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关键词： 灵长类动物   牙冠延长术   生物学宽度   形成  

摘要： 本研究的目的是明确生物学宽度在牙冠延长术后能否及如何重建的问题。以3只成年猴为实验对象，对其上下颌的右侧或左侧中、侧切牙实施牙冠延长术，以未手术的对侧牙为对照。术后12周，切除组织块进行组织学分析。组织测量结果显示，生物学宽度在牙冠延长术后得以重建；结合上皮多迁移至根面平整区的根方；骨嵴顶上方结缔组织纤维束的距离由牙槽嵴顶发生骨吸收而产生。

关键词： 分子生物学技术   基因工程   转基因   动物营养学  

摘要： 本文从营养与基因表达调控、基因工程、转基因等三个方面综述了分子生物学技术在动物营养学中应用的最新进展，并对动物营养学的发展前景作了展望。

关键词： 霉菌总数   细菌总数   大肠埃希菌   沙门菌   微生物学   实验动物   ^60Co照射   饲料微生物   直接饲喂   贮存  

摘要： 为了探讨粉料、制粒后出机料、成品料的微生物学质量变化情况，指导实际工作，应用常规的检测方法，对普通级实验动物鼠及兔饲料细菌总数、霉菌总数、大肠埃希菌最近似数（MPN）及致病性沙门菌等进行了检测。其结果表明：1. 所有检测样品均未检出大肠埃希菌及致病性沙门菌。2. 所有粉料的细菌总数及霉菌总数均超过国标（鼠料5×104、1×102，兔料1×105、1×102）。3. 出机时的鼠料其微生物学质量均符合国家标准，而兔料的细菌总数及霉菌总数均超标。4. 成品鼠料，贮存一周，细菌总数及霉菌总数均低于国标，贮存二周，霉菌总数低于国标，但细菌总数大于国标，三周、四周后细菌总数及霉菌总数均大于国标；成品兔料，其细菌数和霉菌数均高于国标。提示：出机时的鼠料可直接饲喂一级动物，成品鼠料，保存时间不易超过一周；兔料必须经过80 ℃、2 h 或60Co照射等处理方可食用。

关键词： global mammal conservation priorities   international conservation journals   IUCN Red List   resources allocation  

摘要： Recent upsurge of interest in biological diversity requests that resources for conservation be allocated to taxonomic groups and geographic areas of greater priority, independent of the 'attractiveness' of individual species. The aim of this paper is to assess if contributed papers on four of the most important international conservation journals in the last ten years reflect our increasing concern for threatened mammals. Our results show that some orders receive disproportionally more attention than predicted by their absolute number and percentage of threatened species. The Nearctic and Palearctic Regions are far more studied than other like, for instance, the Oriental Region, which are badly neglected considering their higher rates of endangered and endemic mammals. Furthermore, it was found that among many orders most of the species covered in contributed papers are not presently considered threatened by IUCN. Our work highlights the need of assessing conservation priorities at least at continental level and of devoting more resources to research in tropical countries.

关键词： asexual reproduction   bryozoan   Cristatella mucedo   gene flow   genetic variation   metapopulation   microsatellites  

摘要： Theoretical models of the impact of a metapopulation structure on the genetics of a species have resulted in multiple predictions that have seldom been empirically evaluated. Here we present microsatellite data from 14 populations of a freshwater bryozoan, Cristatella mucedo, collected along a waterfowl migratory route in north-western Europe. C. mucedo is facultatively sexual and has the unusual tactic of dispersing via asexually generated propagules. These propagules are likely to be dispersed by waterfowl and therefore the populations that we sampled were expected to maintain some degree of connectivity. Our data illustrate a metapopulation comprising well-differentiated populations connected by low levels of ongoing gene flow, patterns that agree with predictions based on theoretical work. However, contrary to expectations of a metapopulation, particularly one in which asexual reproduction predominates, genetic variation within populations was often high. This diversity seems to be at least partially attributable to the gene flow that results from ongoing dispersal.

关键词： 稀土   畜牧生产   水产养殖   作用机理   生物学效应  

关键词： Electromagnetic Fields   Mechanoreceptors   Nervous System Physiology   电磁场   机械感受器   神经系统生理学   neurobiology   Vertebrates   Mechanoreceptors   magnetic field   Electromagnetic induction   Nervous System Physiological Phenomena  

摘要： Diverse vertebrate animals can sense the earth's magnetic field, but little is known about the physiological mechanisms that underlie this sensory ability. Three major hypotheses of magnetic-field detection have been proposed. Electrosensitive marine fish might sense the geomagnetic field through electromagnetic induction, although definitive evidence that such fish actually do so has not yet been obtained. Studies with other vertebrates have provided evidence consistent with two different mechanisms: biogenic magnetite and chemical reactions that are modulated by magnetic fields. Despite recent progress, however, primary magnetoreceptors have not yet been identified unambiguously in any animal.

关键词： Apodemus sylvaticus   Eimeria hungaryensis   Eimeria uptoni   Eimeria apionodes   prevalence   capture/recapture  

摘要： The first long-term (27 month) survey of single species of Eimeria occurring in a population of Apodemus sylvaticus in the UK showed that Eimeria apionodes, E. hungaryensis and E. uptoni occurred throughout the period whilst E. sp. E. was only found during 4 months. In first-captured animals, overall prevalence of Eimeria spp. was 73 % : a figure higher than previously published, but possibly an underestimate. Multiple infections (2 or 3 species) occurred in 34 % of first-capture infected animals, but without significant associations. There were no significant differences of prevalence rates between the sexes, nor between adults and juveniles, except for E. uptoni which was more common in juveniles than in adults. E. hungaryensis and E. uptoni probably occurred as near-continuous infections whilst E. apionodes occurred more intermittently but with no long-term total immunity. Monthly prevalence data indicated ongoing trends over the 27 months. Prevalences of E. apionodes indicated an annual cycle, lowest in January-May and with a peak in October-November, correlating positively with both the number of animals and the percentage of juveniles in the host population and also with the environmental relative humidity. There was no consistent pattern for E. uptoni and an annual cycle for E. hungaryensis was not apparent.

关键词： 原生动物   分子生物学技术  

摘要： 随着研究方法的进步，分子生物学技术在原生动物研究中得到了越来越广泛的应用．综述同工酶、ＰＣＲ、ＲＡＰＤ、序列测定及核酸原位杂交在原生动物研究中的应用．

关键词： 虹彩病毒   水生动物   病毒病害   鱼类   两栖类   分子生物学   特性   系统性疾病   研究进展   感染  

摘要： 在水生动物病毒病害中，虹彩病毒引起的系统性疾病占有很重要的地位，而且虹彩病毒能感染鱼类、两栖类及爬行类动物，给全世界水产业带来了重大经济损失。本文拟就虹彩病毒各方面的特性作一叙述。