Gerald Pier (gpier at warren.med.harvard.edu) wrote:
: In article <44rnn6$89o at news.internetmci.com>, "Gregory P. Harhay"
: <gpharhay at internetmci.com> wrote:
: > 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
: One more thing to consider: Some organisms, like P. fluorescens, rapidly
: adhere to glass or plastic culture vessels in some buffers, particularly
: those lacking protein (i.e. saline, PBS, etc.). So an OD reading followed
: by dilutions and plate counts can be highly misleading as the organisms
: stick to the dilution vessle walls quicker than you can pipette an aliquot
: into the next vessel. So I'd be careful and do my dilutions for plate
: counts in several different buffers, including ones that have something
: like 1% proteose peptone or BSA in them.
: Jerry Pier
--
Tina Coan Texas Institute for Applied
Sr. Research Assistant Environmental Research
817/968-9563 P.O. Box T-258
fax 817-968-9568 Tarleton State University
email: coan at tiaer.tarleton.edu Stephenville, Tx. 76402
