Moving Dots in cell culture - Contamination? - (Jan/09/2006 )

I have noticed black dots in my cell culture. They fidget, but do not move from one place to another. When I left cultures overnight, the medium (DMEM) was not clouded (as it usually is upon bacterial contamination) and the contamination had not increased (to my notice).
Under 20x magnification they look more like small rods than dots. But I can't make out, whether several organsims form a rod.
Any ideas?

I have noticed black dots in my cell culture. They fidget, but do not move from one place to another. When I left cultures overnight, the medium (DMEM) was not clouded (as it usually is upon bacterial contamination) and the contamination had not increased (to my notice).
Under 20x magnification they look more like small rods than dots. But I can't make out, whether several organsims form a rod.
Any ideas?

I think they are not necessarily bacteria. If you watch any cultured cells, you will see a few moving or vibrating dot, rods in a high power field. I can see them in my cells without antibiotics and they don't develop into contamination. If ther is a contamination, you will see such dots and rods full of the field. I remember there is a paper published last year in Science describing such phenomenon.

Yes. I had the same thing in my ES cell culture. I didn't have that before. And just suddenly before christmas, I started to see them and couldn't get rid of them. The neigbouring lab also see this. But they don't affect cells and don't propagate. As suggested by someone, we did DAPI staining for culture, which is supposed to identify living organism. We found out in some field, there are DAPI dots around ES colony but we are not sure it is cell debris. So the conclusion is still elusive. We really don't think it is some kind of contamination. We rather think maybe they come from the FCS since our lab and neighbouring lab are using same lot serum from invitrogen.

I searched the forum and found some old threads discussing this mysterious UFO (unidentified fidgeting object)


http://www.protocol-online.org/forums/inde...?showtopic=4305
http://www.protocol-online.org/archive/posts/5489.html
http://www.protocol-online.org/archive/posts/5668.html

Couldn't find the article in science, but if my boss approves of it (i.e. we have enough money), I will send some of these ugly litttle things to our microbiology labs. i justt can't afford to lose these cells!! But thanks very much for your help!

Sorry I couldn't find the paper either. But this phenomenon may quite fit into Brownian Motion

The term Brownian motion (in honor of the botanist Robert Brown) refers to either

The physical phenomenon that minute particles immersed in a fluid move about randomly.

http://en.wikipedia.org/wiki/Brown_movement

Click here to see a simulation of Brownian motion.

Hi
I am also seeing these small uneven shape black thing floating in our culture.
One thing is there that this black thing is also get absorbed by the cell and
cell are become loaded with these but cell are still attached and are spread alsobut they are stop growingI don't know what is going on please help