Emil Heitz (botanist)

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Johann Heinrich Emil Heitz (born October 29, 1892 in Strasbourg ; † July 8, 1965 in Lugano ) was a German - Swiss botanist and a pioneer of botanical and zoological cytogenetics . The terms euchromatin and heterochromatin , coined in 1928, go back to him. He identified nucleolus chromosomes and discovered selective polytenization .

Life

Emil Heitz was the fourth child of Karl Timotheus Paul Heitz (1857–1943) and Mathilde, geb. Swallow (1862-1892). The birth mother died thirteen days after he was born. Paul Heitz then married his sister-in-law Helene Schwalb (1871–1947) in 1894; they had a son and a daughter. Emil always called Helene, his stepmother and aunt, mother . The Heitz dynasty had a great tradition as a publisher and as the owner of the university printing plant in Strasbourg.

After a short apprenticeship in the family business, Emil Heitz decided in 1912 to study natural sciences, especially biology . After two semesters each in Munich and Strasbourg , he served the entire First World War in the foot artillery , both on the western and eastern fronts. In May 1919 he resumed his studies in Basel , in 1920 he went to Ludwig Jost at the University of Heidelberg and received his doctorate there on June 7, 1921. In December 1921, he married Martha Elisabeth Staehelin , a former colleague in Tübingen . Heitz worked at various German institutes, most recently at the University of Greifswald , before Hans Winkler persuaded him in 1926 to work at the Institute for General Botany at the University of Hamburg . He completed his habilitation in 1926 and was appointed associate professor in 1932. Heitz distinguished himself as an outstanding cytogeneticist. In November 1933 he was one of the signatories of the professors' commitment at German universities and colleges to Adolf Hitler and the National Socialist state .

His maternal grandfather, Moritz Schwalb (1833–1916; Protestant pastor), was a Jew. In accordance with § 18 of the Reich Habilitation Regulations of December 13, 1934 , the Minister for Science, Education and Public Education, Emil Heitz, withdrew his teaching license in 1937 because of non-Aryan descent. At the same time, Heitz lost the title of non-civil servant associate professor and his salaries. The academic degree Dr. habil. he was allowed to continue. The reference to his other grandfather of the same name did not help against the racially insane law: Johann Heinrich Emil Heitz (1825–1890; classical philologist) had been rector of the German Kaiser Wilhelm University in Strasbourg.

The dismissed botanist then emigrated with four children and his wife Elisabeth to their hometown of Basel in Switzerland . After another habilitation at the University of Basel , Heitz was again appointed associate professor with Venia legendi in 1938. Neither university after state took on "any further obligations, especially of a pecuniary nature". The family lived there in financially difficult circumstances.

Emil Heitz was only able to accept an invitation from the maize geneticist Lewis John Stadler to the University of Missouri in Columbia in 1939 after the end of the Second World War . He acquired Swiss citizenship in 1947 and was a visiting professor in Columbia from February to June 1947. He did not want to make up his mind to stay in the USA for a longer period of time , so he returned to Basel.

The situation only improved in 1955 when the Max Planck Society appointed Emil Heitz a Scientific Member at their new Max Planck Institute for Biology in Tübingen . In 1955 he also became honorary professor for cytology at the University of Tübingen , and the Leopoldina in Halle awarded him the Schleiden Medal . He now shifted his research to electron microscopy of the plastids and mitochondria .

Heitz retired in October 1961 and retired to Switzerland. On the occasion of his 70th birthday in 1962, the Universities of Hamburg and Cologne and the Free University of Berlin each awarded him honorary doctorates . Emil Heitz died in Lugano on July 8, 1965 after an accident. His urn is buried with that of his wife Elisabeth in Allschwil near Basel.

Basic research

In 1928 Heitz discovered a previously unknown phenomenon in Moosen: the longitudinal differentiation of the chromosomes by heteropycnosis . With this he specified the term chromatin, coined by Walther Flemming in 1880 : "It consists of heterochromatin and euchromatin ."

Even then he drew attention to satellites (satellites), which often appear at the ends of chromosomes. The corresponding SAT chromosomes occupied him until he proved their connection with one nucleolus each . Barbara McClintock also examined the phenomenon during her stay in Germany.

Garden hair mosquito, female

A sensational proof was achieved in collaboration with Hans Bauer on the garden hair mosquito : The huge, loop-like structures in their oversized cell nuclei are actually chromosomes that arise through internal multiplication ( endoreplication ). The botanist Heitz's interest in cytogenetics was not limited to plants. He examined various Diptera (Diptera), mainly five kinds of fruit flies : Drosophila funebris, D. hydei, D. melanogaster, D. simulans and D. virilis . In contrast to euchromatin, heterochromatin contains only a few, mostly passive, genes . Finally, Heitz came to the conclusion: "Genes that are in heterochromatin (can) intervene in the development of an organism."

Not to be forgotten: Emil Heitz was the first to describe the morphological effects of selective endoreplication in D. virilis : "While the euchromatic parts of the chromosomes enlarge as the nuclei grow, the heterochromatic parts combined to form the collective chromosome cannot." In In this work he also referred to the constancy of the chromomers , by which he understood the individual band or transverse disk pattern that characterizes every polytene chromosome . As a result of the latter discovery, the first maps of polytene chromosomes were created.

The only book by Emil Heitz that was essentially written in Basel during the Second World War is exceptional. It deals with the elements of botany on a single plant, the small-headed Pippau .

Publications (selection)

  • The heterochromatin of the mosses: I. In: Yearbooks for scientific botany. 69/1928, pp. 762-818.
  • Heterochromatin, chromocentres, chromomers. In: Reports of the German Botanical Society. 47/1929, pp. 274-284.
  • The structure of the somatic nuclei of Drosophila melanogaster. In: Journal for inductive descent and inheritance. 54/1930, p. 248 f.
  • The cause of the regular number, position, shape and size of plant nucleoli. In: Planta. 12/1931, pp. 775-844.
  • with farmer Hans: Evidence for the chromosomal nature of the nuclear loops in the tangled nuclei of Bibio hortulanus L. Cytological investigations on Diptera: I. In: Journal for Cell Research and Microscopic Anatomy. 17/1933, pp. 67-82.
  • About total and partial heteropycnosis and structural sex chromosomes in Drosophila funebris. Cytological investigations on Diptera: II. In: Journal for cell research and microscopic anatomy. 19/1933, pp. 720-742.
  • About α- and β-heterochromatin as well as constancy and structure of the chromomers in Drosophila. In: Biological Zentralblatt. 54/1934, p. 596, p. 601.
  • Chromosome structure and genes. In: Journal for inductive descent and inheritance. 70/1935, pp. 402-447.
  • Investigations into the structure of the plastids: I. The directed chlorophyll disks of the chloroplasts. In: Planta. 26/1937, pp. 134-163.
  • X-ray mutations in Pellia Neesiana. In: Negotiations of Switzerland. Natural Research Society. 194/1940, p. 170 f.
  • On the relationship between polyploidy and mixed sex in mosses. In: Archives of the Julius Klaus Foundation. 17/1942, pp. 444-448.
  • Moss mutations: I. Spontaneous and colchicine-induced polyploid mutants in Aulacomnium androgynum. In: Archive of the Julius Klaus Foundation for Heredity Research, Social Anthropology and Racial Hygiene. 20/1945, pp. 119-125.
  • Elements of botany. Instructions for studying the plant through observations and experiments on Crepis capillaris (L.) Wall. Springer, Vienna 1950.
  • Small contributions to cell theory: IV. About large nuclei in Collembola. In: Zoologischer Anzeiger. 146/1951, pp. 197-201.
  • with Maly Roland: On the question of the origin of the Grana. In: Journal for Nature Research. 8b / 1953, pp. 243-249.
  • Contribution to the knowledge of the chloroplast structure. In: Bargmann W., Peters D., Wolpers C. (Hg): Biological-medical part; Fourth international congress for electron microscopy. Springer, Berlin 1960, pp. 501-503.

literature

  • Beermann Wolfgang : giant chromosomes. Springer, Vienna 1962.
  • Beermann Wolfgang (Hg): Developmental studies on giant chromosomes. Springer, Berlin 1972. ISBN 3-540-05748-X .
  • Belyaeva Elena S. et al., Zhimulev Igor F .: Late replication domains in polytene and non-polytene cells of Drosophila melanogaster. In: Public Library of Science PLoS ONE . 7 (1) / 2012. e30035. doi : 10.1371 / journal.pone.0030035 PMC 3254639 (free full text)
  • Brower-Toland Brent et al., Elgin Sarah C. R: Multiple SET methyltransferases are required to maintain normal heterochromatin domains in the genome of Drosophila melanogaster. In: Genetics. 181/2009, pp. 1303-1319. doi : 10.1534 / genetics.108.100271 PMC 2666501 (free full text)
  • Brodsky VY, Uryvaeva IV: Genome multiplication in growth and development: Biology of polyploidy and polytene cells. University Press, Cambridge 1985. ISBN 0-521-25323-3
  • Brown Spencer W: heterochromatin. In: Science . 151/1966, pp. 417-425.
  • Henikoff Steven et al .: Reaching for new Heitz. In: Genetica. 109/2000, p. 7 f.
  • Lohe Allan R., Hilliker Arthur James: Return of the H-word (heterochromatin). In: Current Opinion in Genetics and Development. 5/1995, pp. 746-755.
  • Madalena Christiane RG, Díez José Luís, Gorab Eduardo: Chromatin structure of ribosomal RNA genes in Dipterans and its relationship to the location of nucleolar organizers. In: Public Library of Science PLoS ONE. 7 (8) / 2012, e44006. doi : 10.1371 / journal.pone.0044006
  • Nordman Jared et al., Orr-Weaver Terry L .: Developmental control of the DNA replication and transcription programs. In: Genome Research. 21/2011, pp. 175-181. PMC 3032921 (free full text)
  • Passarge Eberhard: Emil Heitz and the concept of heterochromatin: Longitudinal chromosome differentiation was recognized fifty years ago. In: Am. J. Human Genet. 31/1979, pp. 106-115.
  • Redi Carlo Alberto et al .: The other chromatin. In: Chromosoma. 110/2001, p. 136 f, doi: 10.1007 / s004120000114 .
  • Verma Ram S. (Ed): Heterochromatin: Molecular and structural aspects. University Press, Cambridge 1988. ISBN 0-521-33480-2 .
  • Zacharias Helmut: Emil Heitz (1892–1965): Chloroplasts, heterochromatin, and polytene chromosomes. In: Genetics. 141/1995, pp. 7-14. PMC 1206741 (free full text)
  • Zhimulev Igor F., Koryakov Dmitry E .: Polytene chromosomes. In: Wiley Online. 15 MAR 2009. doi : 10.1002 / 9780470015902.a0001183.pub2

Web links

Individual evidence

  1. ^ Heitz Emil: 102 field post letters and cards from 1916. (private collection; viewed in 2011).
  2. ^ Heitz Paul: Commemorative publication for the bicentenary of the printer and publisher HEITZ in Strasbourg, 1719-1919. Printed as a manuscript. (JH Ed.Heitz,) Strasbourg 1918.
  3. ↑ Heitz Emil: Prof. Dr. phil. nat. Emil Heitz. Curriculum vitae in: Nova Acta Leopoldina, treatises of the German Academy of Natural Scientists. New series 17/1955, p. 441.
  4. ↑ Heitz Emil: Investigations into the division of chloroplasts together with observations about cell size and chromatophore size. Inaugural dissertation to obtain a doctorate from a high natural science and mathematics faculty at the Ruprecht-Karls-Universität zu Heidelberg. Heidelberg University Library, call number 5046029.9.
  5. ^ Hamburg State Archives : Higher Education. Lecturer and personnel files IV / 384: Heitz, Emil October 29, 1892. No. 14, Berlin August 17, 1937.
  6. ^ Hamburg State Archives: Higher Education. Lecturer and personnel files IV / 384: Heitz, Emil October 29, 1892. No. 15, Hamburg August 15, 1937.
  7. ^ State Archives of the Canton of Basel-Stadt : Education files CC 28d. Basel, information on August 9, 1994.
  8. ^ Max Planck Society: Scientific member of the institute Professor HEITZ. In: Yearbook of the Max Planck Society for the Advancement of Science e. V., Part 2: History of the Max Planck Institute for Biology. 1961, pp. 145-147.
  9. ^ Heitz Emil: About the structure of chromosomes and chloroplasts: Lecture at the annual meeting of the "Leopoldina" on the occasion of the reception of the Schleiden Medal in 1955 on November 13, 1955 in Halle. In: Nova Acta Leopoldina, treatises of the German Academy of Natural Scientists. New series 17/1955, pp. 517-540.
  10. ↑ Heitz Emil: Crystal lattice structure of the granum of young chloroplasts from Chlorophytum. In: Experimental Cell Research. 7/1954, pp. 606-608.
  11. ↑ Heitz Emil: The structural relationships between plant and animal chondriosomes. In: Journal for Nature Research. 12b / 1957, pp. 576-578.
  12. ^ Confederazione Svizzera, Cantone Ticino: Atto di morte. L'ufficiale dello stato civile, Lugano 1965: “Estratto del registro delle morti del circondario dello stato civile di Lugano vol 1965 pag. 96 n °. 192: Il giorno otto luglio millenovecento sessantacinque alle ore tre e dieci minuti è morto a Lugano Heitz , Johann Heinrich Emil . "
  13. ^ Heitz Emil: The Heterochromatin der Moose: I. In: Year books for scientific botany. 69/1928, pp. 762-818.
  14. ^ Heitz Emil: Heterochromatin, Chromocentren, Chromomere. In: Reports of the German Botanical Society. 47/1929, p. 277.
  15. ↑ Heitz Emil: The cause of the regular number, position, shape and size of plant nucleoli. In: Planta. 12/1931, pp. 775-844.
  16. ^ McClintock Barbara: The relation of a particular chromosomal element to the development of the nucleoli in Zea Mays. In: Journal of Microscopic Anatomy. 21/1934, pp. 294-328. Also in: Cell and Tissue Research. 21/1934, pp. 294-326.
  17. ↑ Heitz Emil, Bauer Hans: Evidence for the chromosome nature of the nuclear loops in the tangled nuclei of Bibio hortulanus L. Cytological investigations on Diptera: I. In: Journal for cell research and microscopic anatomy. 17/1933, pp. 67-82.
  18. ↑ Heitz Emil: The somatic heteropycnosis in Drosophila melanogaster and its genetic significance. In: Journal of Cell Research and Microscopic Anatomy. 20/1934, p. 266.
  19. ↑ Heitz Emil: About α- and β-heterochromatin as well as constancy and structure of the chromomers in Drosophila. In: Biological Zentralblatt. 54/1934, p. 596, p. 601.
  20. ↑ Bridges Calvin B .: Salivary chromosome maps. With a key to the banding of the chromosomes of Drosophila melanogaster. In: Journal of Heredity. 26/1935, pp. 60-64.
  21. ↑ Heitz Emil: Elements of Botany: Instructions for studying the plant through observation and experiments on Crepis capillaris <L.> Wallr. Springer, Vienna 1950.
personal data
SURNAME Heitz, Emil
ALTERNATIVE NAMES Heitz, Johann Heinrich Emil
BRIEF DESCRIPTION German-Swiss botanist, cytogeneticist
DATE OF BIRTH October 29, 1892
PLACE OF BIRTH Strasbourg
DATE OF DEATH July 8, 1965
Place of death Lugano