Guess how many different types of fungi are located on Earth?
Actually there are millions! However, only a small percentage (a couple hundred) of them are
of any danger to humans. Quite a few of them are useful to us in one way or another: some have medicinal qualities, and others are tasty! You’ve probably eaten some variety of mushroom in your life, whether it be in Asian dishes, steak and mushroom pie or steak with mushroom sauce: examples of edible mushrooms include white button mushrooms, Swiss brown mushrooms (as shown in the picture), shittake mushrooms and field mushrooms. All mushrooms fall under the group of fungi.
In regards to those fungi which are considered dangerous, thankfully, as the Smart Art Graphic below shows, we have several defense mechanisms in place in order to prevent fungal infection.
You can read more about innate and acquired immunity in Intro to the Immune System. In general, those who have healthy immune systems don’t tend to become infected with fungal infections: (and if they do, it is localized in one location such as in the toe nails) it is only those with weakened defenses that develop fungal infections through the body. Fungi tend to enter the body via inhalation of spores or through trauma such as wounds. Most fungi that cause disease in humans tend to be dimorphic in nature: by that I mean that they have one form (the protective form i.e. yeast) in the external environment, and another form within a host, thereby allowing it to survive. You can read about fungal infections that go at the brain in Fungal Infections.
Is there any specialized terminology associated with fungi?
Yes there is. Mycology (or the study of fungi) uses quite a unique set of terminology: some of which are used in everyday language, but others are more specialized. The terms are explained in the table alongside. The names of the fungi may differ depending on the anamorph (the asexual state) and the teleomorph (the sexual state).
What techniques do you use to pick up fungi in the lab?
The diagnosis of a fungal infection is determined by the patients’ clinical history and the morphology of the fungi. Fungi are grown in the lab on Sabouraud agar, as shown in the example below. Typically, nail clippings are given to the lab to be used as samples.
What types of fungi are there?
There are four different divisions of fungi, and within those four divisions there are several classes. They can seen seen in the table below.
Basidiomycota include basidiomycetes, teliomycetes and ustomycetes.
- Basidiomycetes are more commonly known as mushrooms and toadstools. Some are edible and tasty, but others such as Amanita phalloides are deadly because they cause renal damage.
- They are made up of hyphae with occasional clamp connections, and they sexually reproduce by means of basidiospores.
- Ascomycetes are more commonly known as moulds (molds in the American spelling), and their list of subcategories is
extensive. Examples include cramp balls, sac fungi, cup fungi, earth tongues and dung buttons.
- They can both sexually and asexually reproduce: the former they do by means of eight ascospores within asci, and the latter they do via conidia.
- They are made up of hyphae with simple pores.
- Ascomycetes are often seen on plants.
- Zygomycetes are more commonly known as bread moulds (molds) or pin moulds.
- They are fairly primitive in nature, and are made up of hyphae.
- Like ascomycetes, they are capable of reproducing either asexually or sexually. Most strains of zygomycetes are heterothallic in nature.
- They tend to reproduce asexually by means of zygospores and sexually by means of zygospores in a zygote; however the latter process is quite rare.
- An agent of the zygomycete group, Mucor, is involved in brain infections. For more information, you can look at Fungal Infections.
- All fungi that are placed within this category have had their teleomorphic (sexual reproductive) state classified either as non-existent or unknown.
- Ascomycetes anamorphs (asexual ascomycetes, in other words) are often placed within this particular category.