Confirmation of bacterial transformation and DNA as inducing materialConfirmation of bacterial transformation and DNA as inducing materialConfirmation of transformation and DNA as inducing materialIntroductionThe experiments presented in this report are a reconstruction of the famous experiments of Griffith and Avery who discovered the transformation process that bacteria can undertake and that DNA is the genetic material respectively (Griffth, 1928. Avery 1944). Bacteria can incorporate foreign DNA found in their environment into their genome during a process called transformation. This process can be accelerated in a CaCl solution at colder temperatures. The first part of this report aims to confirm that the transformation does indeed occur according to a standard procedure, and the second part of the report uses a similar procedure to confirm that DNA is the particle that induces the transformation. Methods In the following procedures, Escherichia coli was used: (Part 1) For the first set of experiments, a solution consisting of one-half of a live ampicillin-susceptible strain and one-half of a resistant to heat-killed ampicillin was mixed and incubated at 37°C for forty-five minutes. The resulting fluid was spread onto prewarmed LB medium and prewarmed LB Amp100 medium, respectively. Additionally, six controls were installed sharing an LB bracket and an LB Amp100 bracket. These controls were given their own area on the holder and a ridged plate. The controls consisted of the live ampicillin-sensitive strain, the dead ampicillin-resistant strain, and the live ampicillin-resistant strain plated on each medium. Aseptic technique was used to handle all solutions, media, and transfers between them. (Part 2) In the second set of experiments, 1.0 µL of kanamycin-susceptible bacteria was added to two test tubes, both subjected to the same treatment. The bacteria in the middle of the paper......colonies of living cells sensitive to ampicillin grown on LB Amp100 support with only the buffer. Colonies found on media treated with both live sensitive ampicillin and heat-killed resistant bacteria generated colonies with one exception: the treatment that used DNAse. This treatment showed the same result as those without heat-killed bacteria: no growth was observed, indicating that the transformation could not take place without DNA. In conclusion, this confirms that DNA is the hereditary medium that can transform bacteria, as discovered by Avery in 1944. ReferencesAvery, OT, MacLeod, CM & McCarty, M. (1944). Studies on the chemical nature of the substance inducing the transformation of pneumococcal types. The Journal of Experimental Medicine, 79, 137-158. Griffith F. (1928). The importance of pneumococcal types. Epidermiology and infection, 27(2), 113-159.

Essay / Confirmation of bacterial transformation and DNA as inducing materialConfirmation of bacterial transformation and DNA as inducing materialConfirmation of transformation and DNA as inducing materialIntroductionThe experiments presented in this report are a reconstruction of the famous experiments of Griffith and Avery who discovered the transformation process that bacteria can undertake and that DNA is the genetic material respectively (Griffth, 1928. Avery 1944). Bacteria can incorporate foreign DNA found in their environment into their genome during a process called transformation. This process can be accelerated in a CaCl solution at colder temperatures. The first part of this report aims to confirm that the transformation does indeed occur according to a standard procedure, and the second part of the report uses a similar procedure to confirm that DNA is the particle that induces the transformation. Methods In the following procedures, Escherichia coli was used: (Part 1) For the first set of experiments, a solution consisting of one-half of a live ampicillin-susceptible strain and one-half of a resistant to heat-killed ampicillin was mixed and incubated at 37°C for forty-five minutes. The resulting fluid was spread onto prewarmed LB medium and prewarmed LB Amp100 medium, respectively. Additionally, six controls were installed sharing an LB bracket and an LB Amp100 bracket. These controls were given their own area on the holder and a ridged plate. The controls consisted of the live ampicillin-sensitive strain, the dead ampicillin-resistant strain, and the live ampicillin-resistant strain plated on each medium. Aseptic technique was used to handle all solutions, media, and transfers between them. (Part 2) In the second set of experiments, 1.0 µL of kanamycin-susceptible bacteria was added to two test tubes, both subjected to the same treatment. The bacteria in the middle of the paper......colonies of living cells sensitive to ampicillin grown on LB Amp100 support with only the buffer. Colonies found on media treated with both live sensitive ampicillin and heat-killed resistant bacteria generated colonies with one exception: the treatment that used DNAse. This treatment showed the same result as those without heat-killed bacteria: no growth was observed, indicating that the transformation could not take place without DNA. In conclusion, this confirms that DNA is the hereditary medium that can transform bacteria, as discovered by Avery in 1944. ReferencesAvery, OT, MacLeod, CM & McCarty, M. (1944). Studies on the chemical nature of the substance inducing the transformation of pneumococcal types. The Journal of Experimental Medicine, 79, 137-158. Griffith F. (1928). The importance of pneumococcal types. Epidermiology and infection, 27(2), 113-159.

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