3 replies to this topic

[LMD2011]

Hi I am culturing some A431 cells and they appear to have a very slow growing infection. If the cells are split twice a week then its hard to detect but if you leave them a day over then the media begins to get very cloudy and when you look down the microscope you can see small adherent black dots.  I know that normally if you have a bacterial contamination the black dots would be floating has anyone ever seen adherent black dots ? any ideas of what it could be?  The cells are routinely grown in the absence of antibiotics.

[searcher]

LMD2011, on Mar 18 2005, 01:46 AM, said:

Hi I am culturing some A431 cells and they appear to have a very slow growing infection. If the cells are split twice a week then its hard to detect but if you leave them a day over then the media begins to get very cloudy and when you look down the microscope you can see small adherent black dots.  I know that normally if you have a bacterial contamination the black dots would be floating has anyone ever seen adherent black dots ? any ideas of what it could be?  The cells are routinely grown in the absence of antibiotics.

Is the pH in medium dropping? If so then it may be bacteria, otherwise you have to do more specific tests for common agents.

[Sg_ACC]

I have seen adherent black dots in my cultures as well but floating black particles were also observed. initially, i suspected them to be contaminated with bacteria. in my case the media do not turn cloudy unless there r loads of dead cells as a result of trypsinization.

do u see them as motile? if so then they are 99% contamination. do u have loads of dead cells? which might resulted in the cloudiness of ur media.?

[LMD2011]

Sg_ACC, on Mar 20 2005, 08:08 PM, said:

I have seen adherent black dots in my cultures as well but floating black particles were also observed. initially, i suspected them to be contaminated with bacteria. in my case the media do not turn cloudy unless there r loads of dead cells as a result of trypsinization.

do u see them as motile? if so then they are 99% contamination. do u have loads of dead cells? which might resulted in the cloudiness of ur media.?

<{POST_SNAPBACK}>

no they are not motile mostly static.  The cells appear ok, no morphology changes and no dead cells.  Its something I havent seen before and whatever it is it is very slow growing as the cells need to be in culture for a few days before it is noticeable.

Edited by LMD2011, 21 March 2005 - 12:37 AM.