Frederick Griffith

Frederick Griffith.

Frederick Griffith (* 1877 in Hale ( Cheshire ), † 1941 in London ) was a British medic and bacteriologist .

Griffith worked as a bacteriologist in the Pathology Laboratory of the UK Ministry of Health in London. He died in his laboratory in a German bombing raid on London in 1941.

Griffith became known through his experiment with pneumococci (1928), named after Griffith's experiment , in which he demonstrated the uptake of a genetic factor by a strain of pneumococci: Griffith worked with two strains, an R and an S strain. "S" stands for "smooth" because they are able to form mucous capsules and "r" for "rough" because they have lost their hereditary ability to form capsules.

In an animal experiment , the S-strain proved to be fatal for mice, the R-strain as harmless, as it does not have a protective mucous capsule and is therefore broken down by the host cell's enzymes. If the bacteria in the deadly S strain were killed and injected into the mouse, the animal was not harmed. But if she was injected with a mixture of living R-bacteria and killed S-bacteria, they died. The previously harmless R pneumococci had taken over the lethal factor of the S strain.

Today we know that the DNA of the S bacteria survived the heating process and could therefore be absorbed by the R pneumococci. The DNA of the S-strain contained the crucial gene that protected from the host's immune system .

Griffith was one of the first to describe the possibility of gene exchange between bacteria. Today this process is known as transformation .

See also: Oswald Avery

literature

• F. Griffith: The significance of pneumococcal types. In: J. Hyg. 27, 1928, pp. 113-159.
• Fred Griffith. In: John Daintith (Ed.) Biographical Encyclopedia of Scientists. CRC Press, 2009, ISBN 978-1-4200-7271-6 .