Transformation is a process by which genetic material is introduced into a host cell, allowing it to express new traits or functions. One common method for transformation is the use of Escherichia coli (E. coli) as a host cell and a plasmid containing the desired genetic material. In this lab report, we will describe the transformation of E. coli with a plasmid containing the gene for production of galactose (pgal).
To begin the transformation, a competent strain of E. coli was prepared by chemically treating the cells to make them more receptive to the uptake of foreign DNA. The competent cells were then mixed with the pgal plasmid, which had been purified from a bacterial culture. The mixture was incubated for a brief period of time to allow the plasmid to enter the cells.
After the incubation, the cells were plated on a nutrient agar medium containing the antibiotic ampicillin. Ampicillin resistance is a trait conferred by the pgal plasmid, so only cells that have taken up the plasmid will be able to grow on this medium. The cells were incubated at 37°C for 24 hours, allowing them to form colonies.
The next day, the colonies were counted and the transformation efficiency was calculated by dividing the number of colonies by the number of cells plated. A high transformation efficiency indicates that a large proportion of the cells were able to take up the plasmid and express the ampicillin resistance trait.
To confirm that the transformation was successful and the pgal plasmid was present in the cells, we performed a polymerase chain reaction (PCR) to amplify the gene encoding the enzyme responsible for production of galactose. The PCR product was then separated by electrophoresis and the resulting band was visualized under ultraviolet light. A band of the expected size indicated that the pgal gene was present in the transformed cells.
In conclusion, the transformation of E. coli with the pgal plasmid was successful, as indicated by the high transformation efficiency and the presence of the pgal gene in the cells as confirmed by PCR. This transformation demonstrates the versatility of E. coli as a host cell for the expression of foreign genes and the usefulness of plasmids as a means of introducing these genes into the host cells.
