False-colour transmission electron micrograph (TEM) of Neisseria gonorrhoeae (the gonococcus) the species of bacteria causing sexually- transmitted disease gonorrhoea. Individual bacterium are Gram- negative, non-motile, kidney- shaped & are typically found in pairs (centre). Infection occurs through genital mucous membranes of either sex: symptoms include pain on passing urine, a discharge of pus from penis (men) & vagina (women - some women experience no initial symptmoms). If untreated, infection spreads & may cause sterility (women): severe inflammation of urethra (men) may prevent passage of urine. Magnification: X 22,000 at 35mm size.