KLETT units?

[mpa...@ulys.unil.ch]

Hello

I am comparing bacterial growth curves from the litterature and I wonder about
biomass measurements in KLETT units? What is the definition of these (old)
units and what is the relationship with nephelometric density or optical
density.

Any information would be grrrreeeaaatly appreciated

Marco PAGNI
Institut de Genetique et de Biologie Microbienne
Lausanne
Switzerland

MPG...@IGBM.UNIL.CH

[Robert Preston]

Marco, et al., KLETT units are proportional to "absorbance" units, with
1000 KLETT being very very roughly similar to absorbance = 1 at a particular
wavelength. The Klett machines used any of various color filters, and that
would have to be known to figure out the exact proportionality constant.
However, to be reasonably accurate, you would need to compare a value of
KLETTS to a value of absorbance-on-your-own-particular colorimeter using
a suspension of your particular organism, since "absorbance" is always
an instrument-dependent number when one is dealing with turbid systems rather
than true solutions. (and it is also particle-size and -shape dependent,
hence the caveat that you use your particular bug of interest for the
comparison, and that the physiological state of the bug be the same for the
measurements in the two machines that are being compared.

Rob Preston
ra...@med.pitt.edu

>
>
> I am comparing bacterial growth curves from the litterature and I wonder about
> biomass measurements in KLETT units? What is the definition of these (old)
> units and what is the relationship with nephelometric density or optical
> density.
> Any information would be grrrreeeaaatly appreciated
>
> Marco PAGNI

> MPG...@IGBM.UNIL.CH
>

[PMacklon]

Klett units = OD divided by two with decimal point eliminated. Thus:

250 KU = OD 0.500

These machines never die!!
Peter
U of C