Dr. Joachim Hämmerling (9 March 1901 - 5 August 1980) was a pioneering Danish-German biologist funded by

Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...

who determined that the

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

of a cell controls the development of organisms. His experimentation with the green algae ''

Acetabularia ''Acetabularia'' is a genus of green algae in the family Polyphysaceae, Typically found in subtropical waters, ''Acetabularia'' is a single-celled organism, but gigantic in size and complex in form, making it an excellent model organism for stu ...

'' provided a model subject for modern cell biological research, and proved the existence of morphogenetic substances, or mRNP.

Early life and professions

Joachim August Wilhelm Hämmerling was born on 9 March 1901 in

Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...

. He was educated at the

University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative ...

and

University of Marburg The Philipps University of Marburg (german: Philipps-Universität Marburg) was founded in 1527 by Philip I, Landgrave of Hesse, which makes it one of Germany's oldest universities and the oldest still operating Protestant university in the wor ...

. He received his doctorate in 1924. From 1924 to 1931 he was a research assistant at the

Kaiser Wilhelm Institute The Kaiser Wilhelm Society for the Advancement of Science (German: ''Kaiser-Wilhelm-Gesellschaft zur Förderung der Wissenschaften'') was a German scientific institution established in the German Empire in 1911. Its functions were taken over by ...

for Biology, and from 1931 to 1940 a lecturer. In 1940 he became Director of the German-Italian Institute of Marine Biology. In 1942 he became an associate professor of marine biology at the University of Berlin, before becoming the head of the Kaiser Wilhelm Institute for Biology in Langenargen am Bodensee in 1946. From 1949-1970 he served as the Director of the

Max Planck Institute Max or MAX may refer to: Animals * Max (dog) (1983–2013), at one time purported to be the world's oldest living dog * Max (English Springer Spaniel), the first pet dog to win the PDSA Order of Merit (animal equivalent of OBE) * Max (gorilla) ...

for Marine Biology, ultimately retiring in 1970.

''Acetabularia'' experiments

Hämmerling began growing ''Acetabularia'' in laboratories in the 1930s."Systematics and age of the Dasycladales"
Sigrid Berger. Heidelberger Institut für Pflanzen-wissenschaften. 2006. . There he discovered that the plant had one cell and the nucleus was always located in the

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...

. Then he began studying the roles of the

and

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

by experimenting with the ''

''."Invitation to Biology"
Helena Curtis, N. Sue Barnes. Macmillan, 1994. p. 93. , . In 1938 while working at the

for Biology, Hämmerling received a grant through a biology division within the

Third Reich Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...

headed by Konrad Meyer to study exclusively the effect of the nucleus on development.

1943 breakthrough

The groundbreaking experiment came in 1943 when he determined the role of the nucleus. In his experiments, he removed the nucleus from a specific species of ''Acetabularia'' called ''A. crenulata'' and grafted it onto the cell of another a ''Acetabularia'' species called ''A. mediterranea'', in which Hämmerling had removed specific parts of the organism. Shortly thereafter, the ''mediterranea'' regenerated the removed parts, but with the characteristics from the ''crenulata'' species. This experiment demonstrated that the nucleus contains the genetic information and controls development. The experiment also proved the existence of morphogenetic substances, which would eventually become known as mRNP.

Species namesake

Because of his work with ''Acetabularia'', when a new species of the plant was discovered in the Pacific Ocean in the 1970s, it was named after Hämmerling and called ''A. haemmerlingii''."Advances in marine biology, Volume 14"
Frederick S. Russell. Academic Press, 1976. p. 127. , .

Later years

In 1970 he was elected a Foreign Member at the

Royal Society of London The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

. He died on 5 August 1980.

References

{{DEFAULTSORT:Haemmerling, Joachim 20th-century biologists 20th-century German biologists 20th-century Danish scientists Danish biologists Cell biologists Foreign Members of the Royal Society Scientists from Berlin 1901 births 1980 deaths German emigrants to Denmark Max Planck Institute directors University of Marburg alumni