E.coli transformation protocol

Peter Alefounder Bioc pra1 at mole.bio.cam.ac.uk
Wed Aug 24 05:01:14 EST 1994


In article <1994Aug22.102122.1 at rand>, mccallo at rand writes:
|> I find it hard to believe that an OD600 of 1.0 is "too late" when 0.94-0.95 is
|> your target.  There must be at least that much variation between any two
|> spectrophotometers/colorimeters.  
|> 
|> Owen McCall
|> Abbott Laboratories

There certainly is variation. What is measured is largely light scattering, and
depends on the distance between the cuvette and the photomultiplier tube (or
whatever else is used to measure the light). I know someone who got a new
spectrophotometer and compared it to ours. He found a two-fold difference with
cell suspensions (and virtually identical readings when testing without light
scattering).
                                                            Peter Alefounder.



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