Forty minutes on transformation protocol and media secletion, SD-his-trp. One student volunteer to explain the transformation and selection principle on the board.
During the discussion of ampR on pMSH2, I am not sure whether it would be expressed in yeast, because it may be under a bacterial promoter.
Some students were slow to grasp the selection media. I used food recipe as an analogy. I am lactose intolerant, if the Spelman cafeteria only have whole milk as food, I would not survive on spelman campus.
Students heated carrier DNA at 99C for 2 min, immediately chilled on ice.
During transformation, after cells were spun down, students were shown to pipitte the cells up-and-down with water to wash the cells.
Only the mutant plasmid was used for transformation.
To add 3 ul of plasmid using the 10ul pipette, some students mistook 0.3ul as 3ul.
Students used glass beads to spread transformed yeast on SD-his-trp plates. Most group did not what to do about resuspend cells with water. One group spread yeast cells on the cover.
To make sure that students pay attention, I told them that notebook will be checked. At the end of the class, I went over every student's note and gave a grade.
I made a mistake on the role of lithium acetate: Wikipedia show that lithium is used to permeate cell wall.
Lithium acetate is also used to permeabilize the cell wall of yeast for use in DNA transformation. It is believed that the beneficial effect of LiAc is caused by its chaotropic effect; denaturing DNA, RNA and proteins.[2]
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