Tagged: cell biology

the composition and functions of fungal cells

Fusarium molds 0

#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.

Fusarium verticillioides spores 0

#204: Fumonisins

Humans have very little to worry about from fumonisins, mycotoxins produced by Fusarium fungi that cause Fusarium ear rot disease of corn (maize). The toxins are linked with esophageal cancer, but scientists cannot prove that they cause cancer. However, fumonisins are a major problem for horses and pigs. In horses, the toxins cause liquefaction of the brain tissue, while in pigs they cause the lungs to fill with water.

Fusarium head blight 1

#203: Deoxynivalenol

Deoxynivalenol (DON) is a toxin found in grains infected with the fungus Fusarium graminearum and other Fusarium species. It is often called “vomitoxin” because it primarily causes vomiting in humans and livestock. Its long-term effects are mild, but it is still a very important mycotoxin because it is the most common mycotoxin found in food.

Aspergillus flavus 2

#202: Aflatoxins

Fungi produce innumerable “mycotoxins” – compounds that are toxic to humans. In mushrooms, these cause symptoms ranging from gastrointestinal upset to death (see FFF#091–100 for more). Although these are of significant concern to mushroom hunters, their impact is relatively small. The most significant mycotoxins in terms of the number of people affected are produced by molds that naturally grow on food. Over the next few weeks, I will discuss some of the most problematic food-borne mycotoxins. Topping that list are the aflatoxins, which cause liver cancer and are especially problematic for people in developing nations.

Fungi in the News Image 0

2017 Fall 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 what we’ve learned about fungi from August through October 2017. Read below to learn about: ballistospory, chromosome evolution, fighting fungal pathogens (in humans, bats, and bananas), psilocybin, oil-eating fungi, and more! Visit the associated links to get the full story.

Tremella mesenterica 0

#059 Tremella mesenterica, Witch’s Butter

One day as you check your mailbox you notice a yellow smear on the entrance to your house (for example a wooden gate). After retrieving your mail, you take a closer look and see that it’s a yellow gelatinous lobed blob – Witch’s Butter! Oh no, you think, I’ve been hexed by a witch! Knowing just what to do, you run back to the house, collect a few straight pins, and stab them through the offending substance to drain its juices and kill the spell. Unfortunately, this method doesn’t work very well for two reasons. First, this blob is actually the jelly fungus Tremella mesenterica. Like all jelly fungi, it is specifically designed to survive repeated dehydration and rehydration. Second, the main body of the fungus is still living inside the wood; unless you replace the wood, the mushroom will probably reappear in the same place!

sweet clover flowering 0

#195: Warfarin, from Cow Disease to Medicine

Warfarin is one of the most successful drugs of all time. Seventy years after it was first synthesized, warfarin is still the most widely prescribed anticoagulant. Warfarin has a unique story. What began as depression-era research into a mysterious disease of cattle ended up producing two life-saving medicines and a rat poison that are still in use today.

Fungi in the News Image 0

2017 Summer 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 what we’ve learned about fungi from May through early July 2017. Read below to learn about: early fungal fossils, fungal epigenetics, the best way to cook mushrooms, liver disease, malaria, and more! Visit the associated links to get the full story.

Inky cap gill face 22

#013: Characteristics of Division Basidiomycota

Division Basidiomycota (also called Phylum Basidiomycota) accounts for about 37% of all described fungal species. This division contains the fungi that people are most familiar with. The classic “Mario mushroom” (based on Amanita muscaria), the grocery store button mushroom and other varieties of Agaricus bisporus, shiitakes, oyster mushrooms, and even the major “magic mushrooms” are all basidiomycetes. However, the Basidiomycota also include rusts and smuts, which are economically important plant pathogens, some yeasts, and a few lichenized fungi. Like the Ascomycota, the Basidiomycota fill a variety of different ecological roles. Many form mycorrhizas with plants, others parasitize plants, a lot decompose organic material, and some live in a variety of symbioses with insects. The Basidiomycota are commonly referred to as “basidiomycetes,” “basidios,” or “club fungi.”

arbuscules in root 2

#015: Characteristics of Division Glomeromycota

The Glomeromycota are unusual and poorly understood organisms. Fungi from this division rarely produce easily visible structures and cannot be grown without a plant host, so investigating them is very difficult. Glomeromycotan fungi are some of the most important fungi on Earth because they form arbuscular mycorrhizas, which provide essential nutrients to the vast majority of terrestrial plants.