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关键词： 克隆技术   生殖生物学   中国科学院   动物研究所   国家重点实验室   无性繁殖   细胞克隆   人民政协   大元   发展情况  

摘要： 陈大元教授是中国科学院动物研究所生殖生物学国家重点实验室研究员、受精生物学学科带头人、博士生导师。同时担任科技部"克隆大熊猫研究"攀登项目首席科学家。最近他就我国克隆技术的发展情况接受了《人民政协报》记者专访。

关键词： receptor   γ-Aminobutyric Acid   Molecular Biology   Mammals   Growth  

摘要： gamma-Aminobutyric acid (GABA) is the predominant inhibitory neurotransmitter in the mammalian central nervous system. After release from nerve terminals, GABA binds to at least two classes of postsynaptic receptors (ie, GABA(A) and GABA(B)), which are nearly ubiquitous in the brain. GABA(A) receptors are postsynaptic heteropentameric complexes that display unique physiologic and pharmacologic properties based on subunit composition. Activation of GABA(A) receptors in mature neurons results in membrane hyperpolarization, which is mediated principally by inward chloride flux, whereas in early stages of brain development, GABA(A) receptor activation causes depolarization of the postsynaptic membrane. GABA(B) receptors reside both presynaptically and postsynaptically, exist as heterodimers and are coupled to voltage-dependent ion channels through interactions with heterotrimeric G proteins. This review summarizes the molecular biology and ontogeny of GABA(A) and GABA(B) receptors, highlighting some of their putative roles during normal brain development as well as in disease states such as epilepsy.

关键词： SKELETON   VERTEBRATES  

摘要： This paper examines the origin and philosophical significance of Richard Owen's (1804-92) theory of the archetypal vertebrate in relation to the important methodological developments of German-inspired anti-empiricist methodologies in England in the 1814-45 period, particularly as articulated by Samuel Taylor Coleridge and his close disciple, the surgeon Joseph Henry Green (1791-1863), and in a parallel form by William Whewell. Positioned in intimate contact with both Green and Whewell in the crucial 1840s period, Owen was able to develop his theory of the archetype in direct contact with these methodological insights. This warrants the recognition of determinative intellectual and conceptual issues in the formulation of this theory in addition to the social constructivist factors suggested by Nicolaas Rupke and Adrian Desmond. The general conclusion of the paper suggests that both kinds of factor are needed to understand Owen's important theoretical development.

关键词： GASTROPODA   ANIMAL morphology   MOLECULAR genetics  

摘要： The new genus Fagora of the family Pachychilidae Troschel, 1857 is described for the type species Melania asperata Lamarck, 1822 from the Philippines. In addition to F. asperata, a second endemic species of the new genus, F.. dactylus (I. Lea & H.C. Lea, 1850), is recognized on the basis of shell morphometry and molecular genetic data (cytochrome C oxidase I and 16S rRNA). The taxonomic history of F. asperata and F. dactylus is revised and the recent distribution documented on basis of available museum material and the authors' own field collections. F. asperata occurs on Luzon and its satellite islands Leyte and Samar, while F. dactylus is restricted to the Visayan islands Bohol, Cebu, and Guimeras. The morphology of the two species is presented and illustrated in detail, and compared to taxa of the closely related genus Brotia H. Adams, 1866 to which they were previously assigned. Among the South-east Asian freshwater Cerithioidea of the family Pachychilidae, which were previously subsumed under Brotia for their more or less similar shell morphology and operculum, three distinct lineages can be distinguished, in particular by means of distinct reproductive anatomy: (1) the species of Brotia sensu stricto from mainland Southeast Asia, Sumatra, Borneo and Java, which all exhibit a subhaemocoelic brood pouch;(2) the pachychilid species endemic to Sulawesi, currently assigned to the genera Brotia and Tylomelania, as well as both species of Pseudopotamis endemic to the Torres Strait Islands, which possess a uterine brood pouch;(3) the females of the Philippine Fagora, which carry egg capsules, embryos and advanced juvenile stages within the mantle cavity-a unique reproductive feature. Associated with this mode of ovoviviparity, Fagora is characterized by additional unique properties of the reproductive system including a deeply incised and long sperm gutter in the medial lamina, a very short and posteriorly positioned spermatophore bursa formed by the medial lamina, an

关键词： biometry   computers   phylogeny   statistics   systematics  

摘要： The twentieth century witnessed a dramatic increase in the use of statistics by biologists, including systematists. The modern synthesis and new systematics stimulated this development, particularly after World War II. The rise of "the statistical frame of mind" resulted in a rethinking of the relationship between biological and mathematical points of view, the roles of objectivity and subjectivity in systematic research, the implications of new computing technologies, and the place of systematics among the biological disciplines.

关键词： 微生物学   食品检验   农产品   食品   细菌纲   试验   基准方法   微生物有机体   厌氧的   微生物分析   肉制品   亚硫酸还原生物   梭菌属   细菌计数方法   肉   肉食分析   计数方法(微生物学)   检测   定义   倒出和切割板法  

标准号: ISO 15213-2003

摘要： This International Standard specifies a horizontal method for the enumeration of sulfite-reducing bacteria growing under anaerobic conditions. It is applicable to — products intended for human consumption and the feeding of animals, and — environmental samples in the area of food production and food handling.

关键词： 琼脂法   定义   农产品   食品   方法   BAIRD-PARKER琼脂   实验室试验   额定值   分析方法   微生物学   精密度   计数   试验   微生物分析   计数方法(微生物学)   营养液   分析   葡萄球菌属   琼脂   食品检验   饲料   生化分析法   菌落计数技术   测定   凝固酶   实验室间试验   微生物   调查方法  

标准号: ISO 6888-1 AMD 1-2003

摘要： This is Amendment 1 to ISO 6888-1-1999 (Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of coagulase-positive staphylococci {Staphylococcus aureus and other species) — Part 1: Technique using Baird-Parker agar medium)

关键词： 实验室试验   分析方法   测定   计数   微生物学   食品   葡萄球菌属   饲料   分析   微生物分析   计数方法(微生物学)   菌落计数技术   血纤维蛋白原   营养液   凝血酶   菌落计数   食品检验   定义   验证   调查方法   试验   微生物   农产品  

标准号: DIN EN ISO 6888-3-2003

关键词： 食品   稀释   规范(验收)   试验室   定义   微生物分析   试样制备   农产品   生物测定   食品检验   微生物学   稀释法   鱼类   悬浮液   饲料   生物试验   鱼制品   比率的   饮食   鱼肉  

标准号: EN ISO 6887-3-2003

关键词： 微生物分析   试样制备   验证   定义   试验   计数   食品   细菌培养   细菌计数方法   农产品   一般条件   肠杆菌科   食品检验   微生物学   水平的   饲料   细菌纲   方法   微生物   测定  

标准号: DIN EN ISO 10273-2003

摘要： This standard describes a horizontal method for the detection of Yersinia enterocolitica.