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 study 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 work on embryonic development was suggested to Spemann 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."
15 years ago - on July 5, 1996, Dolly the sheep, the first cloned living creature, was born.
In the same year, Chinese researcher Tong Dizhou cloned fish for the first time. He transplanted the genetic material of an adult Asian carp into eggs, from which a new individual emerged, which subsequently brought offspring.
In 1964, Cornell University professor Frederic Steward grew whole carrots from completely isolated rhizome cells, thus proving the possibility of cloning using differentiated (isolated) cells.
In 1969, Harvard University professors James Shapiero and Jonathan Bechwith isolated the first gene.
In 1972 Stanford University professor Paul Berg created the first recombinant DNA molecules.
In 1979 Karl Illmensee announced that he had succeeded in cloning three mice.
In 1983, Kary Mullis developed the polymerase chain reaction (PCR) method, which makes it possible to achieve a significant increase in low concentrations of certain nucleic acid (DNA) fragments in a biological material (sample).
In 1984, Danish scientist Steen Willadsen cloned a sheep from embryonic cells. This was the first experiment in cloning a mammal. Villadsen used the nuclear transfer method.
In 1986, Villadsen cloned a cow from differentiated cells from a one-week-old embryo. In the same year, University of Wisconsin professors Neal First, Randal Prather, and Willard Eyestone also cloned a cow from fetal cells.
In 1990, the Human Genome Project was launched, an international research program aimed at determining the sequence of more than 3 billion nucleotides that make up the human genetic code.
In 1995, professors at the Roslyn Institute in Scotland, Ian Wilmut and Keith Campbell, successfully cloned two sheep, Megan and Morag, using genetic material from two isolated embryos.
In 1996, Wilmut and Campbell first set up an experiment to clone an animal from adult cells, which resulted in the birth of Dolly the sheep on July 5, 1996.
In 1997, in the laboratory of Don Wolf (Don Wolf) Oregon Regional Center for the Study of Primates (Oregon Regional Primate Research Center), scientists managed to clone two rhesus monkeys.
In the same year, US President Bill Clinton banned the use of public funds to fund human cloning.
In 1997, Ian Wilmuth and Keith Campbell used laboratory-grown skin cells with a genetically implanted human gene and cloned another sheep, Polly.
In 1998 Dolly gave birth to three healthy naturally conceived lambs.
In the same year, at the University of Hawaii, a group of scientists led by Professor Ryuzo Yanagimachi cloned 50 mice from adult cells. The first clone mouse was nicknamed Cumulina.
On December 22, 2001, the world's first cloned domestic cat named Sisi (CopyCat, CC) was born at the Texas A&M University. Two years later, the first cloned deer, Dewey, and the first cloned horse, Prometheus, were born at the university.
In 2001, scientists from Advanced Cell Technology, Inc. announced the birth of a gaur bull named Noah, who became the first cloned animal belonging to an endangered species. This experiment opened up the prospect of saving endangered animal species through cloning.
In 2003, Dolly the world-famous sheep was euthanized. The cause was a progressive lung cancer caused by a virus. Dolly was 6.5 years old.
In 2005, the world's first cloned dog, the African greyhound Snappi, was born in South Korea.
In 2009, the first cloned camel was born in Dubai (UAE) - Injas, translated from Arabic as "achievement".
Despite a number of statements about successful experiments on cloning a human embryo (1998, 2004 - in South Korea, 2002 - in the USA), there is no scientific confirmation of this to date.
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 Julius von Sachs (who was actually one of the discoverers of photosynthesis) and, accordingly.
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.
German embryologist, one of the founders of experimental embryology.
Winner of the Nobel Prize in Physiology or Medicine in 1935 "for his discovery of organizing effects in embryonic development."
"Research Wilhelm Roux expanded and deepened the German embryologist Hans Spemann. He had a richer 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, he 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. He also set up a reverse experiment: taking part of the epidermis of the second embryo, he placed it in place of the neural plate in the first, where it developed into a full-fledged brain.
He formulated the so-called theory - "organizational centers", describing 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. Human capabilities in this respect are very modest, while, for example, new tails grow in lizards, and even new limbs in newts. (How wonderful it would be if a person had such opportunities!)
Appreciating the results Speman, experts at the Karolinska Institute decided in 1935 to award him the Nobel Prize in Physiology or Medicine for his discovery of "organization centers" in the developing embryo.
The problem of cell interaction is closely related to genetic engineering and a new direction in immunology - immune engineering. These directions are gradually combined, providing an amazing synthesis that will open up the possibility of controlling living matter for a person.
Valery Cholakov, Nobel Prizes. Scientists and discoveries, M., Mir, 1986, p. 339-340.
Anning was 12 when she and her younger brother found the first complete ichthyosaur skeleton in the rocks near their hometown of Lyme Regis (Dorset, England). Since then, Mary has been obsessed with finding fossils. Usually she went on a “hunt” after a storm, hoping that the wind and water would open access to the next remains buried in the thickness of limestone and shale. This woman managed to discover the first complete skeletons of a plesiosaur and a pterosaur (pterodactyl). And although contemporaries used the results of her work, Mary was not allowed into official scientific circles, and her work was often quoted without reference to the original source.