1886 Adolf Mayer
Adolf Mayer, Director of the Agricultural Experiment Station at Wageningen in The Netherlands, was first called in 1879 to sutdy a peculiar disease of tobacco. He is credited as the first person to transmit tobacco mosaic by using the juice extracts from the diseased plant as the inoculum to infect other plants. He published a paper in 1886 describing the disease and its symptoms in detail.
1892 Dmitri Ivanowski
Ivanowski did a number of filtration experiments using porcelain Chamberland filter-candles, which were considered to be the ultimate test for bacteria, as they would be retained on the filter. He determined that the cuase was either an unculturable bacterium or the result of a toxin produced by the bacteria. If it was the unculturable bacterium then it was smaller than any other known bacterium.
1898 Martinus Beijerinck
Beijerinck looked for "microbes" associated with tobacco mosaic but found none. He repeated the filtration experiments and concluded that what passed through porcelain filters remained infectious and was sterile of microorganisms. He concluded that it was a "contagium vivum fluidum", a contagious living fluid. He conducted other experiments and found the agent causing the disease was indeed soluble, the agent reproduced in the diseased plant, the infectious extract was stable during a 3 month test, virulence did not increase or decrease in the extract (further evidence that it was not bacterial), the agent remained viable even when tissue is dried, and that heating the extract to 90 degrees inactivated it. He correctly deduced that it moved through the phloem.
1935 W. M. Stanley
Stanley, an American scientist added ammonium sulfate to tobacco juice extracted form infected tobacco leaves and obtained a crystalline protein sediment, which could be rubbed on tobacco to cause disease. He concluded that the virus was an autocatalytic protein that could multiply within living cells (later he was proved to be wrong). He received an Nobel Prize in Chemistry for his work in 1946.
1936 F. C. Bawden and Colleagues
Bawden and colleagues demonstrated that the crystalline preparations of virus actually consisted of not only protein but also a small amount of ribonucleic acid (RNA).
1939 Von G. A. Kausche and Colleagues
Viewed
particles of tobacco mosaic virus with an electronmicroscope.
