Spemann (Spemann), Hans

June 27, 1869, Mr.. - September 12, 1941
German embryologist Hans Spemann was born in Stuttgart, in the family publishing house of Johann Wilhelm Spemann and Lizinki Spemann (Hoffman). Hans was the eldest of four children Shpemanov. SH. Eberhard Ludwig graduated from high school and, although it is very fond of classical literature, he decided to devote himself to medicine. Having worked for a year at a school his father and another year having served in the Army, W. in 1891. enrolled in the University of Heidelberg.
Initially W. going to become a doctor, but during training he was so interested in embryology, he decided to leave medical practice and engage in research activities. At the end of 1893. He left Heidelberg, during the winter studied at Munich University, and spring has begun work on a dissertation on embryology at the Zoological Institute of Wц?rzburg University. His head was Theodor Boveri, one of the leading embryologists in the world.
At the outset of their research careers W. set a series of questions that agitated while embryologists. Subsequently, he formulated these questions as follows: 'How To Network harmonious interaction between the individual processes, . a result of which formed a single integrated process razvitiyaN whether these processes are taking place independently of each other, . Being from the outset so precisely balanced, . that eventually resulted in a complicated 'product' of the whole organism, . or carried out their mutual influence, . which they reinforce, . support or limit each drugaN ',
. The direction of the first works W
. on embryonic development was prompted him to his colleague at the University of Heidelberg, Gustav Wolff. This scientist found that if the developing eye of newt embryo to remove the lens, then from the edge of the retina would develop a new lens. SH. was struck by the experiments of Wolf and decided to continue them, focusing not only on how to regenerate the lens, but rather on what is the mechanism of its original formation.
. In a normal lens of the eye develops from the triton group of cells of the ectoderm (outer layer of embryonic tissue) at a time when a particular outgrowth of the brain - the optic cup - reaches the surface of the embryo
. SH. proved that the signal for the formation of the lens comes precisely from the optic cup. He found that if you remove the ectoderm, from which must be formed lens and replace it with cells from a completely different area of the embryo, some of these transplanted cells began to develop a normal lens. To solve their problems W. developed a highly sophisticated methods and instruments, many of which are used by today embryology and neuroscience for the delicate manipulation of individual cells.
Meanwhile W. finished his doctoral dissertation and in 1895. was awarded a doctorate. After that he stayed in Wurzburg and 3 years later was promoted to a lecturer in zoology. In 1908, Mr.. he moved to Rostock, where he took the post of Professor of Zoology and Comparative Anatomy. By the beginning of the First World War, he became Deputy Director of the Institute of Biology of the Kaiser Wilhelm (now Max Planck Institute) in Dahlem (a suburb of Berlin) and has served in this position throughout the war. In 1919, Mr.. he became professor of zoology at the University of Freiburg.
In his early experiments on the lens and eye glass W. showed that the development of the ectoderm, from which the lens is formed, depends on the influence of the retina. Then he decided to study, in which the same shall be determined by the development of the embryo as a whole. For this purpose he divided the egg into two halves triton with loops made of human hair. It turns out that if this operation to make the early stages of embryogenesis (embryo development), then from each half may develop a holistic, albeit smaller than normal, the embryo. If the same operation to make later, then from each half will grow half of the embryo. This W. concluded that the 'development plan' for each half of the egg is determined in the interim period.
W. not pay particular attention to the mechanisms of processes determining the development of. He believed that embryonic development is too complex for that, so it can be analyzed at the molecular level, and therefore focused its efforts on its temporal sequence, ie. on what part of the embryo are determined in their development, the first relationship and what is between the different parts.
In order to answer these questions, W. producing tissue transplantation between embryos belonging to two closely related species triton. Because individuals of these species differ in color, W. could easily trace the fate of transplanted cells. With. colleagues (in particular, . with Hilde and Otto Mangold), he found, . what, . as in the first experiments with the lens of the Wolf, . the fate of the grafted tissue is almost entirely dependent not on, . which body should have been out of it to develop into its former position, . but from its new localization,
. At the same time, W. identified and one surprising exception. Turned, . that a certain area of the embryo, . near the connection between the three major cell sheets (ectoderm, . endoderm and mesoderm), . being transplanted to any place of another embryo of the same period, . not developed in accordance with its new location, . but rather continued to line their own development and directed the development of the surrounding tissues,
. These data were published by W. and Hilde Mangold in 1922, it was shown, . that there is a section of the embryo, . tissue from which, . being transplanted to any place other embryo, . is organizing primordial structures (the earliest discernible structures, . appear during embryonic development) of the second embryo,
. In this regard, these areas were called 'organizing centers'.
How to write W. subsequently, . in his subsequent works on the transplantation of tissues between embryos of different species showed, . that 'inducing stimuli do not determine any specific properties [induced body], . but start the development of those properties, . are already inherent in the reacting tissue ..,
. The complexity of developing systems is mainly determined by the structure of the reacting tissue, and ... inductor has only runs and in some cases directing effect '.
In 1935. SH. was awarded the Nobel Prize in Physiology or Medicine for the 'discovery of organizing effects in embryonic development'. However, in spite of the importance of this discovery, it constituted only one of many scientific achievements W. His method and questions asked direction of embryology in the first half of XX. In 1936, Mr.. He summed up many of his works in the book 'Embryonic development and induction' ( 'Embryonic Development and Induction'), which became a classic in the field of developmental biology.
W. able to show that in some cases, the interaction between the embryonic leaves depends on the further development of specific groups of cells (and their daughter cells) in those tissues and organs in which they have become a mature embryo. Precise experiments W. led him to the formulation of clear questions about the causal relationship between specific and clearly defined development processes identified cell groups. The totality of his work laid the foundation for the modern theory of the development of the embryo
In 1895, Mr.. SH. marries Clara Binder. The family had two children. Leisure Time W. liked to discuss with friends and colleagues the problems of art, literature and philosophy. He often repeated: 'The scientist, whose analytical mind does not go well, at least a small degree, with artistic inclinations, in my opinion, not capable of understanding the organism as a whole'. September 12, 1941 W. died at his country house near Vryburg.