help needed on library screening

[Alex Knight]

In article <9311251954.AA09492 at fraser.sfu.ca> , suisheng at sfu.ca writes:
> I have a question about a cDNA library screen. I don't know why there
> are a few big round(2-4 mm diameter) clear plaques among those normal
> size plaques in the plates. 

You have contamination with some sort of phage. You have to eliminate
this: you probably need to decontaminate your incubator, replace all your
buffers and stock solutions, get fresh bugs: basically sterilise
everything!

This should fix your problem. Good luck!

Alex
alex at mrc-lmb.cam.ac.uk