• Vikki Lawman

Food for Fungus - The environmental importance of fungi



When we think about fungi or fungus we can often think of nasty, unpleasant moulds or spores, however, fungi play a crucial role in the balance of ecosystems and also play a vital role in the recycling of nutrients.

Fungi are the major decomposers of nature; they break down organic matter which would otherwise not be recycled. They colonise most habitats on earth, preferring dark, moist conditions and they can thrive in seemingly hostile environments, such as the tundra. However, most members of the Kingdom Fungi grow on the forest floor where the dark and damp environment is rich in decaying organic debris from plants and animals.

The food web would be incomplete without organisms that decompose organic matter. Some elements, such as nitrogen (N) and phosphorus (P), are required in large quantities by biological systems; yet, they are not abundant in the environment. The action of fungi releases these elements from decaying matter, making them available to other living organisms such as plants. Trace elements present in low amounts in many habitats are essential for growth but would remain tied up in rotting organic matter if fungi and bacteria did not return them to the environment via their metabolic activity.

It has been estimated that the number of fungi species worldwide is somewhere in the region of 2.2 to 3.8 million, with 120,000 currently accepted species. (Hawksworth, 2017). This includes yeasts, rusts, smuts, mildews, moulds, and mushrooms. There are also many fungus-like organisms, including slime moulds and oomycetes (water moulds), that do not belong to kingdom Fungi but are often called fungi.

Fungi over time, have been found to provide benefits to humans and have medicinal properties or can be consumed as food however, some are highly poisonous and toxic to humans and animals.


Let's explore some of the different species below, but please remember never to eat a Fungi unless you are 100% sure of what it is, or you could be a taking a trip to the hospital and that’s not fun…


Poisonous fungi


The Fly Agaric (Amanita muscaria) is an iconic mushroom well known for its red and white spotted cap. It is widely distributed in forests and woodlands of the temperate and boreal regions of the northern hemisphere, including Europe, northern Asia and North America. This toadstool has turned up in many fairy tale stories and features in the story of Alice in Wonderland when she is given some fly Agaric to eat. Fly Agaric is poisonous and infamous for its psychoactive and hallucinogenic properties, explored further on in this article. That being said, reports of human deaths are extremely rare. It was traditionally used as an insecticide and the cap was broken up and sprinkled into saucers of milk. It is known to contain ibotenic acid, which both attracts and kills flies – which gave it its name.


The Death Cap (Amanita phalloides) is perhaps the deadliest of all mushrooms and is found

throughout Europe. It closely resembles edible straw mushrooms and Caesar's mushrooms and its heat-stable amatoxins withstand cooking temperatures and quickly damage cells throughout the body.

Within 6 to 12 hours after consumption, violent abdominal pain, vomiting, and bloody diarrhea appear, causing rapid loss of fluid from the tissues and intense thirst. Signs of severe involvement of the liver, kidneys, and central nervous system soon follow, including a decrease in urinary output and a lowering of blood sugar. It has been reported that the death rate is between 25% and 50% of ingestion incidents! (Berthaud and Descotes, 1996). There have also been some notable victims of the Death Cap and include Pope Clement VII, who died of accidental death cap poisoning in 1534, and Roman Emperor Claudius in 54 CE who was poisoned, possibly thought to have been by the death cap.


Edible fungi


Some of the most popular edible mushrooms include Button mushrooms, Portobello mushrooms, Oyster mushrooms and Porcini mushrooms. Edible mushrooms have tastes ranging from sweet to nutty and even meaty! Other varieties can be used for their medicinal benefits containing antioxidants, such as selenium, to boost your immune system. They also contain the dietary fibre beta-glucan which has been shown to lower cholesterol.


There are several edible mushrooms that have significant medicinal metabolites. These mushrooms can make better prebiotics to stimulate the gut microbiota it has been found. (Jayachandran et al.,2017).

Foraging has become popular in recent years, but with so many varieties of mushrooms, and not all being safe for human consumption, it’s important that you heed caution before dashing out to your

nearest woodland.


Psilocybin mushrooms


Psilocybin mushrooms are the most popular “magic mushrooms”, which means that they have psychoactive properties. Psilocybin and other classic psychedelics have been used for centuries as sacraments within indigenous cultures, especially in Central and South America. In the mid-twentieth century they were a focus within psychiatry as both probes of brain function and experimental therapeutics. By the late 1960s and early 1970s these scientific inquires fell out of favour because classic psychedelics were being used outside of medical research and in association with the emerging counter culture. However, in the twenty-first century, scientific interest in classic psychedelics has returned and grown as a result of several promising studies, validating some earlier research.


Scientific studies have shown that consuming psilocybin mushrooms can have a beneficial effect for individuals suffering from various psychiatric disorders, from anxiety to OCD and depression. A study in 2016 concluded that when administered under psychologically supportive, double-blind conditions, a single dose of psilocybin produced substantial and enduring decreases in depressed mood and anxiety along with increases in quality of life and also decreases in death anxiety in patients with a life-threatening cancer diagnosis. (Griffiths et al., 2016).

A subsequent study conducted in 2018 concluded that psilocybin with psychological support might correct pessimism biases in treatment-resistant depression, enabling a more positive and accurate outlook (Lyons et.al., 2018).


Lichens


Lichens display a range of colours and textures. They can survive in the most unusual and hostile habitats and they cover rocks, gravestones, tree bark, and the ground in the tundra where plant roots cannot penetrate. Lichens can survive extended periods of drought; they become completely desiccated and then rapidly become active once water is available again. Lichens fulfill many ecological roles, including acting as biological indicator species, which allow scientists to track the health of a habitat because of their sensitivity to air pollution.


The emergence of multidrug resistant bacteria has driven the need for novel antibiotics and it has been found that Lichens naturally produce a wide range of unique defense chemicals and have already, historically shown medicinal efficacy. A study in 2019 looked at ten common churchyard species and found that seven of the species contained antimicrobial properties. (Taylor and Fourie, 2019).


Yeasts


Yeasts are widely dispersed in nature with a wide variety of habitats. They are commonly found on plant leaves, flowers, and fruits, as well as in soil.  Yeast are also found on the surface of the skin and in the intestinal tracts of warm-blooded animals, where they may live symbiotically or as parasites. They are small, lemon-shaped single cells that are about the same size as red blood cells and they multiply by budding a daughter cell off from the original parent cell or by binary fission. Yeasts such as Saccharomyces play an important role in the production of bread and in beer brewing. They are also one of the most widely used model organisms for genetic studies, for example in cancer research.

In the past, work with yeast has provided a great deal of mechanistic insight into fundamental cellular processes that are also relevant for mammalian cells, such as TOR signalling, organelle biogenesis, the secretory pathway, and cell cycle progression. (Natter et al., 2013). Other species of yeast such as Candida are opportunistic pathogens and cause infections in individuals who do not have a healthy immune system.


These fungi are just some of the fascinating species that are found on our planet, doing their bit for nature, health and the environment.



Thanks for reading




References

Berthaud S and Descotes J. (1996) 'Mushrooms'. Human Toxicology. Amsterdam: pp. 719-729

Griffiths, Roland R et al. (2016) ‘Psilocybin produces substantial and sustained decreases in

depression and anxiety in patients with life-threatening cancer: A randomized double-blind

trial’, Journal of psychopharmacology (Oxford). London, England: SAGE Publications, 30(12), pp.

1181–1197. doi: 10.1177/0269881116675513.

Hawksworth D, Lücking R. (2017) 'Fungal Diversity Revisited: 2.2 to 3.8 Million Species'. Microbiol

Spectrum 5(4):FUNK-0052-2016. doi:10.1128/microbiolspec.FUNK-0052-2016.

Jayachandran, Muthukumaran, Xiao, Jianbo and Xu, Baojun (2017) ‘A Critical Review on Health

Promoting Benefits of Edible Mushrooms through Gut Microbiota’, International journal of

molecular sciences. Switzerland: MDPI AG, 18(9), p. 1934. doi: 10.3390/ijms18091934.

Lyons, Taylor and Carhart-Harris, Robin Lester (2018) ‘More Realistic Forecasting of Future Life

Events After Psilocybin for Treatment-Resistant Depression’, Frontiers in psychology. Switzerland:

Frontiers Research Foundation, 9, p. 1721. doi: 10.3389/fpsyg.2018.01721.

Natter, Klaus and Kohlwein, Sepp D (2013) ‘Yeast and cancer cells – common principles in lipid

metabolism’, BBA - Molecular and Cell Biology of Lipids. Elsevier B.V, 1831(2), pp. 314–326. doi:

10.1016/j.bbalip.2012.09.003.

Taylor and Fourie (2019) ‘Antimicrobial properties from lichens: An evaluation of the antimicrobial

properties of English churchyard lichens’. Microbiology Society. doi:

10.1099/acmi.amrmeds2019.po0001.