Folding At Home: Fact of the Day Log

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Folding fact #107
1915 Frederick Twort discovered a "disease" of bacteria called "glassy transformation" and showed the disease agent is transmissible, filterable, invisible with a light microscope and does not grow in the absence of the living host bacterium. Twort proposed three possible explanations, including a filterable virus and an enzyme.

 

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Folding fact #108
1916 George Harrison Shull, a pioneering corn breeder and Princeton genetics professor, published the inaugural issue of the scientific journal Genetics.

 

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Folding fact #109
1917 Plough demonstrated the rearrangement of chromosomes known as 'crossing over'. F. D'Herelle described "an invisible microbe" that antagonizes the bacillus that causes dysentery and coined the term "bacteriophage" for the antagonist. Phage caused plaques on bacterial lawns, analogous to colonies on agar plates. Later plaques will prove useful in preparing pure cultures and characterizing different strains of the bacteriophages or bacterial viruses.

 

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Folding fact #110
1917-1918 Sewall Wright analyzed the inheritance of coat colors in guinea pigs, mice, rats, rabbits, horses, and other mammals. Wright showed that production of the pigment determining coat color in mammals requires biochemical steps, taking place in fixed temporal order. He suggested that each step is mediated by a different, specific enzyme.

 

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Folding fact #111
1918 Herbert M. Evans found (incorrectly) that human cells contain 48 chromosomes. The German army used acetone produced by plants to make bombs. Yeast was grown in large quantities to produce glycerol, and activated sludge was produced in large quantities for sewage treatment processing. A world-wide epidemic of influenza killed 20 million people, more than killed in The World War.

 

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Folding fact #112
1920-1930 Plant hybridization became widespread in the United States, greatly improving the productivity of agriculture.

 

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Folding fact #113
1921 Hermann J. Muller, another of Thomas Hunt Morgan's students, wrote a paper about the nature of the gene that proved to be astonishingly prescient. He conceived of the gene as a particle that, despite its ultramicroscopic size, exhibits a complex structure of different parts.

 

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Folding fact #114
1924 Politicians encouraged by the eugenics movement passed the U.S. Immigration Act of 1924, limiting the influx of poorly educated immigrants from Southern and Eastern Europe on the grounds of suspected genetic inferiority.

 

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Folding fact #115
1925 Nikolai Vavilov led Russian plant hunters on the first attempt to "cover the globe" in search of wild plants and primitive cultivators. For his scientific curiosity, he was later thrown in prison, dying there of malnutrition in 1943. Congress voted to cut the Seed Distribution Program, which had consumed more than 10% of the USDA's total budget in 1921. The decades-old flood of free seed to the agricultural community suddenly stopped.

 

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Folding fact #116
1926 Thomas Hunt Morgan published 'The theory of the gene', the culmination of work on the physical basis for Mendelian genetics based on breeding studies and optical microscopy.

Hermann Muller discovered that X-rays induce genetic mutations in fruit flies 1,500 times more quickly than under normal circumstances. This discovery provided researchers with a way to induce mutations, an important tool for discovering what genes do on their own.

 

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Folding fact #117
Henry Agard Wallace, US Secretary of Agriculture during the Franklin Roosevelt's first two terms, and Vice-president during his third, founded the Hi-Bred Company - a hybrid corn seed producer and marketer known today as Pioneer Hi-Bred International, Inc.

 

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Folding fact #118
1928 Fredrick Griffiths noticed that a rough type of bacterium changed to a smooth type when an unknown "transforming principle" from the smooth type was present. Sixteen years later, Oswald Avery identified that "transforming principle" as DNA.

Lewis Stadler showed that ultraviolet radiation can also cause mutations.

Alexander Fleming noticed that all the bacteria in a radius surrounding a bit of mold in a petrie dish had died. The age of penicillin thus began, although it would be almost 15 years before it was made available to the community for medicinal use.

 

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Folding fact #119
1928-35 Linus Pauling elucidated the physical laws governing how atoms are arranged within molecules. He also described sickle cell anemia, defining it a molecular disease.

 

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Folding fact #120
1929 Phoebus Levene discovered a previously unknown sugar, deoxyribose, in nucleic acids that do not contain ribose; those nucleic acids are now known as deoxyribonucleic acids, or DNA.

 

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Folding fact #121
1933 T.S. Painter announced in a brief article in Science that he had charted perceptible differences among chromosomes under the microscope - differences detailed enough to correlate crossing-over of genes as shown in the statistical tables with physical interchanges in the material of the chromosomes.

 

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Folding fact #122
1934 Desmond Bernal showed that giant molecules, such as proteins, can be studied using X-ray crystallography. Martin Schlesinger purified bacteriophage and found about equal amounts of protein and DNA. Which of these was the informational molecule remained unclear.

 

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Folding fact #123
1935 Wendell Meredith Stanley crystallized tobacco mosaic virus, the first such purification of a virus. He believed, incorrectly, that protein was the active agent of the virus George Beadle and Boris Ephrussi transplanted tissue between larvae of fruit flies bred with various mutations of eye color and observed the mature flies development.

Andrei Nikolaevitch Belozersky isolated DNA in the pure state for the first time.

 

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Folding fact #124
1936 Wendell M. Stanley isolated nucleic acids from the tobacco mosaic virus, which later (1955) will be found to cause the viral activity.

 

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Folding fact #125
1937 Frederick Charles Bawden discovered that tobacco mosaic virus contains RNA.

 

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Folding fact #126
1938 Howard Florey and Ernst Chain of Oxford University in England isolated the antimicrobial agent penicillin.

 

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Folding fact #127
1938 Proteins and DNA were studied in various labs with X-ray crystallography. The term "molecular biology" was coined.

 

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Folding fact #128
1939 Gauteret cultivated carrot callus cultures. Andrei Nikolaevitch Belozersky started his experimental work showing that both DNA and RNA are always present in bacteria.

 

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Folding fact #129
1940-1945 Large-scale production of penicillin was achieved.

 

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Folding fact #130
1940-1950 Countries in the West made the transition from animal power to mechanical power on farms.

 

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Folding fact #131
1941 George Beadle and Edward Tatum experimented with Neurospora, a mold that grows on bread in the tropics, developing the "one-gene-one-enzyme" hypothesis: each gene is translated into an enzyme to perform tasks within an organism. They examined X-ray-damaged mold specimens that would not grow on the sample medium, but would grow if they added a certain vitamin. They hypothesized that the X-rays had damaged the genes that synthesized the proteins.