共查询到20条相似文献，搜索用时 137 毫秒
1.
K D Wing 《Science (New York, N.Y.)》1988,241(4864):467-469
The steroid molting hormone 20-hydroxyecdysone is the physiological inducer of molting and metamorphosis in insects. In ecdysone-sensitive Drosophila Kc cells, the insecticide RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine) mimics the action of 20-hydroxyecdysone by causing the formation of processes, an inhibition of cell proliferation, and induction of acetylcholinesterase. RH 5849 also competes with [3H]ponasterone A for high-affinity ecdysone receptor sites from Kc cell extracts. Resistant cell populations selected by growth in the continued presence of either RH 5849 or 20-hydroxyecdysone are insensitive to both compounds and exhibit a decreased titer of measurable ecdysone receptors. Although it is less potent than 20-hydroxyecdysone in both whole-cell and cell-free receptor assays, RH 5849 is the first nonsteroidal ecdysone agonist. 相似文献
2.
Ecdysone, the major steroid hormone of Drosophila melanogaster, is known for its role in development and reproduction. Flies that are heterozygous for mutations of the ecdysone receptor exhibit increases in life-span and resistance to various stresses, with no apparent deficit in fertility or activity. A mutant involved in the biosynthesis of ecdysone displays similar effects, which are suppressed by feeding ecdysone to the flies. These observations demonstrate the importance of the ecdysone hormonal pathway, a new player in regulating longevity. 相似文献
3.
Role of histone H3 lysine 27 methylation in X inactivation 总被引：1，自引：0，他引：1
Plath K Fang J Mlynarczyk-Evans SK Cao R Worringer KA Wang H de la Cruz CC Otte AP Panning B Zhang Y 《Science (New York, N.Y.)》2003,300(5616):131-135
The Polycomb group (PcG) protein Eed is implicated in regulation of imprinted X-chromosome inactivation in extraembryonic cells but not of random X inactivation in embryonic cells. The Drosophila homolog of the Eed-Ezh2 PcG protein complex achieves gene silencing through methylation of histone H3 on lysine 27 (H3-K27), which suggests a role for H3-K27 methylation in imprinted X inactivation. Here we demonstrate that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation. Recruitment of the complex and methylation on the Xi depend on Xist RNA but are independent of its silencing function. Together, our results suggest a role for Eed-Ezh2-mediated H3-K27 methylation during initiation of both imprinted and random X inactivation and demonstrate that H3-K27 methylation is not sufficient for silencing of the Xi. 相似文献
4.
Imaginal discs secrete insulin-like peptide 8 to mediate plasticity of growth and maturation 总被引：1，自引：0，他引：1
Garelli A Gontijo AM Miguela V Caparros E Dominguez M 《Science (New York, N.Y.)》2012,336(6081):579-582
Developing animals frequently adjust their growth programs and/or their maturation or metamorphosis to compensate for growth disturbances (such as injury or tumor) and ensure normal adult size. Such plasticity entails tissue and organ communication to preserve their proportions and symmetry. Here, we show that imaginal discs autonomously activate DILP8, a Drosophila insulin-like peptide, to communicate abnormal growth and postpone maturation. DILP8 delays metamorphosis by inhibiting ecdysone biosynthesis, slowing growth in the imaginal discs, and generating normal-sized animals. Loss of dilp8 yields asymmetric individuals with an unusually large variation in size and a more varied time of maturation. Thus, DILP8 is a fundamental element of the hitherto ill-defined machinery governing the plasticity that ensures developmental stability and robustness. 相似文献
5.
During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells, tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. Clonal analysis and fate mapping of single, identified cells show that tracheal system remodeling at metamorphosis involves a classical imaginal cell population and a population of differentiated, functional larval tracheal cells that reenter the cell cycle and regain developmental potency. In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling. Thus, Drosophila pupal/adult tissue progenitors can arise both by early allocation of multipotent cells and late return of differentiated cells to a multipotent state, even within a single tissue. 相似文献
6.
家蚕蜕皮激素合成相关的细胞色素P450基因的鉴定分析 总被引：3，自引：3，他引：0
【目的】昆虫变态发育的启动主要受前胸腺合成分泌的蜕皮激素所调控,而蜕皮激素的合成是由细胞色素P450基因催化完成。家蚕（Bombyx mori）是一种产丝昆虫,蚕业生产中如果能阻断或延迟家蚕蛹变态发育进程,将有利于改进蚕茧处理工艺,提高蚕丝品质。论文旨在鉴定参与家蚕蜕皮激素合成的细胞色素P450基因,从而为人为遗传调节家蚕变态发育提供靶基因。【方法】基于序列同源性比对,筛选家蚕及其他昆虫中参与蜕皮激素合成的P450基因。利用ClustalW软件,分析昆虫蜕皮激素合成相关P450基因的遗传发生关系。通过全基因组表达芯片数据分析及RT-PCR验证,调查家蚕蜕皮激素合成相关P450基因的时空表达特征。利用RNAi技术分析Cyp314a1表达下调对家蚕变态发育的影响。【结果】家蚕基因组中有4个参与家蚕蜕皮激素合成的P450基因,即Cyp306a1、Cyp302a1、Cyp315a1和Cyp314a1。比较分析显示,这4个蜕皮激素合成相关的P450基因在家蚕及其他昆虫中都是单拷贝,而且每个基因的同源体在遗传发生树上能很好地聚成一类,表明昆虫蜕皮激素合成相关的P450基因及其负责的蜕皮激素合成通路非常保守。时空表达谱分析显示,在家蚕幼虫5龄第3天,Cyp302a1、Cyp315a1和Cyp314a1主要在家蚕幼虫卵巢、精巢和头部等组织器官中高表达;在幼虫-蛹-成虫变态发育进程中,Cyp302a1、Cyp315a1和Cyp314a1主要在蛹变态发育后期表达,其中Cyp314a1分别在上簇、化蛹及羽化前高表达,这与蜕皮激素滴度高峰出现的时期基本一致。Cyp314a1的RNAi导致家蚕不能正常化蛹及雌蛾卵巢发育异常,且降低了蜕皮激素信号通路关键基因HR3及Ftz-f1的表达。【结论】家蚕蜕皮激素合成相关的P450基因在进化上非常保守,其表达水平降低能引起家蚕蛹变态发育受阻,暗示蜕皮激素合成相关P450基因可以用作家蚕变态发育控制的靶标基因之一。 相似文献
7.
Beach R 《Science (New York, N.Y.)》1979,205(4408):829-831
Biting in Anopheles freeborni is inhibited during ovarian development. Biting inhibition is triggered by ecdysone, a hormone produced by the ovary during oogenesis. Biting inhibition does not occur in females after the removal of ovaries, but is restored by replacing ovaries or injecting ecdysone. Ecdysone also inhibits biting behavior when it is fed to females. This is the first example of ecdysone controlling a nonmolt-related behavior in insects. 相似文献
8.
【目的】蜕皮激素（ecdysone）是昆虫体内一种重要的激素,参与调控昆虫的生长发育,并且能对环境胁迫进行响应。研究旨在明确橘小实蝇（Bactrocera dorsalis Hendel）蜕皮激素合成通路基因（ecdysone synthesis pathway gene）的分布和特定条件下的表达特性,为进一步开展橘小实蝇变态发育与抗逆胁迫机制的研究提供理论支持。【方法】采用RT-PCR和RACE技术克隆蜕皮激素合成通路基因BdCyp302a1、BdCyp315a1和BdCyp314a1,利用实时定量PCR（qPCR）技术检测该合成通路基因BdNvd、BdCyp306a1、BdCyp302a1、BdCyp315a1和BdCyp314a1在幼虫不同发育阶段（幼虫1-8日龄）、不同组织（前胸腺复合体、脂肪体、中肠、马氏管、表皮和气管）和饥饿条件下的表达模式,明确饥饿对幼虫发育的影响。【结果】克隆获得了3个蜕皮激素合成通路基因序列的开放阅读框,分别为BdCyp302a1（GenBank登录号：JQ027284）、BdCyp315a1（GenBank登录号：KC515377）和BdCyp314a1（GenBank登录号：JQ229645）,且上述序列均具备P450典型结构域：Helix-C/I/K、PERF基序、血红蛋白结合位点以及脯氨酸/甘氨酸富集区,其氨基酸序列较为保守。qPCR检测结果显示蜕皮激素合成通路基因BdNvd、BdCyp306a1和BdCyp314a1幼虫末龄阶段表达量显著升高,其最高表达量分别是最低点的7.33、10.89和7.82倍,但在幼虫前4 d表达量差异不显著。而BdCyp302a1和BdCyp315a1在整个幼虫阶段表达量保持相对稳定。对不同组织的研究发现,蜕皮激素合成通路基因在所选的6个组织中均有表达,其中BdNvd、BdCyp306a1和BdCyp315a1在幼虫前胸腺表达量最高,在其他组织中表达量差异不显著;BdCyp302a1在各组织中的表达量由高到低为脂肪体>前胸腺>表皮/马氏管>气管/中肠,该基因在脂肪体的表达量是中肠的30倍;BdCyp314a1在中肠、马氏管和脂肪体内的表达量依次降低,但均极显著高于其他3个组织。橘小实蝇幼虫在饥饿处理12 h后即出现化蛹现象,其化蛹比例随饥饿时间延长而上升。对蛹宽和蛹长的测量中发现,饥饿导致蛹个体显著缩小,但未影响其存活率。同时,饥饿导致蜕皮激素合成通路基因BdNvd、BdCyp302a1和BdCyp314a1表达量在饥饿处理6 h后出现显著上调,并在处理48 h后出现显著下调;但饥饿处理并未影响BdCyp315a1的表达水平。【结论】蜕皮激素合成通路基因在橘小实蝇幼虫组织的表达具有差异性,并参与介导幼虫-蛹的变态过程和对营养胁迫的响应。 相似文献
9.
In animals, appendages develop in proportion to overall body size; when individual size varies, appendages covary proportionally. In insects with complete metamorphosis, adult appendages develop from precursor tissues called imaginal disks that grow after somatic growth has ceased. It is unclear, however, how the growth of these appendages is matched to the already established body size. We studied the pattern of cell division in the tobacco hornworm Manduca sexta and found that both the rate of cell division and the duration of growth of the wing imaginal disks depend on the size of the body in which they develop. Moreover, we found that both of these processes are controlled by the level and duration of secretion of the steroid hormone ecdysone. Thus, proportional growth is under hormonal control and indirectly regulated by the central nervous system. 相似文献
10.
Inatani M Irie F Plump AS Tessier-Lavigne M Yamaguchi Y 《Science (New York, N.Y.)》2003,302(5647):1044-1046
Heparan sulfate (HS) is required for morphogen signaling during Drosophila pattern formation, but little is known about its physiological importance in mammalian development. To define the developmental role of HS in mammalian species, we conditionally disrupted the HS-polymerizing enzyme EXT1 in the embryonic mouse brain. The EXT1-null brain exhibited patterning defects that are composites of those caused by mutations of multiple HS-binding morphogens. Furthermore, the EXT1-null brain displayed severe guidance errors in major commissural tracts, revealing a pivotal role of HS in midline axon guidance. These findings demonstrate that HS is essential for mammalian brain development. 相似文献
11.
藤壶属节肢动物门(Arthropoda)甲壳亚门(Crustacea)蔓足下纲(Cirripedia)围胸总目(Thoracica), 具备特殊的形态结构、生活史和种群生态特征,是最主要的海洋污损生物。其幼虫阶段通常经历6期无节幼体和1期不摄食的金星幼虫,从浮游的金星幼虫附着变态成固着的稚体是藤壶生活史中的一个关键环节。外界化学和生物因子中成体提取物、水溶性信息素、足迹、神经递质、激素、生物膜等均影响藤壶金星幼虫的附着变态;内在因子即金星幼虫的生理状态(能量储量和年龄)决定了其对外界因子的反应程度。概括了近年来藤壶附着变态生理机制和分子机制研究的进展,可为深入了解藤壶金星幼虫附着变态机制提供参考,也为开发新型、高效、环保的防污剂提供理论指导。 相似文献
12.
13.
Nautilus, long recognized as the most primitive living cephalopod, provides insight into molluscan evolution. Despite many attempts, embryos have not been observed until now. This report details the surface morphology and extraembryonic circulatory pattern. It was found that development, as in other extant cephalopods, is direct, without larval stages. There appears to be no embryonic protoconch associated with shell ontogeny. 相似文献
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15.
探讨3种性类固醇激素在北方山溪鲵精子发育过程中的调控作用.用免疫细胞化学方法对3种激素在山溪鲵精子发生周期不同时期在精巢中的细胞定位进行检测.结果表明雄激素分布在精原细胞的胞质中,尔后转移到精母细胞及精子细胞的核中;雌激素一直存在于生精细胞的胞质及核膜周围;孕激素分布在精原细胞及精母细胞的胞质中,随后在精子细胞的核质中有表达.雄激素在早期的精子发生和转型中起作用,而雌激素主要以非基因组效应参与生精细胞的增殖,孕激素在精子发育后期精子细胞的变态中起作用.3种激素以不同的方式调控精子的发生. 相似文献
16.
为了探讨miR-202在鱼类胚胎发育中的功能,采用实时定量反转录PCR技术和整体原位杂交技术检测了miR-202在斑马鱼胚胎发育阶段的表达。结果发现miR-202是母源性分子并在斑马鱼胚胎发育过程中持续表达,尤其在早期胚胎发育阶段表达水平较高。在此基础上,采用基因沉默技术在斑马鱼受精卵中显微注射miR-202的反义锁核苷酸,实时荧光定量反转录PCR技术和整体原位杂交技术结果显示miR-202反义锁核苷酸可以显著下调斑马鱼胚胎中miR-202表达水平,同时发现反义抑制miR-202后胚胎发育停滞在4 hpf时左右。共同注射miR-202前体可以部分挽救反义抑制miR-202后导致的胚胎发育停滞。本研究证明miR-202在斑马鱼胚胎发育过程中起着重要的调控作用,其功能是斑马鱼胚胎早期发育所必需的。为进一步探索miR-202在鱼类胚胎发育过程的功能奠定了基础。 相似文献
17.
The two major molting hormones of insects, alpha ecdysone and 20-hydroxyecdysone, were isolated in crystalline form from dry pinnae of the bracken fern, Pteridium aquilinum (L.) Kuhn. Three unidentified substances with molting hormone activity were also detected. Bracken is the first plant found to contain both of the major insect ecdysones, and it is the first known plant source of alpha ecdysone. 相似文献
18.
Molecular cloning of the Bombyx mori prothoracicotropic hormone 总被引：17，自引：0，他引：17
A Kawakami H Kataoka T Oka A Mizoguchi M Kimura-Kawakami T Adachi M Iwami H Nagasawa A Suzuki H Ishizaki 《Science (New York, N.Y.)》1990,247(4948):1333-1335
Prothoracicotropic hormone (PTTH), a brain secretory polypeptide of insects, stimulates the prothoracic glands to produce and release ecdysone, the steroid essential to insect development. The complementary DNAs encoding PTTH of the silkmoth Bombyx mori were cloned and characterized, and the complete amino acid sequence was deduced. The data indicated that PTTH is first synthesized as a 224-amino acid polypeptide precursor containing three proteolytic cleavage signals. The carboxyl-terminal component (109 amino acids) that follows the last cleavage signal represents one PTTH subunit. Two PTTH subunits are linked together by disulfide bonds, before or after cleavage from prepro-PTTH, to form a homodimeric PTTH. When introduced into Escherichia coli cells, the complementary DNA directed the expression of an active substance that was functionally indistinguishable from natural PTTH. In situ hybridization showed the localization of the prepro-PTTH mRNA to two dorsolateral neurosecretory cells of the Bombyx brain. 相似文献
19.
In Drosophila, the Jun amino-terminal kinase (JNK) homolog Basket (Bsk) is required for epidermal closure. Mutants for Src42A, a Drosophila c-src protooncogene homolog, are described. Src42A functions in epidermal closure during both embryogenesis and metamorphosis. The severity of the epidermal closure defect in the Src42A mutant depended on the amount of Bsk activity, and the amount of Bsk activity depended on the amount of Src42A. Thus, activation of the Bsk pathway is required downstream of Src42A in epidermal closure. This work confirms mammalian studies that demonstrated a physiological link between Src and JNK. 相似文献
20.
牙鲆胚后发育阶段HDAC1基因的空间表达 总被引：1，自引：1，他引：0
组蛋白去乙酰化酶(HDACs)可通过调节染色质结构和抑制特异性转录因子活性来调控细胞生长和分化。鉴于HDACs在蝌蚪变态发育过程中的作用,本研究克隆了牙鲆(Paralichthys olivaceus)HDAC1基因全长cDNA序列,并调查了其在牙鲆变态前和变态阶段的空间表达。牙鲆HDAC1全长cDNA序列为2 540 bp,包含长度为126 bp的5'UTR,1 470 bp的ORF和944 bp的3'UTR。HDAC1基因在牙鲆变态前以及变态阶段均有表达,这和蝌蚪中仅在变态前表达的现象不同。HDAC1在冠状幼鳍上的表达是随着幼鳍原基的生长发育逐渐增强的,直至冠状幼鳍分化成形后,基因表达减弱;随着牙鲆仔鱼肠道的变粗变短,HDAC1在肠壁的表达强度逐渐增强,孵化后第16天(16DAH)开始减弱并最终消失;鳍褶中HDAC1在9DAH开始表达,18DAH时主要在鳍褶基部表达,进入变态阶段,HDAC1可见在支鳍骨上表达,在变态高峰期表达最为强烈。在整个变态发育期HDAC1在鳃上均表达,变态开始后表达逐渐增强,而到变态后期表达减弱。牙鲆变态前及变态阶段的HDAC1基因表达模式表明,HDAC1参与了牙鲆冠状幼鳍、鳍条、肠道等多种器官的发育调控以及变态阶段眼睛移动的过程。 相似文献