False-colour transmission electron micrograph (TEM) of the rod-shaped,Gram-negative bacterium Escherichia coli. In this image,two bacteria are seen in the process of dividing (replicating by binary fission). E. coli,as the bacterium is commonly known,is found in the human intestines,where it is normally harmless. Under certain conditions,however,it may become pathogenic,causing urinogenital infections & diarrhoea. It is also the organism most commonly used in microbiological studies & genetic engineering experiments. Magnification: x10,000 at 6x7cm size |