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关键词： Animals   China   Echinodermata/anatomy & histology   Echinodermata/classification   Fossils   Phylogeny   Phylogeny   Time Factors  

摘要： Provides information on the origins of echinoderms based on the newly discovered fossils from China. Illustrative example of sea urchin symmetry as the unique pentaradiate form of echinoderms; Interpretation of paleontologists on the characteristics of vetulocystids, group of echinoderms which is difficult to interpret even their basic anatomical organization; Details of information on the branch of the animal kingdom of echinoderms.

关键词： Cerithium atratum   spatio-temporal distribution   migration   allometry   growth   secondary production   Sao Sebastiao Channel  

摘要： The spatial distribution, population structure and secondary production of the gastropod Cerithium atratum were studied in the intertidal region of Engenho d'Agua Beach in Sao Sebastiao Channel on the northern coast of the state of Sao Paulo, Brazil, from May 1998 to April 1999. Twenty monthly samples were taken using a 0.25x0.25 m quadrat in each of two areas. Individuals showed a clustered dispersion pattern in both areas throughout the sampling period. Abundance and mean shell size were related to period of the year and to intertidal level, although no consistent pattern could be described when comparing the two sampling areas due to significant interaction between time and locality. Migratory events were evidenced by marked year-round variations in the frequency of individuals in the largest size classes. Thus, the size structure of this population could not be explained by recruitment and growth alone. Almost 90% of the intertidal population was represented by small individuals that recruited at the beginning of the sampling period (May to August 1998). The intertidal population was composed of annual cohorts formed by individuals recruited in different years. Each annual cohort could be divided into sub-cohorts with closely spaced recruitment periods in the same breeding season. The growth and annual P/(B) over bar ratio (where P is the annual somatic production and (B) over bar is the mean annual biomass) was estimated for the first year of life of recruits from 1998 occupying the intertidal region. Individuals may have an increment of up to 15 mm in shell length during the first year of life, but the growth was more pronounced in summer months. The high value of P/(B) over bar (3.902) was a consequence of the dominance of small-sized individuals, which have a higher weight-specific increment than large-sized ones.

关键词： .Animal Viruses  

关键词： 分子生物学   动物   营养水平   基因表达  

摘要： 综述了分子生物学在动物营养研究中的应用:从分子水平上阐述营养与基因表达、调控的关系;利用生物学技术改变动物体内的代谢途径或生产酶制剂、氨基酸等动物营养物质前景广阔。

关键词： 驼科动物   动物起源   生物学特性   生活环境  

摘要： 一直以来,驼科动物是这一生物界创造的杰作,它们伴随着人类,成为人类生产生活的忠实伙伴.驼科动物由于其特殊的生活环境,形成了它们特殊的生活特性.

关键词： 滑膜   滑膜囊   滑液   滑膜细胞  

摘要： 目的　建立动物皮下滑液囊模型 ,研究其功能结构特点 ,探讨形成的可能机制。方法　在兔皮下埋置硅胶气囊 ,经扩张按摩刺激 ,逐渐形成包裹囊腔 ,通过对大体形态、组织学和超微结构、细胞表型、UDPGD功能性酶以及滑囊液HA浓度的研究 ,与正常滑膜囊比较。结果　术后 2周时 ,皮下形成“滑囊腔”结构 ,肉眼见囊腔内表面光滑 ,扫描电镜见囊壁内表面有微绒毛结构 ,囊壁表层有A、B型细胞的超微结构特征 ;细胞分别表达CD68、VCAM 1和UDPGDmRNA ,囊壁表层UDPGD酶活性高于深部 (P <0 .0 1) ;囊内液体清亮透明 ,未发现细胞成分 ,透明质酸近似浓度 160ng ml,高于血清水平 (P<0 .0 1)而接近关节滑液 (P >0 .0 5 )。结论　皮下形成的滑囊腔模型 ,其功能结构在一定程度上类似关节滑囊腔 ,囊壁表层细胞具有滑膜细胞的表型特征。

关键词： Nannophrys ceylonensis   breeding   polygyny   paternal care  

摘要： Nannophrys ceylonensis (Ranidae) is a terrestrial breeding anuran, found on wet vertical or near-vertical rock surfaces. Non-breeding adult males and females take refuge in separate crevices in the rock surfaces during the day and emerge at night to forage. Males can be polygynous;mating takes place inside crevices. Fathers exhibit paternal care for multiple clutches of eggs and guard eggs from predators. Paternal care of this species is obligatory;hatching success decreases without it. Females do not contribute to parental care. Males show nest site fidelity and defend territories against conspecifics. A scarcity of suitable nest sites may limit reproductive success in N. ceylonensis. Larvae hatch at Gosner stages 21-22 and leave their nests at stages 24-25 to live as truly terrestrial tadpoles, foraging on the rock surfaces near their natal nests.

关键词： Crytosporidium spp.   livestock   companion animals   prevention  

摘要： The epidemiology of cryptosporidiosis, an infection caused by several genotypically and phenotypically diverse Cryptosporidium species, has been dynamically changing over the past decade from that of a rare, largely asymptomatic infection to an acute enteric disease of animals and humans. In this review, the current understanding of factors (biology and epidemiology) contributing to the emergence of cryptosporidiosis in animals, including parasite biology, genetic diversity, environmental spread, livestock production trends, presence of the parasite in livestock and companion animals, and potential risk of transmission from animals to humans is highlighted. Potential control measures and the role of veterinary and medical professionals in the prevention of cryptosporidiosis are also discussed. (C) 2004 Elsevier SAS. All rights reserved.

关键词： 分析   饲料   食品检验   食品   食品检测   微生物分析   微生物学   抽样方法   药棉方法   试验   验证  

标准号: BS ISO 18593-2004

摘要： ISO 18593:2004 specifies horizontal methods for sampling techniques using contact plates or swabs on surfaces in the food industry environment (and food processing plants), with a view of detecting or enumerating viable microorganisms.

关键词： bacterial surface display   cytokines   IL-4   immobilization   signal transduction  

摘要： We describe a novel procedure that allows the rapid determination of cytokine activity on cells that express their cognate receptor. The four-helix bundle cytokine interleukin-4 (IL-4) was inducibly expressed as a fusion with the E. coli outer-membrane protein intimin, such that IL-4 was presented on the surfaces of the bacteria. Expression and accessibility of the cytokine on the cell exteriors were monitored by Western blotting and fluorescence microscopy, making use of two epitopes flanking the IL-4 component of the fusion protein. To demonstrate the biological activity of the immobilized cytokine, a Ba/F3-derived cell line stably transfected with both the bipartite human IL-4 receptor and an IL-4-specific luciferase reporter gene construct was employed. Bacterial cells displaying interleukin-4 elicited a specific, dose-dependent response in the reporter cells. Two variants of IL-4 with previously characterized (partial) antagonistic properties were also expressed as membrane-bound fusion proteins and were tested for their activity in the immobilized state. In comparison with bacteria displaying wild-type IL-4, E. coli clones presenting variants IL-4 Y124G and Y124D showed diminished or abolished activity respectively, on murine reporter cells. The relative signaling potencies of the immobilized IL-4 variants thus closely mirror the agonistic properties of the corresponding soluble cytokines. This approach should be generally applicable for the mutational analysis of numerous signal mediators that trigger cellular responses through dimerization of transmembrane receptors.