Hello Sunando, your description is suggestive of mycoplasm- media does not become turbid, but following fixation and DAPI staining you get positive signal for bacterial contamination inside the cells. Are you seeing a change in the doubling time/growth characteristics of the MDA cells as well? Mycoplasma will also do this, although more pronounced in normal cells vs. transformed. There is a Hoechst 33258-based assay to ID mycoplasma, but it seems like your DAPI results provide the same data. There was a reagent you could add to media over many passages to remove the mycoplasma, the name escapes me now, but I recall that it was pretty effective. I'm sure you will find something online following a search for mycoplasma removal. Best to get to the bottom of this asap because it can spread. Good luck. Cheers. Farid.
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Subject: Is it bacterial contamination
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Dear Confocal list users
we are seeing a large number of small rod like staining in the dapi
channel in ATCC MDA-MB 231 cells. The media and the cells do not turn
turbid if incubated at 37Deg C for 48 Hrs.
We see more of these particles when the cells are grown in absence of
PS. In presence of PS, the number grows with passage of cells and actin
starts showing very thin needle like outward projections although the
cells grow (divide) normally.
What would be the possible contamination and what is the most probable
source and remedy?
Thank you in advance
Best
Sunando
Sunando Datta
Assistant Professor
Dept. of Biological Sciences
Indian Institute of Science Education and Research
Bhopal
India
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