Complementation

[Malay]

Dear Netters:

I am trying to complement the strain UQ285 of E.coli, carrying a temperature
sensitive mutation of sigma-70 gene with a genomic library of a Pseudomonas
strain. I transform and plated several dilutions of the transformed cells.
When I plate around 400-500 cells per plate I get nothing. But when I plate
almost a lawn of cells I get some colonies growing but very poorly.

My question is as follows:

Does the density of the plating has anything to do with the complemation of
a temperature sensitive strain? If so then what is the ideal plating titre?

Any comments or suggestion will be appreciated.

Malay K Basu
curiouser at ccmb.ap.nic.in