发头裸腹蚤卵和胚胎发育形态研究

在实验室恒温条件下,观察了发头裸腹蚤的卵和胚胎发育,结果表明,该种枝角类的卵是均有分裂的,并具有螺旋卵裂的特点。它的发育过程大致可分为４个阶段,其间可分若干小期。发头裸腹蚤卵和胚胎发育所需时间与温度的关系十分密切,在１０、２０、３０℃时发育所需分别为１５０、４７和２３．５小时,对该种蚤的形态特点进行了讨论。     

意大利蝗的胚胎发育及卵滞育发生的胚胎发育阶段

【目的】明确意大利蝗Calliptamus italicus (L.)胚胎发育及卵滞育发生的胚胎发育阶段。【方法】2013-2014年间,通过室外胚胎发育进度检测和室内孵化培养观察,研究其胚胎发育等级、滞育和越冬的胚胎阶段及自然越冬滞育的解除。【结果】意大利蝗的胚胎发育可划分为18个阶段;意大利蝗胚胎有反向移转、转旋和顺向移动3种胚胎转动方式;意大利蝗卵滞育发生的胚胎发育阶段为第Ⅻ阶段。自然条件下,意大利蝗卵发育至次年1月21日,仅部分卵解除滞育,解除滞育卵的发育历期最长;随着越冬时间的延长,解除滞育的卵逐渐增多,其发育历期逐渐缩短;直至次年3月29日卵基本完全解除滞育。意大利蝗雌成虫所产的早中期卵（7月27日-8月16日所产卵）以胚胎发育第Ⅻ阶段（滞育发生的胚胎发育阶段）越冬,于翌年4月16日（侯地温平均值：7.59℃,最高温：15.95℃,最低温：2.67℃）继续发育;雌成虫所产的晚期卵（8月28日-9月4日所产卵）,自11月4日（侯地温平均值：7.32℃,最高温：9.00℃,最低温：5.18℃）开始以胚胎第Ⅹ阶段越冬,于翌年3月29日（侯地温平均值：3.78℃,最高温：10.27℃,最低温：0.14℃）继续发育。【结论】意大利蝗雌成虫所产的早中期和晚期卵,其越冬胚胎发育阶段、开始越冬时间及越冬后继续发育的时间均不同。     

中华稻蝗的胚胎发育及卵滞育发生的胚胎发育阶段

为弄清中华稻蝗Oxya chinensis(Thunberg)卵滞育发生的胚胎发育阶段,观察了其胚胎发育过程,检测了中华稻蝗铁岭、济南、长沙及儋州种群产卵后卵粒含水量的变化规律和胚胎发育的停滞时期.根据胚胎形态,自原头与原颚胸折叠的胚胎发育阶段开始,将中华稻蝗的胚胎发育过程划分为11个阶段.在25℃的温度条件下,4个地...     

鹌鹑、红嘴鸥、黑翅长脚鹬胚胎期 小肠黏膜表面形态结构

应用扫描电镜观察了鹌鹑（Coturnix coturnix）、红嘴鸥（Larus ridibundus）、黑翅长脚鹬（Himantopus himantopus）胚胎期小肠黏膜的形态变化。鹌鹑与红嘴鸥胚胎发育过程中,小肠黏膜形态结构可分为3个阶段。第一阶段为鹌鹑卵孵育第10 ~ 11天、红嘴鸥卵孵育第13 ~ 14天（相当于胚胎发育60%的阶段）,小肠黏膜为山脊状纵行皱襞;第二阶段为鹌鹑卵孵育第12 ~ 13天、红嘴鸥卵孵育第15 ~ 16天（相当于胚胎发育70%的阶段）,小肠黏膜为“W”形板状皱襞;第三阶段为鹌鹑卵孵育第14 ~ 17天、红嘴鸥卵孵育第17 ~ 22天（相当于胚胎发育到80% ~ 100%阶段）,小肠黏膜为指状绒毛。黑翅长脚鹬卵孵育第10天（相当于胚胎发育到60%的阶段）,小肠黏膜为山脊状纵行皱襞;从卵孵育第12天（相当于胚胎发育到70%的阶段）一直到孵出小肠黏膜均为“W”形板状皱襞。初步判断3种鸟小肠黏膜形态发生这种有规律的变化可能是鸟类对其祖先系统发育的重演。     

绢丝丽蚌胚胎发育的研究

绢丝丽蚌卵为均黄卵,爱精卵在雌蚌外鳃中进行胚胎发育,其卵裂为不等完全卵裂。在秋季自然常湿（水温变幅为２４－８℃）时,胚胎发育历时５１ｄ,经过卵裂期、原肠期,发育为具有透明原壳、过钩、闭壳肌丝、内足丝、刚毛和外足丝的成熟钩介幼虫。胚胎发育的不同时期与外鳃特征具相关性。     

昆虫卵的孵化及破卵器

昆虫的发育,从卵受精到胚胎发育,这是一个过程。一旦胚胎发育完成以后,就必须破卵而出,进行其胚后发育过程,由幼期发育成长,进而至成虫羽化。胚胎发育是一个依靠母体留给营养,在卵内发育的阶段;胚后发育则是在自然环境中自行取食、获得营养成分,适应环境条件的独立生活阶段。这两个截然不同的发育阶段,在昆虫生活中是一个很大的转折。从胚胎发育阶段,转化为胚后发育阶段,其分界线就是孵化。所以孵化是昆虫一生中很重要的一步。刚刚完成胚胎发育的幼期,其体力自然十分纤弱,如何能破卵而出?在其生理上和行为上必须具备一定的适应条件,否则就会夭折。     

背瘤丽蚌胚胎发育的初步研究

用显微技术研究了背瘤丽蚌(Lamprotula leai)胚胎发育和钩介幼虫结构。结果表明,背瘤丽蚌卵为均黄卵,受精卵分布在雌蚌内、外鳃腔中进行胚胎发育;胚胎发育同步;胚胎发育过程包括受精卵、卵裂期、囊胚期、原肠期、膜内钩介幼虫期和钩介幼虫期;卵裂为螺旋不等完全卵裂;未受精的成熟卵在鳃腔内退化;胚胎发育期与胚胎、外鳃和内鳃颜色相关;怀卵母蚌胚胎在外界环境变化时容易全部流产。分析认为背瘤丽蚌胚胎发育期的繁殖特征可指导人工苗种生产。     

尖唇散白蚁胚胎发育激光共聚焦扫描显微镜观察

【目的】本研究旨在探究尖唇散白蚁Reticulitermes aculabialis胚胎在不同发育阶段的变化特征。【方法】每日收集尖唇散白蚁的卵,并固定其胚胎发育状态,采用DAPI染剂对白蚁胚胎进行染色,通过激光共聚焦扫描显微镜观察记录尖唇散白蚁胚胎在不同发育阶段的形态特征。【结果】在25℃下尖唇散白蚁胚胎发育过程历经25~30 d,按照发育特征将其划分为12个阶段。胚胎发育早期,卵黄细胞均匀分布在卵内部,卵内细胞核向卵的中间浓缩,在细胞到达卵的后表面时形成浓缩的囊胚细胞作为胚盘;胚胎发育中期,胚胎开始进行“反转型”的囊胚运动,头部和前后轴从后极到前极反转,胚带出现明显的“双弯”结构。胚胎发育中后期,胚胎变宽,内部器官逐渐开始发育,出现明显的伸长与分节;胚胎发育后期,附肢发育明显,内部器官发育成熟。【结论】尖唇散白蚁胚胎发育过程历经12个阶段,属于短胚带型,胚带出现“双弯”结构,发育中期经历两次囊胚反转。本研究为真社会性昆虫白蚁的胚胎发育过程提供了形态学和生物学依据。     

新疆石河子棉蚜越冬卵的发育规律

棉蚜雌性蚜交配个体平均产卵量为 6 3± 1 1粒 ;未交配个体也产卵 ,卵亦变色 ,但卵量极少。越冬卵经 5 %NaOH浸泡 2 4h后卵壳透明 ,镜下观察可见受精卵胚胎发育到体躯分节期开始越冬。冬后胚胎发育仅处在颗粒团状的饱满卵应为无效卵 ,不会孵化 ;颜色发亮的卵处理后胚胎外貌清晰可见 ,此种卵当天即可破壳。棉蚜卵为滞育卵 ,春季降水对孵化有促进作用 ;室外棉蚜卵的饱满率和饱满卵的孵化率较低。该地区秋冬气候特点可能是石河子地区棉蚜卵低温条件下安全越冬的重要因素     

西伯利亚蝗越冬卵的呼吸代谢规律研究

[目的]西伯利亚蝗Gomphocerus sibiricus L.是新疆亚高山草原和林间草地重要的指示物种,本研究主要探讨西伯利亚蝗卵越冬过程中的呼吸生理变化。[方法]采用多通道昆虫呼吸系统,逐月测定越冬卵的呼吸率、代谢率和呼吸商等指标,分析其变化特征,并监测其环境温度变化,同时解剖蝗卵以观察胚胎发育进度。[结果]越冬过程中,蝗卵的呼吸代谢水平总体呈上升趋势,高低顺序为越冬前期越冬期间越冬后期。越冬前(8—10月)和越冬期间(11—2月),同阶段各月份之间的呼吸代谢水平无显著差异(P0.05);越冬后期(3—4月)呼吸率和代谢率显著升高(P0.05)。越冬前蝗卵的平均呼吸商为0.66,说明其代谢底物主要为脂质;越冬期间蝗卵的平均呼吸商为0.80,表明其代谢底物除脂质外还有部分糖类参与;越冬后期,呼吸商显著升高(P0.05),平均值为1.01,表明其呼吸代谢底物主要为糖类物质。早期胚胎发育主要发生在越冬前期,此时头、胸、腹和附肢等结构已分化完全;越冬期间胚胎发育停滞;越冬后胚胎发育迅速恢复。[结论]越冬过程中,西伯利亚蝗卵的呼吸代谢水平与胚胎发育进度密切相关。为适应胚胎发育需要,蝗卵通过调节呼吸代谢水平及代谢底物来调整其生理状态,以适应外界环境条件的周期性变化,从而顺利越冬。     

Integrating developmental biology into the undergraduate curriculum at the University of Bath,United Kingdom

The undergraduate curriculum for bioscience degrees at the University of Bath is outlined, and the place is described of the developmental biology components within it. In the first year, all students receive four lectures on animal development and four on plant development. In the second year, many choose substantial lecture and practical courses on animal development, which outline the early development of Xenopus, mouse and Drosophila. The third year is usually spent on placement, with a company or research institute, a few of which are developmental biology-based, and may also involve some distance learning. The fourth year is spent back in Bath. Students interested in developmental biology can opt for advanced courses covering vertebrate organogenesis, developmental neurobiology and plant development. There are also one-semester, final-year projects spent in the labs of faculty members, several of whom specialise in developmental biology and offer projects accordingly.     

Proteomic Characterization of Caenorhabditis elegans Larval Development

The nematode Caenorhabditis elegans is widely used as a model organism to study cell and developmental biology. Quantitative proteomics of C. elegans is still in its infancy and, so far, most studies have been performed on adult worm samples. Here, we used quantitative mass spectrometry to characterize protein level changes across the four larval developmental stages (L1–L4) of C. elegans. In total, we identified 4130 proteins, and quantified 1541 proteins that were present across all four stages in three biological replicates from independent experiments. Using hierarchical clustering and functional ontological analyses, we identified 21 clusters containing proteins with similar protein profiles across the four stages, and highlighted the most overrepresented biological functions in each of these protein clusters. In addition, we used the dataset to identify putative larval stage‐specific proteins in each individual developmental stage, as well as in the early and late developmental stages. In summary, this dataset provides system‐wide analysis of protein level changes across the four C. elegans larval developmental stages, which serves as a useful resource for the C. elegans research community. MS data were deposited in ProteomeXchange ( http://proteomecentral.proteomexchange.org ) via the PRIDE partner repository with the primary accession identifier PXD006676.     

Genetic control of male fertility in Arabidopsis thaliana: structural analysis of premeiotic developmental mutants

We have taken a mutational approach to identify genes important for male fertility in Arabidopsis thaliana and have isolated a number of nuclear male/ sterile mutants in which vegetative growth and female fertility are not altered. Here we describe detailed developmental analyses of four mutants, each of which defines a complementation group and has a distinct developmental end point. All four mutants represent premeiotic developmental lesions. In ms3, tapetum and middle layer hypertrophy result in the degeneration of microsporocytes. In ms4, microspore dyads persist for most of anther development as a result of impaired meiotic division. In ms5, degeneration occurs in all anther cells at an early stage of development. In ms15, both the tapetum and microsporocytes degenerate early in anther development. Each of these mutants had shorter filaments and a greater number of inflorescences than congenic male-fertile plants. The differences in the developmental phenotypes of these mutants, together with the non-allelic nature of the mutations indicate that four different genes important for pollen development, have been identified.     

Developmental stability in plants: Symmetries,stress and epigenesis

Plant developmental stability has received little attention in the past three or four decades. Here we review differences in plant and animal development, and discuss the advantages of using plants as experimental subjects in exploring developmental stability. We argue that any type of developmental invariant may be used to assess developmental stability and review the use of fluctuating asymmetry in studies of plant developmental stability. We also examine the use of deviations from translatory, radial, and self-symmetry as measures of developmental instability. The role of nonlinear dynamics and epigenesis in the production of the phenotype is also discussed.     

The effect of prey density on the developmental time of larvae of an aquatic beetle: <Emphasis Type="Italic">Tropisternus setiger</Emphasis> (Insecta,Coleoptera: Hydrophilidae)

Predaceous larvae of the water scavenger beetle Tropisternus setiger (Germar) are common inhabitants of variable environments in which prey availability may vary widely. We conducted laboratory experiments to assess the effect of prey density on developmental times and survivorship of the preimaginal stages of T. setiger. We also examined the effect of the number of consumed prey on the larval size of instar III. Four different prey densities (one, two, four, and eight preys a day) were tested and both developmental time and survivorship differed significantly among them. Larvae fed one or two preys daily showed a longer developmental time and a lower survivorship than larvae fed four or eight preys a day. Moreover the consumption of four preys a day increased larval developmental success, and to consume one prey a day affected survivorship through the larval period. On the other hand, prey density had no effect on the final larval size. Handling editor: K. Martens     

Developmental traits and life strategy of redlichiid trilobites

The developmental mode of four redlichiid trilobites is summarized, based upon exceptionally well-preserved, articulated specimens from Cambrian Series 2 (stages 3 and 4) strata in southwestern China and South Australia. These relatively complete developmental sequences indicate a balanced rate in segment increase and addition to the thorax during the meraspid phase, which might explain why most redlichiids possess micropygous body patterning during ontogeny. In addition, an analysis of the size distribution, developmental strategy, and distribution of specimen numbers at different growth stages reveals a distinct developmental strategy during the redlichiid life cycle. A relatively short pre-holaspid and a prolonged holaspid phase in these redlichiid taxa offers insight into the developmental control and life strategy in these primitive arthropods.     

四种鳞翅目害虫精氨酸激酶基因的表达谱及基于RNAi的功能分析

【目的】精氨酸激酶(arginine kinase, AK)(EC 2.7.3.3)是昆虫体内重要的磷酸原激酶(能量代谢调节因子),也是唯一能够形成有效ATP的磷酰基供体,起着与脊椎动物中肌酸激酶相同的作用。本研究旨在了解鳞翅目害虫AK基因的表达和功能。【方法】利用qRT-PCR方法测定AK基因在大螟Sesamia inferens、二化螟Chilo suppressalis、甜菜夜蛾Spodoptera exigua和斜纹夜蛾Spodoptera litura 这4种鳞翅目害虫不同发育阶段和3龄幼虫不同组织中的表达谱;通过终点法检测了这4种害虫不同发育阶段和幼虫不同组织中的AK酶活性;采用RNAi技术抑制该基因的表达并分析其功能。【结果】AK基因在大螟、二化螟、甜菜夜蛾和斜纹夜蛾这4种鳞翅目昆虫的不同发育阶段和3龄幼虫不同组织中均有表达,说明该基因的表达不具有发育时期和组织特异性。不同发育时期和3龄幼虫不同组织中AK酶活性与基因表达量变化趋势大体一致。注射以AK基因为靶标的dsRNA 6 d后,4种害虫体内AK基因的mRNA表达下降30%~50%,AK酶活性降低30%左右;14 d后幼虫的死亡率达50%左右,显著高于对照组幼虫的死亡率。【结论】AK基因在上述4种鳞翅目害虫中为组成型表达,RNAi抑制AK基因的表达可导致4种害虫的幼虫死亡,研究结果为开发以AK基因为靶标的鳞翅目害虫防治新技术提供了理论依据。     

Developmental stability in brown trout: are there any effects of heterozygosity or environmental stress?

We studied the developmental stability of brown trout, Salmo trutta L., in 10 populations (five acidified, five control) in Norway, measured as fluctuating asymmetry (FA) and departure from the morphological norm. We measured four meristic and four morphometric characters, and scored the level of biochemical heterozygosity at 49 loci (20 polymorphic). We reared eggs of a single population in a hatchery using four different water qualities (three replicates of each treatment) to test the effect of acidification stress on developmental instability. There were no significant differences in the level of FA, in departure from the morphological norm between brown trout sampled from lakes with acidified or control water qualities, or in brown trout hatched at different water qualities. There was no correlation between level of heterozygosity and FA or departure from the morphological norm, either when tested within populations or among populations. There were no single-locus effects on developmental stability tested for 11 loci. We conclude that measures of developmental stability or morphological variability are not useful for detecting acidification stress in brown trout. Furthermore, we conclude that developmental stability in our material varies independently of heterozygosity.     

Serial analysis of gene expression in the silkworm, Bombyx mori

The silkworm Bombyx mori is one of the most economically important insects and serves as a model for Lepidoptera insects. We used serial analysis of gene expression (SAGE) to derive profiles of expressed genes during the developmental life cycle of the silkworm and to create a reference for understanding silkworm metamorphosis. We generated four SAGE libraries, one from each of the four developmental stages of the silkworm. In total we obtained 257,964 SAGE tags, of which 39,485 were unique tags. Sorted by copy number, 14.1% of the unique tags were detected at a median to high level (five or more copies), 24.2% at lower levels (two to four copies), and 61.7% as single copies. Using a basic local alignment search tool on the EST database, 35% of the tags matched known silkworm expressed sequence tags. SAGE demonstrated that a number of the genes were up- or down-regulated during the four developmental phases of the egg, larva, pupa, and adult. Furthermore, we found that the generation of longer cDNA fragments from SAGE tags constituted the most efficient method of gene identification, which facilitated the analysis of a large number of unknown genes.     

Variance in developmental event timing is greatest at low biological levels: implications for heterochrony

Intraspecific variation in developmental event timing is common and may be the raw material from which heterochronies (altered timing of developmental events between ancestors and descendants) arise. However, our understanding of how variance in intraspecific developmental event timing is distributed across different hierarchical, biological levels is poor, despite recent evidence suggesting a genetic basis for such inter‐individual differences. In the present study, we used high (temporal and spatial) resolution bio‐imaging of the entire embryonic development of the pond snail, Radix balthica, to investigate how variance was partitioned between the biological levels of interpopulation, inter‐egg mass and individual, with respect to the relative timing of four key developmental events (four‐cell division, a discrete heart beat, capsule rupture, and hatching), as well as egg volume (an index of maternal investment), hatchling size and shape (to compare embryonic with post‐hatch variance). We found that the timing of all but one (four cell division) of the developmental events, together with all measures of hatchling size and shape, had most variance partitioned at the individual level; variance at the interpopulation level was surprisingly low despite sampling populations from across the geographical range of R. balthica. These patterns highlight the importance of studying the distribution of variance in developmental event timing with the aim of understanding how it might drive organismal ecology and evolution. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 581–590.