- Frederick Griffith
Frederick Griffith (1879 - 1941) was a British medical officer and geneticist. In 1928, in what is today known as
Griffith's experiment, he discovered what he called a "transforming principle", which is today known to be DNA. [cite journal |author=Lorenz MG, Wackernagel W |title=Bacterial gene transfer by natural genetic transformation in the environment |journal=Microbiol. Rev. |volume=58 |issue=3 |pages=563–602 |year=1994 |pmid=7968924 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=7968924] [cite journal |author=Downie AW |title=Pneumococcal transformation--a backward view. Fourth Griffith Memorial Lecture |journal=J. Gen. Microbiol. |volume=73 |issue=1 |pages=1–11 |year=1972 |pmid=4143929] He was born in Hale, England and attended Liverpool Universitywhere he studied genetics. In his younger days he worked for the Liverpool Royal Infirmary, the Thompson Yates Laboratory, and the Royal Commission on Tuberculosis.
In 1910 he was hired by the British government to work for the Ministry of Health under Arthur Eastwood. The government spent money sparingly in times of expected war, so the laboratories Griffith worked in were primitive. However, his creativity and inquisitive mind allowed him to excel in his scientific exploration. One of his friends claimed that "he could do more with a kerosene tin and a primus stove than most men could do with a palace."
The famous experiment was done when Griffith was trying to make a vaccine to prevent
pneumoniainfections in the " Spanish flu" influenzapandemic after World War I, by using two strains of the "Streptococcus pneumoniae" bacterium. The smooth strain (S strain) had a polysaccharide capsule and was " virulent" when injected, causing pneumonia and killing mice in a day or two. The capsule is a slimy layer on the cells' surface that allows the bacteria to resist the human immune system. The rough strain (R strain) did not cause pneumonia when injected into mice (it was "avirulent"), since it lacked a capsule. When the virulent S strain was heated to kill it, and then injected into mice, it produced no ill effects. However, when dead S strain mixed with live R strain was injected into the mouse, the R/S mouse died.
After isolating bacteria from the blood of the R/S mice, Griffith discovered that the previously avirulent R bacteria had acquired capsules. The bacteria isolated from the mice infected with the mixture of live R and heat-killed S were now all of the S strain, and maintained this
phenotypeover many generations. Griffith hypothesized that some "transforming principle" from the heat-killed S strain converted the R strain into the virulent S strain.
Griffith was killed at work in his laboratory in 1941, along with longtime friend and bacteriologist William M. Scott in London as a result of an air raid in the
London Blitz. It wasn't until several years later that Griffith's "transforming principle" was identified as DNA by Oswald Theodore Avery, along with coworkers Colin MacLeodand Maclyn McCarty, in 1944. [cite journal |author=Avery O, MacLeod C, McCarty M |title=Studies on the chemical nature of the substance inducing transformation of pneumococcal types. Inductions of transformation by a desoxyribonucleic acid fraction isolated from pneumococcus type III | url=http://www.jem.org/cgi/reprint/149/2/297 | journal=J Exp Med |volume=79 |issue=2 | pages=137–158 |year=1944 |doi=10.1084/jem.79.2.137]
He was the uncle of John Stanley Griffith, a winner of the Royal Society's Faraday Medal.
* [http://profiles.nlm.nih.gov/CC/B/B/C/C/_/ccbbcc.pdf Frederick Griffith] "Lancet", (3 May 1941): 588. Obituary
* [http://library.thinkquest.org/27819/ch6_2.shtml The Famous DNA Experiments]
* [http://www.dnaftb.org/dnaftb/17/concept/ A Gene Is Made of DNA]
* [http://www.madsci.org/posts/archives/dec96/845176773.Ge.r.html MadSci Network: Genetics]
* [http://www.bact.wisc.edu/Microtextbook/index.php?module=Book&func=displayarticle&art_id=33 Studying microbes provides insight into life at the molecular level]
* [http://projects.edtech.sandi.net/miramesa/DNAproject/griffith.html Griffith's Experiment on Bacterial Transformation]
* [http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/11.1b.jpgSinauer Associations Inc.]
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