Either you, or me
The planet is replete with organisms of all shapes and sizes fighting for their survival. Humans included. The best part of an organism's life is spent looking for the right nutrients and conditions to thrive, and over time Nature has designed a variety of subtle mechanisms to sense them. In this way, plants bind photons from sunlight to transform it into energy, while their roots absorb nitrogen to synthesize amino acids. Animals on the other hand harness oxygen to consume their fuel, and bacteria pick up iron for vital metabolic processes. Two organisms may find themselves having to share nutrients. Or, on the contrary, having to fight for them. During the process of infection, for example, neither the host nor the pathogen are out to share, and common nutrients can actually lay the foundations for ruthless conflict. Take copper for instance. Cryptococcus neoformans is a fungal pathogen which infects cells by using the copper it finds in them for its own metabolism, while the host retaliates by raising the concentration of metal to create a toxic environment for the pathogen. In C.neoformans, a protein known as Cuf1 is at the heart of this quarrel over copper.
