Microbiology List: FW: plating efficiency

Neil MacCallister nmaccallister at webtv.net
Sat Jan 6 15:51:47 EST 2001


Thank you for this information,..it seems you prefer the light
microscope for truly accurate counts,and that is reasonable, especially
if you can differentiate "out" the non-viables with a stain. I know that
even the Gram-stain prefers
"actively growing bacteria"..(giving some protection in that regard,
especially for gram +'s)..Which stain do you use for active ribosomal
marking..(sorry, I'm no expert here!)?
Will that stain mark after heat-fixing?..or better yet, will it, or
another,...mark the cell while it is growing in a broth, so that it
might be immediately transferred to a counting chamber (Petroff-Hauser)
and physically counted? Wouldn't that be the greatest!?..(2 drops of
stain,..transfer to chamber,..and count!)

More questions?..Sure!: Does a phase contrast microscope adequately
remove the need for any stain when counting a broth culture in
chamber?...(The "set up",..of good quality phase-contrast microscope and
P-H counting chamber,..would cost about 6-7K,..but would be worth it if
it reduced the time/improved the accuracy of counts in solution,..and
that's why I ask.)
..........Thank you,..and your statements regarding e.coli counting
were also of interest.
                      ..Lastly,.."Happy New Year!"






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