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关键词： 铬   生物学功能   动物生产  

摘要： 铬具有提高动物生长、生产和免疫性能,改善胴体品质和繁殖性能,缓解应激反应等作用。文章就铬的生物学功能、铬在动物生产上的应用效果进行了综合阐述。

关键词： 大豆黄酮   生物学功能   应用  

摘要： 大豆黄酮(Daidzein,DA)是广泛存在于豆科牧草中的具有雌性激素作用的天然活性物质。它具有降低心肌耗氧量、强心、降血脂、提高机体免疫机能和抑制雌激素依赖性肿瘤生长作用,还具有扩张冠状动脉、促进循环、改善心脏功能和抗氧化等功能。它可以从胃肠道吸收,8h达到最高血药浓度,代谢较为迅速。通过研究证明:大豆黄酮能参与畜禽神经内分泌生长轴和生殖轴功能的调节,具有促生长,提高泌乳性能,改善仔猪育成率和母鸡产蛋率的功能。因此研究和开发其作为新型饲料添加剂将具有较大的潜力和广阔的发展前景。

关键词： grouper   protogynous hermaphroditism   reef fisheries management   sexual pattern   spawning aggregation   spawning season  

摘要： The reproductive biology of Great Barrier Reef populations of the long-lived grouper Epinephelus fuscoguttatus (brown-marbled grouper or flowery cod) was investigated using histological analyses. Evidence provided by gonad morphology and age-based demographics suggested monandric protogynous hermaphroditism. Younger age groups contained only immature and mature females, and all males were above the size and age of 100% female maturity, consistent with secondary males derived from mature females by adult sex change. Fishing records confirmed that spawning aggregations of this species and the co-occurring Epinephelus polyphekadion (camouflage grouper) are sometimes targeted on the Great Barrier Reef. Sampling data revealed strong spawning seasonality for E. fuscoguttatus, with a relatively narrow annual spawning period (November to January). The temporal pattern of reproductive activity within the spawning period, based on occurrence of near spawning ovaries (containing hydrated oocytes), indicated spawning events may occur throughout much of the lunar cycle and only partly coincide with seasonal fishing closure periods on the Great Barrier Reef. The results indicate that protection would be enhanced by a longer seasonal closure. (C) 2007 The Authors. Journal compilation (C) 2007 The Fisheries Society of the British Isles.

关键词： artiodactyla   extinction   bushmeat   hunting   economic development and phylogenetic comparative methods  

摘要： Half of all artiodactyls ( even-toed hoofed mammals) are threatened with extinction, around double the mammalian average. Here, using a complete species-level phylogeny, we construct a multivariate model to assess for the first time which intrinsic ( biological) and extrinsic ( anthropogenic and environmental) factors influence variation in extinction risk in artiodactyls. Globally artiodactyls at greatest risk live in economically less developed areas, have older weaning ages and smaller geographical ranges. Our findings suggest that identifying predictors of threat is complicated by interactions between both biological and anthropogenic factors, resulting in differential responses to threatening processes. Artiodactyl species that experience unregulated hunting live in significantly less economically developed areas than those that are not hunted;however, hunted species are more susceptible to extinction if they have slower reproductive rates ( older weaning ages). In contrast, risk in non-hunted artiodactyls is unrelated to reproductive rate and more closely associated with the economic development of the region in which they live.

关键词： LECTURES & lecturing   ANIMAL communication   PHEROMONES   COMPARATIVE studies   CHEMICAL senses  

关键词： chemosignals   dispersal   infanticide   mating systems   predation risk   rodents   social behavior  

摘要： Herein, I summarize some basic components of rodent social biology. The material in this paper is summarized andcondensed from a recent book “Rodent Societies: An Ecological and Evolutionary Perspective” edited by J. *** and P. W. Sherman (2007). I describe the four basic spacing patterns and illustrate how female territoriality isa function of offspring defense and male mating tactics are a function of female defensibility. The vulnerability ofyoung to infanticide shapes female spacing and mating behavior. Food does not appear to be a defensible resourcefor rodents, except for those species that larder hoard nonperishable items such as seeds. Philopatry and theformation of kin groups result in genetic sub-structuring of the population, which in turn affects effectivepopulation size and genetic diversity. Dispersal is male biased and typically involves emigration from the maternalsite to avoid female relatives and to seek unrelated mates. Scent marking is a major form of communication and isused in reproductive competition and to assess prospective mates, but it is also eavesdropped by predators to locateprey. Females do not appear to alter the sex ratio of litters in response to maternal condition but among arvicolinerodents daughters appear to be favored in spring and sons in autumn. Rodents are relatively monomorphic;however, females tend to be larger than males in the smallest species and smaller in the larger species. Predationrisk results from an interaction among foraging time and vulnerability and in turn affects behavioral and life historycharacteristics.

关键词： biology.   Integration   ecology  

摘要： Most papers presented in this, the previous and thenext special issue of Integrative Zoology were presentedat the 3rd International Conference on Rodent Biologyand Management (3rd ICRBM) that was held in earlyAugust in Hanoi, Vietnam 20061 . The conference attractedan international audience of 130 participants from35 countries and provided an opportunity for all participantsto refresh and update their knowledge of scientific,technical and extension developments in the field ofrodent biology. There were about 110 spoken papers andabout 50 posters. The three main themes of the conferencewere (1) rodent biology, (2) rodent ecology, and (3)rodent management.

关键词： habitat change   population declines   research bias   herpetology   sampling  

摘要： The recent shift in research attention by amphibian biologists towards the causes of "enigmatic" population declines appears paradoxical given the almost unanimous recognition that habitat change is the primary cause of population declines worldwide. justification for this shift is given by the growing concern associated with more novel stressors, as well as a general presumption that we have a good understanding of the ecological mechanisms that underlie the effects of habitat change. We tested the validity of this presumption by conducting a global scale review of the state of research regarding the consequences of structural habitat change (fragmentation, logging, fire, native regeneration and plantations) for amphibians and reptiles. We reveal a number of serious deficiencies, namely that existing research efforts are characterised by distinct geographic and study biases (e.g. most studies are confined to North America and focus on amphibians), a lack of clear consensus regarding the consequences of many forms of habitat change with many studies reporting seemingly contradictory results, and a number of common limitations in sampling design. The recent shift in research agenda towards the study of more novel stressors, and away from a focus on structural habitat change, cannot therefore be easily explained by differences in our understanding of the threats currently facing amphibians and reptiles. If research priorities are to be dictated by differences in scientific uncertainty then our results suggest that the study of habitat change is deserving of considerably more attention. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： biopharmaceutical manufacturing   gene regulation   synthetic biology  

摘要： With the recent development of a wide range of inducible mammalian transgene control systems it has now become possible to create functional synthetic gene networks by linking and connecting systems into various configurations. The past 5 years has thus seen the design and construction of the first synthetic mammalian gene regulatory networks. These networks have built upon pioneering advances in prokaryotic synthetic networks and possess an impressive range of functionalities that will some day enable the engineering of sophisticated inter- and intra-cellular functions to become a reality. At a relatively simple level, the modular linking of transcriptional components has enabled the creation of genetic networks that are strongly analogous to the architectural design and functionality of electronic circuits. Thus, by combining components in different serial or parallel configurations it is possible to produce networks that follow strict logic in integrating multiple independent signals (logic gates and transcriptional cascades) or which temporally modify input signals (time-delay circuits). Progressing in terms of sophistication, synthetic transcriptional networks have also been constructed which emulate naturally occurring genetic properties, such as bistability or dynamic instability. Toggle switches which possess "memory" so as to remember transient administered inputs, hysteric switches which are resistant to stochastic fluctuations in inputs, and oscillatory networks which produce regularly timed expression outputs, are all examples of networks that have been constructed using such properties. Initial steps have also been made in designing the above networks to respond not only to exogenous signals, but also endogenous signals that may be associated with aberrant cellular function or physiology thereby providing a means for tightly controlled gene therapy applications. Moving beyond pure transcriptional control, synthetic networks have also been created which

关键词： 肿瘤切除手术   肿瘤转移   疾病模型,动物  

摘要： 目的建立人癌术后转移动物模型,观察不同瘤源所建模型生物学特性的差异。方法肿瘤生长至瘤径为1.5cm时,把在裸小鼠皮下传代的GBC、HCT-116、NCI-H460和SMMC-7721移植瘤切除,建立术后转移裸小鼠模型,观察动物的生存状态和体内转移情况。结果GBC对照组裸小鼠8周时未发现体内转移;术后组10周时肺转移6只(75%),切瘤后动物生存期延长2周。HCT-116对照组9周时肺转移3只(23.1%);术后组17周时肺转移15只(100%),脾脏转移5只(33.3%),淋巴结转移15只(100%),切瘤后动物生存期延长超过8周。NCI-H460对照组10周时裸小鼠未发现转移,术后组14周时肺转移5只(100%),切瘤后动物生存期延长4周。SMMC-7721对照组和术后组动物出现衰竭体征时均未发现体内转移,切瘤后动物生存期延长6周。结论皮下移植瘤切除后,可以延长动物生存期,提高体内转移发生率,但是否发生高转移与瘤源自身的生物学特性有关。