MIO medium?

hantash hantash at happy.cc.utexas.edu
Sat Mar 11 12:54:33 EST 1995

In article <1995Mar10.071906.2245 at lafn.org>, Pong Nim <ak507 at lafn.org> wrote:
>Anyone familiar with the usage
>Anyone out there familiar with the usage of MIO medium the detect
>motility (M), indole (I), and ornithine (O) all using this one
>Pong Nim                         LOS ANGELES MISSION COLLEGE
>Life Science Lab Tech            13356  Eldridge Ave.
>ak507 at lafn.org                   Sylmar,  CA 91342-3244
>(818) 364-7744

For the motility; THe low content of agar in the media allows for the spreading
of bacterial growth. SO if you see bacterial growth away from the stab line
this means bacteria are motile.

Indole: an indole strip is placed at the rim of tube after culture inoculation and the cap is tightened. If the organism produces tryptophanase and indole
is produced then the strip should become pink-red in colr. if not
then stays yellow.

Ornithine; this detects the production of ornithine decarboxylase by an
organism. For this two conditions must be satisfied to activate the enzyme,
1)low pH; which will be achieved by glucose fermentation in the media (if you check the media after few hours of inoculation it will be yellow)
2)anaerobic conditions: tightening the cap helps.
So one these two conditions are met; ornithine decarboxylase is activated, breakingthe -COOH group from ornithine. This leads to a rize in the pH of the medium and the color turns back to purple (The original colr of the medium). If the
organism is negative, the media remains yellow.
One thing about Ornithine decarboxylase, if the enzyme is workking well, the
colr of the medium will be bleached to gray.


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