All moral rights asserted. Recolouring or alteration of the image is prohibited without permission. Light micrograph of forming fruiting bodies of the social amoeba, or slime mould, Dictyostelium discoideum. Under favourable conditions, D. discoideum lives as a unicellular organism in the soil. When there is a lack of nutrients, the unicellular amoeba form a multicellular aggregation known as a slug. The cells within the slug differentiate, with some forming a fruiting body, or sorocarp, on a long stalk, which releases spores when mature. Research is ongoing to use D. discoideum as unicellular 'factories' to produce a number of molecules including antibiotics and olivetolic acid, a precursor of tetrahydrocannabinol (THC), the psychoactive substance in cannabis. Magnification: x40 when printed at 15 centimetres wide.