culture contamination

Leman Leman at Leman.org
Wed Mar 28 18:12:18 EST 2001

On Sun, 25 Mar 2001 11:54:26 +0200, maya <maya-khorchide at bigfoot.de>

>I am working with cell cultures and it seems that I have a contamination
>Under light microscopy dark dots are visible in the cells and are likely
>to be also moving on their surface. Cell growth, attachment and
>viability are affected.

Sounds like mycoplasma.

>These mysterious creatures are only observed in association with cells
>but not in incubated cell free medium.

Sounds even more like it!

>Years ago only some cultures were involved but now the infection is
>worsening and spreading about other cultures.

And yet more!

>If you have an idea who these intruders could be or have an advice how
>to recognize them or get rid of them please help me.

Solution # 1:
Buy Mycoplasma Removal Agent from ICN (Cat. # 30-500-44)
Pass your cells lightly (so that they don't get confluent for a week),
use your regular medium plus 1:100 of MRA.
Incubate for a week. Pass into media with MRA. Next passage can be
grown in your regular media - mycoplasma will be gone.

Solution # 2:
As I was told, EVERYBODY contaminates cell cultures with mycoplasma.
There is no way to completely prevent it. The difference is in the
number of particles we introduce and their agressiveness. We carry
different strains and different amounts. That is why some people never
seem to have mycoplasma problems, while others suffer from it more
often, inspite of any aseptic measures. Find out who in your lab is
the unlucky one and who is more fortunate in this sense.

Note: It is easier and cheaper to just treat your cultures once in
awhile (MRA is safe) than to test them (and then treat some anyway).

Good luck,


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