False colour freeze-fracture transmission electron micrograph of a single bacterium of Escherichia coli, a species of motile, rod-shaped, gram negative bacteria found as part of the normal fauna in the human gut. The bacterium is in process of dividing by binary fission. Under certain conditions they may become pathogenic causing infection to the urinogenital tract & diarrhoea in children. E. coli has played an important role in the development of genetic engineering and the emergence of the biotechnology industry. A large amount of experimental work on genetic manipulation was performed using DNA from E. coli. Magnification: X 16,400 at 35mm size. Original is bw print b230/020