The micrograph, taken using a scanning electron microscope, shows two cyanobacterial filaments at 6000-fold magnification. The lower filament has been infected by several chytrid spores -- the round structures at the tip of the filament. The parasite penetrates the filament, takes up the nutrients from its interior and uses it for its growth. This helps the spores to develop into bigger structures. Once the so-called sporangia are mature, they release new spores capable of infecting other hosts.