Theodor Boveri (biologist)

Theodor Boveri around 1908.

Theodor Heinrich Boveri (born October 12, 1862 in Bamberg , † October 15, 1915 in Würzburg ) was a German zoologist , comparative anatomist and co-founder of modern cytology . In 1904 Boveri recognized the chromosomes as the carrier of the genetic make-up .

From 1880 to 1882 Eduard Strasburger and Theodor Boveri described the constancy of the number of chromosomes in different species (this is typical for each species) and the individuality of the chromosomes.

In 1888 he coined the term centrosome , the meaning of which he recognized for cell division. In 1904, following Walter Sutton, he founded the chromosome theory of inheritance , after approaches to it had already been formulated by Carl Wilhelm von Nägeli , Édouard van Beneden , Oscar Hertwig , Albert von Koelliker and August Weismann .

Life

Family and school time

The Seehaus Höfen, drawn by eleven-year-old Boveri.

Portrait of Theodor Boveri in 1880

Theodor Boveri was born on October 12th, 1862 as the son of a middle-class family in Bamberg . His mother Antonie Boveri was born in Elssner. His father, who was also called Theodor Boveri (full name Johann Eugen Theodor), was a doctor and not very successful financially. He only practiced irregularly and gradually sold the property he had inherited. As a result, the eldest son Albert (died 1918) was still able to study with his father's money, but the second, Theodor, was only able to do so with a scholarship. The third son, Walter Boveri , could no longer study at the university; at the age of 17 he went to the Royal Industrial School in Nuremberg. After graduating, he moved to Switzerland at the age of 20, where he became a well-known industrial entrepreneur. The company Brown, Boveri & Cie. and the successor Asea Brown Boveri (ABB) bear his name. The youngest brother Robert was born in 1871. Probably because Theodor junior left his parents 'house a few years later, Walter Boveri wrote in an obituary for Theodor that he was brought up with an older and a younger brother in his parents' house.

Theodor Boveri went to elementary school in Bamberg and the first three classes of the Latin school . At the age of 13 he attended a secondary school in Nuremberg from October 1875 , which he graduated with honors in 1881. The father said that he was destined to be an architect or engineer and that this type of school prepared better in this direction. In Nuremberg he lived with the family of Robert Steuer, a friend of his father's and founder and director of the city music school, who also gave Boveri music lessons. From then on, Theodor was only with his family during the holidays, who regularly spent the summer holidays at the Höfen estate near Bamberg. He visited this place again and again until the end of his life.

Munich

Studies, doctorates, habilitation and scholarships

Boveri began studying at the Ludwig Maximilians University in Munich in 1881 . He began with historical-philosophical studies. However, his graduation from the Realgymnasium did not meet the formal requirements. He already had the required knowledge of Latin from Bamberg's times, he learned Greek within nine months and then passed the humanistic school leaving examination with distinction. As a result, he was accepted into the Maximilianeum , a Bavarian state institution for the promotion of gifted children, which gave him free board and lodging for several years. This made him less dependent on his parents' increasingly difficult financial circumstances.

After a semester of historical studies, Boveri switched to natural science and medicine, first to anatomy. At Karl Wilhelm von Kupffer he worked temporarily as an assistant, probably also for financial reasons. Kupffer also wrote the anatomical- histological doctoral thesis on the knowledge of nerve fibers, submitted to the Faculty of Philosophy and Natural Sciences in 1885 . He became a doctor of philosophy summa cum laude .

In the spring of 1885 he received a five-year Lamont scholarship from the philosophical and natural science faculty, which was later extended by two years. The scholarships, named after the founder Johann von Lamont , were to serve from 1854 to “train young scholars” who were Catholic and born in Bavaria. The scholarship allowed him to give up the assistant position and to devote himself entirely to research. In May he switched to Richard Hertwig's zoological institute , who introduced him to cell theory a few days after he moved to Munich. Influenced by Édouard van Beneden's work on egg cells and their fertilization, Boveri began his work on chromosomes. Even before the doctoral thesis was submitted, a lifelong friendship began with August Pauly , twelve years his senior , who was an assistant and private lecturer at the zoological institute. At the end of November 1887, Boveri completed his habilitation in zoology and comparative anatomy. The topic of the work was the polar bodies of the egg cells .

Naples and Amphioxus

Boveri 1889, when he was in Munich.

From January to the end of April 1888 and again in spring 1889, Boveri visited the Naples Zoological Station founded by Anton Dohrn , where he worked with sea urchin eggs. During his first stay he discovered that the egg and sperm cell have the same set of chromosomes. During his second stay, he carried out the merogony experiments. Another seven stays followed in the years up to 1914.

In 1890 he published his discovery of the kidney of the lancetfish , then called Amphioxus, a work that protected him from being viewed as a pure cell specialist.

Illness, private and professional situation, appointment to Würzburg

A serious crisis began for Boveri in 1890. The father, Theodor Boveri senior, had accumulated heavy debts and became seriously ill. Since the brother Walter lived further away from his native Bamberg in Switzerland, the 27-year-old Theodor Boveri junior took over the negotiations with the creditors. Thanks to the efforts of the two sons and the courtesy of the creditors, the loss of parental assets was prevented. However, Theodor Boveri junior became ill himself. Influenza was diagnosed and he himself later wrote of severe neurasthenia . From the middle of 1890 to the summer of 1891 he was unable to work, sometimes with severe depression. After initially arranging the financial situation of his parents in Bamberg, he was briefly in Munich before going to Konstanz for a cure . Back in Munich, the news reached him that his father was dying and he returned to Bamberg. After the funeral, he attended a mental institution in Constance. He deeply regretted that his illness prevented him from attending his brother's wedding in Switzerland in February. Four months later he felt better, although he remained prone to illness. For the winter semester of 1891 he went back to Munich.

In 1891 the Lamont Scholarship expired. At the zoological institute he was able to take up the assistant position at Hertwig that Pauly previously held. Although by this point he had already acquired an international reputation that was unusual for an assistant, a better professional opportunity did not initially arise. However, his reputation meant that some of the institute's foreign guest researchers wanted to work for him. Among them was the first known cell biologist in the USA, Edmund B. Wilson , six years his senior , with whom a lasting friendship developed. Despite uncertain career prospects, Boveri turned down a lectureship at Clark University in the USA, as well as an adjunct position at a Munich museum, which would not have allowed him to pursue his research interests.

On January 1, 1893, he received a letter from the Würzburg botany professor Julius Sachs , who asked for his list of publications, as he wanted to propose him to the Ministry for a professorship in Würzburg. At the beginning of February he was invited to an interview with the minister. He wrote to his brother Walter's wife

"I am usually not an optimist, but ... after the whole situation, I consider the story to be won, had a fine tailcoat made for the performance along with trousers and vest, which achievement even tempted me to do it for 7 years to go to a ball again ... The position in Würzburg is very pleasant in every respect; in particular, the institute is beautifully and excellently furnished. "

- Theodor Boveri : Letter to his sister-in-law Victoire Boveri

Wurzburg

Start in Würzburg, Marcella I. O'Grady

Portraits of Theodor Boveri and his wife Marcella, née O'Grady, in their wedding year 1897.

On March 22, 1893, the thirty-year- old was appointed full professor of zoology and comparative anatomy by the University of Würzburg and appointed director of the Zoological- Zootomic Institute. Despite a few calls to other places, he stayed in Würzburg until his death. His research career was thus financially secured. However, when he took office, he again suffered from severe neurasthenia, so that he was concerned about whether he would be able to fulfill his new duties. Boveri went with Pauly for a few days to Lake Starnberg southwest of Munich, where Pauly Boveri also gave an introduction to entomology, an area that Boveri had to teach in the coming semester.

In 1896 the American visiting scholar Marcella O'Grady came to Würzburg to work at Boveri. A year younger than Boveri, the student of his friend EB Wilson was already a lecturer at Vassar College , at that time an all-women college. Although Boveri refused to study women, both were fond of each other. Boveri suffered a severe rheumatism attack with temporary paralysis of his right arm, which forced him to stay in hospital again. He wrote to his sister-in-law

“My American student visited me a few times; Mom, my friendship with her is already worrying. "

- Theodor Boveri : Letter to his sister-in-law Victoire Boveri

O'Grady established himself in the scientific circles of Würzburg. In December 1896 she was accepted as the first female guest in the Würzburg Physico-Medical Society, to which both Boveri and Wilhelm Conrad Röntgen belonged. After the Röntgen couple invited the researcher regularly, a lasting friendship developed between the two couples. In June 1897 Boveri wrote to his sister-in-law that they were now engaged. The wedding took place in Boston on October 5, 1897 . Two biographers T. Boveris, Fritz Baltzer and Leopold von Ubisch , who were both assistants at Boveri, report that Ms. Boveri took an “active part” or “active part” in her husband's work. Baltzer writes:

“[Her previous investigations] gave [Ms. Boveri] familiarity with the development of sea urchins and thus the experience that she benefited from working with her husband in Naples during numerous joint work. There she shared his happiness and satisfaction with successful experiments and his disappointment with failed experiments. "

- Fritz Baltzer : Theodor Boveri, 1962; P. 25.

However, there are no publications with both authors, Ms. Boveri's contribution has not been recognized. There is only one publication from her time in Germany: In the first year she wrote a dissertation in Würzburg, but because of her marriage she waived the examination and doctorate. The work was published in 1903.

The Boveris' only child, the future journalist Margret Boveri , was born in the spring of 1900. Boveri's mother died in 1910 at the age of 68. Boveri wrote to a former student that this had hit him hard and that he suddenly felt old.

Job situation, illness and death

Around 1907, Boveri in his study at the Würzburg Zoological Institute.

Boveri was famous in science at the turn of the century, at the university he rose in the hierarchy and was therefore increasingly entrusted with administrative matters. He became a member of the Senate and the Administrative Committee and was entrusted with appointments. He received several offers from other universities. In 1911 he considered going to Freiburg im Breisgau , but decided against it. Shortly afterwards he was offered the management of a new Kaiser Wilhelm Institute for Biology in Berlin. He was torn between accepting the appointment or staying in Würzburg. During the protracted negotiations in 1912 he proposed a department structure as well as department head Max Hartmann for protozoa, Richard Goldschmidt for genetics, Hans Spemann for developmental physiology and Otto Warburg for biochemistry, all of which were then appointed. Two of these then young researchers later became Nobel Prize winners. In the end, he turned down the offer for himself. Another decisive factor was another episode of the disease with weak paralysis of the right half of the body. He feared that his health in Berlin would continue to deteriorate.

Boveri was still ailing. In August 1915, the ulcerated gallbladder and a gallstone were removed. In September he wrote about pleurisy and fever. He died on October 15, 1915 at the age of only 53.

There are very different reports about the disease that leads to death. His student and biographer Baltzer wrote in 1962: "The nature of the disease remained uncertain". His wife assumed it was pulmonary tuberculosis. It is also reported that Ferdinand Sauerbruch suspected poisoning with radium through remote diagnosis . The radioactive element was used by Boveri in some of his experiments. Based on the symptoms described in his letters, the diagnosis in medical history was made in the 21st century that Boveri had died of an Ascaris lumbricoides infestation with which he had experimented. At least that he was infected with Ascaris is historically certain, even if it is not certain whether it was the cause of death. He wrote

“The day before yesterday I lost an Ascaris lumbricoides (male) with an intestine so strongly brown-green in color that I suspect that the beast might have got lost in the biliary tract. It is common when the critters you have dealt with now deal with you. "

- Theodor Boveri : Letter to Spemann, July 2, 1915, UB Wü NLB

The fact that neither Baltzer nor Boveri's daughter mentioned the Ascaris infection led a later biographer to the assumption that in their eyes “such an embarrassing laboratory accident would not have been good for the father and great biologist”.

personality

Painting by Boveri, landscape near Ruhpolding .

Boveri's biographers describe young people as well as adults as a man who was less given the gift of brilliant speech than the art of convincing discussion. A high level of comprehension enabled him to recognize the essentials of a matter and to present it concisely. An urge to be the center of attention was alien to him. Boveri was not only gifted scientifically, but also musically and artistically. The latter found expression in many pictures and drawings that he made, not least drawings in his scientific work.

plant

Boveri used the light microscope to examine the processes involved in fertilizing the animal egg. His preferred objects of investigation were the horse roundworm Ascaris megalocephala (today divided into the two species Parascaris equorum and Parascaris univalens ), of which he could easily obtain larger quantities in Würzburg, and sea ​​urchin eggs, which he had available in the zoological station in Naples. He describes the advantages of the Ascaris egg as follows:

"Only for those ... who ... not only stay in the middle of the country for most of the year, but also have to be prepared to be interrupted in the pursuit of a living object, form the Ascaris eggs an unsurpassable material because of its insensitivity and unpretentiousness. Eggs spread on a slide can be kept dry in a cold room for at least a few months without them changing. If you have time to work on them, this is done at room temperature, where they slowly develop; if one wants to accelerate the development for some time, one brings the eggs into the warming cabinet; if you have to interrupt work, you put it in the cold again for any length of time, so that when you continue your work you can find it again just as you left it.
If one adds that unlimited quantities of these eggs can be kept available throughout the year, that much of what can only be determined about other germs through complicated preparation can be followed in life, ... these are advantages and some disadvantages outweigh. "

- Theodor Boveri : The potencies of the Ascaris blastomeres with modified furrowing. 1910.

Centrosomes

Boveri and, independently of that, Édouard van Beneden discovered the importance of the central body or centrosome for the formation of the spindle during cell nucleus division ( mitosis ) in animal cells. On the sea urchin egg, Boveri observed that the active centrosome in the fertilized egg cell originates from the middle section of the sperm. This divides and the poles of the first dividing spindle are formed on the two daughter centrosomes. Accordingly, a component of the sperm gives the signal to start further development. In 1887 he published in 1887 that the paternal centrosome plays the decisive role for all subsequent nuclear divisions, while the maternal centrosome is inactive.

Constant number of chromosomes, parental contribution

He also showed that sperm nuclei and egg cells of the same species each contained the same number of chromosomes. An important question was whether the chromosomes of father and mother are equally important for the development of the new organism. Jacques Loeb had shown that unfertilized sea urchin eggs can also develop into normal larvae, which seemed to speak against an important role played by the paternal chromosomes. Boveri demonstrated, however, that unfertilized eggs from which the (maternal) cell nucleus has been removed and which have been fertilized with a sperm can grow into normal larvae. Organisms that only contained the chromosomes from the sperm were called merogons . These investigations also showed that the size of the cell nuclei and also of the cell depended on the number of chromosome sets (stable nucleus-plasma relationship ). In a continuation of these experiments, he used enucleated egg cells and sperm of various types . However, he could not cleanly separate nucleated and nucleated egg cells. After fertilization he received larvae corresponding to the paternal species and mixed forms. He assumed that the purely paternal ones originated from the egg cells without a maternal nucleus, the hybrid forms from those with maternal nuclei or nucleus parts. Hence, he concluded that the traits were inherited solely from the core. However, due to the experimental difficulties, this view did not gain general acceptance. It was also later shown that some aspects of the larvae are definitely influenced by the mother's cytoplasm.

Chromosome individuality, chromosomes and cancer

Building on Carl Rabl's knowledge that chromosomes are also present between two nuclear divisions in the cell nucleus , he developed the concept of chromosome individuality, i.e. the assumption that chromosomes retain their individuality (and differences from other chromosomes) from nucleus division to nucleus division. This finding is a cornerstone of the chromosal theory of inheritance. Research into this issue was made easier by the fact that the two subspecies of Ascaris only have two and four large chromosomes per cell, respectively.

Through complex experiments on sea urchin eggs, he was also able to prove that the different chromosomes contain different genetic makeup. He also suggested a connection between misdirected mitoses and cancer formation, an assumption that was initially rejected by medical professionals and that would only be confirmed many decades later.

Diminution

When cells divide in an organism, both daughter cells usually receive the same chromosome structure as the mother cell. There are exceptions to this rule, however, and one such exception, known as diminution or chromatin diminution , was discovered by Boveri on the fertilized Ascaris egg: only the germ line cells receive the complete chromosome structure of the fertilized egg cell. The future somatic cells or somatic cells , on the other hand, break down parts of the chromosomes.

Lancet kidney

In Amphioxus, the lancet fish , he discovered the segmental kidneys and thus made a contribution to research into the evolution of vertebrates.

Awards and honors

• From 1903 he was a corresponding member of the Bavarian Academy of Sciences .
• In 1906 he was elected a corresponding member of the Russian Academy of Sciences in Saint Petersburg .
• Also member of the academies in Berlin, Copenhagen, Philadelphia and New York.
• Dr. med. hc from the University of Marburg
• 1913 Bavarian Maximilian Order for Science and Art
• 1913 election to the National Academy of Sciences

literature

• “Memories of Theodor Boveri”, Tübingen, 1918, various authors. Online version at the University of Würzburg.
• Walter Rühm:  Boveri, Theodor Heinrich. In: New German Biography (NDB). Volume 2, Duncker & Humblot, Berlin 1955, ISBN 3-428-00183-4 , p. 493 f. ( Digitized version ).
• Fritz Baltzer : Theodor Boveri: A trailblazer for heredity and cell research In: Researchers and scientists in Europe today. 2. Physicians, biologists, anthropologists. Edited by Hans Schwerte & Wilhelm Spengler . Series: Gestalter Our Time, Vol. 4. Stalling, Oldenburg 1955, pp. 183–192. (The editors were SS cadres.)
• Fritz Baltzer: Theodor Boveri. Life and work of a great biologist, 1862–1915 (=  Great Natural Scientist . Volume 25 ). Scientific publishing company MBH, Stuttgart 1962 (194 pages).
• Margret Boveri : Branches. An autobiography. Edited by Uwe Johnson . Piper, Munich 1977. There pp. 65–74: Amputations I - The Father. ISBN 3-492-02309-6
• Herbert A. Neumann: From Ascaris to Tumor. Life and work of the biologist Theodor Boveri (1862–1915) . Blackwell, Berlin 1998.
• Ilse Jahn : Boveri, Theodor. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 202.
• Gerhard Krause, Martin Lindauer : The zoology in Würzburg from the natural history cabinet of Father Bonavita Blank to the theory of chromosome individuality by Theodor Boveri. In: Peter Baumgart (Ed.): Four hundred years of the University of Würzburg. A commemorative publication. Degener & Co. (Gerhard Gessner), Neustadt an der Aisch 1982 (= sources and contributions to the history of the University of Würzburg. Volume 6), ISBN 3-7686-9062-8 , pp. 629–636; here: 631 ff.
• Bernd Krebs: Contributions to the conceptual history of the nomenclature of cell theory up to the beginning of the 20th century. Dissertation, Ruhr University Bochum, Bochum 2013, pp. 38–40 [1]

Web links

Commons : Theodor Boveri  - Collection of images, videos and audio files

• Biography ( Memento from July 9, 2013 in the Internet Archive ) Theodor Boveri Institute of the University of Würzburg
• Developmental Biology Online - Theodor Boveri
• Three original works by Boveri on www.biolib.de :
  • "Cell Studies" (1888) . Here also the first mention of the term “Centrosoma”.
  • "Cell studies, booklet 5. About the dependence of the nucleus size and number of cells in sea urchin larvae on the number of chromosomes in the parent cells" (1905)
  • "Cell studies, booklet 6. Development of dispersed sea urchin eggs. A contribution to the theory of fertilization and the theory of the nucleus. "(1907)
• Theodor Boveri: The blastomer nuclei of Ascaris megalocephala and the theory of chromosome individuality. Archives for Cell Research 3, 181-268. (1909)
• Part of the estate is in the Bavarian State Library

Individual evidence

1. ↑ ^{a b c} Dr. Walter Boveri : Parents and Childhood . In: Memories of Theodor Boveri . Verlag von JCB Mohr (Paul Siebeck), Tübingen 1918, p. 1–3 ( online at the University Library of Würzburg ).
2. ↑ ^{a b c d e f g h i j k l m} Leopold von Ubisch : Theodor Boveri . In: Hugo Freund and Alexander Berg (eds.): History of microscopy. Life and work of great researchers . tape 1 , biology. Umschau Verlag, Frankfurt am Main 1963, p. 121-132 .
3. ^ Herbert A. Neumann: From the Ascaris to the tumor. Life and work of the biologist Theodor Boveri (1862–1915) . Blackwell Wissenschafts-Verlag, Berlin, Vienna 1988, ISBN 3-89412-384-2 , pp. 64-65 (250 pages).
4. ↑ ^{a b c d e f g h i j k l m n o p} Fritz Baltzer: Theodor Boveri, Life and Work of a Great Biologist, 1862–1915 (=  Great Natural Scientist . Volume 25 ). Scientific publishing company MBH, Stuttgart 1962 (194 pages).
5. ^ Neumann, 1988. Page 77.
6. ↑ Boveri Theodor: Cell studies I. The formation of the directional bodies in Ascaris megalocephala and Ascaris lumbricoides. In: Journal of Natural Sciences. 21/1887, pp. 423-515.
7. ↑ Baltzer 1962, pages 15, 16 and 71
8. ↑ Theodor Boveri: About the kidney of Amphioxus. Seat area d. Ges. F. Morph. U. Phys. Munich. Vol. 6. 1890. Quoted from Baltzer, 1962.
9. ^ Neumann Herbert A .: From Ascaris to Tumor. Blackwell, Berlin 1998. There p. 102.
10. ↑ ^{a b c d e} Helga Satzinger: Difference and Heredity: Gender Orders in Genetics and Hormone Research 1890–1950 . Böhlau Verlag, Cologne Weimar 2009, ISBN 978-3-412-20339-9 , p. 484 pages ( online at Google Books). , Pp. 59–64
11. ↑ Baltzer, 1962. Page 24. von Ubisch, 1963. Page 121
12. ↑ Marcella Boveri: On mitoses with unilateral chromosome binding . In: Jen. Magazine f. Natural tape 37 , 1903, pp. 401-445 ( Plates XXI-XXIII).
13. ↑ Baltzer (1962), p. 32.
14. ^ Neumann Herbert A .: From Ascaris to Tumor. Blackwell, Berlin 1998. There pp. 222-225.
15. ↑ General Hermann Beeg , Munich: Theodor Boveri in his youth development . In: Memories of Theodor Boveri . Verlag von JCB Mohr (Paul Siebeck), Tübingen 1918, p. 4–11 ( online at the University Library of Würzburg ). Hermann Beeg was a school friend of Boveri.
16. ^ C. Goday, S. Pimpinelli: Chromosome organization and heterochromatin elimination in parascaris. In: Science . Volume 224, Number 4647, April 1984, pp. 411-413, doi: 10.1126 / science.224.4647.411 , PMID 17741221 .
17. ↑ Theodor Boveri: The potencies of the Ascaris blastomeres with modified furrowing . In: Festschrift for Richard Hertwig's sixtieth birthday . tape III . Verlag von Gustav Fischer, Jena 1910, p. 133–214 (with 6 plates and 24 text figures).
18. ↑ Thomas Cremer: From the cell theory to the chromosome theory . Springer-Verlag, Berlin; Heidelberg; New York; Tokyo 1985, ISBN 3-540-13987-7 , pp. 109 .
19. ↑ Thomas Cremer: From the cell theory to the chromosome theory . Springer-Verlag, Berlin; Heidelberg; New York; Tokyo 1985, ISBN 3-540-13987-7 , pp. 155 .
20. ↑ Theodor Boveri: On the question of the development of malignant tumors. Jena 1914.
21. ^ Theodor Boveri's membership entry at the Bavarian Academy of Sciences , accessed on December 26, 2016.
22. ^ Foreign members of the Russian Academy of Sciences since 1724. Theodor Boveri. Russian Academy of Sciences, accessed August 2, 2015 . 
23. ^ ^{A b} Walter Rühm:  Boveri, Theodor Heinrich. In: New German Biography (NDB). Volume 2, Duncker & Humblot, Berlin 1955, ISBN 3-428-00183-4 , p. 493 f. ( Digitized version ).