Attached is a picture of ZR-75-1's contaminated with what looks like floating "bubbles". Some of these bubbles have 2 smaller bubbles inside them, like the one pictured in the center. They float in the media as well as attach to the bottom of the flask, and reappear after media changes. The media is not cloudy, nor has the pH changed. But as you can see the cells don't look too happy. After a few weeks these bubbles appeared in our MCF-7 and T47D cultures as well. We regularly use Pen/Strep in our media. Treating with AmpB did not have an affect, so most likely not fungal.
Thanks so much for your help!
I think we have a consensus here - yeast it is, in my humble opinion. I guess there is no shame in admitting we all had a problem like that at some point in our scientific careers . I worked next to the yeast 2 hybrid lab a long time ago, and we would have ongoing battles with those pesky critters getting into the flasks from time to time. Time to reorder a fresh bullet from ATCC, uncork fresh medium and FBS and cross your fingers! Good luck!
sounds like yeast, they are usually in gemmation, they look like 2 circles.
Hi, I humbly agree with the people said here.. It seems like yeast contamination.
Hi,
I do agree with Radu suggestion. Just keep this flask for a long time at the same conditions. If they increase in numbers, that means it is yeasts if not means fats may due cell line disorder. As there is no turbidity, so there are no bacterial contaminations same time there are no hyphae, so no fungal contamination.
At the end of day, I prefer to wake up new cells.
Good Luck.
I'm with Radu and Marwan. It's notable that the "bubbles" are different sizes. I would expect yeast to be more uniform in size. Also, one can often observe budding, which we mostly don't see here. (Maybe there is a hint of a bud in the upper-right corner) [oops, edited to say upper _right_]. I'm not saying it's _not_ yeast, but it doesn't look like a classical yeast contamination.
On the next media change, could you take an aliquot and inoculate a tube with yeast media and let that grow a few days? Or, maybe you could even spread it onto a yeast plate. I remember that there were several yeast groups at the UofA (way back in the stone age when I was there). If you have a friend who could try to culture the yeast there, it might give you an idea.
Thanks so much for everyone's input! We're currently testing the cells for mycoplasma, yeast, and fungi. Our TC room has also been abnormally warm and humid, so that may have facilitated the contamination (we're in the middle of our monsoon season, so rain and blowing dust galore).
There was another suggestion from someone here that those "bubbles" may be cell artifacts from dying cells being killed by an invisible contaminant (virus maybe?). Will be contacting virologists here for their opinion.
I'll let everyone know what we find, in case anyone's curious :) Thanks again for all your wonderful help! I really appreciate it!
Dear Julia
Can you attach more pics of your culture and of other cell lines too, this will help us in identifying the problem.
Hi all,
Once again, I want to thank everyone for taking the time to give their input. I really appreciate it!
We haven't be able to ID the contaminant, but our lab has made the decision to halt the hunt (which was taking up too much precious research time) and just do a deep clean/decontamination of our TC room and hope our multiple rounds of cleaning, ethanol-ing, autoclaving, and filter changes will take care of the problem. Fingers crossed :)
Thanks again for everyone's help!
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