Natural Science Forum / Biology / Microbiology / August 2005

Well, it is not a molecule so it does not have a molecular weight.

Further, the mass of a bacterial cell varies widely, over at least an
order of magnitude, depending on conditions.

A rule of thumb for E coli is that it weighs about a picogram. That is
dry weight, I think, so multiply that by 5-10. If you need a ballpark
number, that is probably similar for S.a. But again, caution, there is
no meaningful right number that is good to 1%, to even to a  factor of
2.

To make things worse, S.a. tends to form clusters. Do you want the
weight of one cell, or of a cluster?

bob

The weight of a bacteria would vary depending on it's stage of growth,
you would be better off finding a unique protein from staph, and
developing a method of lysing the bacteria and capturing the unique
protein in your sensor...

I'm thinking monoclonal antibody covalently attached to your sensor?

This has been worked out in some detail..  See the text --Physiology of the
bacterial cell by Neidhart, Ingraham, and Schaechter, published in 1990 by
Sinaur associates.