Question: lambda plaques not transparent, bacterial lawn not opaque

Michael Lassner mikel51 at
Sat Feb 10 10:39:16 EST 1996

> >Hello Fierce Molecular Wizards --
> >        I have an amplified library from Stratagene, and I suspect I am not 
> >growing it correctly.  The library is in lambda zap II, the host is XL1 blue 
> >MRF' as recommended, and I am growing it at 37C on LB agar with LB top 
> >agarose.  Two unexpected things have occurred.  
> >
> >        2)  The bacterial lawn is not opaque (even when the bugs are not 
> >infected).  There is definitely a bacterial lawn, but the bugs have not
> >nearly as thick and as opaque as they were when I grew the same bugs as 
> >colonies.
> >
I find that it helps to use way more plating bacteria than they
recommend.  You will get a much thicker lawn, and more defined plaques.  
Try using 3-10X the recommended number of plating bacteria.

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