In the 1946 scientists were perplexed at how bacteria transferred genetic material aside from normal reproductive capabilities. Joshua Lederberg studied a phenomenon that allowed bacteria to acquire certain traits without the process of replication. At the time it was accepted that Bacteria could pass on genetic information via binary fission, however Lederberg proposed that there was another process that contributed to bacterial success. He discovered conjugation: a process that utilizes plasmid DNA and transfers it to other bacterial cells, thereby giving those cells identical characteristics.
Plasmids are naturally occurring circular DNA molecules that are found in cytoplasm of bacterial cells. Chromosomes contain essential information…show more content… In order to obtain plasmids, we first begin with a tube 1.5ml of cultured bacteria that harbor the plasmid traits we want to isolate. These bacteria will be in a liquid growth solution that keeps them viable. We then separate the bacteria from the liquid solution via centrifugation and add a 250-microliter re-suspension buffer. The re-suspenstion buffer will contain RNAase to breakdown RNA. After re-suspension, 250-microliters of lysis buffer containing SDS is added. SDS breaks open the bacterial cell membrane allowing internal cell contents to spill out (including plasmids). Once the plasmids and other cellular contents are in solution a neutralization buffer is added to precipitate cellular contents. The neutralization buffer leaves the plasmids in solution while other contents precipitate in solution. The solution is then centrifuged for 1 minute to collect the precipitate for disposal. After removal of unnecessary content of the cell, the solution containing the plasmids is poured into a spin column that contains a silica matrix. Plasmids will bind to this matrix as the solution is carefully poured into it. There may still be contaminants that are in the sample of the isolated plasmids, thus we use a wash buffer to increase the purity of the sample. Finally an elution buffer is used to release the isolated plasmids into a fresh tube for
