Modification on Transformation protocol opens new windows

I modified my transformation protocol by chance. Just as I found the transformation protocol by a tube to be thrown away. This time it is the plate which seems of no use tells me something really interesting. Firstly, when the stimulating ampicillin is about 5 microgram per mililiter (actually it should be 2 microgram per mililiter with particularly new). Ampicillin degrades very quick. Even after several days, you will find that one has to add two volume of that used previously for suppressing cells at the threshold concentration. It is quite complicate to explain all my data that I recently get and I do not have much time to write at this moment because I have experiments to do and I am hurry to go back for my meal. I present some of my conclusions here. Ampicillin do affect transformation. But it is difficult to detect when you just use the wild type cell and the rec-2 homologue (I use rec-2 here because many people might not be familiar with ycaI in E. coli, I hope this can be changed after my results are published). When the concentration of ampicillin is fixed at 5, the difference between wild type and the rec-2 homologue mutant is quite obvious (more than 6-fold difference without overlapping in the SD). The result can be covered if I try to test it is ampicillin or the ycaI lead to this difference. Importantly, it is ycaI mutant which has higher transformation frequency. I tested transformation with a plasmid conferring both amp and spc resistant, the second selection marker of an antibiotic which inhibits protein synthesis. Similar results were obteined since no difference if the second selection plates containing ampicillin or spectinomycine. This further confirm that ampicillin should has an effect to enlarge the difference between wild type and rec-2 mutant. This implied rec-2 homologue in E. coli is active although with an adversal effect. Often the friend and the enemy come together. I have many words to say, but I have no time now. Talk later.