A hemolytic peptide from the mycophilic fungus Sepedonium chrysospermum (Bull.) Fr.

Abstract

The hemolytic activity of an extract of the mycoparasite Sepedonium chrysospermum (teleomorph Hypomyces chrysospermus) was detected and characterized. Extraction of the fungal biomass by methanol yielded a fraction in which the hemolytic activity against human red blood cells corresponded to a peptide with a molecular mass of 7,653.72 Da and an isoelectric point of approximately 5.8. The peptide was temperature resistant, and the hemolysis was only partially inhibited, even after a 30-min pre-incubation at 100°C. Its hemolytic activity was unaffected by treatment with proteolytic enzymes such as trypsin. Among the divalent cations assayed, Hg(2+) was the strongest inhibitor of hemolysis. The reducing agent, dithiothreitol, and the membrane lipid, cholesterol, demonstrated concentration-dependent inhibitory activities. Finally, hemolytic activity triggered by the peptide was analyzed by scanning electron microscopy, and a pore-forming activity was detected.

Chemical ecology of fungi

“…The virulence of this mycoparasite towards Boletaceae might be attributed to a so far not fully characterised haemolytic peptide. 236 Some mycoparasitic fungi are able to parasitise lichens, despite the fact that lichens produce a variety of antibiotic secondary metabolites. 237,219 For instance, a Fusarium species is able to degrade lecanoric acid, thus inactivating an important chemical defence compound of the lichens Lasallia papulosa and Lasallia pensylvanica.…”