need help with lac- strain e.coli problem

Matthew Chan csv at calweb.com
Wed Apr 3 20:57:21 EST 1996

I am sending this for a friend who is doing an individual experiment in 
High School.  Message as follows:

My name is Mike LeFevre and I am doing an experiment to try to test the
mutation rate of E.Coli bacteria.  I am using the lac- strain and
growing it on Endo Agar.  Supposedly, a coliform bacteria that cannot
use lactose will grow on the agar, but one that can use lactose will
react with the fischin in the agar and turn red.  My problem is that I
cannot get either the lac- or the wild type to grow on Endo Agar.  I
tried Serial Dilution, Streaking, and Direct Innoculation with a pour
plate.  I have gotten absolutely no growth.  What am I doing wrong?

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