Fungus Fact Friday

Tagged: cell biology

the composition and functions of fungal cells

2

Current / Fungus Fact

#235: Developmental Mycology

Developmental biology focuses on the question, “How do organisms start out as a single cell and then become large complicated structures with distinct tissues, shapes, and sizes?” In the context of mycology, studying development means researching the formation of structures such as mushrooms, sclerotia, and rhizomorphs. Not surprisingly, most developmental mycology research focuses on mushrooms, which are the largest and most interesting of the complex structures formed by fungi. In my previous post (FFF#234), I summarized what we know about mushroom development. Today, I will go into more detail on the mechanisms and processes that drive fruitbody development.

Amanita muscaria development 2

Current / Fungus Fact

#234: Mushroom Development

My first introduction to mushrooms was as a child seeing them appear as if by magic in my family’s lawn. This mysterious way that fungi appear to pop into existence still captures my imagination, which brought me to the small but interesting field of mushroom development. So, can science explain how mushrooms appear out of thin air? Mostly, but there is still much we don’t know. Obviously, mushrooms don’t materialize out of nothing – instead, they sprout from the mycelium already growing in the substrate. Typically, this proceeds as follows: the mycelium bunches up, then the various mushroom tissues are created, and finally whole fruitbody gets larger. However, this generalized model has limitations and can’t explain all the variation we see in mushroom shapes. Why Study Mushroom Development? Before we get into the details, it is useful to discuss why mushroom development should be studied. One of the major reasons...

0

Fungus Fact

#011: Characteristics of Fungi

What is a fungus?  That question has been answered many ways over the years, reflecting an evolving understanding of this strange group of organisms.  Initially, fungi were classified as a class in kingdom Plantae.  As our understanding of the chemistry, life history, and evolution of fungi improved, Fungi was elevated to the rank of kingdom.  Kingdom Fungi is placed in domain Eukarya and belongs to the major clade Opisthokonta.  Opisthokonta also includes the kingdom Animalia, which makes animals close relatives of the fungi.  But going beyond taxonomic definitions, what makes a fungus a fungus?  It’s hard to answer that question because the fungal kingdom is very diverse and there are many similar organisms in other kingdoms.  As a simple answer, Fungi are heterotrophic filamentous (or unicellular) eukaryotes with a chitin cell wall that reproduce by spores and digest their food externally.

Fungi in the News Image 0

News Update

2018 Fall and Winter Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of news stories that have taught me something about fungi from September through December 2018. Read each summary to learn about: zombie ants, mushroom poisonings, White Nose Syndrome, Bananas, and more.

1

Fungus Fact

#085: Schizophyllum commune, The Mushroom with Over 28,000 Sexes

If you think dating is complicated in the human world, be glad you’re not Schizophyllum commune.  Humans have two basic biological sexes and six or more gender identities to deal with, but S. commune has to choose from over 28,000 different sexes!  This overly complex system is based on genetics and the weird way fungi reproduce.  But this isn’t just a weird example, it’s also one of the most common mushrooms in the world.  You can probably find the mushroom out now, and identify it easily.  The little white mushroom is easily distinguished by its small gills, which appear to be split lengthwise.  This unique feature has led to its common name, the “Split Gill” or sometimes “Common Split Gill.”

Fungi in the News Image 0

News Update

2018 Summer Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of news stories that have taught me something about fungi from mid-May through Early September 2018. Read each summary to learn about: zombie ants, mushroom poisonings, White Nose Syndrome, Bananas, and more.

Fungi in the News Image 0

News Update

Spring 2018 Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of news stories that have taught me something about fungi from mid-February through mid-May 2018. Read each summary to learn about: gut fungi, ambrosia beetles, gravity detection, prehistoric mushroom use, diseases of toes, ants, frogs, bats, and ohia trees, and more.

#207: Ergot Alkaloids 0

Fungus Fact

#207: Ergot Alkaloids

Ergot Alkaloids (EAs) belong to a large class of mycotoxins. They are primarily produced by fungi in the genera Claviceps and Epichloë, although Claviceps purpurea is responsible for most of the impacts on humans. EAs are most common in rye, but can be found in any cereal grain. The toxins were a significant problem in the middle ages, but modern agricultural techniques mean that exposure to enough EAs to cause symptoms is extremely rare.1,2 Sources Many fungi produce ergot alkaloids in many different plant hosts. Humans are impacted most by species of Claviceps, which infect seeds of grasses. The most problematic species is C. purpurea (see FFF#061), which infects rye. A variety of other species infect cereal grains but cause less contamination. Livestock can be sickened by infected grain or by ergot alkaloids produced by endophytes in pasture grasses, most notably by Epichloë coenophiala.1–3 This post focuses on Claviceps and...

Ochratoxin-producing molds 0

Fungus Fact

#206: Ochratoxins

Unlike most other mycotoxins found in food, the ochratoxins are primarily produced during food storage. Fungi in the genera Aspergillus and Penicillium are common molds that decompose a variety of foods, from grains to coffee to grapes. In the process, many of those fungi produce ochratoxins, which can damage the kidneys and cause cancer in many animals. Ochratoxins presumably impact humans the same way, but researchers have so far been unable to directly link ochratoxins to any human disease. This is probably because human consumption of ochratoxins is usually very low.

Fusarium molds 0

Fungus Fact

#205: Zearalenone

Zearalenone is a fascinating mycotoxin produced by Fusarium species. It is the only mycotoxin that mimics the effects of the hormone estrogen. In high doses, it causes sexual organs to develop incorrectly. Pigs are the most susceptible animals and suffer estrogenism and vulvovaginitis when exposed to high levels of zearalenone. The toxin is present in many grain-based foods intended for human consumption, but usually at very low levels. As a result, zearalenone is generally harmless to humans.