蒙古人与蒙古马

蒙古马是世界多个马科类的一种,很早以前就生活在中亚北部广阔的草原。世界上除了蒙古马以外,还有很多种马。这些马种从身个到神态,乃至其习性都有很大的差异。蒙古马这一称谓源于蒙古人与它们赖以生存的蒙古草原。蒙古马与蒙古人最早结缘。     

Children and Their Pets

Abstract

This study examines the frequency of pet possession and its covariation with family variables (family size, housing conditions, parents' employment, maternal support) among elementary school children. Additionally, children's pet caring activities and their emotional relationship to pets were investigated. Subjects were 426 fourth graders (213 boys, 213 girls). Results indicate that pets are very frequently present in families, with the dog as the most common and most preferred animal. Parents' employment and maternal support do not covariate with pet possession, but housing conditions do. The child-pet relationship depends on childrens' gender, pet type and status of ownership (child vs. family). The intensity of pet caring is mainly related to pet type and ownership, whereas the quality of emotional contact depends on pet type and childrens' gender. On the background of manifold articles reporting case studies and educational, respectively clinical counseling experiences the discussion emphasizes the need for sound empirical research on the relationship between personality characteristics and pet ownership.     

GDNF家族及其受体

神经营养因子对神经系统的发育和维持起着至关重要的作用。它们不但能够促进神经元的分化和存活 ,而且抑制与神经系统退行性疾病、神经损伤和神经毒相关的神经元的退化。最近被确认的ＧＤＮＦ家族是ＴＧＦ β家族成员的远亲。ＧＤＮＦ作为该家族的第一个成员 ,发现于 1 993年 ,由Ｌｉｎ等人[1] 由大鼠胶质细胞株Ｂ49中提纯到 ,发现它能促进胚胎中脑多巴胺能神经元的存活和形态分化 ,以及提高它们对高亲和性多巴胺的摄取。最近的研究发现 ,与其它神经营养因子相比 ,ＧＤＮＦ对多巴胺能神经元和去甲状腺能神经元有更强的促活能力[2 ] ,并且对…     

金属硫蛋白及其生物学功能

金属硫蛋白(metallothionein, MT) 是一类富含半胱氨酸的低分子质量蛋白质,已鉴定4种亚型：MT-1、MT-2、MT-3和MT-4,基于各亚型功能的相对异质性而使MT呈现其生物学作用的多样性。金属硫蛋白通过与金属离子结合而参与基因表达调控和机体的重金属解毒过程;金属硫蛋白通过抑制多种氧化应激途径而保护细胞免受损伤;金属硫蛋白通过参与细胞的增殖、分化和凋亡的调节而影响肿瘤及其他重大疾病的发生发展。本文在金属硫蛋白的结构和分类的基础上综述其生物学作用及其相关机制。     

植物中的反转录转座子及其应用

反转录转座子是植物中最不稳定的遗传元件之一,它们对基因组的大小、结构、功能和进化都有重要作用。本文综述了近年来对植物反转录转座子类型和结构、在基因组中表达、调控、转座活动、进化等方面的研究进展,讨论了它们在遗传研究中的应用前景。 Abstract:Retrotransposons are one of the most unstable genetic elements in the plant kingdom,they have the potential to dramatically affect gene function and host genome structure.The current status of their types and structure,expression regulation,transposition,and evolution are reviewed.Their potential as genetic tools are also discussed.     

Human Associations and Their Characteristics

Human associations are among the chief, yet perhaps least explored, problems in Soviet social psychology. Moreover, terminology regarding this subject, which is still very fluid, complicates the problem even further. Often the same concept conceals different meanings or, conversely, the same meaning is covered by different concepts.     

微量营养素与抗氧化防御作用

现代医学证明,机体和氧进行正常交换时产生的自由基,能损伤蛋白质、核酸等生物大分子,改变细胞结构与功能,从而影响人体健康、引发疾病、甚至危及生命。微量营养素中的维生素E、维生素C、β-胡萝卜素等维生素和某些抗氧化酶依赖的硒、锌、铜等元素,是生物体内抗氧化防御系统的组成成分,可直接或间接地清除活性氧或阻断连锁氧化反应,保护细胞及生物大分子免受氧化损伤。因此,它们在抗氧化防御系统中具有重要的作用,合理摄入这些微量营养素,对预防动脉硬化、抗癌、改善免疫功能及延缓衰老等有着特殊的意义。     

拟糖多肽及其应用

细胞表面的糖链不仅参与细胞粘着、信号转导等正常生理过程,也介导许多病原体(病毒和细菌)及毒素与宿主细胞的吸附。并且,还在许多肿瘤细胞表面观察到有别于正常细胞的糖链,它们影响着肿瘤细胞的生长、发展和转移。因此,以糖作为抑制剂或疫苗而影响上述糖链与配体大分子间的相互作用就成为治疗许多疾病的出发点。然而,以糖类作为药物有一些天然的缺陷:(1)纯化与合成困难;(2)免疫原性较差,而且极易受到免疫系统的攻击,等等。因此,必须寻找糖的模拟物。其中一种模拟物就是肽或者多肽。这一思想最先源于免疫学的理论:如果抗体1(Ａｂ1)是针对某…