Hans Kautsky ( German: Hans Kautsky ; April 13, 1891 , Vienna - May 15, 1966 , Slovenia, Kamniska-Bystrica [1] ) is an Austrian chemist [2] , the discoverer of singlet oxygen , chlorophyll fluorescence , and the Kautsky effect named after him. He also made a significant contribution to the study of the assimilation of carbon dioxide and silicon chemistry [3] .
| Hans Kautsky | |
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| Date of Birth | |
| Place of Birth | |
| Date of death | |
| A place of death | Little Stone-Bystrica, Slovenia |
| A country | |
| Scientific field | Silicon chemistry, photosynthesis |
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| Academic degree | |
| Known as | discoverer of the same effect |
Content
Family
Father Hans Wilhelm Joseph Kautsky (1864-1937) was a professor of art and a painter at the imperial court of Prussia and worked in Vienna and Berlin. Younger brothers Robert Kautsky (1895-1962; Vienna State Opera - chief master of props) and Fritz (geologist in Sweden). Grandfather Wenzel Johann the Baptist of Kautsky (1827–1896) was an artist and stage designer in Prague, and grandmother Minna Kautsky (1837–1912) was an actress and writer. Uncle Hans Kautsky was the Social Democratic theorist Karl Kautsky (1854-1938). Hans was the eldest child in a family of five, he had two brothers and two sisters. [2]
The son of Hans Kautsky, Dr. Hans Kautsky Jr., was educated as an oceanographer in Leipzig and for many years led research on the famous Meteor ship, and was also a member of the International Atomic Energy Agency in Paris and Vienna [2] .
Biography
Hans Kautsky was first educated as a painter and draftsman in Holland, although from a young age he was more interested in chemistry. In 1911-1917, Kautsky studied chemistry at the Berlin Higher Technical School . During the First World War, he served in the testing laboratory for monitoring the quality of production of gas masks. In 1919 he married a friend of his youth, Martha Urban, they lived in a harmonious marriage for more than 40 years. In 1920, they had a son [2] . After the war, he worked as an assistant at the Kaiser Wilhelm Institute under the direction of Herbert Freundlich and in 1922 received his doctorate, defending a thesis on unsaturated silicon compounds. In 1928, he defended his doctoral dissertation in Heidelberg, where in 1934 he received the title of assistant professor of inorganic chemistry. From spring 1936 to 1945, Kautsky taught at the University of Leipzig with the rank of professor at the Department of Inorganic and Structural Chemistry. In 1943, his institute was destroyed. The Americans praised the studies at the University of Leipzig and in June 1945, the professors were transported to Weilburg. Since 1947, he tried to re-organize the Institute of Inorganic Chemistry at the University of Marburg , where he received the post of professor, but failed [3] .
Scientific work
The main focus of Kautsky's scientific activity was silicon chemistry . In particular, he studied the formation of siloxanes, two-dimensional polymer compounds of silicon, oxygen and hydrogen from calcium disilicide (CaSi 2 ). Along with this, he studied the hydrosols of silicic acid in the expectation of the possibility of their use for catalysis . His interests also included surface chemistry, namely the aspect of energy transformations on the surface ( fluorescence , phosphorescence, and photochemical reactions). He conducted extensive research on the fluorescence of chlorophyll in the context of the conversion of solar energy into chemical energy in the process of carbon assimilation [4] .
Professor Kautsky and his co-author A. Hirsch found an increase in the fluorescence of photosynthetic objects kept in the dark after irradiation with light, observing the change in fluorescence exclusively with their eyes. They published these observations in a one-page article entitled “New experiments on the assimilation of carbon dioxide” in the journal Naturwissenschaften [5] . The time-dependent change in chlorophyll fluorescence had a good negative correlation with the CO 2 absorption curve previously published by Otto Warburg in 1920 [6] .
Kautsky came across the phenomenon of chlorophyll fluorescence by a fluke. At that time, the prevailing idea was that the chlorophyll molecule directly binds CO 2 and, absorbing the energy of light, directly converts it into chemical bond energy. When Kautsky in his 1931 work stated that the fluorescence of chlorophyll does not change depending on the CO 2 content in the environment, most scientists thought that its equipment was faulty: it seemed inconceivable that fluorescence was in no way dependent on the concentration of carbon dioxide. Kautsky, although he was not a plant physiologist, but was educated in the field of physical chemistry, suggested that light reactions and carbon dioxide fixation are two separate processes of photosynthesis. His idea remained unrecognized until 1951, when the work of Rabinovich and Duyensens was published, and the concept of the dark and light phase of photosynthesis appeared [7] .
Studying the fluorescence of chlorophyll in living objects, Kautsky and colleagues noticed that it is significantly weaker than the bright red fluorescence of the chlorophyll extract and also attenuates with time. Trying to explain this phenomenon, they suggested that there is a quenching of fluorescence by some unknown molecule. Kautsky suggested that this molecule may be oxygen. To prove this idea, he conducted a simple experiment: the photosensitizer was fixed on a silica gel substrate and placed in one solution with an organic substrate, also fixed on the substrate. When irradiated with light, the substrate was oxidized, from which it followed that the oxidation was mediated by some gaseous particle. Kautsky also discovered that oxygen extinguishes the fluorescence and delayed fluorescence of dyes fixed on a substrate. From these results, and also relying on the data of Robert Mulliken , who recently deciphered the structure of energy levels of O 2 , he made the correct conclusion that during photosynthesis and fixation of CO 2 energy can transfer to oxygen with the formation of singlet oxygen 1 O 2 . However, he incorrectly believed that oxygen could be the first acceptor of energy or electrons in ETC photosynthesis . Nevertheless, at that time this concept was not recognized, and Kautsky’s work was ignored for a long time because of its innovativeness. Kautsky died, not knowing that in 1964, almost 33 years after his first publication in this field, his conclusions about the importance of oxygen in the process of photosynthesis were fully confirmed [8] .
See also
- Kautsky effect
Notes
- ↑ Lothar Beyer, Eberhard Hoyer. Franz Hein, Arthur Schleede, Hans Kautsky und die Anorganische Chemie in Leipzig. - 2000. - Vol. 48. - P. 1493–1497. - DOI : 10.1002 / nadc.20000481212 .
- ↑ 1 2 3 4 Ausführliche Biografie bei biospektrum.de .
- ↑ 1 2 Prof. Dr. Dr. hc Lothar Beyer, Dr. Jens Blecher. KAUTSKY (German) . Universität Leipzig (7. Februar 2008).
- ↑ Gerhard Fritz: Das Porträt: Hans Kautsky (1891-1966), Chemie in unserer Zeit, 15. Jahrg. 1981, Nr. 6, S. 197-200, ISSN 0009-2851 , DOI : 10.1002 / ciuz.19810150605
- ↑ Kautsky, H., Hirsch, A. (1931), Neue Versuche zur Kohlensäureassimilation, Naturwissenschaften, 19: 964-964.
- ↑ Govindjee. Sixty-Three Years Since Kautsky: Chlorophyll a Fluorescence (Eng.) // Plant Physiology : journal. - American Society of Plant Biologists , 1995. - Vol. 22 , no. 2 . - P. 131-160 . - DOI : 10.1071 / PP9950131 .
- ↑ Practical Applications of Chlorophyll Fluorescence in Plant Biology / edited by Jennifer R. DeEll, PMA Toivonen. - Boston: Kluwer Academic Publishers: Springer, 2003 .-- P. 32. - ISBN 978-1-4613-5065-1 .
- ↑ AA Krasnovsky. Primary mechanisms of photoactivation of molecular oxygen. History of development and the modern status of research (English) // Biochemistry (Moscow) : journal. - October 2007. - Vol. 72 , no. 10 . - P. 1065-1080 . - DOI : 10.1134 / S0006297907100057 .
Literature
- H. Kautsky u. U. Franck: Chlorophyllfluoreszenz und Kohlensäureassimilation, 9.-12. Mitteilung. In: Biochemische Zeitschrift 315, 1943, S. 10-232