Good evening, friends, and Happy Spring Equinox.
This week’s mushroom is the Mossy Mazegill Polypore (Cerrena unicolor). I most recently found this while hiking up in New Hampshire where it was enduring the harsh winter at around ~3,000 feet. You can also find it a lot closer than that, just check out some dead trees in your local park and woods. When I first started digging into this mushroom I was shocked to see the quantity of information and abundant possibilities that have been explored within- from industrial waste remediation to killing leukemia cells. In fact, this is the most references I’ve ever consulted for a Mushroom Monday. Safe to say this mossy-capped mushroom has all the gusto needed to carry us into the spring season.
C. unicolor produces a variety of compounds that have industrial applications - one specific type of compound are the laccases (enzymes the fungus excretes to digest wood). It’s been scientifically shown to breakdown micropollutants, like Bisphenol A (BPAs), that become endocrine (hormone) disruptors when they bioaccumulate in humans. It’s not well understood how or why the fungus produces these robust laccases, but the current understanding is that these compounds allow the fungus to adapt to environmental changes and light conditions.
Another study demonstrated that it produced the widest variety of enzymes when cultivated in the dark and was subsequently more resistant to chemical pollution in its own environment. The fungus did not have as robust of an array of enzymes when cultivated in the light. Perhaps this suggests the fungus is better suited to digesting wood that still possesses bark (i.e. wood that is recently dead) and isn’t as comfortable as a secondary decomposer. It just so happens that all of the specimens I found have been on wood with bark still present.
Pharmacological Fun Facts
In the mid-2010s a few intrepid researchers discovered that some of these unique also possessed anticancer and antiviral properties. One compound in particular, a “highly active extracellular laccase” known as Ex-LAC, was able to initiate apoptosis - normal cell death, what cancer cells fail to do - in leukemia cells.¹ This study was conducted in humans (nine patients, but still, better than none) and the ex-LAC started killing cancer cells within forty-eight hours after initial treatment.
Another study showed that these “bioactive fungal molecules” had additional anti-oxidant and antibacterial properties. The compounds were affective against a variety of different bacteria harmful to humans but were particularly effective in killing Staphylococcus aureus, the bacterial responsible for Staph infections.²
Ecological Fun Facts
Let’s now transition from dense, peer-reviewed chemical analysis studies to a more digestible and fascinating ecological relationship between C. unicolor and two types of wasps - Horntail wasps (family Siricidae) and Darwin wasp (Ichneumonidae). The two wasps both have intimidating ovipositors (those needle-like tails) that they use to lay eggs and fortunately not sting humans.
The relationship is rather intricate, and we likely don’t comprehend all the dynamics, but the general understanding is as follows. A pigeon horntail wasp will use that robust ovipositor (that got cropped out of the above left photo) and drill into dying or recently dead wood to deposit eggs. In addition to eggs, she also deposits C. unicolor spores/mycelium from mucus-filled pouches near the base of the ovipositor. The spores germinate and the fungus then begins to use that robust chemical arsenal to digest the wood. In turn, the mossy mazegill’s expanding mycelium serves as a food source for the horntail.
However, it appears that the fungus isn’t entirely comfortable with the dynamics of the relationship and releases pheromones to signal for a third partner, the ichneumon wasp, to get involved. The ichneumon wasp then uses its own ovipositor to stab through the wood directly into a horntail larva and inject eggs into the grub. The eggs germinate into larvae themselves and then eat their host horntail. No better time than the equinox to appreciate how intricate and fascinating this world is. For an even more detailed description check out Reference 4.
In close, we’ll touch on a few of the basics. You may have already deduced this but C. unicolor is saprobic, using those laccases to digest a variety of hardwoods. It can be found year-round in temperate forests of the northern hemisphere - note I just found it in February in New Hampshire. The difference in color on the underside of the mushroom is a helpful identifier; just the fringe outer margin is white whereas the majority is a brownish grey (that’s correct, I waited until no one was reading to test out the semicolon). The top of the cap is hairy with concentric bands of color - despite the fact that unicolor means “all one color”. Hmm. I’ve read too many PubMed abstracts today to go down that rabbit hole so have a great evening and a great start to your spring,
PS. Thanks to everyone who came out Saturday, it was a lot of fun.
1) Pawlik A, Ruminowicz-Stefaniuk M, Frąc M, Mazur A, Wielbo J, Janusz G. The wood decay fungus Cerrena unicolor adjusts its metabolism to grow on various types of wood and light conditions. PLoS One. 2019 Feb 5;14(2):e0211744. doi: 10.1371/journal.pone.0211744. PMID: 30721259; PMCID: PMC6363171.
2) Jaszek M, Osińska-Jaroszuk M, Janusz G, Matuszewska A, Stefaniuk D, Sulej J, Polak J, Ruminowicz M, Grzywnowicz K, Jarosz-Wilkołazka A. New bioactive fungal molecules with high antioxidant and antimicrobial capacity isolated from Cerrena unicolor idiophasic cultures. Biomed Res Int. 2013;2013:497492. doi: 10.1155/2013/497492. Epub 2013 Jul 15. PMID: 23936810; PMCID: PMC3727119.
3) Kuo, M. (2007, March). Cerrena unicolor. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/cerrena_unicolor.html
4) Songulashvili G, Jimenéz-Tobón GA, Jaspers C, Penninckx MJ. Immobilized laccase of Cerrena unicolor for elimination of endocrine disruptor micropollutants. Fungal Biol. 2012 Aug;116(8):883-9. doi: 10.1016/j.funbio.2012.05.005. Epub 2012 May 29. PMID: 22862916.
5) Eaton, Eric R. “Wasp and Fungus Are Mutually Supportive.” Burlington Free Press, 4 July 2014. https://www.burlingtonfreepress.com/story/life/2014/07/04/wasp-fungus-mutually-supportive/12202803/
7) Mizerska-Dudka M, Jaszek M, Błachowicz A, Rejczak TP, Matuszewska A, Osińska-Jaroszuk M, Stefaniuk D, Janusz G, Sulej J, Kandefer-Szerszeń M. Fungus Cerrena unicolor as an effective source of new antiviral, immunomodulatory, and anticancer compounds. Int J Biol Macromol. 2015 Aug;79:459-68. doi: 10.1016/j.ijbiomac.2015.05.015. Epub 2015 May 21. PMID: 26003302.
1 - Matuszewska A, Karp M, Jaszek M, Janusz G, Osińska-Jaroszuk M, Sulej J, Stefaniuk D, Tomczak W, Giannopoulos K. Laccase purified from Cerrena unicolor exerts antitumor activity against leukemic cells. Oncol Lett. 2016 Mar;11(3):2009-2018. doi: 10.3892/ol.2016.4220. Epub 2016 Feb 9. PMID: 26998114; PMCID: PMC4774592.
2 - Jaszek M, Osińska-Jaroszuk M, Janusz G, Matuszewska A, Stefaniuk D, Sulej J, Polak J, Ruminowicz M, Grzywnowicz K, Jarosz-Wilkołazka A. New bioactive fungal molecules with high antioxidant and antimicrobial capacity isolated from Cerrena unicolor idiophasic cultures. Biomed Res Int. 2013;2013:497492. doi: 10.1155/2013/497492. Epub 2013 Jul 15. PMID: 23936810; PMCID: PMC3727119.