Strange dots around the cell+Photo - (Jun/09/2009 )

Hi everybody,

I'm really glad to come across this forum. I'm growing MDA-MB-231 breast cancer cell line with DMEM 10% FBS and AB. They have been great so far, but today I noticed that the cells have small round dots around them... it's not contamination coz they are not moving (I really hope it's not contamination ). They are just very tiny white dots attached to the cell (I mean all around the cell)...and I have seen many of them floating, but not moving,, what I mean is that only when moving the plate they move... can someone help me with this..

Never seen such a thing..

But it seems like something you don' want in your cells..

It looks liKe a yeast contamination to me. Yeast isn't motile. I got an infection like this before. Only thing for it is to start a new batch of cells. And if you're afraid it will happen again you could add fungizone to your media as a precaution.

Interested in this for others' opinions. I will say that I do work with mouse periodontal ligament stem cells which involves harvesting the cells from teeth of mice. Usually, if a well of teeth is contaminated (which happens more than rarely), that's what it looks like (lots of little white dots). I don't know if it is bacterial contamination or maybe a subpopulation of other mouse cells that I don't want, or what. They usually just go away after 1 trypsinization, probably they can't survive it.

I guess a way to see if it is contamination is if they thrive/flourish (are they dividing?)

I second the yeast contamination - they are pretty common in cell culture, as your skin and hair will be naturally covered in them. If you look closely at your culture you should see yeast cells with smaller ones budding off the sides.

Certainly yeast... But that was mentioned before. You must not drink beer at work!
No, honestly, I had them bugs a long time in my culture. It helped me (besides throwing all away, also frozen stock) to spray my hand and forearm with ethanol, like a surgeon...

Minna

Thanks all, I've already stopped them yesterday and started a new batch today.
I think I'll stop the other cell line coz it is starting to have the same thing..
So strange that I got them,I spray my hands alot before starting the work.. , I thought it's from the media so I checked it today and nothing was there..
It's my first time in getting yeast infection, I've never seen something like that before..but this will delay me alot.. waiting for a whole week for them to grow