False-colour transmission electron micrograph (TEM) of Bacillus subtilis bacteria undergoing a cellular division. Here, in this late phase of replication, the cell wall (at centre, pink) separating the two new sister cells has almost completely formed. A membranous structure is seen in each cell; bacteria do not contain a nucleus, and the DNA genetic material is scattered (light pink on yellow). B. subtilis, or the Hay Bacillus, is an aerobic rod-shaped Gram- positive bacteria. It is sometimes pathogenic on humans: causing severe eye infections (iridocyclitis & panopthal- mitis). Magnification: x7,400 at 6x7cm size.