Amensalism is any relationship between organisms of different species in which one organism is inhibited or destroyed while the other organism remains unaffected. It is a type of ecological interaction. A very prominent example of ammensalism is observed during the production of antibiotics. The production of penicillin by Penicillium on a nutrient agar medium shows a zone of inhibition in which other microbes cannot grow. This interaction is also called antibiosis, in which Penicillium gains nothing but adversely affects other microbes.