Q: Klett-Unit???

Robert Solomon Bioc rgs at mole.bio.cam.ac.uk
Tue Nov 14 13:35:10 EST 1995


mantei at neuro.biol.ethz.ch (Ned Mantei) writes:

>doerner at papin.HRZ.Uni-Marburg.DE (Doerner Wolfgang) wrote:

>> anyone out there who knows what a Klett-Unit is?

>I used a Klett spectrophotometer as a student in the 1960's, and even then
>had the impression that the instrument was an old design (1940's?). The
>absorbance was indeed measured in "Klett units", but I don't know how many
>correspond to an O.D. unit.

The Klett was basically a value for light-scattering by bacterial suspensions.
You will not be able to convert to OD600 or to cell density (cfu/mL) with
any reliability (as all these measures are strain ependent, as so often noted
in similar discussions in this newsgroup).  When it comes to that, OD600 is
only a light-scattering measure too, so sneer not at the humble Klett.

On the instrument I was raised on, Klett 40 was early log, 100 about mid-log
and growth normally plateaued at around 350.  For coli (a K12 derivative).

Wouldn't like to bet this is the same for all Klett machines or strains.

Rob







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