August Rauber (1841-1917): from the primitive streak to Cellularmechanik

In the early 19th century Karl Ernst von Baer initiated a new research program searching for the mechanisms by which an egg transforms itself into an embryo. August Rauber (1841-1917) took up this challenge. He considered the phylogenetic principle as the right tool to explain the similitude of embryogenetic processes. In extending Baer's approach, he combined comparative embryology and histology in his studies of avian and mammalian embryos. His earlier work demonstrated that the two-layered chick embryo is a modified gastrula and not a "disc" as Wilhelm His had claimed. From the 1880s onwards, he concentrated on the issue of how the development of germ layers is related to tissue differentiation. To address this, he studied the blastopore, epiblast, primitive streak, teratology and the relative importance of nucleus and cytoplasm in heredity. This paper reconstructs some of Rauber's work and concludes that his observations and reflections constituted a new approach combining embryology and histology with "phylogenetic" reasoning.     

Q & A. Philip Ingham

Philip Ingham grew up in Liverpool and graduated from Cambridge University in 1977. He did his D.Phil in Developmental Genetics at Sussex University and postdoctoral work in Strasbourg, France before joining the laboratory of David Ish-Horowicz at the ICRF Mill Hill Laboratories. Here he applied the emerging technique of tissue in situ hybridisation to the analysis of the Drosophila segmentation genes. After a short spell at the MRC Laboratory of Molecular Biology in Cambridge, he rejoined the ICRF as a Research Scientist at the Developmental Biology Unit in Oxford. His group pioneered the analysis of the Hedgehog signalling pathway in Drosophila and in collaboration with the labs of Andy McMahon and Cliff Tabin at Harvard University, discovered the Hedgehog gene family in vertebrates. In 1996 he was appointed Professor of Developmental Genetics at the University of Sheffield where he has established the Centre for Developmental Genetics.     

Evolutionary embryology resurrected in Japan with a new molecular basis: Nori Satoh and the history of ascidian studies originating in Kyoto during the 20th century

This article briefly summarizes the scientific contributions of Nori Satoh, the winner of the 2005 edition of the Kowalevsky Medal, to Developmental Biology and especially to Evo-Devo with his 30 years of research on tunicates - a primitive chordate species. His research began with his pure developmental interest in the clock mechanism of cell differentiation and later expanded into various aspects of evolutionary and developmental phenomena. He is not only known as a founder of molecular biology-based tunicate studies, but also for his world-wide service to education and his prestigious publications in international scientific journals.     

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.     

Recognizing scientific excellence in the biology of cell adhesion

The prestigious 2005 Japan Prize for Cell Biology has been awarded to Dr. Masatoshi Takeichi, Director of RIKEN Developmental Biology, Kobe, Japan, and Dr. Erkki Ruoslahti, Distinguished Professor, The Burnham Institute, La Jolla, USA for their "Fundamental contribution in elucidating the molecular mechanisms of cell adhesion". The award is scheduled to be presented to the scientists in ceremonies in Tokyo on April 20, 2005 as part of a week-long celebration of "Japan Prize Week".     

The Mechanisms of Embryonic Scaling

Russian Journal of Developmental Biology - The phenomenon of scaling, i.e., preserving the proportions of the embryo’s spatial pattern in dependence on its overall size, is the most prominent...     

Global cell sorting is mediated by local cell-cell interactions in the C. elegans embryo

The Caenorhabditis elegans embryo achieves pattern formation by sorting cells into coherent regions before morphogenesis is initiated. The sorting of cells is coupled to their fate. Cells move extensively relative to each other to reach their correct position in the body plan. Analyzing the mechanism of cell sorting in in vitro culture experiments using 4D microscopy, we show that all AB-derived cells sort only according to their local neighbors, and that all cells are able to communicate with each other. The directions of cell movement do not depend on a cellular polarity but only on local cell-cell interactions; in experimental situations, this allows even the reversal of the polarity of whole regions of the embryo. The work defines a new mechanism of pattern formation we call "cell focusing".     

REVIEWS

Books reviewed in this article:
Developmental Biology of Physarum. By H. W. S auer
Climatic Change in Later Prehistory . Ed. by A. H arding
Climate from Tree-rings. Ed. by M. K. H ughes , P. M. K elly , J. R. P ilcher and V. C. L a M abche J r
Berichte des Geobotanischen Institutes der Eidg. Techn. Hochschule Stiftung Rübel , vol. 49. Ed. By Prof. E. Landolt
Plant Cell Structure and Metabolism , By J. L. H all , T. J. F lowers and R. M. R oberts
Experimental Embryology of Vascular Plants. Ed. by B. M. J ohri     

Structural and Functional Features of the Wheat Embryo Sac’s Antipodal Cells during Differentiation

Russian Journal of Developmental Biology - A detailed study into the structural features of the multilevel antipodal complex of wheat Triticum aestivum L. embryo sac was performed at different...     

My perpetual cycle: from student to researcher to teacher to student ..

This contribution stems from the personal experience of the author regarding how he became acquainted with embryology and how he finally entered the field of developmental biology. It reports his feelings as a student of the Histology and Embryology course as it was taught in the late 1970s, and his present efforts in teaching developmental biology to university students. In the Developmental Biology course at Pisa University today, students are taught the tissue, molecular and genetic mechanisms that regulate development of several model systems. Drosophila is introduced at the beginning, because of the great knowledge that it has brought to the unraveling of the molecular aspects of development and because it allows several basic concepts to be introduced, and vertebrate systems follow. Other topics include the classic experiments on amphibian systems, which are explained in the light of recent molecular advances, as well as the genetically more versatile vertebrate systems such as the mouse.     

Sharpening the focus; the business of epithelial cell biology. An interview with Chris Potten by David Pearton

Dr Chris Potten is a singularly influential figure in the field of epithelial biology. His contributions have been seminal and include the introduction of the epidermal proliferative unit and of the concept of epidermal stem cells. With around 400 scientific papers and reviews to his credit as well as two books, he has certainly made his mark. His contributions have been recognised by the award of the Curie medal and recently the Weiss medal for radiation biology. Dr. Potten graciously agreed to be interviewed for this Special Issue of The International Journal of Developmental Biology. This interview was conducted via e-mail during June -August 2003.     

One Upward,Two Steps Down: Order of Floral Organ Initiation

Russian Journal of Developmental Biology - In most angiosperms, floral organs are acropetally initiated, i.e., from the perianth upwards to the gynoecium. The review surveys examples of deviation...     

A history of normal plates, tables and stages in vertebrate embryology

Developmental biology is today unimaginable without the normal stages that define standard divisions of development. This history of normal stages, and the related normal plates and normal tables, shows how these standards have shaped and been shaped by disciplinary change in vertebrate embryology. The article highlights the Normal Plates of the Development of the Vertebrates edited by the German anatomist Franz Keibel (16 volumes, 1897-1938). These were a major response to problems in the relations between ontogeny and phylogeny that amounted in practical terms to a crisis in staging embryos, not just between, but (for some) also within species. Keibel's design adapted a plate by Wilhelm His and tables by Albert Oppel in order to go beyond the already controversial comparative plates of the Darwinist propagandist Ernst Haeckel. The project responded to local pressures, including intense concern with individual variation, but recruited internationally and mapped an embryological empire. Though theoretically inconclusive, the plates became standard laboratory tools and forged a network within which the Institut International d'Embryologie (today the International Society of Developmental Biologists) was founded in 1911. After World War I, experimentalists, led by Ross Harrison and Viktor Hamburger, and human embryologists, especially George Streeter at the Carnegie Department of Embryology, transformed Keibel's complex, bulky tomes to suit their own contrasting demands. In developmental biology after World War II, normal stages-reduced to a few journal pages-helped domesticate model organisms. Staging systems had emerged from discussions that questioned the very possibility of assigning an embryo to a stage. The historical issues resonate today as developmental biologists work to improve and extend stage series, to make results from different laboratories easier to compare and to take individual variation into account.     

Extensive nerve overgrowth and paucity of the tailed asymmetric form (16 S) of acetylcholinesterase in the developing skeletal neuromuscular system of the dysgenic (mdg/mdg) mouse

Segmentation of the mesoderm in the head of a newt embryo is revealed by scanning electron microscopy. By the end of gastrulation, the newt embryo is already segmented from one end to the other, with additional segments added later by the tail bud. This metameric segmentation appears long before the first “somite” can be seen in the late neurula by light microscopy. The six segments found in the newt head look much like the six most-cranial segments described decades ago in shark embryos. Mesodermal segments in the newt head are similar to somitomeres in amniote embryos, but in amniote embryos, the numbers and relationships of head segments are quite different from those of the newt. In both amniote and newt, the first segment abuts the prosencephalon, but for each more caudal head segment, where the newt embryo has one segment, the amniote has two. Although the pattern and distribution of cranial neural crest is quite similar in newt and amniote embryos, there are different relationships between migrating crest masses and mesodermal segments due to the doubling of most of the cranial segments in amniotes. It now appears that all vertebrate embryos, regardless of their mode of gastrulation, form similar mesodermal segments from one end of the embryo to the other, and this metameric pattern is established during gastrulation.     

Richard Pattle and the early days of comparative respiratory biology

After a distinguished academic career Richard Pattle was well qualified as a Physicist and Physical Chemist. Following a brief spell in the army (REME) he was appointed as a biophysicist in the Chemical Defence Experimental Laboratory at Porton Down. Such centres here and in USA initiated work which led to important discoveries relating to lung surfactants. His 1955 paper led to an expansion in studies of surfactant and the lung lining and appreciation of its importance in Respiratory Distress Syndrome of the newborn. This period (late 1950s and 1960s) was also when comparative studies in respiration were beginning to expand. Because of the relevance of his work to RDS it was inevitable that Pattle became closely associated with Human Physiologists. But he was also interested in other mammals and later the lungs of primates and lower vertebrates and this was extended to fish and the transition from water to air breathing. It was a time notable for the getting-together of medically-trained and zoologically-based scientists. I was always fascinated by the simplicity of his bubble technique and encouraged him to summarise it and his findings at Bhagalpur in 1974 when he introduced the term 'surpellic'. He also made important studies on bird lung surfactants.     

Early stages of neural crest ontogeny: formation and regulation of cell delamination

Long standing research of the Neural Crest embodies the most fundamental questions of Developmental Biology. Understanding the mechanisms responsible for specification, delamination, migration and phenotypic differentiation of this highly diversifying group of progenitors has been a challenge for many researchers over the years and continues to attract newcomers into the field. Only a few leaps were more significant than the discovery and successful exploitation of the quail-chick model by Nicole Le Douarin and colleagues from the Institute of Embryology at Nogent-sur-Marne. The accurate fate mapping of the neural crest performed at virtually all axial levels was followed by the determination of its developmental potentialities as initially analysed at a population level and then followed by many other significant findings. Altogether, these results paved the way to innumerable questions which brought us from an organismic view to mechanistic approaches. Among them, elucidation of functions played by identified genes is now rapidly underway. Emerging results lead the way back to an integrated understanding of the nature of interactions between the developing neural crest and neighbouring structures. The Nogent Institute thus performed an authentic "tour de force" in bringing the Neural Crest to the forefront of Developmental Biology. The present review is dedicated to the pivotal contributions of Nicole Le Douarin and her collaborators and to unforgettable memories that one of the authors bears from the time spent in the Nogent Institute. We summarize here recent advances in our understanding of early stages of crest ontogeny that comprise specification of epithelial progenitors to a neural crest fate and the onset of neural crest migration. Particular emphasis is given to signaling by BMP and Wnt molecules, to the role of the cell cycle in generating cell movement and to possible interactions between both mechanisms.     

An interview with Dr. Frank Slack on his highly cited paper published in Cell Cycle

Frank Slack received his B.Sc from the University of Cape Town in South Africa, before completing his Ph.D in molecular biology at Tufts University School of Medicine. He started work on microRNAs as a postdoctoral fellow in Gary Ruvkun’s laboratory at Harvard Medical School, where he co-discovered the second known microRNA, let-7. He is currently an Associate Professor in the Department of Molecular, Cellular and Developmental Biology at Yale University. The Slack laboratory studies the roles of microRNAs and their targets in development, disease and aging.     

Adventitious shoot-based propagation of Franklinia alatamaha for commercial horticulture and restoration

In Vitro Cellular & Developmental Biology - Plant - Franklinia is a monotypic genus of the family Theaceae that is now extinct in the wild. F. alatamaha Bartram ex Marshall has been maintained...