Contamination of U937 - (Jul/24/2007 )

Hi all!!

I am currently culturing U937 for my work. Recently, i got contamination problem with my U937. I plated the supernatant and cells suspension on LB agar and after incubating for 24 hrs nothing grow. But after 48 hrs, yellow small colonies shown. What happen to my cells? Is it bacterial contamination or worse? Can someone help me? And I induced my U937 with PMA in RPMI without antibiotic, after 24 hrs, it seems to attached very well, but after 48 hours, the cells seemed to be detached. I plated the culture to check. Can anyone tell me what happen and any advice to solve these problems? Need help urgently!! Thank you!

-syLoc-

Probably yeast contamination

-tap14-

can yeast form bacteria-like colony on LB agar plate? how to differentiate between yeast and bacteria colony on agar plate?

-sanjiun81-

QUOTE (tap14 @ Jul 25 2007, 09:20 PM)

Probably yeast contamination

I plated the cells suspension on LB plates. I only manage to see colony forming after 48 hours. Yellow colonies which grew bigger with days. Any idea what contaminant it is? Thank you!

-syLoc-

QUOTE (syLoc @ Jul 31 2007, 05:28 AM)

I plated the cells suspension on LB plates. I only manage to see colony forming after 48 hours. Yellow colonies which grew bigger with days. Any idea what contaminant it is? Thank you!

Have you analyzed your colonies under a microscope? Gram stain would help identify if bacteria are present. IME it sounds like a eukaryotic contaminant as I would expect bacterial contamination to cause your media to become visibly turbid within 24 hours.

-hpylori-