This video provides tips for phosphorylating fragments prior to performing a ligation reaction.

What are the composition of sonication buffer for bl21 de3 containing his tag proteins? 

I am working with leukemia/floating cells. Typically, I spin down the cells, wash them with ice-cold PBS, spin again and then lyse the cells immediately.
I am thinking If you could snap freeze the...

The unit definition uses 0.12 μM (300 μg/ml) lambda HindIII fragments. The high DNA concentration can be used for linker ligation. To promote circle formation, useful in transformation, a lower total DNA concentration should be used.