the kingdom of fungi

The word ‘fungus’ is latin for the word mushrooms. But mushrooms are not the only fungi on earth! Fungi are found all over the world in many shapes and sizes. Some are microscopically small, and some are very large. Some fungi are dangerous for us and some fungi are edible for us, or processed in our food. Apart from the many differences, all fungi share some similarities too. 

The cells of a fungus have a cell wall, a vacuole and a cell membrane. They also have a nucleus. Fungi can be unicellular or multicellular. An example of a unicellular fungus is yeast. Unicellular fungi reproduce by division.

An example of a multicellular fungus is a mushroom. Multicellular fungi have a part that can be seen, the toadstool, and a hidden part in the ground, the mycelium.

Fungi can be useful. Some fungi produce chemical substances that kill bacteria. We use these chemical substances, called antibiotics, to cure bacterial infections. Some fungi are used to make cheese. Other fungi, called yeast, are used for making beer, wine and bread.

Fungi have no chloroplasts, so they cannot produce their own food. Therefore, they often live on the remains of dead organisms, which they break down for food.

Fungi that make threads, like those that feed on old bread, are called moulds. The threads are called hyphae.

Some multicellular fungi, like mushrooms, are edible. However, fungi can also be harmful and cause disease in plants (banana leave disease), animals and humans (athlete’s foot). Fungi that cause disease are also called parasites.

It seemed like just another day in September 1928 at St. Mary’s Hospital in London, England. The Scottish professor of Bacteriology, Dr. Alexander Fleming, just returned from a holiday in Scotland. Two weeks before, he had left a few Petri dishes on his deck, inoculated with Staphylococcus aureus bacteria, his current research interest.

What’s this, he thought? He expected to see large smears of bacterial growth all over the Petri dishes. Instead he saw a bacteria-free zone, surrounding a yellow-green mould colony that had accidentally contaminated one of the dishes. Apparently, a spore of a rare fungus called Penicillium notatum had drifted in from a lab one floor below. A mould, yes, but this whole clear area with no Staphylococcus colonies growing around it