In article <44rnn6$89o at news.internetmci.com> "Gregory P. Harhay" <gpharhay at internetmci.com> writes:
>I need to convert my O.D. 600 nm "absorption" readings of pure
>cultures of Pseudomonas fluorescens (ATCC 13525) and
>Brochothrix thermosphacta (ATCC 11509) suspended in buffer
>to an estimate of their concentration in the buffer. Are there
>any good references out there? ATCC is no help
>>Thanks,
>Greg Harhay
>
Just to be (not in fact) pedantic, please drop the "absorption" or
even absorbance. OD is NOT absorbance (but scattering). Rule of
thumb for bugs says (in the Beer-Lambert range, typically up to OD
0.6) that 1 OD = 0.5 mg dw/ml. Every bug is different, and
it depends on where the cuvette is in the spec and the optics
thereof - you have to make your own calibration curve. The ref I
usually cite is Mallette, M.F. (1969) Evaluation of growth by
physical and chemical means. in Methods in Microbiology (ed.
JR Norris & DW Ribbons) Vol 1, 521-566. Academic Press,
London.
Douglas.
