Otto Kandler

Between 1945 and 1946 he reconstructed his father's market garden and earned some money by growing and selling vegetable, especially cabbage, and flowers to finance his life and his future studies.

[1][3][10] Kandler was very interested in science, but only in 1946 was he able to enrol at Ludwig Maximilian University of Munich in botany, zoology, geology, chemistry and physics.

He used these tissue cultures to study for instance metabolism and the influence of auxins under defined in vitro conditions, received his doctor's degree with honors in 1949 and became assistant professor of botany at the University of Munich.

For his early publications on photophosphorylation[11][12][13] he received a generous research fellowship from the Rockefeller Foundation and, in 1956/1957 he was able to work on basic questions of photosynthesis for one year in the USA.

[3] In 1960 he was appointed full professor of Applied Botany of the Technical University Munich, where research conditions still at that time were bad.

In 1968 he was appointed full professor and Head of the Department of Botany at the Ludwig Maximilian University of Munich, taught and conducted research until his retirement in 1986.

In these years, in the aftermath of World War II, the original Chemical Institute of the Ludwig Maximilian University of Munich was still in ruins and Feodor Lynen and his assistant Helmut Holzer were working temporarily as guests in the Botanical Institute just next door to the laboratory where Kandler was engaged in his thesis in botany.

[22] Kandler's early publications on light-dependent formation of ATP[11][12][13] led the Rockefeller Foundation to offer him a one-year research fellowship in the USA.

[31] As a result, they suggested comparative cell wall chemistry as a marker for the deep branches in the phylogenetic tree of bacteria.

In some "archaebacteria" Kandler and König identified pseudomurein, now also called pseudopeptidoglycan, a novel cell wall component, and elucidated its structure and biosynthesis.

[34] Together with Hans Günter Schlegel, Kandler was substantially involved in the foundation of the German collection of microorganisms and cell cultures (DSMZ) in Braunschweig.

Therefore, Kandler was delighted when he learned from a letter by Ralph F. Wolfe, expert on methanogens, on 11 November 1976, that Wolfe's colleague Carl Woese (University of Illinois, Urbana, USA) had just discovered basic differences between methanogens and bacteria with his novel 16S ribosomal RNA gene sequencing method.

Kandler wrote back immediately how impressed he was with Woese's findings and ideas and that he looked forward to investigate Wolfe's methanogens.

In his reply Kandler also mentioned that methanogens and halophiles may be "ancient relics" that have branched off from the bulk of the prokaryotes before peptidoglycan had been "invented".

In their fundamental frequently cited publication, Woese and Fox (November 1977)[35] introduced the term "archaebacteria", at that time, comprising only methanogens.

Only in 1990, in their publication on the phylogenetic tree of life, Woese and Kandler[7] proposed the term "domain" for the three groups Bacteria, Archaea, Eucarya, see below).

In the summer of 1979, Kandler invited Woese again to give a lecture at a meeting of the "Deutsche Gesellschaft für Mikrobiologie und Hygiene" in Munich.

After the conference, the "archaebacteria" were celebrated by Woese, Wolfe and Kandler on an excursion to the close Alps climbing the top of Hochiss (2299 m) in the Rofan mountains (see Photos).

[39] Meanwhile, the support for the "archaebacteria" concept – and also for the idea of a phylogenetic division into three groups on the basis of 16S rRNA sequencing and additional characteristics – had grown, but had still not yet been generally accepted by the scientific community.

Also an intensive controversial discussion about the level of classification and terminology was taking place (e.g. terms like urkingdom, primary kingdom, empire etc.

[10] Finally, after about 13 years of cooperation, in their publication of 1990 (Woese, Kandler, Wheelis),[7] Woese and Kandler proposed a "tree of life" consisting of three lines of descent (see adjacent "Phylogenetic Tree of Life") for which they introduced the term domain as the highest rank of classification, above the kingdom level.

Up to date, this publication is one of the most frequently cited papers in the Proceedings of the National Academy of Sciences of the United States of America.

[9]: 22 Kandler's contribution to our understanding of the early evolution of life was valued several times, e.g. Müller 1998,[19] Wiegel 1998,[44] Wächtershäuser 2003[45] and 2006,[46] Schleifer 2011.

He also tested several procedures for the fermentation of milk and vegetable products or proposed methods for successfully combating micro-organisms in cooling water systems (more examples see Schleifer 2011.

[40] His interest in ecology was broad; for instance he dealt with bacterial interactions, forest conditions and the return of lichens into the city of Munich.

[40][48] Since the early 1980s, research on the so-called "Waldsterben" (forest death) in Germany was substantially sponsored by the German Ministry of Science and Technology.

Otto Kandler in 1983, with a molecular model of pseudomurein( pseudopeptidoglycan )
Wall mosaic in the great entrance hall of the historical building of the Botanical Institute, Ludwig Maximilian University of Munich
Carl Woese (left), Otto Kandler and Ralph Wolfe on their way to Mt. Hochiss in 1981 (photo by Gertraud Kandler)
Carl Woese (left), Ralph Wolfe and Otto Kandler (right), celebrating the "archaebacteria" (now archaea) on top of Mt. Hochiss in 1981 (photo by Gertraud Kandler)
Universal phylogenetic tree in rooted form, showing the three domains (Woese, Kandler, Wheelis 1990, p. 4578 [ 7 ] )
Early diversification of life with Kandler's pre-cell theory (Kandler 1998, p. 22) [ 9 ]