Theodor O. Diener

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Theodor O. Diener

Theodor Otto Diener (born February 28, 1921 in Zurich ) is a Swiss - American plant pathologist . He discovered, characterized and named the viroids , which are the smallest known structures capable of replication, 80 to 100 times smaller than the smallest viruses. Viroid and viroid-like satellite RNA have been recognized by the International Committee on Virus Taxonomy as a new order of subviral agents .

In a compilation of the most important milestones of the past millennium in plant pathology, published in 2000, the American Phytopathological Society recognized Theodor Otto Diener's discovery of the viroids in 1971 as one of the ten most important pathogen discoveries of the millennium.

The discovery of the viroids was the third major expansion of the biosphere - after the discovery of the visually invisible (i.e. "subvisual") microorganisms by Antoni van Leeuwenhoek in 1675 and that of the "submicroscopic" viruses by Dmitri Iossifowitsch Iwanowski in 1892.

As Ricardo Flores and colleagues wrote: "Viroids and viruses have the most characteristic property of living organisms: in a suitable environment they are able to produce copies of themselves, that is, they are capable of autonomous replication (and evolution). In In this regard, viroids (with 246 to 401 nucleotides) are at the limit of life - an aspect that should attract anyone interested in biology. "

life and career

After a little promising childhood, Diener passed the entrance examination at the Swiss Federal Institute of Technology (ETH Zurich), from which he received his diploma in natural sciences in 1944 and in which he was awarded a Dr. sc. nat. PhD in plant pathology . He then became an assistant to Samuel Blumer , a prominent mycologist at the time at the Federal Research Institute for Fruit, Viticulture and Horticulture in Wädenswil , where he found a rust fungus ( Puccinia cerasi ) on the leaves of a local cherry tree on the first day at work . P. cerasi is widespread south of the Alps, but is rarely seen north of the Alps. This mushroom was only seen once in Wädenswil, more than a hundred years earlier. Although Diener had a good and secure job in Waedenswil, he emigrated to the USA in the hope of being able to do basic research there and thus contribute something to the great revolution in biology that was beginning at that time, which was not possible in Wädenswil.

He made his way through odd jobs in the United States and rose in four months from dishwasher to manager of a luxury restaurant, spent six months at Rhode Island State University , where he tested a xylene- soluble copper compound for toxicity to fungi and plants, and took 1949 a position as Assistant Plant Pathologist at the Irrigation Experiment Station in Prosser , Washington. There was a small, remote Washington State University research facility . However, he quickly learned that virological basic research was also not possible there. He became an assistant and then associate professor at Washington State University, where he showed that an unusual amino acid ( pipecolic acid ) only builds up in measurable quantities in peach leaves when the leaves show symptoms of peach western X disease. Likewise, healthy peach cuttings injected with pure pipecolic acid have been shown to develop symptoms very similar to those of Peach X Disease. This proved that pipecolic acid plays an important role in disease production.

From 1959 to 1988 he was at the Plant Virology Laboratory of the Agricultural Research Service (ARS) in Beltsville , which owed its creation to the Sputnik shock . During this time, Diener learned of the unexpected difficulties that made it impossible for plant virologists to isolate the causative agent of potato spindle tuber addiction . He decided to investigate this problem. This led to the unexpected discovery of the novel pathogen, which Diener proposed to name "Viroid". Later, the viroids were characterized as single-stranded, covalently ring-shaped closed RNA, which appears as rod-shaped structures with a high proportion of base pairing . Viroids and the viroid-like satellite RNA have been classified as the new order of subviral agents by the International Committee on Taxonomy of Viruses . When the system was published in 2014, the viroids comprised two families, eight genera and 32 species. In the following years Diener and other independent, biochemically oriented colleagues succeeded in clarifying the chemical structure of the viroids. Viroids are single-stranded, circularly closed RNA macromolecules. In 1989, Diener made a detour into evolutionary research by proposing a hypothesis that showed that the viruses were more plausible relics of the hypothetical RNA world than other RNAs previously considered as such.

From 1989 he was Distinguished University Professor and since 1994 he has been Professor Emeritus at the University of Maryland, College Park .

Diener has been married to Sybil Mary Fox since 1968 and has three sons. He is a Swiss and US citizen.

research

In 1971, when Diener was investigating the cause of Potato Spindle Tuber Disease (PSTVd ​​for short) in potatoes, Diener discovered that it was caused by a pathogen that was smaller than a virus , a piece of RNA with no protein, a viroid . Its size was only 130,000 daltons , while it was previously assumed that an infectious agent would have to be at least 1 million daltons. Research at PSTVd ​​was started at ARS by William B. Raymer and Muriel O'Brien. For example, they found that tomatoes were more suitable for studying the pathogen than potatoes, for which the latency period can be several years. The pathogen, however, resisted discovery by simple centrifugation and Raymer called in servants around 1965. Using density gradient centrifugation , they discovered that the pathogen was smaller than a common virus. Experiments with various enzymes that break down DNA, RNA or proteins led to the conclusion that the pathogen consisted only of RNA. Raymer went into industry in 1966 and for the next five years Diener continued to research alone until he was sure that his results would convince the professional world. In the following years, Diener and several independent groups of biochemical colleagues succeeded in showing that viroids are single-stranded, circularly closed RNA.

In 1989 Diener hypothesized that they are relics of the hypothetical RNA world from the development phase of life on earth.

Honors and memberships

He is a member of the US National Academy of Sciences , the American Academy of Arts and Sciences and has been a member of the Leopoldina since 1980 . In 1987 he received the National Medal of Science and the Wolf Prize in Agricultural Sciences. In 1968 he received the Campbell Prize of the American Institute of Biological Sciences, in 1975 he received the Humboldt Research Prize , in 1977 the Distinguished Service Award of the US Department of Agriculture, and in 1979 Cornell University named him Andrew D. White Professor-at-Large. In 1988 he received the University of Minnesota EC Stakman Award. In 1989, Diener was inducted into the Science Hall of Fame of the Agricultural Research Service ( USDA ).

Fonts (selection)

  • Viroids and Viroid Diseases, Wiley-Interscience 1979
  • as editor: The Viroids, Plenum Press 1987
  • TO servant: A rust fungus on cherry leaves. Zeitschrift für Obst- und Weinbau, Volume 58, 1949. pp. 228-230.
  • TO servant: Potato spindle tuber "virus". IV. A replicating, low molecular weight RNA. Virology, Vol. 45, 1971, pp. 411-428, PMID 5095900
  • BD Stollar, TO Diener: Potato spindle tuber viroid. V. Failure of immunological tests to disclose double-stranded RNA or RNA-DNA hybrids. Virology, Volume 46, 1971, pp. 168-170, PMID 5166353
  • TO Diener, JM Sogo, T. Koller: Potato spindle tuber viroid. X. Visualization and size determination by electron microscopy, Virology, Vol. 55, 1973, pp. 70-80
  • TO Diener, WB Raymer: Potato spindle tuber virus. A plant virus with properties of a free nucleic acid. Science, Vol. 158, 1967, pp. 378-381.
  • TO Diener: Circular RNAs: relics of precellular evolution ?. Proc. Natl. Acad. Sci. USA, Volume 86, 1989, pp. 9370-9374. PMID 2480600
  • TO servant: Viroids: "living fossils" of primordial RNAs? In: Biology direct. Volume 11, number 1, March 2016, p. 15, doi: 10.1186 / s13062-016-0116-7 , PMID 27016066 , PMC 4807594 (free full text).

Web links

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

Individual evidence

  1. ↑ Life data according to American Men and Women of Science , Thomson Gale 2004
  2. ^ Brian WJ Mahy: Encyclopedia of Virology. Academic Press, 2008, ISBN 978-0-12-373935-3 . P. 332.
  3. ↑ From Y1K to 2K: Millennial Milestones in Plant Pathology, American Phytopathological Society Publications, APSnet Features, (prepared by Thor Kommedahl, University of Minnesota), 2000, 7pp. doi : 10.1094 / APSFeature-2000-0100
  4. ↑ R. Flores, S. Ruiz-Ruiz, P Serra: Viroids and Hepatitis Delta Virus . BSemin Liver Dis. 2012, 32 (3): 201-210.
  5. ^ TO Diener (1949): A rust fungus on cherry leaves , Switzerland. Magazine f. Fruit and wine growing. 58: 228-230.
  6. ^ TO Diener, CA Dekker (1954): Isolation and identification of L-pipecolic acid from Western-X-diseased peach leaves , Phytopathology: 44: 643-645.
  7. ^ TO Diener and ML Weaver (1957): On the significance of proline and pipecolic acid accumulation in Western-X-diseased peach leaves , Phytopathology Volume 47, Edition 8. ISBN 978-1-4787-2253-3 .
  8. ↑ TO servant: Potato spindle tuber "virus". IV. A replicating, low molecular weight RNA . In: Virology . 45, No. 2, 1971, pp. 411-28. PMID 5095900 .
  9. ↑ TO Diener: Potato spindle tuber viroid. 8. Correlation of infectivity with a UV-absorbing component and thermal denaturation properties of the RNA . In: Virology . 50, No. 2, 1972, pp. 606-9. PMID 4636118 .
  10. ^ HL Singer, G. Klotz, D. Riesner, HJ Gross, AK Kleinschmidt: Viroids are single-stranded covalently closed circular RNA molecules existing as highly base-paired rod-like structures . In: Proceedings of the National Academy of Sciences . 73, No. 11, 1976, pp. 3852-6. PMID 1069269 . PMC 431239 (free full text).
  11. ↑ AMQ King, MJ Adams, EB Carstens, EJ Lefkovitz et al. (2012): Virus Taxonomy , Elsevier Academic Press, PP. 1221-1259, TN: 949565
  12. ^ F. Di Serio, R. Flores, JT Verhoeven, SF Li, V. Pallás, JW Randles, T. Sano, G. Vidalakis, RA Owens: Current status of viroid taxonomy . In: Archives of Virology . 159, No. 12, 2014, pp. 3467-78. doi : 10.1007 / s00705-014-2200-6 . PMID 25216773 .
  13. ^ Member entry by Theodor O. Diener at the German Academy of Natural Scientists Leopoldina , accessed on July 4, 2016.
personal data
SURNAME Servant, Theodor O.
ALTERNATIVE NAMES Diener, Theodor Otto (full name)
BRIEF DESCRIPTION American plant pathologist
DATE OF BIRTH February 28, 1921
PLACE OF BIRTH Zurich