虚拟生物实验室实例

虚拟生物实验室在生物课程资源中有巨大并且尚未开发的潜力。它对于不同级别学生的学习都是有利的。介绍了虚拟生物实验室的一些实例。并展望了其应用前景。     

分子人类学与现代人的起源*

1953年Watson & Crick 对于DNA双螺旋结构模型的提出及对其遗传机理的解释,标志着现代分子生物学的诞生。其后短短50年的时间里,分子生物学在各个学科之间广泛渗透,相互促进,不断深入和发展。在以研究人类的起源和进化为首要任务的人类学领域,由于现代分子生物学理论和方法的应用,诞生了分子人类学这一全新的结合型分支学科,为人类学的发展提供了科学可信的研究方法和具发展前景的研究方向。系统地介绍了分子人类学的发展历史、研究方法及原理;另外,结合分子人类学在古人类学研究中的应用,讨论了关于现代人起源的“非洲起源说”和“多地区连续演化说”。Abstract: Since Watson & Crick put forward the double-helix model of DNA structure and hereditary mechanism in 1953, it is generally accepted that this event marks the birth of modern molecular biology. This new field of biology has experienced a flourishing development in the past 50 years. On one hand, the development of molecular biology has been deeply influencing many relative fields; on the other hand, its own proceeding pace has been accelerated by the reaction from the other fields. Anthropology is one of the fields most deeply impacted by the theory and method of molecular biology. Most importantly, molecular anthropology was born as a result of combination of molecular biology, anthropology as well as paleoanthropology. This new branch provides reliable method and vital direction for paleoanthropology. This paper systematically reviews the history, principle and method of molecular anthropology. Two hypotheses on the origin of modern human, which include “out-of-African theory” and “theory of multiregional evolution” are also discussed for the purpose of showing how molecular anthropology is applied in paleoanthropology.     

山医群体中国地鼠近交E家系RAPD分析

目的　分析山医群体中国地鼠E家系的遗传纯度。方法　应用经过筛选的 3 1条随机引物对中国地鼠E家系 12只个体基因组DNA进行RAPD扩增 ,计算近交个体间的相似系数。结果　所有样品的相似系数0 943 1到 0 9978之间变动 ,平均相似系数为 0 9749,聚类分析得到了这些个体的同源树资料。结论　山医群体E家系有较高的遗传纯度     

Kinetics of ultrasonic degradation and polymerisation degree distribution of sonochemically degraded chitosans

The process of physical degradation by means of the ultrasonic action towards chitosans with mole fraction of 2-acetamido-2-deoxy-β- -glucopyranose units (the degree of N-acetylation, F_A) in the range of 0.10≤F_A≤0.28, and the weight average polymerisation degree in the range of has been investigated. The decrease of as well as changes in the distribution of the degree of polymerisation (P) has been determined as a function of time, F_A, temperature, concentration of chitosan solution and concentration of acetic acid in the solution. The use of low-power ultrasound emitter allowed to establish that in the case of chitosan (binary heteropolysaccharide) the general rate parameter (k) increased with F_A. This can be explained by the relatively stronger aggregation of macromolecules with higher F_A, which results in size increase of macromolecular individuals and hence in their higher susceptibility to ultrasonic action. It was also observed that k decreased with chitosan concentration and temperature. The value of limiting degree of polimerisation (x_e) was found to be influenced by structural parameters of chitosan chains (F_A, aggregation). The increase of acetic acid concentration caused the increase in the k value, what indicated accelerating effect of ultrasound towards acidic hydrolysis of chitosan. The shape of the P curve of sonochemically degraded chitosans are in good correlation with the mid-point breakage concept of degradation accepted in sonochemical degradation of polymers.     

RAPD divergence caused by microsite edaphic selection in wild barley

Random amplified polymorphic DNA polymerase chain reaction (RAPDPCR) was used to assess genetic diversity in four subpopulations (86 individuals) of wild barley, Hordeum spontaneum, sampled from Tabigha microsite near the Sea of Galilee, Israel. The microsite consists of two 100 m transects that are topographically separated by 100 m, each equally subdivided into 50 m of basalt and terra rossa soil types. Despite the same macroclimate characterizing the area around the Sea of Galilee, the microsite offers two edaphically different microhabitats, with basalt being a more ecologically heterogeneous and broader-niche than the relatively drier but more homogeneous and narrow-niche terra rossa. Analysis of 118 putative loci revealed significant (P<0.05) genetic differentiation in polymorphism (P0.05) between the two soils across the transects with P being higher in the more heterogeneous basalt (mean P0.05 = 0.902), than in terra rossa (mean P0.05 = 0.820). Gene diversity (He) was higher in basalt (mean He=0.371), than in terra rossa (mean He=0.259). Furthermore, unique alleles were confined to one soil type, either in one or both transects. Rare alleles were observed more frequently in terra rossa than basalt, and in transect II only. Gametic phase disequilibria showed a larger multilocus association of alleles in basalt than terra rossa, and in transect I than II. Spearman rank correlation (r_s) revealed a strong association between specific loci and soil types, and transects. Also, analysis of multilocus organization revealed soil-specific multilocus-genotypes. Therefore, our results suggest an edaphically differentiated genetic structure, which corroborates the niche width-variation hypothesis, and can be explained, in part, by natural selection. This pattern of RAPD diversity is in agreement with allozyme and hordein protein diversities in the same subpopulations studied previously. This revised version was published online in July 2006 with corrections to the Cover Date.     

观赏植物花期调控途径及其分子机制

开花期控制对观赏植物的生产和应用具有重要意义。目前关于高等植物成花机理的研究已经取得了突破性进展,为观赏植物花期调控开辟了新途径。该文总结了观赏植物花期调控的途径和方法,并对改良观赏植物花期的技术思路做了初步分析。通过与高等植物成花机制研究的对比分析发现,观赏植物开花机理的研究已有了长足发展,一些观赏植物的转基因研究也取得了丰硕成果。利用分子设计育种途径改良观赏植物的开花期,突破了传统方法的局限性,其研究和应用前景非常广阔。     

粳稻SRAP分子标记遗传群的构建与分析

用超级稻品种‘沈农606’和普通粳稻‘丽江新团黑谷’为亲本杂交获得的102份F_2代单株,通过SRAP分子标记遗传分析,构建了包含14个连锁群,由129个多态性位点组成的水稻连锁图谱,此图谱覆盖基因组长度1671.5 cM,平均图距13.0 cM。连锁群上有17.2%的多态性位点表现偏分离,偏分离标记在连锁群上存在热点区域。     

鞘翅目昆虫核酸分子系统学研究现状

从研究对象、研究种类、研究内容等方面对鞘翅目Coleoptera核酸分子系统学研究的近况进行了总结和分析,研究中应用的技术主要有DNA序列分析、RELP技术、RAPD技术、AFLP技术、分子杂交技术和SSCD技术。并认为这些技术的应用对补充和完善传统分类方法,深入探讨各类群的分类地位和系统发育关系具有重要作用。     

人胎肝细胞分泌的低分子抑瘤物对白血病细胞的抑制作用

本工作证明了在胎儿组织中存在一类低分子天然肿瘤抑制物,它是胎儿组织细胞生成和分泌的,对瘤株细胞和原代白血病细胞有选择性抑制作用。初发期或复发期急性非淋巴细胞白血病患者的骨髓在体外液体培养条件下与肝细胞上清及其甲醇提取物共同孵育4d,可使所有病例的骨髓AML—CFU降低到不可检出的程度。因而,低分子天然抑瘤物是天然肿瘤免疫中的一个组成部分,它在肿瘤的诊断和治疗中有着深远的意义。     

肌球蛋白Ⅵ定向运动的蒙特卡罗模拟

根据myosin Ⅵ分子马达头部核苷的变化建立一个四态循环,然后利用蒙特卡罗方法模拟分子马达的动力学性质,讨论了myosin Ⅵ速度、滞留时间与溶液中ATP浓度、ADP浓度和负载力F的关系。模拟得到：myosin Ⅵ会在轨道微丝上进行梯跳运动并且每次在微丝上的滞留时间并不相同;另外,myosin Ⅵ的速度会随着ATP浓度的增加而增大,随着ADP浓度和负载力的增加而减小;负载力对myosin Ⅵ在胞内执行输运还是连接功能起一定的调节作用。