Wondrium Series Explores Fungi and Fungal Infections

series explains athlete's foot, ringworm

By Jonny Lupsha, Wondrium Staff Writer

Fungal infections are an unpleasant but undeniable part of life. From histoplasmosis to diaper rashes, fungi disrupt humanity in an obnoxious and occasionally disgusting way. Where do they come from?

Rhizopus (bread mold) is a genus of common saprophytic fungi,Rhizopus (bread mold) under the microscope.
Fungi are a type of eukaryotic organisms that include yeasts and molds. Photo by Rattiya Thongdumhyu / Shutterstock

Sometimes, health problems can be pretty unappetizing. Let’s face it: Nobody wants to think about fungal infections. However, understanding them at their roots can help demystify them and shake off some of our fears and misconceptions about them. Fungi are eukaryotic cells, meaning they have a nucleus and membrane-bound organelles. Prokaryotic cells have neither. Aside from that, what are fungi and how do they affect us?

A deeper look at fungi can help us understand what’s happening to our bodies when we get fungal infections. In his video series An Introduction to Infectious Diseases, Dr. Barry Fox, Clinical Professor of Infectious Disease at the University of Wisconsin School of Medicine and Public Health, does the dirty work of exploring fungi and fungal infections.

What Are Fungi?

“Fungi are structurally divided into yeasts—similar to the yeast used in baking bread—and molds—the green circles on moldy pieces of bread in the refrigerator, or blocks of cheese that you find in the back of the refrigerator,” Dr. Fox said.

Molds are composed of hyphae, which are “threadlike, branching tubules” which themselves are composed of fungal cells that are attached end to end. Fungi are usually either yeasts or molds, but some fungi are dimorphic, meaning they’re one shape in the human body and another in cultures in the laboratory. Yeasts reproduce by budding, while molds reproduce through spores.

“Cell membranes of fungi are also more complex than those of bacteria,” Dr. Fox said. “The outer cell contains a building block known as ergosterol. Ergosterol is similar in structure to cholesterol, which is an ingredient of human cell membranes. This can be important since some antifungal medications may have side effects that are associated with the structural similarity between ergosterol and cholesterol.”

What Are Surface-Level Fungal Infections Like?

Fungal infections of the skin surfaces, hair, and nails are called dermatophytes. These fungi live in the outer layers of dead skin, in nails, and the hair, all of which contain a protein called keratin. Dermatophytes secrete an enzyme called keratinase that partially digests layers of these components, leading to hair loss, scaling skin, and crumbling of the nails.

“When the nails are involved, the term is known as onychomycosis,” Dr. Fox said. “This leads to thickened, discolored, and brittle nails. Fungal nail infections do become more prevalent as we age, and about half of adults over the age of 70 are affected.”

These superficial fungal infections have been given the nickname “tinea.” Ringworm is actually a fungal infection called tinea corporis that gets its nickname from its appearance, which forms a ring shape that has a red, raised border. When dermatophytes involve the scalp, they’re called tinea capitis. Finally, tinea pedis affects the foot and is known as athlete’s foot, which causes the skin between the toes to crack and peel.

An Introduction to Infectious Diseases is now available to stream on Wondrium.

Edited by Angela Shoemaker, Wondrium Daily