黄河鲤越冬前后的生长特点分析

黄河鲤是我国优良的地方品种, 为了对其继续选育, 以黄河鲤为研究对象, 在越冬前后各测量一次数据, 观察其生长发育特点, 并通过统计学手段研究其发育规律。结果显示:体重、体长、体厚、体高4个指标在生长的第二阶段均比第一阶段显著提高, 其中体重幅度较大, 体厚增长较小; 体长和体高的比例没有发生变化, 体长和体厚比显著降低; 3维图显示第2阶段明显迁移, 第二阶段图形的集中度高。经过体重的标准化后, 2阶段3个指标的三维图发生了逆转。这些结果说明, 黄河鲤经过一段时间的生长, 主要生长指标均有提高, 3个指标3D图趋向整齐, 并发现这些体型的变化主要由于体重引起, 更值得一提的是经过这个阶段的增重体长和体厚的比值显著降低, 说明黄河鲤的体型偏向于宽度的增加。研究还通过建立多元逐步回归方程和聚类图来说明2个生长阶段体重和3个体型指标的关系, 再次验证了2阶段体重在3个体型指标中的重要影响和体型偏向于宽度增长的结论。       

Owning an Overweight or Underweight Body: Distinguishing the Physical,Experienced and Virtual Body

Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant''s experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups.     

蜜蜂脂肪体的形态和功能研究进展

脂肪体是昆虫体内的一种多功能器官,近似于脊椎动物的肝脏,分布于昆虫腹部、胸部甚至头部腔体中,以腹部脂肪体最为发达。蜜蜂脂肪体有外周脂肪体和围脏脂肪体两种类型,由营养细胞、尿酸盐细胞和绛色细胞组成。同其他昆虫中类似,脂肪体在蜜蜂的生命活动中扮演着重要的角色,其形态和功能随发育阶段、季节和劳动分工的变化而变化。脂肪体结构相对简单,但生理功能非常复杂。脂肪体最主要的功能是能量物质的储存和代谢,其不仅是蜜蜂营养物质(即脂质、碳水化合物和蛋白质)的中央储存库,而且是营养代谢的中间站,具有多种能量和物质相互转换的酶系,承担代谢水的供应并合成嘌呤和嘧啶及许多重要的蛋白质。同时,脂肪体是昆虫发育和行为调控过程中各种激素和营养信号的交换中心,脂肪体激素和营养信号参与调控蜜蜂脂肪体发育、营养物质代谢、生殖及劳动分工。脂肪体兼具能量储存和释放、生物合成和分解、营养感知调节、代谢信号整合、内分泌调节、免疫和解毒、磁场感受、提高抗寒能力、保护体腔内器官等多种功能。鉴于脂肪体的重要作用,蜜蜂脂肪体形态和功能的研究成果可以对昆虫营养信号通路的解析、蜂产品高产良种的选育和蜜蜂病害防治的研究提供参考和思路。     

Body mass changes in a biparental incubator: the Redshank Tringa totanus

Incubation is a period of high energetic costs and accordingly body mass losses are often detected. Why birds lose body mass during incubation is not well understood; suggestions are that it is either a consequence of energetic constraints or adaptations to an optimal mass trajectory. We studied body mass changes through the incubation period in the Common Redshank Tringa totanus, a biparental incubator, on southern Gotland in the Baltic Sea. In contrast to what has been found in other biparental incubators, body mass of both sexes decreased linearly through the incubation period. The estimated mean body mass loss was 6.7 g (SE 1.7), corresponding to ca. 5% of initial body mass at incubation start. Hatching success in males was not related to body mass and size. In contrast, reproductive success, measured as successful production of fledged juveniles, in males was negatively related to body mass during incubation and positively related to body size. This finding supports the theory that body mass loss might follow an optimal mass trajectory, possibly to increase agility through the chick-rearing stage. However, energy constraints causing body mass loss cannot be ruled out; in fact, it is not unlikely that body mass may change due to a combination of both adaptation and stress.     

Relationships between brood size and offspring body size in an ovoviviparous fish: maternal effects and genetic trade-off

Maternal effects can form an important source of variation in offspring fitness and have important evolutionary and ecological consequences. To explore genetic control for body size of newborn offspring, the present study examined maternal brood size and offspring body size in 14 strains and performed cross experiments in an ovoviviparous fish, guppy. Correlation analyses among the strains indicated that the strains with larger brood size have smaller offspring body size. Diallel and reciprocal crosses among four strains revealed a large maternal, but no paternal, contribution to offspring body size. To examine whether offspring body size is determined by maternal genotypes and whether offspring body size correlates with albinism, backcrosses were performed between a wild-type strain with large offspring body size and an albino strain. Offspring body size differed from both the parental strains in one generation of backcrossing but was not significantly different from the paternal strains after three generations. In the backcross generations, the offspring yielded by albino individuals showed significantly smaller body size than those yielded by normal individuals. These results indicated that offspring body size is determined by maternal genotypes, suggesting that offspring body size is influenced by the maternal albinism gene or the maternal locus linked with the albinism locus. The significant negative correlation between maternal brood size and offspring body size detected through our experiments showed that the maternal genetic character of brood size strongly correlated with offspring body size, indicating genetic trade-off between maternal brood size and offspring body size in the guppy.     

Systematics and body size: implications for feeding adaptations in New World monkeys.

The relationship between body size and feeding ecology is well established for primates. It is argued that the evolutionary history of modern New World monkeys and, in particular, the path to attainment of current body size is significant in understanding the similarities and differences between dietary strategies and other ecological parameters of similar-sized monkeys. Current interpretations of New World monkey evolutionary relationships are reviewed. Based on a synthesis of available body weights and the assumption that the earliest New World monkeys weighed close to 1 kg, similar to modern Aotus and Callicebus, predicted patterns of body size change in each lineage are given. Restrictions on directions of body size change in primates are discussed, and it is shown that "Stanley's Rule" offers a good explanation for differing body size ranges in New and Old World anthropoids. Predicted ecological correlates to body size drawn from the mammalian literature are offered and tested using data on New World monkeys, which show some concurrence and several interesting departures from predicted patterns. Sexual dimorphism in body weight of New World monkey species is reviewed, based on the new summary of body weight data given.     

The enigmatic meiotic dense body and its newly discovered component,SCML1, are dispensable for fertility and gametogenesis in mice

Meiosis is a critical phase in the life cycle of sexually reproducing organisms. Chromosome numbers are halved during meiosis, which requires meiosis-specific modification of chromosome behaviour. Furthermore, suppression of transposons is particularly important during meiosis to allow the transmission of undamaged genomic information between generations. Correspondingly, specialized genome defence mechanisms and nuclear structures characterize the germ line during meiosis. Survival of mammalian spermatocytes requires that the sex chromosomes form a distinct silenced chromatin domain, called the sex body. An enigmatic spherical DNA-negative structure, called the meiotic dense body, forms in association with the sex body. The dense body contains small non-coding RNAs including microRNAs and PIWI-associated RNAs. These observations gave rise to speculations that the dense body may be involved in sex body formation and or small non-coding RNA functions, e.g. the silencing of transposons. Nevertheless, the function of the dense body has remained mysterious because no protein essential for dense body formation has been reported yet. We discovered that the polycomb-related sex comb on midleg-like 1 (SCML1) is a meiosis-specific protein and is an essential component of the meiotic dense body. Despite abolished dense body formation, Scml1-deficient mice are fertile and proficient in sex body formation, transposon silencing and in timely progression through meiosis and gametogenesis. Thus, we conclude that dense body formation is not an essential component of the gametogenetic program in the mammalian germ line.     

The Body Plan Concept and Its Centrality in Evo-Devo

A body plan is a suite of characters shared by a group of phylogenetically related animals at some point during their development. The concept of bauplane, or body plans, has played and continues to play a central role in the study of evolutionary developmental biology (evo-devo). Despite the importance of the body plan concept in evo-devo, many researchers may not be familiar with the progression of ideas that have led to our current understanding of body plans, and/or current research on the origin and maintenance of body plans. This lack of familiarity, as well as former ties between the body plan concept and metaphysical ideology is likely responsible for our underappreciation of the body plan concept in its own right, as well as its role in evo-devo. My aim in this review is to outline how we have arrived at our modern definition of body plan, the controversies associated with the concept, its role in evo-devo, and how current research is informing us on body plans. To this end, I integrate concepts such as the nature of phyla, the Cambrian explosion, constraint, evolvability, and results from recent research on gene regulatory networks with the much older concept of the body plan.     

The Evolution of Plant Body Plans--A Biomechanical Perspective

Defining ‘plants’ inclusively as ‘photosyntheticeukaryotes’, four basic body plans are identifiable amongplant lineages (unicellular, siphonous, colonial and multicellular).All of these body plans occur in most plant lineages, but onlythe multicellular body plan was carried onto land by the embryophytes.Extensive morphological and anatomical homoplasy is evidentamong species with different body plans. This is ascribed tothe facts that the acquisition of nutrients and radiant energyis affected by plant body size, shape and geometry, and that,with the exception of the unicellular body plan, each of theother body plans involves an ‘open and indeterminate’ontogeny capable of modifying body size, shape and geometryregardless of how organized growth is achieved. In terms ofunicellular species, the available data indicate that size-dependentvariations in surface area, metabolic constituents (e.g. photosyntheticpigments), and reproductive rates limit maximum body size innutrient poor habitats or those that change rapidly or unpredictably.This maximum size can be exceeded in more stable niches by eitherthe cooperation of conspecific cells sharing a common extracellularmatrix (i.e. the ‘colonial’ body plan) or by repeatedmitotic cellular division associated with sustained cytoplasmic(symplastic) continuity (i.e. multicellularity). The siphonousplant body plan may have been evolutionarily derived from aunicellular or multicellular ancestral life form. Each of theplant body plans is reviewed in terms of its biomechanical advantagesand disadvantages. Variants of the multicellular body plan,especially those of the Chlorophyta, Charophyta, and Embryophyta,are given special emphasis. Copyright 2000 Annals of BotanyCompany Algae, biomechanics, body plans, body size, embryophytes, evolution, multicellularity, plants     

The evolution of body size in birds. I. Evidence for non-random diversification

The hypothesis that evolution of body size in birds was a random process coupled with an absolute lower boundary on body mass was tested using data on 6217 species of extant birds. The test was based on the fact that subclades within birds that have body masses much larger than this minimum should not have skewed log body mass distributions, while clades close to this boundary should. Bird species were classified into 23 orders suggested by Sibley and Monroe (1988). Thirteen orders that had average log body masses greater than the average for all birds had significantly skewed log body mass distributions. This is inconsistent with the hypothesis that evolution of body size in birds is random, but is constrained only at the smallest body masses. Most orders of birds cannot be considered random samples from the parental distribution of all birds. When the pattern of body mass evolution in birds is reconstructed using an estimate of the phylogenetic relationships among orders, there are many more instances where a large taxon putatively originated from a smaller one than vice versa. The non-random nature of body mass evolution in birds is consistent with models that postulate that evolution is constrained by the ability of individuals to turn resources into offspring.     

Maternal body composition: methods for measuring short-term changes.

The measurement of short-term changes in maternal body composition during the post-partum period under field conditions poses many problems: (1) body composition techniques depend on the constancy of the proportions of components or their physical properties and are less suitable for measuring changes; (2) many of the techniques require expensive, technically sophisticated apparatus that is inappropriate to field conditions in many countries; (3) changes in body composition affect some areas of the body more than others so regional as well as whole body approaches are required. The measurements of body weight, triceps and subscapular skinfold thicknesses and upper arm circumference are essential measurements. These can be supplemented with further skinfold thicknesses and circumferences, and possibly body density and body water measurements. There is little to be gained by transforming anthropometric variables into whole body composition indices in these circumstances.     

Evaluation of Total Body Electrical Conductivity to Estimate Body Composition of a Small Mammal

ABSTRACT The ability to measure body composition is critical for studying the physiological ecology of animals. This is particularly true for small mammals that have a high metabolic rate. We evaluated a nondestructive method of body composition analysis that would allow accurate assessment of body fat, body water, and lean mass. We used total body electrical conductivity (TOBEC) to estimate body composition in the little brown myotis (Myotis lucifugus). In a sample of 46 individuals, TOBEC was both accurate and precise in estimating total body water and lean mass but was less effective at estimating total body fat. Mass-independent or whole-body compartments (i.e., total body water, total body fat, lean dry mass, and lean body mass) were more accurately estimated than mass-dependent or mass-specific body composition compartments (i.e., water content, fat index, and % lean dry mass). The TOBEC measurements we made using an SA-3000 analyzer were influenced by extremes in body temperature, as well as by aluminum and incoloy wing bands. Our study also presents a new method of restraint especially suited for small mammals and birds that increases precision of TOBEC measurements. This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.     

柳江人身体大小和形状——体重、身体比例及相对脑量的分析

发现于广西柳江的更新世晚期人类化石除1具完整的头骨外,还包含有右侧髋骨、骶骨、两段股骨及若干件椎骨。根据各方面的特征分析,初步认定这些化石属于同一个体。这一有利条件为我们比较准确地获取与该个体身体大小和形状有关的指标数据提供了可能。本文通过对柳江人头骨及复原骨盆的测量,计算了柳江人的身高、体重、身体比例、相对脑量等。在此基础上分析了柳江人的身体大小和形状。本研究发现:柳江人化石所代表的个体具有适应温暖气候环境的纤细型身体比例,代表相对脑量的EQ指数5.602大于金牛山、山顶洞等中国更新世中、晚期化石人类,而与包括港川人在内的更新世末期及现代人类的EQ指数接近。柳江人体重52.0kg小于金牛山、山顶洞、尼安德特人等生活在高纬度地区的化石人类,而与港川、非洲的KNM-ER3883、KNM-ER3733等生活在温暖环境的古人类接近。作者认为这些发现除说明柳江人生活的气候环境外,还提示柳江人身体大小、比例及相对脑量与更新世末期及现代人类接近。     

Exchangeable body sodium in normal man: analysis of various frames of reference

Exchangeable sodium is a reliable measure of body sodium contents. Since fat tissue contains significantly less sodium per unit of weight than other tissues, leanness of an individual may considerably affect exchangeable body sodium. Thus, subjects of different body size can be compared only when body build is considered. To evaluate various frames of reference, we analysed the relationship between exchangeable sodium as determined by isotope dilution and various parameters of body size. Body weight, body height, body surface area, and leanness index correlated significantly with exchangeable sodium, the closest relationship having been obtained with body surface area (r = 0.790; p less than 0.001). When analysing males and females separately (n = 18 and 36, resp.), best parallelism of regression lines was also obtained with body surface area. It is concluded that exchangeable sodium should be referred to unit of body surface area, expressing each individual's value as percent of the normal predicted value calculated from the regression equations y = 1388x + 370 and y = 1554x - 196 for males and females, respectively.     

Body size evolution of oxyurid (Nematoda) parasites: the role of hosts

Studying the diversification of body size in a taxon of parasites allows comparison of patterns of variation observed in the parasites with patterns found in free-living organisms. The distributions of body size of oxyurid nematodes (obligate parasites of vertebrates and invertebrates) are lognormally right-skewed, except for male oxyurids in invertebrates which show left-skewed distributions. In these parasitic forms, speciose genera do not have the smallest body sizes. Parasite body size is positively correlated with host body size, the largest hosts possessing the largest parasites. This trend is shown to occur within one monophyletic group of oxyurids, those of Old World primates. Comparative methods are used to take account of the effects of phylogeny. The use of multiple linear regression on distance matrices allows measurements of the contribution of phylogeny to the evolution of body size of parasites. Evolution of body size in female pinworms of Old World primates appears to be dependent only on the body size of their hosts. The tendency of parasite body size to increase with host body size is discussed in the light of the evolution of life-history traits.     

Variability within families and the evolution of body-condition-dependent dispersal

In a population where body condition varies between and within families, we investigate the evolution of dispersal as a function of body condition ('strength', e.g. body size). Strong individuals are better competitors in a weighted lottery. If body condition does not influence survival during dispersal, then there is no unique evolutionarily stable strategy. Instead, there are infinitely many dispersal strategies that all lead to the same non-dispersing weight in a patch. These strategies are all selectively neutral but determine wildly different relationships between body condition and disposal probability. This may explain why there is no consistent pattern between body condition and dispersal found in empirical studies. If body condition influences survival during dispersal, then neutrality is removed and individuals with higher survival probability disperse. Dispersal may be the competitively weaker individuals if smaller body size helps to avoid dispersal risks.     

SOME LESSER KNOWN FEATURES OF THE ANCIENT CEPHALOPOD ORDER ELLESMEROCERIDA (NAUTILOIDEA, CEPHALOPODA)

Abstract:  Three specimens of the small breviconic ellesmeroceratid Paradakeoceras minor Flower, 1964 from the Tremadocian of the New York area preserve the annular elevation and muscle scars in moulds of the body chamber. The annular elevation is positioned at the base of the body chamber and is wider on the convex side of the shell than on the concave side. Multiple paired muscle scars can be seen within this annular elevation. A well-preserved body chamber of the breviconic ellesmeroceratid Levisoceras cf. edwardsi Ulrich, Foerste and Miller is described. Its body chamber shows a strong anterior–posterior asymmetry, which is common within the Ellesmeroceratida. The shape of the body chamber and of the soft body attachment structures has led to a reconstruction of an ellesmeroceratid soft body that is organized like a primitive conchiferan mollusc. Based on this reconstruction, a tryblidian cephalopod ancestor is supported. An evolutionary scenario is reconstructed from an ancestral nautiloid that is stretched along the anterior–posterior axis, and has serially arranged shell muscles and a small mantle cavity, towards a modern cephalopod with a dorsal–ventral body orientation, reduced number of shell muscles and a large mantle cavity.     

脊椎动物松果器官的形态结构比较和演化初探

对脊椎动物６个纲中日本七鳃鳗、鲫鱼、黑斑蛙、丽斑麻蜥、家鸽和高原鼠兔等几种动物松果器官的形态结构进行了观察和比较,并对其演化作了初步探讨。脊椎动物的松果器官分为二大类,一类为变温动物的松果器官,由副松果体和松果体构成,其中副松果体是一个典型的光感受器,松果体亦主要具有感光的结构。另一类为恒温动物的松果器官,仅包含松果体,无副松果体,其结构主要具有内分泌腺的特征。在系统演化中,后一类松果器官可能是由前一类演变来的。从演化揭示：最早脊椎动物的松果眼是２个。哺乳动物的松果腺是由一种光感受器演变来的。     

ULTRASTRUCTURE AND CYTOCHEMISTRY OF METABOLIC DNA IN TIPULA

A DNA body is present in the females of the fly Tipula oleracea and is formed in contact with the sex chromosomes in the oogonial interphases. At each oogonial mitosis, the DNA body follows the chromosomes to one anaphase group and is included in one of the telophase nuclei. The body increases appreciably in size during the interphase of meiosis. All oocytes have the body, but only a few nurse cells possess it. The DNA body synthesizes its DNA at a different time than the chromosomes, as is shown by incorporation of tritiated thymidine, and contains 59% of the DNA of the nucleus, as is disclosed by spectrophotometric measurements. At late diplotene the DNA body disintegrates, releasing its DNA into either the nucleus or the cytoplasm. When studied in the electron microscope, the DNA body appears composed of a tight mass of intertwined fibrils. Demonstration that the main mass of the body is composed of DNA is obtained from cytochemical tests which reveal that the DNA body is Feulgen positive, stains green with azure B, incorporates H³-thymidine, and after digestion with DNase is Feulgen negative. The DNA of the body is complexed with histone, like the DNA of the chromosomes, as is revealed by an intense alkaline fast green staining. Electron microscope examination of oocytes reveals that one side of the DNA body is in close contact with the nuclear envelope and that the other side possesses an outer shell composed mainly of particles 150 to 250 A in diameter. Between the outer shell and the chromosomes there is a band of low electron opacity, 4000 to 7000 A thick. In the light microscope, this light band together with the outer shell is Feulgen negative and stains violet with azure B; this is confirmation of the presence of RNA. In the oocytes the nucleoli are found inside the DNA body. These nucleoli have a nucleolonema composed mainly of particles 150 to 250 A. The nucleoli are Feulgen negative, alkaline fast green negative, stain violet with azure B, and do not stain with azure B after RNase digestion, thus confirming their RNA content. The presence of the nucleoli inside the DNA body and of a band of RNA between the body and the chromosomes is indicative of a high RNA synthetic activity. Since the DNA of the body is complexed with histone, as in the chromosomes, and the nucleoli are located inside the body, the simplest interpretation of the DNA body is that it represents hundreds of copies of the operons of the nucleolar organizing region or neighboring regions. The situation found in Tipula has several basic features in common with the polytene chromosomes of other Diptera and with the hundreds of nucleoli present in Triturus oocytes. In all three cases, genes seem to be copied hundreds of times but are kept in different types of packages. A DNA body like the one in Tipula oleracea is found in other species of Diptera and in the Coleoptera. There is no indication, from the present investigation, that the DNA body is in any way associated with a virus.