肿瘤,一个发育生物学问题

发育生物学是研究生物变化过程的科学,尤其是对胚胎,因为胚胎是动植物从受精卵发育到成体的必经之途,是介于基因型和表型之间的过渡体。肿瘤,是分化异常、生长失控的细胞集合体,恶性肿瘤严重威胁着人们的身心健康。在发育生物学领域,人类对自身的认识,尤其是对受精卵到个体发育的解读在不断地探索。同样,人们对肿瘤的研究也在不断地深入。研究发现肿瘤细胞和胚胎细胞生物学行为存在某些相似之处,这启发人们从发育生物学角度去认识肿瘤的发生、发展。本文从发育生物学角度详细评述了肿瘤细胞的起源、胚胎与肿瘤相似性和差异性比较及肿瘤与胚胎相互作用的研究进展。     

Microbead Implantation in the Zebrafish Embryo

The zebrafish has emerged as a valuable genetic model system for the study of developmental biology and disease. Zebrafish share a high degree of genomic conservation, as well as similarities in cellular, molecular, and physiological processes, with other vertebrates including humans. During early ontogeny, zebrafish embryos are optically transparent, allowing researchers to visualize the dynamics of organogenesis using a simple stereomicroscope. Microbead implantation is a method that enables tissue manipulation through the alteration of factors in local environments. This allows researchers to assay the effects of any number of signaling molecules of interest, such as secreted peptides, at specific spatial and temporal points within the developing embryo. Here, we detail a protocol for how to manipulate and implant beads during early zebrafish development.     

The chick embryo: hatching a model for contemporary biomedical research

Animal models play a crucial role in fundamental and medical research. Progress in the fields of drug discovery, regenerative medicine and cancer research among others are heavily dependent on in vivo models to validate in vitro observations, and develop new therapeutic approaches. However, conventional rodent and large animal experiments face ethical, practical and technical issues that limit their usage. The chick embryo represents an accessible and economical in vivo model, which has long been used in developmental biology, gene expression analysis and loss/gain of function experiments. It is also an established model for tissue/cell transplantation, and because of its lack of immune system in early development, the chick embryo is increasingly recognised as a model of choice for mammalian biology with new applications for stem cell and cancer research. Here, we review novel applications of the chick embryo model, and discuss future developments of this in vivo model for biomedical research.     

鸡胚早期发育过程中细胞迁移的基因调控

鸡胚是发育生物学研究的经典动物模型,通过基因导入技术调节胚胎发育的基因功能,研究鸡胚早期发育过程中的细胞迁移,有助于更好地诠释相关先天性疾病的发生发展过程。在早期胚胎发育的过程中,原肠胚期三胚层的形成、心管的发生及神经嵴的发育都伴随着显著的细胞迁移过程。该文将结合近年来国内外对该过程的研究进展,介绍这三个不同时期细胞的迁移及相关基因调控。     

现代丰年虾卵的腐解实验——对早期化石胚胎研究的启示

早寒武世和埃迪卡拉纪中的球状化石,一些已被归入可能的后生动物胚胎化石,由于具较为完好的三维保存方式以及近乎完美的胚胎发育序列,为早期后生动物的起源、分类、谱系演化及发育生物学提供了难得的实证材料。然而随着研究的深入,多数寒武纪胚胎的生物学分类位置未定;而数量异常巨大、又有独自的保存方式的晚元古代陡山沱组胚胎的真伪和生物学归属,更是争议未消。通过对现生生物胚胎的实验埋藏研究,可以揭示出各类生物胚胎在腐解、埋藏各阶段的保存潜力,而现代胚胎在各实验埋藏阶段形态、结构的变化,也能为化石胚胎的研究提供重要的实证材料。本文就是通过对虾卵胚胎各发育阶段腐解保存潜力的实验模拟研究,试图为球状化石的形成机制和化石归属提供一些实验室依据。     

Haeckel's ABC of evolution and development

One of the central, unresolved controversies in biology concerns the distribution of primitive versus advanced characters at different stages of vertebrate development. This controversy has major implications for evolutionary developmental biology and phylogenetics. Ernst Haeckel addressed the issue with his Biogenetic Law, and his embryo drawings functioned as supporting data. We re-examine Haeckel's work and its significance for modern efforts to develop a rigorous comparative framework for developmental studies. Haeckel's comparative embryology was evolutionary but non-quantitative. It was based on developmental sequences, and treated heterochrony as a sequence change. It is not always clear whether he believed in recapitulation of single characters or entire stages. The Biogenetic Law is supported by several recent studies -- if applied to single characters only. Haeckel's important but overlooked alphabetical analogy of evolution and development is an advance on von Baer. Haeckel recognized the evolutionary diversity in early embryonic stages, in line with modern thinking. He did not necessarily advocate the strict form of recapitulation and terminal addition commonly attributed to him. Haeckel's much-criticized embryo drawings are important as phylogenetic hypotheses, teaching aids, and evidence for evolution. While some criticisms of the drawings are legitimate, others are more tendentious. In opposition to Haeckel and his embryo drawings, Wilhelm His made major advances towards developing a quantitative comparative embryology based on morphometrics. Unfortunately His's work in this area is largely forgotten. Despite his obvious flaws, Haeckel can be seen as the father of a sequence-based phylogenetic embryology.     

哺乳动物卵母细胞及早期胚胎蛋白质组学研究进展

雌性生殖细胞发育是动物繁殖的基石,哺乳动物卵母细胞和早期胚胎在其生长发育过程中有许多独特的现象和规律,涉及一系列蛋白质合成/降解和磷酸化等状态的动态改变。对卵母细胞分裂、成熟调控机理以及植入前胚胎发育规律的研究是发育生物学领域的一项重要课题。蛋白质组学是以细胞或组织内全部的蛋白质为研究对象,系统鉴定、定量蛋白质并研究这些蛋白质功能的科学。随着蛋白质分离、鉴定技术的快速发展,蛋白质组学为卵母细胞发生、分化、成熟以及质量控制等相关研究提供了新的方法和内容,如在蛋白质定量、修饰、定位和相互作用等方面提供其他组学技术不可获得的重要信息。这些信息将有助于揭示哺乳动物卵母细胞成熟和早期胚胎发育的分子机制,对于进一步完善卵母细胞的体外成熟培养体系,提高胚胎体外生产、体细胞克隆和转基因动物生产效率具有重要意义。     

Metabolome Analysis of Drosophila melanogaster during Embryogenesis

The Drosophila melanogaster embryo has been widely utilized as a model for genetics and developmental biology due to its small size, short generation time, and large brood size. Information on embryonic metabolism during developmental progression is important for further understanding the mechanisms of Drosophila embryogenesis. Therefore, the aim of this study is to assess the changes in embryos’ metabolome that occur at different stages of the Drosophila embryonic development. Time course samples of Drosophila embryos were subjected to GC/MS-based metabolome analysis for profiling of low molecular weight hydrophilic metabolites, including sugars, amino acids, and organic acids. The results showed that the metabolic profiles of Drosophila embryo varied during the course of development and there was a strong correlation between the metabolome and different embryonic stages. Using the metabolome information, we were able to establish a prediction model for developmental stages of embryos starting from their high-resolution quantitative metabolite composition. Among the important metabolites revealed from our model, we suggest that different amino acids appear to play distinct roles in different developmental stages and an appropriate balance in trehalose-glucose ratio is crucial to supply the carbohydrate source for the development of Drosophila embryo.     

哺乳动物早期胚胎体外发育阻滞的研究进展

哺乳动物胚胎在体外培养中普遍存在早期发育阻滞的现象。对此,人们用形态学、生物化学、分子生物学、显微操作等手段开展了磷酸、葡萄糖、次黄嘌呤和细胞质因素对早期胚胎发育阻滞的影响的研究。本综合分析了共培养系统的优缺点。说明了采用完全成分已知的培养液对进行有关研究的必要性。列出了有效运用于克服小鼠、大鼠、仓鼠、兔、猪、羊、牛、猴等动物早期胚胎阻滞的成分知的培养液的名称。     

Bioengineered microenvironment to culture early embryos

The abnormalities of early post‐implantation embryos can lead to early pregnancy loss and many other syndromes. However, it is hard to study embryos after implantation due to the limited accessibility. The success of embryo culture in vitro can avoid the challenges of embryonic development in vivo and provide a powerful research platform for research in developmental biology. The biophysical and chemical cues of the microenvironments impart significant spatiotemporal effects on embryonic development. Here, we summarize the main strategies which enable researchers to grow embryos outside of the body while overcoming the implantation barrier, highlight the roles of engineered microenvironments in regulating early embryonic development, and finally discuss the future challenges and new insights of early embryo culture.     

Offerings from an urchin

There is a natural curiosity about how organisms give rise to offspring like themselves through a series of reproducible developmental events and how, once mature, these offspring mate and continue the process giving rise the next generation. In the mid-1800 s investigators started using gametes and embryos to explore this process. Although the observations and experimental approaches changed over time, embryologists and developmental biologists after them, sought understanding of development and inheritance through the study of gametes and embryos. It is argued here that in their quests to understand these processes embryologists made major conceptual advances that were seminal to the origins of genetics and to the origins of molecular biology. Furthermore these advances derived from the distinct perspective of those investigators with focused interest on the development of the organism. In this essay fundamental discoveries that originated with the sea urchin embryo as an experimental system are used to illustrate this position. The sea urchin has a long and uninterrupted history as a model organism that helped prepare the ground for the emergence of genetics and contributed important aspects to understanding of the central dogma of molecular biology. As molecular biology came of age new concepts and technology of the discipline were transformative for developmental biology and to this day the reciprocal inductive interactions between molecular biology and developmental biology continue to revitalize each other.     

The crucial role and regulations of miRNAs in zebrafish development

To comprehend the events during developmental biology, fundamental knowledge about the basic machinery of regulation is a prerequisite. MicroRNA (miRNAs) act as regulators in most of the biological processes and recently, it has been concluded that miRNAs can act as modulatory factors even during developmental process from lower to higher animal. Zebrafish, because of its favorable attributes like tiny size, transparent embryo, and rapid external embryonic development, has gained a preferable status among all other available experimental animal models. Currently, zebrafish is being utilized for experimental studies related to stem cells, regenerative molecular medicine as well drug discovery. Therefore, it is important to understand precisely about the various miRNAs that controls developmental biology of this vertebrate model. In here, we have discussed about the miRNA-controlled zebrafish developmental stages with a special emphasis on different miRNA families such as miR-430, miR-200, and miR-133. Moreover, we have also reviewed the role of various miRNAs during embryonic and vascular development stages of zebrafish. In addition, efforts have been made to summarize the involvement of miRNAs in the development of different body parts such as the brain, eye, heart, muscle, and fin, etc. In each section, we have tried to fulfill the gaps of zebrafish developmental biology with the help of available knowledge of miRNA research. We hope that precise knowledge about the miRNA-regulated developmental stages of zebrafish may further help the researchers to efficiently utilize this vertebrate model for experimental purpose.     

The study of preimplantation development of mice embryos labelled with green fluorescent protein gene (EGFp)

One of the crucial problems of developmental biology is the study of mechanisms of regulation of gene expression in early embryogenesis. Here we studied dynamics of mosaic appearance of a marker fluorescent protein in in vitro developing mice embryo derived from zygotes after microinjections to male pronuclei of cloned DNA fragment carrying EGFP under control of different promoters. Main attention was paid to initial stages of development, when structural rearrangements and reprogramming of both parental genomes, activation of zygotic genes, and control of development by embryo genome take place.     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科, 它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合, 其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪, 直到20世纪80年代早期, 动物中homeobox基因被发现, 90年代初花发育的 ABC模型被提出, 加之对发育相关基因研究的不断深入, 才使基因型与表型联系了起来, 进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程, 综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状, 讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科,它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合,其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪,直到20世纪80年代早期,动物中homeobox基因被发现,90年代初花发育的ABC模型被提出,加之对发育相关基因研究的不断深入,才使基因型与表型联系了起来,进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程,综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状,讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

Maternal cyclin B levels "Chk" the onset of DNA replication checkpoint control in Drosophila

In many animals, early development of the embryo is characterized by synchronous, biphasic cell divisions. These cell divisions are controlled by maternally inherited proteins and RNAs. A critical question in developmental biology is how the embryo transitions to a later pattern of asynchronous cell divisions and transfers the prior maternal control of development to the zygotic genome. The most-common model regarding how this transition from maternal to zygotic control is regulated posits that this is a consequence of the limitation of maternal gene products, due to their titration during early cell divisions. Here we discuss a recent article by Crest et al.1 that instead proposes that the balance of Cyclin-dependent Kinase 1 and Cyclin B (Cdk1-CycB) activity relative to that of the Drosophila checkpoint kinase Chk1 determines when asynchronous divisions begin.     

Models of maximum stress and strain of zebrafish embryos under indentation

Micro-injection of zebrafish embryo is widely applied in biology for the analysis of early developmental processes. The success of a micro-injection to a large extent depends on the mechanical interaction between the micro-pipette and the membrane of the zebrafish embryo. In this paper, we present the development of (i) a maximum stress model of the deformed membrane with respect to the depth of indentation, (ii) a family-of-conics elongation model to determine the length of the deformed membrane for the estimation of the maximum strain at a given indentation depth, and (iii) an experimental system to generate the required data for these two models. The significance of these results is that the estimated maximum stress provides a performance target for the penetration process, while the estimated corresponding maximum strain serves as an indicator of the extent of deformation sustained by the embryo prior to penetration. Implications of these modeling and experimental results are discussed in the context of optimizing the process of micro-injection.