Define bacterial transformation? Who proved it experimentally & how?
The transformation is a mode of exchange or transfer of genetic information between organisms or from one organism to another. Fredrick Griffith tested the virulence of two strains of Diplococci to show transformation in the following steps:- When S-III strains of bacteria are injected into mice. It developed pneumonia & died. When R-II strains are injected into mice, they do not develop pneumonia & survive. When heat-killed S-III strains of bacteria are injected into mice, No symptoms of pneumonia develop & mice remain healthy. When a mixture of heat-killed S-III strain & live R-II strain is injected into mice, they develop pneumonia & die. From these results, Griffith concluded that the presence of heat-killed S-III bacteria must convert living R-II type bacteria to type S-III so as to restore the capacity for capsule formation. This was called “BACTERIAL TRANSFORMATION” S strain →Inject into mice R strain→Mice die R strain→Inject into mice →Mice live S strain (heat-killed)→Inject into mice→Mice live S strain (heat-killed) + R strain (live)→Inject into mice→Mice die
