Jürgen Aschoff

Jürgen Walther Ludwig Aschoff ( born January 25, 1913 in Freiburg im Breisgau, † October 12, 1998 ) was a German biologist and behavioral physiologist; together with Erwin Bünning and Colin Pittendrigh founder of chronobiology.

Life

Aschoff was born the fifth child of the pathologist Ludwig Aschoff ( Aschoff - Tawara node ) and his wife Clara. After graduating from a grammar school he studied - his own words, " [m ] angels specific interest " - medicine at the University of Bonn, where he joined the fraternity Alemannia Bonn. After graduating in 1937 from the University of Freiburg, he received his doctorate in a year later for Dr. med with the dissertation blood alcohol curve and habituation.

Aschoff was then appointed to the Department of Physiology, University of Göttingen and took on 26 and October 27, 1942 in the meeting about medical issues in distress and Wintertod, where it was also referenced on the " undercooling experiments " in the Dachau concentration camp. He habilitated in 1944. 1947 he was acting director of the Physiological Institute of the University of Würzburg. Two years later he joined his first professorship at the University of Göttingen as a physiologist.

From 1952 he worked at the Max Planck Institute for Medical Research in Heidelberg. He was from 1967 to 1979 director of the Max Planck Institute for Behavioral Physiology in Seewiesen (location Andechs ) and Scientific Member of the Max Planck Society. During the period in Seewiesen he was an adjunct professor in Munich. Furthermore, he was from 1972 to 1976 Senator of the Max Planck Society. Since 1978 he was a member of the Scholars Academy Leopoldina, he still belonged to the mathematical-scientific class of the Bavarian Academy of Sciences from 1984 to 1987 as a full member, when he moved to Freiburg in 1987 he was a corresponding member.

After his retirement to retire 1983 and 1987 after moving back to Freiburg sat Aschoff his scientific work in the form of further publications continued. Only his wife Hilde death could break his extraordinary vitality. Jürgen Aschoff died 10 months after his wife after a brief illness at the age of 85 years.

Work

He received his early publications on physiology of the thermoregulation. Almost inevitably turned Aschoff in his research on the human body temperature ( even in self- tests) 24- hour rhythm of body temperature fluctuations determined. But as a " lone wolf ", as he called himself, he had no contact with other researchers who dealt with these phenomena. In addition, his free-running rhythms in plants were unknown. Aschoff once said that the botanists zoologists would be 103 years ahead of what was concerned the discovery of circadian rhythms.

1953 met Aschoff Erwin Bünning, one of the first Chrono biologists. Their relationship was very amicable. Aschoff and Colin Pittendrigh in 1958 learned to know and remained throughout her life very good friends. Aschoff, Bünning and Pittendrigh 1960 were the main initiators of the " Cold Spring Harbor Symposium on biological clocks ". Here they laid the foundation for the virtual biological rhythms research in the 20th century.

1954 met Aschoff and Gustav Kramer, who had discovered the sun compass orientation in birds, for the first time. 1958 brought Konrad Lorenz and Erich von Holst Aschoff to Seewiesen. Von Erich von Holst, he learned much about the coupling of oscillators and the phenomenon of relative coordination. A short time later Aschoff took over a newly established department for him at the Max Planck Institute for Behavioral Physiology in Erling - Andechs, so that was actually researched physiologically there next to the "classical" and more descriptive ethology.

Shortly after Aschoff had been appointed director of the Max Planck Institute for Behavioral Physiology in Andechs, also Rütger Wever and Eberhard Gwinner began to work in Andechs. The Institute has developed over the years into a Mecca of chronobiology.

Many scientists from around the world came to Andechs to work together with Aschoff, among others, Colin Pittendrigh and Daan Serge. Here they found excellent amenities and - unique in the world - the "Bunker", a dug in the mountain isolation device for the study of human and animal circadian rhythms. The bunker was built with the assistance of NATO in the early 1960s.

Scientific Work

After he had encountered in self- tests on the 24 -hour rhythm in the human temperature regulation, Aschoff grew up with an interest in the underlying mechanisms. He began to carry on experiments on this topic. So he drew birds on hand and watched several generations of mice, he grew under constant conditions in the laboratory. After these attempts, he postulated:

• " The rhythm is innate, and it does not require exposure to a 24 -hour day to produce them."

He continued his work by the influences of exogenous stimuli on the endogenous circadian system examined in birds and humans. The intensity of continuous illumination modulated the frequency predictable, albeit in nocturnal ( nocturnalen ) and diurnal ( diurnal ) animals in the opposite direction - a phenomenon that soon as " Aschoff 's Rule " ( Aschoff's rule) was generalized:

• The free-running period tau ( τ ) in nocturnal animals is longer in L: L than in D: D, whereas in diurnal animals tau in L: L is shorter than D: D where L: L = 24 hours of light and D: D = 24 hours of darkness means

These and other findings led to a new conceptual view of the synchronization of circadian rhythms. He postulated an innate, biological oscillator, which is, for example, synchronized by the day - night cycle in natural surroundings. The synchronizing factor he called " timer ", a word which also has input into the English language.

By applying the physical oscillator theory Aschoff could make predictions about the behavior of circadian systems and their response to different timer. His experimental and theoretical work in the 1950s and 1960s laid the foundation for today's view of circadian rhythms as a product of endogenous oscillators and their constant phase relationship to the light - dark cycle - the most accurate timer, the Earth has to offer.

Aschoff and Wever were able to establish the well- substantiated theory that human physiology and behavior is just as controlled by endogenous circadian oscillators, like that of the animals. This discovery had far-reaching effects in biology and medicine. It led to our current understanding of many socio - Median problems as they arise, for example, shift work, affective disorders, sleep disorders, aging and jet lag. It also laid the basis for the optimization of pharmacological therapies.

Writings (selection )

• With Rütger Wever: beginning and end of the daily activity of wild birds. In: Journal of Ornithology. Vol 103 (1962), H. 1, pp. 2-27, doi: 10.1007/BF01670845.
• Edited: Circadian Clocks: proceedings of the Feldafing Summer School, 7-18 September 1964 North -Holland, Amsterdam 1965..
• Desynchronization and resynchronization of Human Circadian Rhythm. In: Aerospace medicine. Vol 40, H. 8 ( August 1969 ), pp. 844-849, PMID 5,803,983th
• The Circadian System of Man: With Rütger Wever. In: Biological Rhythms. 1981, p 311-331, doi: 10.1007/978-1-4615-6552-9 17