Plasmid Miniprep Experiment

Aim

The aim of this experiment is to extract plasmid DNA pSB1C3 and pSB1AK3 from E. coli DH5α cells using the Qiagen miniprep kit and analysing with the Nanodrop machine.

Materials and Protocol

Please refer to: Minipreps for Qiagen miniprep protocol, Nanodrop Spectrophotometer for nanodrop protocol and Restriction digests for restriction digestion protocol. NOTE: 10 µl of RNAse A have been added into the current P1 buffer from Qiagen.

Result

Figure 1:Gel electrophoresis of the PCR products

• Lane 1: 1kb DNA ladder
• Lane 2: Extraction of pSB1C3 plasmid (No. 1)
• Lane 3: Extraction of pSB1C3 plasmid (No. 2)
• Lane 4: Extraction of pSB1C3 plasmid (No. 3)
• Lane 5: Extraction of plasmid containing lacI (No. 1)
• Lane 6: Extraction of pSB1AK3 plasmid containing double terminator (No. 1)
• Lane 7: 1kb DNA ladder

Table 1: Nanodrop spectrophotometer results. Table represents the amount of plasmid present in µl/ml quantity.

Discussion

Bands around 3000 bp were observed in lanes 2, 3 and 4, thereby indicating the correct products. Lane 5 contain the LacI plasmid,therefore it should be bigger in size as compared to the double terminator plasmid which is in lane 6. Therefore lane 5 might not contain the LacI plasmid. From the nanodrop results, the ratio of 260.280 nm ranged from 1.7 to 1.85, thereby indicating that 260/280 nm ranged from 1.7 to 1.85 and the purity from 92.1 µl/ml to 246.7 µl/ml

Conclusion

Extraction of pSB1C3 plasmid and pSB1AK3 plasmid containing double terminator have been successful.