"Duncan Clark" <junk@[127.0.0.1]> wrote in message
news:FA4mfCK6Yrs8EAp+@[127.0.0.1]...
> Historians believe that in newspost <a8sofb$eip$1 at helle.btinternet.com>
> on Mon, 8 Apr 2002, Graham Shepherd <muhero.nospam at globalnet.co.uk>
> penned the following literary masterpiece:
> >So the dry weight is 0.29 picograms - if wet weight is about double the
dry
> >weight that makes it 0.6 picograms. My original very crude estimate was
0.2
> >picograms. Do Neidhardt et al also publish average dimensions and
density?
> >If so, we can recalculate using a formula for a cylinder with
hemispherical
> >ends and see how close a derived weight is to a measured value.
>> From back of an NEB catalogue for E.coli or Salmonella typhimurium
>> Dry weight 2.8 x 10E-13g
> Wet weight 9.5 x 10E-13g
> Total protein 1.55 x 10E-13g
> Volume 1.15um^3
> Protein concn in cell 135mg/ml
>
Either the wet weight or the volume is a bit off. The calculated density
from these figures is about 0.83 g/cm^3 which would lead to the bugs
floating. The density has to be more than that of 0.15M saline, since that's
widely used for washing cells by centrifugation.
For comparison, the volume of a 1 uM long 0.5uM diameter cylindrical solid
with hemisperical ends is about 0.163 uM^3. These cells are therefore fatter
and/or longer.
GS
