Pbluescript Plasmid

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The pK184hlyA and pBluescript plasmids were cut using EcoR1 and Pst1 restriction enzymes that cut at specific restriction sites. Gel electrophoresis was carried out to check if the digestion procedure was done successfully. Figure 2 shows the results of the electrophoresis. Lanes 5 and 7 indicate the fragments obtained when the plasmids are digested with both restriction enzymes, indicating the approximate fragment size for the hlyA gene, the pK184 plasmid and the pBluescript plasmid. This is useful for identifying the recombinant DNA needed for this experiment The plasmids in lanes 3,4,8 and 9 have been digested using one restriction enzyme and had been cut at one restriction site, resulting in a linear molecule. Comparing lanes 3 and 4 to …show more content…

Haemolytic colonies were classified by a white ring around the patched colony, indicating that haemolysis of the blood agar occurred. Conversely, non-haemolytic colonies were classified by a lack of a white ring, which indicated that no haemolysis took place. While the previous experiment identified colonies containing recombinant DNA, the patching experiment distinguished which colonies contained the hlyA fragment and which ones did not. Colonies that could cause haemolysis of the blood agar plate indicated that recombinant DNA taken up contained the hlyA fragment ligated with pBluescript, which is the desired subcloning product. The hlyA fragment contains the hlyA gene which encodes for a haemolytic protein that causes the red blood cells in the blood agar to lyse. Therefore, non-haemolytic colonies were transformed with pBluescript plasmid ligated with the pK184 fragment and were not able to cause haemolysis as no hlyA gene was present. In theory, this experiment allowed for the aim to be achieved as it identified colonies with the desired product. Inoculating certain colonies in broth culture allowed for gel electrophoresis to be carried out and confirm if the aim of the experiment has been …show more content…

Digestion of the haemolytic and non-haemolytic cells allowed for easier identification of fragments during electrophoresis analysis. Lane 12 in figure 3 show the size markers of SPP1 digested with EcoR1 while lanes 6 and 7 show samples of pK184hlyA and pBluescript digested with EcoR1 and Pst1. Lane 4 was loaded with plasmid DNA from haemolytic cells digested with EcoR1 and Pst1 while lane 5 was loaded with EcoR1 and Pst1 digested DNA from non-haemolytic cells. There was a lack of technical success in both lanes due to no bands appearing in lane 4 and only a single band appearing in lane 5. Theoretically, two bands should appear in both lanes after successful to allow for fragment identification. A possible explanation for the single, large fragment in lane 5 is that successful digestion did not take place and the plasmid was only cut at one restriction site leaving a large linear fragment of plasmid DNA. The absence of bands in lane 4 could be because there was not enough plasmid loaded into the lane. Another possibility could be that low plasmid yield as obtained when eluting the experimental samples in order to purify it. Lanes 8 and 9 belonged to another group and show technical success as two bands were present in both the haemolytic (lane 8) and non-haemolytic (lane 9) lanes. If the

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