![]() ![]() When the rough strain bacteria reproduced, all of the progeny inherited the ability to manufacture the capsule. The only reason that the combination of heat-killed smooth strain plus live rough strain killed the Group 4 mice was because smooth-strain DNA coding for the polysaccharide capsule was incorporated into the genome of the rough strain. If Griffith had injected a fifth group of mice with a combination of heat-killed rough strain and heat-killed smooth strain, would the mice have died? Which of the following processes will be directly affected? Griffith believed the protein from the dead smooth-strain bacteria was the active transforming agent.Ī colony of smooth strain bacteria is grown on a culture containing an experimental drug that cleaves nucleic acid base sequences wherever adenine is paired with uracil. This process later became known as transformation. ![]() Some component had been transferred from the heat-killed smooth-strain bacteria to the live rough-strain bacteria, transforming them into the virulent smooth-strain bacteria. Table 1: Results of Griffith's experiment MiceĪutopsies performed on Group 4 mice revealed blood samples filled with live smooth-strain bacteria. The experimental results are shown in Table 1. The encapsulated strain was called the "smooth strain" because the colonies looked smooth on a culture plate due to their polysaccharide capsules, whereas the unencapsulated strain was denoted as the "rough strain" due to the irregularity of its surface.įour different groups of mice were injected with different combinations of the bacterial strains. In an attempt to develop a vaccine for pneumonia, Fred Griffith performed a series of experiments in 1928 using mice and two strains of the pneumococcus bacteria: a virulent encapsulated strain and a nonvirulent unencapsulated strain. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |