Measure E. coli density at O.D 600nm

nico at nico at
Fri Nov 24 09:50:45 EST 1995

In article <4937bv$n9n at> lpss at (Alex Chang) writes:
>From: lpss at (Alex Chang)
>Subject: Measure E. coli density at O.D 600nm
>Date: 24 Nov 1995 01:32:47 GMT

>Most people measure the density of E. coli at O.D. 600nm. I've also seen 
>people measure it at 540nm.
>The problem we have is that we only have a ELISA reader with UV lamps 
>492nm and 620 nm which are closest to 600nm. I am wondering if that is ok 
>to monitor the growth of my culture with one of them, and how that is 
>compared with the results at 600nm.
>Thanks very much.
>Alex Chang
>University of British Columbia
>achang at

Some people also measure densities at 650nm, so I would use 620nm.
You would need to standardise your plate method against normal 1 cm OD600 
readings, and against plating number if you want to correlate the readings 
against CFU.

Nico.Mertens at
Laboratory of Molecular Biology
Flemish Institute of Biotechnology
Gent, Belgium

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