wierd cell culture contam

[Robin Dover]

In article <1995Mar27.221604.13608 at liberty.uc.wlu.edu>, cjh at nchgr.nih.gov
(C.J. Hussussian, MD) wrote:

> I am having a persistant and frustrating contamination problem with my
> tissue culture. I am doing double transfections in melanoma cell lines
> grown in DMEM. It seems that after a couple of weeks (the timing is
> random), I begin to see black dots in the medium. At first I thought
> that it was cell debris but they persist even when the cells are
> extremely sparse. The dots seem to grow in pairs and chains. They do
> not seem to affect cell growth and do not "take over" the culture as I
> have seen bacteria do. That plus the fact that I have 5 antibiotics in
> the culture (Pen, Strep, Neo, Hygro, Tetracycline) leads me to think
> that they are fungus. I am starting to add Fungizone to the medium,
> although I would prefer not to. Has anyone had this annoying problem?
> What did you do to get rid of it?? Thanks in advance
> 

If you have 5 antibiotics in there it might be acting as a bacteriostatic
agent....sample your medium , dilute with antibiotic free...that may tell
you if they will and can grow rapidly. (Is this good for your cells BTW?)
May be a stupid thought but  but as they are black they aren't cell debris
with pigment and they don't grow but they do stick?

-- 
Live forever or die trying