title: Antioxidant enzymes stimulation in Aspergillus parasiticus by Lentinula edodes inhibits aflatoxin production.
abstract: Biosynthesis of aflatoxins, toxic metabolites produced by Aspergillus parasiticus, is correlated to the fungal oxidative stress and cell ageing. In this paper, the mechanism underlying the aflatoxin-inhibiting effect of the Lentinula edodes culture filtrates was studied by analysing their anti-oxidant activity and beta-glucan content. Mushroom beta-glucans are pharmacologically active compounds stimulating anti-oxidant responses in animal cells. L. edodes lyophilised filtrates stimulate A. parasiticus anti-oxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) and aflatoxin inhibition was better correlated with beta-glucan content than with anti-oxidant activity of the filtrates. RT-PCR analyses on treated mycelia showed a delay in the activation of aflR, and norA, genes of aflatoxin cluster and a synchronous activation of hsf2-like, a homologue of a yeast transcription factor involved in oxidative stress responses. The first evidence of hsf2-like in A. parasiticus and its activation during aflatoxin biosynthesis is reported. L. edodes filtrates could play a role as external stimulus affecting the anti-oxidant status in the fungal cell that, in turn, leads to aflatoxin inhibition. In the fungal cell, beta-glucans present in the filtrates could stimulate the activation of transcription factors related to anti-oxidant response and anti-oxidant enzyme activity with a contemporaneous delay of aflatoxin genes transcription, which led to a marked reduction of aflatoxin production. This research suggests new perspectives to set suitable strategies against aflatoxins and L. edodes could be considered a promising tool.
authors.affiliation: Dipartimento di Biologia Vegetale, Università degli Studi La Sapienza, Largo Cristina di Svezia 24, Rome, Italy. massimo.reverberi@uniroma1.it
authors.forename: M
authors.initials: M
authors.lastname: Reverberi
authors.forename: A A
authors.initials: AA
authors.lastname: Fabbri
authors.forename: S
authors.initials: S
authors.lastname: Zjalic
authors.forename: A
authors.initials: A
authors.lastname: Ricelli
authors.forename: F
authors.initials: F
authors.lastname: Punelli
authors.forename: C
authors.initials: C
authors.lastname: Fanelli
mesh_terms: D000348:Aflatoxins / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001230:Aspergillus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001688:Biological Products / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D025282:Mycelium / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress; D011134:Polysaccharides / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020942:Shiitake Mushrooms / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D047071:beta-Glucans / Q000032:analysis
chemical_list: C113837:AFLR protein, Aspergillus; D000348:Aflatoxins; D000975:Antioxidants; D001688:Biological Products; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011134:Polysaccharides; D014157:Transcription Factors; D047071:beta-Glucans; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase