Analyzing The 1950 ' S Experiments By Salvador Luria Essay

790 Words Mar 2nd, 2016 4 Pages
In the 1950’s experiments by Salvador Luria, Marry Human, Joe Bertani, and Jean Weigle showed that some strains of bacteria were more resistant to bacteriophages than others. Luria, Human, Bertani, and Weigle injected a bacteriophage into bacterial host cells to see if the bacteriophage would use the bacterial host cells machinery to make more copies of its genome and then express bacteriophage genes. Luria, Human, Bertani, and Weigle discovered that certain strains of bacteria were able to keep the bacteriophage from hijacking their cells machinery. With further examination of the bacteriophage resistant bacteria it was determined that enzymes known as restriction enzymes or restriction endonucleases was the key to their self-defense mechanisms. In the 1960s Werner Arber noticed that when bacteriophage deoxyribonucleic acid (DNA) was inserted into bacteriophage resistant bacteria the bacteriophage DNA was degraded and cut into pieces. Arber proposed that bacteriophage resistant bacterial cells might express a certain enzyme that degrades invading bacteriophage DNA but does not harm the DNA of the bacterial cell. Arber also proposed that bacterial cells most likely express two different types of enzymes. A restriction enzyme that recognizes and cuts up foreign bacteriophage DNA and a modification enzyme that recognizes and modifies the bacterial host cell DNA so it is protected from its own restriction enzymes DNA-degrading activity. Arber predicted that the restriction…

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