No license to kill
Organisms need resources to thrive. If they do not have them, they will find ways to get them. For many humans today, a job and a supermarket down the road provide the very basics of what we need to survive but, not so long ago, our ancestors would travel great distances to find a safe place to sleep and track down food for their families. In so doing, they will have steered clear of territory already occupied or perhaps, on the contrary, decided to compete for its resources. There are various ways of doing this. You can annihilate your adversaries, scare them off, get them to provide for you or render them harmless. Over the millennia, humans have practised each of these ways with panache. Microorganisms, too, show similar imagination. Like street sweepers, they have learned to deal with whatever hinders their way by clearing the path before them. Take, for example, the fungus Aspergillus fumigatus which, in the presence of the bacterium Streptomyces rapamycinicus secretes a secondary metabolite that renders the bacterium temporarily unable to germinate. The metabolite is known as fumigermin and is synthesized by the enzyme fumigermin synthase.
