Is this contamination or otherwise? - (Jun/26/2009 )

I have recently seen exactly the same thing in my flasks. This description hits the spot: "These are perfectly round bubbles that seem to attach to cell remnants. I don't know if I am paranoid or whatelse, but if I look into the 'bubble' I swear I see black specks moving around."
Here is a video showing it: http://www.youtube.com/watch?v=lo96fcXfcVs

Has anyone seen this?
Some say it's a contamination and some say it's only cellular debris moving about by brownian motion.

So that bubble that you saw "ejected" from the cell it appears to have a bunch of black dots associated with it, it may be a vesicle (cellular component) but these are unlikely to be intact once they have passed the cell surface, however it could also be soemthing like a bacterial spore being ejected from the cell. It definitely doesn't look like cell debris as this is typically not uniform in size, as those dots appear to be. These are likely to be contaminating bacteria.