Transforming principle by Griffith

transforming principle by F.Griffith, Biochemial characterization of genetic material, genetic material is DNA, search of genetic material

1. Transforming principle ( G riffith’s Experiment) DNA- a genetic material By-Dr R K Upadhyay PGT, Biology

2. Frederick Griffith 1928 Mice Virulent strain of pneumonia (S strain) Non virulent strain of Pneumonia (R strain) Streptococcus pneumoniae ) 

3. ‘S’ and ‘R’ strain Type III-S (smooth) – virulent Type II-R (rough )- nonvirulent . The III-S strain synthesize a   polysaccharide  capsule that protected itself from the host's  immune system , resulting in the death of the host’ While the II-R strain don’t have that protective capsule and was defeated by the host's immune system

4. T ransformation bacteria are capable of transferring genetic information through a process known as  transformation

5. Griffith experiment MICE + S strain- -----mice died due to Pneumonia MICE + R strain- -----mice alive

6. Griffith experiment MICE + heat killed S strain- -----mice live MICE + heat killed S strain + R strain- -----mice died due to Pneumonia.

7. Reason Due to transformation the genetic material from heat killed ‘S’ strain transferred to the ‘R’ strain. ‘R’ strain (non virulent) transformed into ‘S’ strain ( virunet )

8. Biochemical characterization of transforming principle   Oswald Avery ,  Colin MacLeod , and  Maclyn McCarty Prove DNA is genetic material.

9. Use of enzymes Protease, Rnase , DNase MICE + heat killed S strain + R strain + Protease mice died MICE + heat killed S strain + R strain + RNase mice died MICE + heat killed S strain + R strain + Protease mice died

10. Conclusion There is no effect of Proteins and RNA on the virulent property of Bacteria. DNA has virulent property.