Salmonella cell dividing. Coloured Transmission electron micrograph of the bacterium Salmonella typhimurium undergoing division by binary fission. Two daughter cells produced by the division are at top and bottom. At centre, the cells are joined by a narrow neck. Through this neck DNA genetic material is passing in a thin strand (yellow); bacteria do not have a nucleus, and the DNA is scattered in the central region of each developing cell. Once each cell has its full compliment of DNA, they separate. Salmonella typhimurium is a common cause of food poisoning (Salmonellosis) in humans, spread in contaminated food. Magnification: X36, 000 at 6x4.5cm size.