Microbiology List: FW: plating efficiency

gerne at my-deja.com gerne at my-deja.com
Tue Jan 16 17:32:17 EST 2001

for a better understanding of the problems with counting and viability
you might want to look at the special issue of the journal of
microbiological methods available for free at

As you can see in the article of the functional assessment of bacteria,
the correllation between what is in your sample and what will grow on a
plate becomes poor when your cells are not perfectly happy any more.

If you want to get a simple flow cytometer for bacterial counting you
might want to look at

As a practical tip you might want to treat flagellated organisms in a
sonicator waterbath to shear off the flagella and have the holding
still better for the counting.

With kind regards
Gerhard Nebe-von-Caron

In article <1523-3A578563-46 at storefull-114.iap.bryant.webtv.net>,
  nmaccallister at webtv.net (Neil MacCallister) wrote:
> Thank you for this information,..it seems you prefer the light
> microscope for truly accurate counts,and that is reasonable,
> if you can differentiate "out" the non-viables with a stain. I know
> 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
> 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
> P-H counting chamber,..would cost about 6-7K,..but would be worth it
> 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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