Fungi & Mycotoxins

There are many definitions for what a mycotoxin is. Mycotoxins have for example been defined as “natural products from moulds that evoke a toxic response when introduced in low concentrations to vertebrates”. Mycotoxins are products of a fungus’ secondary metabolism, i.e. that part of fungal metabolism that is not essential for cell growth and maintenance of basic cell function. Why fungi produce such substances is not entirely clear, but they may, at least in part, be used for “chemical warfare” and thus provide some advantage to survive in the environment.

Important groups of mycotoxins

Ergot alkaloids	Aflatoxins	Ochratoxins
mainly produced by fungi within the Clavicipitaceae	produced by several Aspergillus spp	primarily produced by Aspergillus and Penicillium spp
cause ergotism	hepatotoxic, strongest natural carcinogens	nephrotoxins, immune suppresive

Fumonisins	Trichotecenes	Zearalenone
mainly producers Fusarium verticilliodes and F. proliferatum	produced by Fusarium spp, four subgroups: type-A – D	produced by Fusarium spp
hepatotoxic, leukoencephalomalacia (horse)	cytotoxic, inhibit protein- and DNA-synthesis	mycoestrogen

Mushroom poisoning is commonly caused after consumption of raw or cooked fruit bodies of toxic species. Poisonous mushrooms are often referred to as toadstools from the German word “Todesstuhl” (= death’s stool). Mushroom toxins may be classified into four groups according to their principal biological effect: