This is a primary glial culture (taken from pups @PD2). Picture taken at 10DIV. Astrocyte layer is completely confluent. We are actually after the microglial layer underneath the astrocytes (Will use Saura et al. mild trypsinization procedure at DIV15). I'm thinking that the smaller cells might be yeast, except some of them have small projections. Thoughts? We are very strict about our cell culture protocols - all culture work is done in a BSC that is rigourously sanitized with 70%ETOH. Anything brought into the hood is sprayed/wiped with 70% ETOH, so not sure how yeast would get into this culture? The only thing I can think of is that during initial harvest, we don't have a downdraft table - it is done in the cell culture room on a counter that is wiped down with 70% ETOH and all instruments are soaked/dried prior to use. Could it be coming in via initial harvest?