The Urban Pantheist

Photographs by cottonmanifesto

Urban species #062: Penicillum notatum (and other species)

My wife insisted that I could not open this article with the sentence below that begins the next paragraph. I'll try to introduce the topic more gently, but the topic after all, is mold. How is it that mold forms, seemingly from nowhere, on food that's been left out, or on flood-damaged walls? How, indeed, is it possible that mold was found to be growing on the International Space Station?

The air is always thoroughly, but invisibly, pregnant with mold spores. They settle on every surface, and if the surface is warm, wet, and organic, the spores may grow into a mature fungus that feeds unseen on that surface. When the fungus is ready, it produces the sporangia that produce the next generation of spores. In species in the genus Penicillium, the masses of spores are typically bluish green. Other molds can be black, orange, or white.

Penicillium is a common household genus, with many species, that grows on food products. There are a few species of Penicillium that are deliberately introduced into foods during production: P. camembertii and P. roquefortii are used to produce the cheeses hinted at in their scientific names. Penicillium notatum is probably the single most important organism in the history of 20th century medicine. In 1928 in a hospital in London, Alexander Fleming discovered, quite by accident, that this mold produced a potent bacteriacide. The discovery of penicillin heralded the age of antibiotics, and saved millions of lives from bacterial diseases.

( Do you dare get closer to the mold? )