False-colour transmission electron micrograph (TEM) of a colony of Nocardia sp, a genus of non- motile, non-capsulated, non-sporing, Gram-positive bacteria which occurs in branched chains. Nuclear material in centre of individual bacterium is stained green; the filaments tend to fragment into conventional bacilli (rods) when grown in artificial cultures. Some species cause disease in man: N. asteroides causes a rare & often fatal lung infection which is often mistaken for tuberculosis. N. madurae is one causative agent of a granulomatous disease of the foot known as Madura foot or mycetoma, which occurs in tropical regions. Magnification: X 7,400 at 35mm size.