From owner-drosophila@net.bio.net Thu Apr 11 23:00:00 1996 Path: biosci!CS.Arizona.EDU!news.Arizona.EDU!hamblin.math.byu.edu!acs2.byu.edu!news.cuny.edu!caen!uwm.edu!cs.utexas.edu!howland.reston.ans.net!newsfeed.internetmci.com!in1.uu.net!utcsri!newsflash.concordia.ca!news.mcgill.ca!NewsWatcher!user From: miron@medcor.mcgill.ca (Mathieu Miron) Newsgroups: bionet.drosophila Subject: Schneider S2 Cells Date: Fri, 12 Apr 1996 08:05:41 -0500 Organization: McGill University Department of Biochemistry Lines: 22 Message-ID: NNTP-Posting-Host: 132.206.101.173 Dear All, I am cuurently growing Schneider S2 cells in Schneider Medium with 10% FBS and a bit of antibiotics. After spliting the cells 1:20 and leaving the cells to grow overnight, I noticed the following morning that the media was cloudy, as if contaminated. I repeated the dilution from my original stock, which did not look "contaminated" and obtained the same result after overnight growth. Now, I am used to growing mammalian cells, both adherent and in suspensions without any problems. This means that all culture work is being done under sterile conditions in a laminar flow hood. My question is the following: Is this cloudy look of the culture media normal? In my experience, when contamination occurs, the cells do not look so good, ie, they loose their nice little round look and it is also possible to see big bacteria and/or yeasts floating around in the plate. I don't see either... Hope someone can help me... Thanks in advance, Mathieu .