Dear Erhan, We often had a similar problem. While Normocin does not help, Normocure (from the same company) does. We use it 1:500 in small cultures; after 2-3 days, the cells are usually cured. Best regards, Josef Loidl Von: Ciliate Molecular Biology [mailto:[log in to unmask]] Im Auftrag von erhan aslan Gesendet: Donnerstag, 19. Juli 2018 17:47 An: [log in to unmask] Betreff: Tetrahymena culture contamination Dear Ciliate Community, I am struggling with contamination in my Tetrahymena cultures for a while. Routinely used antibiotics (pen-strep, amphotericin) don't work. I used normocin from Invitrogen in conbination with pen-strep or kanamycin to get rid of them but no success again. Contaminated wells appear whitish and cloudy (Please see attachment). I noticed that this contamination generally occurs after biolistic bombardment. Sterile cabinet was tested for the possible contamination source but it seems OK. I extensively sterilize the inner chamber of the biolistic gun (which is in our sterile cabinet) and other components with alcohol prior to shot but they show up during passaging when I increase the pm concentration for example. Many thanks in advance for your any kind of suggestions. Best regards. -- Erhan Aslan Anadolu University Graduate School of Sciences Department of Molecular Biology Eskisehir-Turkey Save the environment. Please don't print this email unless you really have to.