Hans Spemann as a scientist. Great German Doctors
German embryologist Hans Spemann
Wikimedia Commons
Hans Spemann
Nobel Prize in Physiology or Medicine in 1935. The wording of the Nobel Committee: "for the discovery of organizing effects in embryonic development" (for his discovery of the organizer effect in embryonic development).
Our hero was supposed to become a bookseller, publisher, or, at worst, a writer. Hans Spemann was the eldest of four children of Johann Wilhelm Spemann and Lizinka Spemann, née Hofmann. Johann Wilhelm was a fairly successful book dealer, and his son grew up among books, adored old folios and classical literature. In the same spirit, he received a secondary education, graduating from the very good Eberhard Ludwig Gymnasium. However, after serving a year in the army (as was customary after graduating from school in Germany), or rather, in the hussars, and then after working a little in the "subsidiary" in Hamburg, Hans nevertheless decided to study as a doctor and in 1891 entered the University of Heidelberg . However, he was also not destined to become a doctor.
Already in Heidelberg, the biologist Gustav Wolf performed an amazing experiment: in the embryo of a newt, the lens was removed from the developing eye, but it again developed from the edge of the retina. Spemann was so struck by the magic of what he saw that, already a student, he abandoned his medical career and decided to become an embryologist. No sooner said than done: he left Heidelberg, briefly studied in Munich, and then moved to the Zoological Institute of the University of Würzburg.
There he earned degrees in zoology, botany and physics, doing research under the guidance of the embryologist Theodor Heinrich Boveri (who established that the number of chromosomes in different types), a student of the great Purkinje Julius von Sachs (who was actually one of the discoverers of photosynthesis) and Wilhelm Conrad von Roentgen, respectively.
Spemann's teacher Julius Sachs
Wikimedia Commons
Spemann's teacher Theodor Boveri
Wikimedia Commons
During normal embryogenesis, the lens of the newt's eye develops from a group of ectoderm cells (the outer sheet of embryonic tissue) when the eyecup, an outgrowth of the newt's brain, reaches the surface of the embryo (it is not for nothing that they say that the eyes are the brain brought out).
With the help of elegant experiments, Spemann proved that it is this brain outgrowth that sends a certain signal that it is time for the eye to grow. Spemann was distinguished by the artistry of the experiment, and his elegant methods are still used in embryology. “A scientist whose analytical mind is not combined, at least to a small extent, with artistic inclinations, in my opinion, is not capable of understanding the organism as a whole,” Spemann liked to say.
He and his graduate student Hilda Mangold found that the fate of transplanted tissue depends almost entirely not on which organ was supposed to develop from it in its previous position, but on its new location. If a piece of the future eye is transplanted into the skin, then it is not the eye that grows, but the skin.
Triton
Flickr
There was also an exception. A certain part of the embryo, located near the junction between the three main cell sheets (ectoderm, endoderm and mesoderm), being transplanted to any place in another embryo of the same period, did not develop in accordance with its new location, but continued the line of its own development and directed the development of others fabrics. As Mangold wrote in her dissertation, “Inducing stimuli do not set specific properties [of the induced organ], but trigger the development of those properties that are already inherent in the responding tissue ... The complexity of developing systems is mainly determined by the structure of the responding tissue, and ... the inductor has only triggering and in some cases guiding effect.
Alas, famous for her dissertation Über Induktion von Embryonalanlagen durch Implantation artfremder Organisatoren("Induction of embryonic origin by implantation of organizational centers in different species") Mangold was unable to build on her success. After receiving her doctorate in 1923, she moved to Berlin with her husband and her young son, Christian. On September 4, 1924, tragedy struck: the gas heater in her house exploded. Hilda died without seeing her results in print: their joint work with Spemann came out only at the end of 1924. Her son died during World War II.
Hilda Mangold with her son
Wikimedia Commons
BUT scientific director Mangold, Hans Spemann, survived his graduate student and managed to live long enough to wait for his Nobel Prize in 1935. By the way, Spemann was not a favorite: 21 out of 177 nominations were from the Japanese scientist Ken Kure, for "work on tonic and trophic innervation of muscles and the spinal parasympathetic system, as well as on progressive muscular dystrophy." But only Japanese scientists "spamed" the Nobel Committee with the Kure nomination, none of the Europeans and Americans mentioned it. A year later, Spemann published the book "Embryonic Development and Induction", which for a long time became a classic of embryology.
The scientist lived the rest of his life quietly - in his country house in Freiburg, where he died in September 1941. Of all the participants in Spemann's key work on "organizational" points, the Second World War was survived only by his former graduate student, who defended his dissertation in 1919 and became an assistant professor, Otto Mangold. The same husband of Hilda, who joined the NSDAP and signed in 1942 the famous letter to the Reich Chancellery, which noted the "tremendous acuteness of the struggle of the Jews against the German people" (and justified the "final solution of the Jewish question"), after which he became president of the German Zoological Society. Alas, this man got off only with suspension from teaching in 1945, but already in 1946 he received the whole Institute of Experimental Biology in Heiligenberg, where he died in 1961.
You can also follow the updates of our blog through it.
Embryonic induction is the process of interaction of parts of the embryo, in which one site influences the fate of another. This concept refers to experimental embryology.
The article is devoted to one of the most important and difficult questions of this science: "What does embryonic induction mean?"
A bit of history
The phenomenon of embryonic induction was discovered in 1901 by such German scientists as Hans Spemann and Hilda Mangold. For the first time, this process was studied using the example of the lens in amphibians in the embryonic state. History has preserved many examples and experiments on this topic, which are based on Spemann's theory.
Hypothesis
As mentioned earlier, embryonic induction is the process of interaction between parts of the embryo. So, according to the hypothesis, there are a number of cells that act on other cells as organizers that provoke changes in development. In order to more clearly illustrate this process, scientists in the 20s of the last century conducted a series of experiments, which we will discuss in more detail below.
Hans Spemann experiment
As a result of his experiments, Dr. Spemann revealed a pattern that development occurs in a strict dependence of some organs on others. The experiment was carried out on tritons. Spemann transplanted a portion of the blastopore lip from the back of one embryo into the abdominal cavity of another. As a result, at the place where the organ was transplanted, the formation of a new embryo began. Normally, the neural tube never forms in the abdominal cavity.
Based on experience, the doctor concluded that there are organizers who influence further development organism. However, the organizers can only start if the cages are competent. What does it mean? Competence is understood as the ability of the germinal material to change its presumptive fate under the influence of different kind influences. When studying inductive interactions in various kinds chordate scientists came to the conclusion that in the areas and terms of competence of various organisms there are many individual features. That is, the organizers act if the cell is able to accept the inductor, but in all organisms this or that process occurs in different ways.
Let us conclude: the development of an organism is a chain process; without one cell, the formation of another is impossible. Embryonic induction gradually determines the formation and differentiation of organs. Also, this process is the basis for the formation appearance developing individual.
Research by Hilda Mangold
Hans Spemann had a graduate student - Hilda Mangold. With amazing dexterity, she was able to perform a series of complex experiments with microscopic newt embryos (1.5 mm in diameter). Separating a small piece of tissue from one embryo, she transplanted it onto an embryo of another species. Moreover, for transplantation, she chose the areas of the embryo where the formation of cells took place, from which the embryo with a particle of another embryo transplanted onto it would continue to develop successfully. And the grafted piece of tissue gave rise to a new body, endowed with a back, spine, abdomen and head.
What was the significance of the experiments? In the course of them, Mangold proved that there is an embryonic induction. This is possible because a small site has these unique properties, it has been called an organizer.
Types of induction
There are two types: heteronomous induction and homonomous induction. What is it and what is the difference? The first type is a process in which a transplanted cell is forced to rebuild itself to a common rhythm, that is, it gives rise to some kind of new organ. The second provokes a change in surrounding cells. Encourages the material to develop in the same direction.
Basic cellular processes
For more clarity, a table is shown below. We propose to study the main cellular processes of embryonic induction using its example.
Forms of cellular interactions | Formation of normal structures | Consequences of violations |
displacement | formation of the neural tube during the movement of primary germ cells | |
selective breeding | organ rudiments | lack of organs |
selective death | separation of fingers, death of epithelial cells during the fusion of the palatine rudiments, nasal processes, etc. | face, spinal hernia |
adhesion | formation of the neural tube from the neural plate, etc. | disturbances in the formation of the neural tube, a violation of the structure |
thickening | limb formation | absence of limbs or the presence of additional |
The manifestation of this phenomenon was found at various stages of development of the organism. Currently, embryonic induction is being actively studied.
Nobel Prize in Physiology or Medicine, 1935
German embryologist Hans Spemann was born in Stuttgart, the son of book publisher Johann Wilhelm Spemann and Lizinka Spemann (Hofmann). Hans was the oldest of the four Spemann children. W. graduated from the gymnasium Eberhard Ludwig and, although he was very fascinated by classical literature, he decided to devote himself to medicine. After working for a year in his father's institution and another year after serving in the army, W. in 1891, he entered the University of Heidelberg.
At first, Sh. was going to become a doctor, but during his studies he became so interested in embryology that he decided to leave practical medicine and do research activities. At the end of 1893 he left Heidelberg, studied during the winter at the University of Munich, and in the spring began work on his dissertation in embryology at the Zoological Institute of the University of Würzburg. Its leader was Theodore Boveri, one of the world's leading embryologists.
Already at the very beginning of his research career W. set himself a number of questions that worried embryologists at that time. Subsequently, he formulated these questions as follows: “How is a harmonious interaction between individual processes established, as a result of which a single integral process of development is formed? Do these processes occur independently of each other, being so finely balanced from the very beginning that they eventually lead to the formation of the most complex “product” of a whole organism, or do they mutually influence, in which they strengthen, support or limit each other?
The direction of the first work W. on embryonic development was suggested to him by his colleague at the University of Heidelberg, Gustav Wolf. This scientist discovered that if the lens is removed from the developing eye of a newt embryo, then a new lens will develop from the edge of the retina. Sh. was struck by the experiments of Wolf and decided to continue them, focusing not so much on how the lens regenerates, but on what is the mechanism of its initial formation.
Normally, the lens of the newt's eye develops from a group of ectoderm cells (the outer sheet of embryonic tissue) at the moment when a special outgrowth of the brain - the eye cup - reaches the surface of the embryo. Sh. proved that the signal for the formation of the lens comes from the eye cup. He discovered that if you remove the ectoderm from which the lens is supposed to form and replace it with cells from a completely different area of the embryo, then a normal lens begins to develop from these transplanted cells. To solve their problems, Sh. developed an extremely complex methods and devices, many of which are still used by embryologists and neuroscientists for the most subtle manipulations with individual cells.
Meanwhile W. completed his doctoral dissertation and in 1895. was awarded the degree of Doctor of Science. After that, he remained in Würzburg and 3 years later received a position as a lecturer in zoology. In 1908 he moved to Rostock, where he became professor of zoology and comparative anatomy. By the outbreak of the First World War, he became deputy director of the Kaiser Wilhelm Institute for Biology (now the Max Planck Institute) in Dahlem (a suburb of Berlin) and worked in this position throughout the war. In 1919 he became professor of zoology at the University of Freiburg.
In their early experiences Sh. showed on the lens and eye cup that the development of the ectoderm, from which the lens is formed, depends on the influence of the retina. Further, he decided to study in what terms the development of the embryo as a whole is determined. To do this, he divided the egg of a newt into two halves using a loop made from a human hair. It turned out that if this operation is performed in the early stages of embryogenesis (development of the embryo), then each half can develop a complete, albeit smaller compared to the norm, embryo. If the same operation is performed later, then half of the embryo will grow from each half. From this W. concluded that the "development plan" of each half of the egg is determined in this interim period.
Sh. did not pay much attention to the mechanisms of the processes that determine development. He believed that embryonic development was too complex to be analyzed at the molecular level, and therefore concentrated his efforts on its temporal sequence, i.e. on which parts of the embryo are determined first in their development and what are the relationships between the various parts.
In order to answer these questions, Sh. produced tissue transplants between embryos belonging to two closely related species of newt. Since individuals of these species differ in color, W. could easily follow the fate of the transplanted cells. Together with. with his colleagues (particularly with Hilda and Otto Mangold) he discovered that, as in Wolff's first experiments with the lens, the fate of the transplanted tissue depends almost entirely not on which organ was supposed to develop from it in its previous position, but on its new location. At the same time, Sh. revealed one surprising exception. It turned out that a certain part of the embryo, located near the junction between the three main cell sheets (ectoderm, endoderm and mesoderm), being transplanted to any place in another embryo of the same period, did not develop in accordance with its new location, but rather continued the line of its own development. and directed the development of surrounding tissues. These data were published by W. and Hilda Mangold in 1922; it has been shown that there is a region of the embryo whose tissue, when transplanted anywhere in another embryo, causes the organization of the primordial structures (the very first discernible structures that appear during embryonic development) of the second embryo. In this regard, such areas were called "organizational centers."
As W. later wrote, in his subsequent work on tissue transplantation between embryos of different species, it was shown that “inducing stimuli do not set specific properties [of the induced organ], but trigger the development of those properties that are already inherent in the responding tissue ... The complexity of developing systems is mainly determined by the structure of the reacting tissue, and ... the inductor has only a triggering and, in some cases, a guiding effect.
In 1935, Mr.. Sh. was awarded the Nobel Prize in Physiology or Medicine for "the discovery of organizing effects in embryonic development." However, for all the importance of this discovery, it was only one of many scientific achievements Sh. The methods developed by him and the questions posed by him set the direction for the development of embryology in the first half of the 20th century. In 1936, he summarized much of his work in Embryonic Development and Induction, which has become a classic work in the field of developmental biology.
Sh. was able to show that in a number of cases, the further development of special groups of cells (and their daughter cells) into those tissues and organs into which they must turn into a mature embryo depends on the interaction between the embryonic sheets. Clear experiments Sh. led him to the formulation of clear questions about the cause-and-effect relationship between certain and well-defined processes of development of identifiable cell groups. The sum total of his work laid the foundation for modern teaching about the development of the embryo.
In 1895, Mr.. W. married Clara Binder. In the family they had two children. In his spare time, Sh liked to discuss with friends and colleagues the problems of art, literature, and philosophy. He often repeated: "A scientist whose analytical mind is not combined, at least to a small extent, with artistic inclinations, in my opinion, is not able to understand the organism as a whole." September 12, 1941 Sh. died in his country house near Freiburg.
Nobel Prize Laureates: Encyclopedia: Per. from English - M .: Progress, 1992.
© The H.W. Wilson Company, 1987.
© Translation into Russian with additions, Progress Publishing House, 1992.
Hans Spemann (German: Hans Spemann) is a German embryologist, winner of the Nobel Prize in Physiology or Medicine in 1935 "for his discovery of organizing effects in embryonic development."
Hans Spemann was born in Stuttgart, the son of book publisher Johann Wilhelm Spemann and Lizinka Spemann (Hofmann). Hans was the eldest of the four Spemann children. He graduated from the Eberhard Ludwig Gymnasium and, although he was very interested in classical literature, he decided to devote himself to medicine. After working for a year in his father's institution and serving another year in the army, Spemann entered the University of Heidelberg in 1891.
During his studies, Hans Spemann became so interested in embryology that he decided to leave practical medicine and engage in research activities. At the end of 1893 he left Heidelberg, studied during the winter at the University of Munich, and in the spring began work on a dissertation in embryology at the Zoological Institute of the University of Würzburg. In 1905 Spemann defended his doctoral dissertation.
In 1908, Spemann moved to Rostock, where he became professor of zoology and comparative anatomy. By the outbreak of the First World War, he had become deputy director of the Kaiser Wilhelm Institute for Biology (now the Max Planck Institute) and worked in this position throughout the war.
The direction of the first scientific works on embryonic development, Spemann was prompted by his colleague at the University of Heidelberg, Gustav Wolf. This scientist discovered that if the lens is removed from the developing eye of a newt embryo, then a new lens will develop from the edge of the retina.
Spemann was amazed by Wolff's experiments and decided to continue them, focusing not so much on how the lens regenerates, but on what is the mechanism of its initial formation.
Hans Spemann did not pay much attention to the mechanisms of the processes that determine development. He believed that embryonic development was too complex to be analyzed at the molecular level, and therefore concentrated his efforts on its temporal sequence, i.e. on which parts of the embryo are determined first in their development and what are the relationships between the various parts.
The scientist had a rich set of tools at his disposal: thin scalpels, micropipettes, hair loops, glass needles. With the help of such instruments, Spemann, demonstrating amazing patience and skill, performed the finest microsurgical operations on the embryo, which allowed him to learn a lot of new and interesting things.
In one of his experiments, Spemann transplanted the eye rudiment into various parts of the body of the embryo and found that the skin above this rudiment everywhere turned into a cornea. This led him to the idea that different parts of the embryo secrete substances that affect the development of neighboring parts.
Spemann carried out his fundamental experiments between 1901 and 1918. And all this time he was looking for new confirmations of his idea, transplanting and swapping different parts of the embryo. From one embryo, he took the neural plate that normally develops into the brain, placed it in the skin of another embryo, and found that there it changed into normal skin.
These experiments allowed the scientist to create the so-called theory - "organizational centers", to describe the various points of the embryo, where substances are released - similar in action to hormones - that affect the differentiation and specialization of cells. These studies are not only extremely interesting theoretically, but also very important for practice, for they shed light on the problem of regeneration.
In 1935, Hans Spemann was awarded the Nobel Prize in Physiology or Medicine for "the discovery of organizing effects in embryonic development." However, for all the importance of this discovery, it represented only one of his many scientific achievements.
The methods he developed and the questions he posed set the direction for the development of embryology in the first half of the 20th century. In 1936, he summarized much of his work in Embryonic Development and Induction, which has become a classic work in the field of developmental biology.
In 1895 Spemann married Clara Binder. In the family they had two children. In his spare time, the scientist liked to discuss with friends and colleagues the problems of art, literature and philosophy. He often repeated: "A scientist whose analytical mind is not combined, at least to a small extent, with artistic inclinations, in my opinion, is not able to understand the organism as a whole."
Hans Spemann
Nobel Prize in Physiology or Medicine in 1935. The wording of the Nobel Committee: "for the discovery of organizing effects in embryonic development" (for his discovery of the organizer effect in embryonic development).
Our hero was supposed to become a bookseller, publisher, or, at worst, a writer. Hans Spemann was the eldest of four children of Johann Wilhelm Spemann and Lizinka Spemann, née Hofmann. Johann Wilhelm was a fairly successful book dealer, and his son grew up among books, adored old folios and classical literature. In the same spirit, he received a secondary education, graduating from the very good Eberhard Ludwig Gymnasium. However, after serving a year in the army (as was customary after graduating from school in Germany), or rather, in the hussars, and then after working a little in the "subsidiary" in Hamburg, Hans nevertheless decided to study as a doctor and in 1891 entered the University of Heidelberg . However, he was also not destined to become a doctor.
Already in Heidelberg, the biologist Gustav Wolf performed an amazing experiment: in the embryo of a newt, the lens was removed from the developing eye, but it again developed from the edge of the retina. Spemann was so struck by the magic of what he saw that, already a student, he abandoned his medical career and decided to become an embryologist. No sooner said than done: he left Heidelberg, briefly studied in Munich, and then moved to the Zoological Institute of the University of Würzburg.
There he takes degrees in zoology, botany and physics, doing research under the guidance of the embryologist Theodor Heinrich Boveri (who established the constancy of the number of chromosomes in different species), a student of the great Julius von Sachs (who was actually one of the discoverers of photosynthesis) and respectively.
Spemann's teacher Julius Sachs
Wikimedia Commons
Spemann's teacher Theodor Boveri
Wikimedia Commons
During normal embryogenesis, the lens of the newt's eye develops from a group of ectoderm cells (the outer sheet of embryonic tissue) when the eyecup, an outgrowth of the newt's brain, reaches the surface of the embryo (it is not for nothing that they say that the eyes are the brain brought out).
With the help of elegant experiments, Spemann proved that it is this brain outgrowth that sends a certain signal that it is time for the eye to grow. Spemann was distinguished by the artistry of the experiment, and his elegant methods are still used in embryology. “A scientist whose analytical mind is not combined, at least to a small extent, with artistic inclinations, in my opinion, is not capable of understanding the organism as a whole,” Spemann liked to say.
He and his graduate student Hilda Mangold found that the fate of transplanted tissue depends almost entirely not on which organ was supposed to develop from it in its previous position, but on its new location. If a piece of the future eye is transplanted into the skin, then it is not the eye that grows, but the skin.
There was also an exception. A certain part of the embryo, located near the junction between the three main cell sheets (ectoderm, endoderm and mesoderm), being transplanted to any place in another embryo of the same period, did not develop in accordance with its new location, but continued the line of its own development and directed the development of others fabrics. As Mangold wrote in her dissertation, “Inducing stimuli do not set specific properties [of the induced organ], but trigger the development of those properties that are already inherent in the responding tissue ... The complexity of developing systems is mainly determined by the structure of the responding tissue, and ... the inductor has only triggering and in some cases guiding effect.
Alas, famous for her dissertation Über Induktion von Embryonalanlagen durch Implantation artfremder Organisatoren("Induction of embryonic origin by implantation of organizational centers in different species") Mangold was unable to build on her success. After receiving her doctorate in 1923, she moved to Berlin with her husband and her young son, Christian. On September 4, 1924, tragedy struck: the gas heater in her house exploded. Hilda died without seeing her results in print: their joint work with Spemann came out only at the end of 1924. Her son died during World War II.
The scientist lived the rest of his life quietly - in his country house in Freiburg, where he died in September 1941. Of all the participants in Spemann's key work on "organizational" points, the Second World War was survived only by his former graduate student, who defended his dissertation in 1919 and became an assistant professor, Otto Mangold. The same husband of Hilda, who joined the NSDAP and signed in 1942 the famous letter to the Reich Chancellery, which noted the "tremendous acuteness of the struggle of the Jews against the German people" (and justified the "final solution of the Jewish question"), after which he became president of the German Zoological Society. Alas, this man got off only with suspension from teaching in 1945, but already in 1946 he received the whole Institute of Experimental Biology in Heiligenberg, where he died in 1961.