primary amino group of the two-chain lipids (1,2-dioleyl-sn-glycero-3-phosphoethanolamine-N-carboxyfluorescein (CFPE) and 1,2-dioleyl-sn-glycero-3-phosphoethanolamine-N-7-hydroxycoumarin) (HC-DOPE). Zeta potentials of the DOTAP-based cationic liposomes and lipoplexes were compared with Psi0 determined using C17HC. The location and relatively low sensitivity of fluorescein to pH changes explains why CFPE is the least efficient in quantifying the differences between the various cationic liposomes and lipoplexes used in this study. The fact that, for all cationic liposomes studied, those containing DOPE as helper lipid have the least positive Psi0 indicates neutralization of the cationic charge by the negatively-charged phosphodiester of the DOPE. Zeta potential is much less positively charged than Psi0 determined by C17HC. The electrostatics affects size changes that occurred to the cationic liposomes upon lipoplex formation. The largest size increase (based on static light scattering measurements) for all formulations occurred at DNA-/L+ charge ratios 0.5-1. Comparing the use of the one-chain C17HC and the two-chain HC-DOPE for monitoring lipoplex electrostatics reveals that both are suitable, as long as there is no serum (or other lipidic assemblies) present in the medium; in the latter case, only the two-chain HC-DOPE gives reliable results. Increasing NaCl concentrations decrease surface potential. Neutralization by DNA is reduced in a NaCl-concentration-dependent manner.     

"基因突变的特征及意义"的主体性教学研讨

在高中生物学过渡教材“基因突变的特征及意义”的教学过程中,笔者采用主体性教学观指导下的课堂设计,引导学生主动参与和积极思维,促使学生主动获取科学知识、形成科学的思维方式。     

《经济动物学》教学模式的探索

合理修订《经济动物学》教学大纲,科学、有效、实用地优化课程内容,强化实践教学;针对地域特点编写了实用型新教材,使教学真正落到实处;变传统教学模式为多媒体计算机辅助教学,运用精心制作的《经济动物学》多媒体教学课件进行教学,提高了教学效率和教学质量;针对成人函授特点,改革考核办法,确保教学质量。