Chemical genetics: adding to the developmental biology toolbox

Recent advances in cell and molecular biology have generated important tools to probe developmental questions. In addition, new genetic model systems such as Danio rerio now make large-scale vertebrate early developmental mutant screens feasible. Nonetheless, some developmental questions remain difficult to study because of the need for finer temporal, spatial, or tuneable control of gene function within a developmental system. New uses for old teratogens as well as novel chemical modulators of development have begun to fill this void.     

Four decades of teaching developmental biology in Germany

I have taught developmental biology in Essen for 30 years. Since my department is named Zoophysiologie (Zoophysiology), besides Developmental Biology, I also have to teach General Animal Physiology. This explains why the time for teaching developmental biology is restricted to a lecture course, a laboratory course and several seminar courses. However, I also try to demonstrate in the lecture courses on General Physiology the close relationship between developmental biology, physiology, morphology, anatomy, teratology, carcinogenesis, evolution and ecology (importance of environmental factors on embryogenesis). Students are informed that developmental biology is a core discipline of biology. In the last decade, knowledge about molecular mechanisms in different organisms has exponentially increased. The students are trained to understand the close relationship between conserved gene structure, gene function and signaling pathways, in addition to or as an extension of, classical concepts. Public reports about the human genome project and stem cell research (especially therapeutic and reproductive cloning) have shown that developmental biology, both in traditional view and at the molecular level, is essential for the understanding of these complex topics and for serious and non-emotional debate.     

Learning developmental biology has priority in the life sciences curriculum in Singapore

Singapore has embraced the life sciences as an important discipline to be emphasized in schools and universities. This is part of the nation's strategic move towards a knowledge-based economy, with the life sciences poised as a new engine for economic growth. In the life sciences, the area of developmental biology is of prime interest, since it is not just intriguing for students to know how a single cell can give rise to a complex, coordinated, functional life that is multicellular and multifaceted, but more importantly, there is much in developmental biology that can have biomedical implications. At different levels in the Singapore educational system, students are exposed to various aspects of developmental biology. The author has given many guest lectures to secondary (ages 12-16) and high school (ages 17-18) students to enthuse them about topics such as embryo cloning and stem cell biology. At the university level, some selected topics in developmental biology are part of a broader course which caters for students not majoring in the life sciences, so that they will learn to comprehend how development takes place and the significance of the knowledge and impacts of the technologies derived in the field. For students majoring in the life sciences, the subject is taught progressively in years two and three, so that students will gain specialist knowledge in developmental biology. As they learn, students are exposed to concepts, principles and mechanisms that underlie development. Different model organisms are studied to demonstrate the rapid advances in this field and to show the interconnectivity of developmental themes among living things. The course inevitably touches on life and death matters, and the social and ethical implications of recent technologies which enable scientists to manipulate life are discussed accordingly, either in class, in a discussion forum, or through essay writing.     

An innovative biology course for first-year university students in Australia

The course ‘Biology of Mankind’ was introduced into the University of New South Wales for first-year students from any faculty wishing to take biology. All students, regardless of their previous background in biology or their reasons for taking the course, followed the same syllabus. Biological principles were taught in the context of the evolution of man in relation to his environment; the importance of scientific methods for the study of these interactions was emphasized. At the beginning of their university studies students were introduced to the relevance of biology for an understanding of many related disciplines. The course represented an educational innovation in both content and teaching methods. It sought to develop some independence in student learning as preparation for subsequent years. The development of the course and its evaluation over a three-year period are reviewed.     

How serendipity shaped a life; an interview with John W. Saunders,Jr. by John F. Fallon

John W. Saunders Jr. is an outstanding contributor to the field of Developmental Biology. His analyses of the apical ectodermal ridge, discovery and study of the zone of polarizing activity, insights into cell death in development, and analytical studies of feather patterns are part of a legacy to developmental biology. The body of his published work remains central to the understanding of limb development and is a major reason for the premiere place that the developmental biology of limbs holds in our research and teaching today. Beyond these things known to nearly everyone, there is John's role as teacher that is equally impressive. His one-on-one style, in small groups or from the podium is engaging, encompassing, and above all else, enthusiastic about the study of the development of living things. His love of developmental biology comes through to students of all ages and is inspirational. And, of course, inimitable charm accompanies the substance of any interaction with John. He still teaches in the Embryology Course at MBL Woods Hole. Recent students say that hearing his lectures and his involvement in the laboratory are highlights of the course. His continued knowledge of science and delight in new advances is a model for students to follow and they recognize it. John Saunders is a scientist and educator par excellence. His contributions have stood the test of time. His personal interactions with colleagues and students have enriched their lives in innumerable ways, large and small. His is a lifetime of outstanding achievements. In this interview, he reflects on his six--going on seven--decades in science and his personal enjoyment of recent advances in Developmental Biology.     

An intense half-semester developmental biology course,as taught at Uppsala University,Sweden

This intensive course, designed for advanced undergraduates and beginning graduate students, was first taught in 1995 at Uppsala University, Sweden, and consists of a half-semester (8-9 weeks) of daily lecture and laboratory sessions covering a broad range of topics and giving an overview of developmental biology and some of its applications. The labs introduce students to a diverse assortment of model systems. The course goals are to present a comparative view of animal development (gametogenesis, fertilization, gastrulation, neurulation, organogenesis), followed by lectures on cellular and molecular mechanisms that regulate development, such as induction mechanisms, cell adhesion and migration, cell-matrix interactions and genomic imprinting. The development of complex systems, such as the nervous system, limbs and flowers, is emphasized, including aspects such as malformations, homeosis and mutant analysis, reproduction and fertility problems, and the connection between development and cancer. Model organisms are emphasized, but evolutionary aspects receive due attention. Typically, during the first 5 weeks, a day begins with lectures in the morning and ends with labs or demonstrations and seminars in the afternoon. Wednesday afternoons are "free" to give time for reading. A theory test is taken at the end of this period. Then, students do supervised research for 3 weeks to give them a feel for what it is like to do "real science." Finally, students present oral and written reports on their projects. This is the only course students enroll in during this portion of the semester, so they are expected to devote full effort to it.     

Mechanisms of Hedgehog gradient formation and interpretation

Morphogens are molecules that spread from localized sites of production, specifying distinct cell outcomes at different concentrations. Members of the Hedgehog (Hh) family of signaling molecules act as morphogens in different developmental systems. If we are to understand how Hh elicits multiple responses in a temporally and spatially specific manner, the molecular mechanism of Hh gradient formation needs to be established. Moreover, understanding the mechanisms of Hh signaling is a central issue in biology, not only because of the role of Hh in morphogenesis, but also because of its involvement in a wide range of human diseases. Here, we review the mechanisms affecting the dynamics of Hh gradient formation, mostly in the context of Drosophila wing development, although parallel findings in vertebrate systems are also discussed.     

Thomas Hunt Morgan as an Embryologist: The View from Bryn Mawr

Thomas Hunt Morgan taught at Bryn Mawr College from 1891 until1904. During his years there he concentrated his research interestson embryology; he included regeneration as an integral partof development. This article maintains that Morgan did not abandonhis interest in embryology when he became a geneticist at Columbia,but it deals mainly with his teaching and research while atBryn Mawr. He worked on the development of a great diversityof organisms, plant and animal, he used widely differing experimentalmethods to investigate them, and he concerned himself with manydifferent general and special problems. He strove to investigateproblems that were directly soluble by experimental intervention,and was highly critical, in the best possible way, of the experimentsand interpretations made by his contemporaries, who regardedhim as a leader. He exerted his influence on developmental biologynot only through his research, but also through a number offine textbooks, and by his teaching. During his Bryn Mawr yearshe encouraged his students, undergraduate and graduate, to carryout independent research. He sometimes published with them asco-author, but dozens of articles by his students were publishedwithout carrying Morgan's name as co-author.     

From field to gel blot: teaching a holistic view of developmental phenomena to undergraduate biology students at the University of Tokyo

We present here an outline of the lectures and laboratory exercises for undergraduate developmental biology students at the University of Tokyo. The main aim of our course is to help students fill the gap between natural history, classical embryology and molecular developmental biology. To achieve this aim, we take up various topics in the lectures, from fertilization and early development to developmental engineering. Our laboratory exercises begin with an introduction to the natural history of the organism. The entire class and the instructors collect newts in the field and discuss features of their mating behavior and so on. In the laboratory, students are absorbed by exercises such as a lampbrush chromosome preparation and an in vitro beating heart induction. After that, students choose their own research projects for which they will employ both classical embryological and modern molecular biological techniques. At the end of our course, the connectivity principle from field to gel blot will be part of the students' understanding.     

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.     

Developmental biology in Ecuador: a 30-year teaching experience

Developmental biology has been taught at the Pontificia Universidad Católica del Ecuador, in Quito for 30 years by the author. The experience of teaching development is described within the broader context of science in Latin America. It is recognized that developmental biology is poorly represented in research and teaching in this part of the world. The teaching of developmental biology to Ecuadorian students contributes to their intellectual training, by helping them to integrate concepts derived from various branches of biology. Moreover, the highly conserved molecular mechanisms of development provide extraordinary examples of the unity of biology, and many complex biological processes can be more easily grasped when studying embryos.     

Using Xenopus as a model system for an undergraduate laboratory course in vertebrate development at the University of Bordeaux,France

The goal of this laboratory course is to introduce vertebrate developmental biology to undergraduate students, emphasizing both classical and contemporary aspects of this field. During the course, the students combine the use of living Xenopus laevis material with active tutorial participation, with the aim of illustrating how the fertilized egg can generate the diversity of cell types and complexity of pattern seen only a few days later in the embryo. Special emphasis is given to the observation and manipulation of living material. The laboratory course includes a comprehensive analysis of both oogenesis and early development and is divided into two overlapping parts that combine tutorial and practical approaches. The first part is devoted to oogenesis; oocytes are sorted out, allowed to mature in vitro and observed in histological section. In the second part, students perform an in vitro fertilization of Xenopus eggs and a mesoderm and neural induction assay of animal cap explants. Successful induction of the explants is confirmed by morphological, histological and molecular analyses. Finally, the students observe and comment on selected slides to illustrate the organization of the body plan of the amphibian embryo at an early stage of organogenesis.     

Howard A. Schneiderman--Planetary Patriot

SYNOPSIS. This symposium on arthropod development is dedicatedto the memory of Howard A. Schneiderman, who died on December5, 1990. Howard devoted much of his professional life to researchon arthropods and was the author of numerous publications onthe developmental biology of moths and flies. At Case-WesternReserve University and at the University of California-Irvinehe founded research institutes devoted to developmental biologyon arthropods as well as other organisms. Howard Schneidermanchampioned the use of insect growth regulators, which derivedfrom his research on the chemistry and physiology of juvenilehormone, as environmentally innocuous methods of controllinginsect pests of our food and fiber. In recent years he was aproponent of the use of molecular biology to alter the plantgenome so that insect-resistant crops might be grown and therebyreduce the use of insecticides. His global perspective was evidentin his understanding of how biotechnology could be applied toworld agriculture. Moreover, he quickly achieved prominencein promoting industry-university relations in his capacity asSenior Vice President for Research and Development at the MonsantoCompany. The cooperation among academic and industrial institutionsthat he fostered stands as a model for such relationships. HowardSchneiderman's influence on science and its applications, andon the universityindustry interface was profound and will befelt for many years to come.     

Michael Akam and the rise of evolutionary developmental biology

Michael Akam has been awarded the 2007 Kowalevsky medal for his many research accomplishments in the area of evolutionary developmental biology. We highlight three tributaries of Michael’s contribution to evolutionary developmental biology. First, he has made major contributions to our understanding of development of the fruit fly, Drosophila melanogaster. Second, he has maintained a consistent focus on several key problems in evolutionary developmental biology, including the evolving role of Hox genes in arthropods and, more recently, the evolution of segmentation mechanisms. Third, Michael has written a series of influential reviews that have integrated progress in developmental biology into an evolutionary perspective. Michael has also made a large impact on the field through his effective mentorship style, his selfless promotion of younger colleagues, and his leadership of the University Museum of Zoology at Cambridge and the European community of evolutionary developmental biologist.     

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.     

A first attempt to bring computational biology into advanced high school biology classrooms

Computer science has become ubiquitous in many areas of biological research, yet most high school and even college students are unaware of this. As a result, many college biology majors graduate without adequate computational skills for contemporary fields of biology. The absence of a computational element in secondary school biology classrooms is of growing concern to the computational biology community and biology teachers who would like to acquaint their students with updated approaches in the discipline. We present a first attempt to correct this absence by introducing a computational biology element to teach genetic evolution into advanced biology classes in two local high schools. Our primary goal was to show students how computation is used in biology and why a basic understanding of computation is necessary for research in many fields of biology. This curriculum is intended to be taught by a computational biologist who has worked with a high school advanced biology teacher to adapt the unit for his/her classroom, but a motivated high school teacher comfortable with mathematics and computing may be able to teach this alone. In this paper, we present our curriculum, which takes into consideration the constraints of the required curriculum, and discuss our experiences teaching it. We describe the successes and challenges we encountered while bringing this unit to high school students, discuss how we addressed these challenges, and make suggestions for future versions of this curriculum.We believe that our curriculum can be a valuable seed for further development of computational activities aimed at high school biology students. Further, our experiences may be of value to others teaching computational biology at this level. Our curriculum can be obtained at http://ecsite.cs.colorado.edu/?page_id=149#biology or by contacting the authors.     

Pieter Nieuwkoop's contributions to the understanding of meso-endoderm induction and neural induction in chordate development

Pieter Nieuwkoop, who died September 18, 1996, at age 79 in Utrecht, The Netherlands, is remembered by developmental biologists for his numerous research contributions and integrative hypotheses over the past 50 years, especially in the areas of neural induction, meso-endoderm induction, and germ cell induction in chordates. Most of his experimentation was done on the embryos of amphibia, the preferred vertebrate embryo of the early years of the 20th century. One of his last publications contains a comparison of the experimental advantages and disadvantages of anuran and urodele amphibians (Nieuwkoop, 1996). The significance of his findings and interpretations for developmental biology can be estimated from the fact that researchers of many laboratories worldwide continue to work on the phenomena he first described and to extend the hypotheses he first formulated. The aim of this article is to review Nieuwkoop's main contributions and to cite the recent extensions by others.     

Perspective on gravitational biology of amphibians]

We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and externally, it is easy to observe their development. Consequently amphibians were the first vertebrates to have their early developmental processes investigated in space. Though several deviations from normal embryonic development occur when amphibians are raised in microgravity, their developmental program is robust enough to return the organisms to an ostensibly normal morphology by the time they hatch. Evolutionally, amphibians were the first vertebrate animal to come out of the water and onto land. Subsequently they diversified and have adaptively radiated to various habitats. They now inhabit aquatic, terrestrial, arboreal and fossorial niches. This diversity can be used to help study the biological effects of gravity at the organismal level, where macroscopic phenomena are associated with gravitational loading. By choosing different amphibian models and using a comparative approach one can effectively identify the action of gravity on biological systems, and the adaptation that vertebrates have made to this loading. Advances in cellular and molecular biology provide powerful tools for the study in many fields, including gravitational biology, and amphibians have proven to be good models for studies at those levels as well. The low metabolic rates of amphibians make them convenient organisms to work with (compared to birds and mammals) in the difficult and confined spaces on orbiting research platforms. We include here a review of what is known about and the potential for further behavioral and physiological researches in space using amphibians.     

Ringing in the new ear: resolution of cell interactions in otic development

The vertebrate inner ear is a marvel of structural and functional complexity, which is all the more remarkable because it develops from such a simple structure, the otic placode. Analysis of inner ear development has long been a fascination of experimental embryologists, who sought to understand cellular mechanisms of otic placode induction. More recently, however, molecular and genetic approaches have made the inner ear a useful model system for studying a much broader range of basic developmental mechanisms, including cell fate specification and differentiation, axial patterning, epithelial morphogenesis, cytoskeletal dynamics, stem cell biology, neurobiology, physiology, etc. Of course, there has also been tremendous progress in understanding the functions and processes peculiar to the inner ear. The goal of this review is to recount how historical approaches have shaped our understanding of the signaling interactions controlling early otic development; to discuss how new findings have led to fundamental new insights; and to point out new problems that need to be resolved in future research.     

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.