Cosmid library screening

Malay curiouser at
Wed Sep 8 04:44:32 EST 1999

Dear Netters:

I've made a cosmid (pLAFR3) genomic library of Pseudomonas. My library is
in 96-well titer plates and I generally grow the colonies on agar plates
overnight on membranes. I use hybond-N+. I am screening the library with 5
different probes. I have a plan to screen with all the probes at one time,
i.e. to add all the labeled probes at one time in the hybridization buffer.
I am using Church's buffer (0.5M Na-phosphate, 7%SDS) for hybridization.
But the signal to noise ratio is very poor. I can hardly make out any
difference. Can anyone help me out?

I am particularly looking for the information regarding any special tricks
of colony blots, hybridization, how much count I should add to buffer etc.

Please help me out.


Malay Kumar Basu
Centre for Cellular and Molecular Biology
Hyderabad 500007

Fax: (00-91)40-7171195
Phone: (00-91)40-7172241
Alone: In bad company.
curiouser at


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