Cover image

Cover The two Escherichia coli chromosome arms (replichores) locate to opposite cell halves. Shown here is a field of exponentially growing cells, where specific chromosomal loci have been visualized by the fluorescent repressor-operator system (FROS). The left (red) and right (green) replichores were tracked by the binding of fluorescent repressors to operator arrays inserted into these specific genetic positions. The cells were raised in minimal medium and treated with the cell division inhibitor, cephalexin, for 1 h. DNA was stained with DAPI (blue). (For details, see Wang et al., p. 1727.)