Griffith experiment bacterial transformation experiment

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This lecture explains about the Griffith experiment about transformation. http://shomusbiology.com/ • Download the study materials here- • http://shomusbiology.com/bio-material... • Remember Shomu’s Biology is created to spread the knowledge of life science and biology by sharing all this free biology lectures video and animation presented by Suman Bhattacharjee in YouTube. All these tutorials are brought to you for free. Please subscribe to our channel so that we can grow together. You can check for any of the following services from Shomu’s Biology- • Buy Shomu’s Biology lecture DVD set- www.shomusbiology.com/dvd-store • Shomu’s Biology assignment services – www.shomusbiology.com/assignment -help • Join Online coaching for CSIR NET exam – www.shomusbiology.com/net-coaching • We are social. Find us on different sites here- • Our Website – www.shomusbiology.com • Facebook page- / shomusbiology • Twitter - / shomusbiology • SlideShare- www.slideshare.net/shomusbiology • Google plus- https://plus.google.com/1136485849827... • LinkedIn - / suman-bhattacharjee-2a051661 • Youtube- / thefunsuman • Thank you for watching • Griffith's experiment, reported in 1928 by Frederick Griffith,[1] was one of the first experiments suggesting that bacteria are capable of transferring genetic information through a process known as transformation.[2][3] • Griffith used two strains of pneumococcus (Streptococcus pneumoniae) bacteria which infect mice -- a type III-S (smooth) and type II-R (rough) strain. The III-S strain covers itself with a polysaccharide capsule that protects it from the host's immune system, resulting in the death of the host, while the II-R strain doesn't have that protective capsule and is defeated by the host's immune system. A German bacteriologist, Fred Neufeld, had discovered the three pneumococcal types (Types I, II, and III) and discovered the Quellung reaction to identify them in vitro.[4] Until Griffith's experiment, bacteriologists believed that the types were fixed and unchangeable, from one generation to another. • In this experiment, bacteria from the III-S strain were killed by heat, and their remains were added to II-R strain bacteria. While neither alone harmed the mice, the combination was able to kill its host. Griffith was also able to isolate both live II-R and live III-S strains of pneumococcus from the blood of these dead mice. Griffith concluded that the type II-R had been transformed into the lethal III-S strain by a transforming principle that was somehow part of the dead III-S strain bacteria. • Today, we know that the transforming principle Griffith observed was the DNA of the III-S strain bacteria. While the bacteria had been killed, the DNA had survived the heating process and was taken up by the II-R strain bacteria. The III-S strain DNA contains the genes that form the protective polysaccharide capsule. Equipped with this gene, the former II-R strain bacteria were now protected from the host's immune system and could kill the host. The exact nature of the transforming principle (DNA) was verified in the experiments done by Avery, McLeod and McCarty and by Hershey and Chase. Source of the article published in description is Wikipedia. I am sharing their material. © by original content developers of Wikipedia. • Link- http://en.wikipedia.org/wiki/Main_Page Material source: Molecular Genetics of Bacteria • Larry Snyder (Author), Joseph E. Peters (Author), Tina M. Henkin (Author), Wendy Champness (Author) • Link: http://www.amazon.com/Molecular-Genet...

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