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关键词： Parasitology   Biochemistry   Pharmacology  

摘要： Small G proteins belong to a superfamily of GTPases related to the protooncogene ras, and function as master control elements for a range of cellular functions. This ability is related to their low rate of substrate turnover;GTPases catalyse the conversion of GTP to GDP, but with a rate in the order of one substrate per second, orders of magnitude slower than 'good' enzyme catalysis, but placing the reaction into the temporal frame of many cellular processes including signal transduction, cytoskeletal reorganization and vesicle trafficking. In this article, Mark Field, Bassam Ali and Helen Field describe some recent advances in G-protein studies in the parasite field, concentrating on the protozoan parasites. Because of their numerous roles in cell biology, understanding parasite G proteins has great potential for increasing our knowledge of parasite cellular physiology, as well as providing important inroads into vital processes for potential therapeutic exploitation.

关键词： 水生动物   汞污染   生物学特征  

摘要： 汞是动物体非必需的重金属元素，它容易被动物体吸收和富集，不易被动物体排除，更不能被动物所分解，它可经由食物链（网）进行传递，对人体健康造成威胁。因此，汞对水生动物的污染早就引起人们的关注，二十世纪５０年代中期日本发生两千多渔民严重汞中毒（即“水俣病”...

关键词： 铜   生物学效应   人体   动物  

摘要： 铜是生物正常生长发育所必需的微量元素之一。１９２８年威斯康星大学哈特（Ｈａｒｔ）的研究证明，由于喂饲乳汁而患贫血症的大白鼠饲料中添加铜和铁，对血红素的形成是必要的。铜在生物体中的作用主要是参与构成体内具有特殊生理机能的物质，是多种酶系统的活化剂、辅因...

关键词： Aggression   Behavior   Biological invasions   Competition   Introduced species  

摘要： A major challenge of invasion biology lies in the development of a predictive understanding of invasion processes. Attempts to identify the proximate causes of invasion success or to predict rates of spread seldom emphasize behavioral characteristics. Recent experimental work, however, illustrates that insight into the proximate causes of animal invasions often hinges on a careful assessment of behavioral mechanisms. For this reason, behavioral analyses should be more fully integrated into research on biological invasions. In addition to enhancing a general understanding of invasion processes, such approaches provide potentially underused opportunities for basic research in animal behavior.

关键词： 自身免疫疾病/遗传学   疾病模型   动物   基因打靶   炎症   淋巴毒素α/遗传学   淋巴毒素α/生理学   主要组织相容性复合物/遗传学   多态现象   遗传   肿瘤坏死因子α/遗传学   肿瘤坏死因子α/生理学   动物   人类  

关键词： calcium wave   CICR   calcium oscillations   oocyte   meiosis arrest   maturation   sperm factor   ICSI   IP3   cADPr   IP3R   RyR   capacitative calcium entry   CaMKII   mouse   sea urchin   protostome   deuterostome  

摘要： During animal fertilizations, each oocyte or egg must produce a proper intracellular calcium signal for development to proceed normally. As a supplement to recent synopses of fertilization-induced calcium responses in mammals, this paper reviews the spatiotemporal properties of calcium signaling during fertilization and egg activation in marine invertebrates and compares these patterns with what has been reported for other animals. Based on the current database, fertilization causes most oocytes or eggs to generate multiple wavelike calcium oscillations that arise at least in part from the release of internal calcium stores sensitive to inositol 1,4,5-trisphosphate (IP3). Such calcium waves are modulated by upstream pathways involving oolemmal receptors and/or soluble sperm factors and in turn regulate calcium-sensitive targets required for subsequent development. Both "protostome" animals (e.g., mollusks, annelids, and arthropods) and "deuterostomes" (e.g., echinoderms and chordates) display fertilization-induced calcium waves, IP3-mediated calcium signaling, and the ability to use a combination of external calcium influx and internal calcium release. Such findings fail to support the dichotomy in calcium signaling modes that had previously been proposed for protostomes vs deuterostomes and instead suggest that various features of fertilization-induced calcium signals are widely shared throughout the animal kingdom, (C) 1999 Academic Press.

关键词： 传入通路/生理学   模型   神经学   疼痛/病理生理学   脊髓/病理生理学   脊髓损伤/病理生理学   动物   人类   大鼠  

摘要： Behavioral models indicate that persistent small afferent input, as generated by tissue injury, results in a hyperalgesia at the site of injury and a tactile allodynia in areas adjacent to the injury site. Hyperalgesia reflects a sensitization of the peripheral terminal and a central facilitation evoked by the persistent small afferent input. The allodynia reflects a central sensitization. The spinal pharmacology of these pain states has been defined in the unanesthetized rat prepared with spinal catheters for Injection and dialysis, After tissue injury, excitatory transmitters (e.g., glutamate and substance P) acting though N-methyl-D-aspartate (NMDA) and neurokinin 1 receptors initiate a cascade that evokes release of (i) NO, (ii) cyclooxygenase products, and (iii) activation of several kinases, Spinal dialysis show amino acid and prostanoid release after cutaneous injury. Spinal neurokinin 1, NMDA, and non-NMDA receptors enhance spinal prostaglandin E2 release. Spinal prostaglandins facilitate release of spinal amino acids and peptides, Activation by intrathecal injection of receptors on spinal C fiber terminals (mu,/partial derivative opiate, alpha 2 adrenergic, neuropeptide Y) prevents release of primary afferent peptides and spinal amino acids and blocks acute and facilitated pain states. Conversely, consistent with their role in facilitated processing, NMDA, cyclooxygenase 2, and NO synthase inhibitors act to diminish only hyperalgesia. Importantly, spinal delivery of several of these agents diminishes human injury pain states. This efficacy emphasizes (i) the role of facilitated states in humans, (ii) shows the importance of spinal systems in human pain processing, and (iii) indicates that these preclinical mechanisms reflect processes that regulate the human pain experience.

关键词： 档案   CD-ROM   数据收集/方法   数据说明   统计   数据库   事实型   环境暴露/统计学和数值数据   国际机构   模型   组织管理   放射生物学   放射性同位素/投药和剂量   放射性同位素/治疗应用   镭   危险性评估/组织和管理   词表   受控   动物   人类  

摘要： Animal experiments have contributed a great deal to our information on effects and risks arising from exposure to radionuclides. This applies, in particular, to alpha-emitting radionuclides where information from man is limited to thorotrast, Ra-224 and Ra-226. The late C.W. Mays was the first to suggest that animal data in conjunction with epidemiological data could allow estimates of human risks for radionuclides - predominantly from actinides - where information in man is scarce. The 'International Radiobiology Archives of Long-term Animal Studies' were created through the combined efforts of European, American and Japanese scientists and aim to safeguard the large amount of existing data on longterm animal experiments and make them available for, among others, an improved assessment of risks from alpha-emitting radionuclides. This paper summarizes the structure of the archives and reviews their present status and future plans. It also demonstrates the extensive information available in these archives on alpha-emitting radionuclides which is suitable for further analysis. Also, the structure of the animal archives could - in a slightly modified form - accommodate the epidemiological data available on Ra-224 and thorotrast and, thus, facilitate a. direct comparison of data from man, dogs and rodents.

关键词： NASA Discipline Exobiology   Non-NASA Center  

摘要： The Cambrian appearance of fossils representing diverse phyla has long inspired hypotheses about possible genetic or environmental catalysts of early animal evolution. Only recently, however, have data begun to emerge that can resolve the sequence of genetic and morphological innovations, environmental events, and ecological interactions that collectively shaped Cambrian evolution. Assembly of the modern genetic tool kit for development and the initial divergence of major animal clades occurred during the Proterozoic Eon. Crown group morphologies diversified in the Cambrian through changes in the genetic regulatory networks that organize animal ontogeny. Cambrian radiation may have been triggered by environmental perturbation near the Proterozoic-Cambrian boundary and subsequently amplified by ecological interactions within reorganized ecosystems.

关键词： 异黄酮植物雌激素   研究   应用  

摘要： 本文对异黄酮植物雌激素的种类、测定方法及在动物体内代谢规律进行了综述 ,同时也就该激素对生殖和乳腺发育双向作用进行了评述 。