Naslov
Cell redox ballance, lipid metabolism and aflatoxin biosynthesis in Aspergilus sect. Flavavi

Autori
Reverberi, Massimi ; Punelli, Marta ; Smith, Carrie ; Zjalic, Slaven ; Ricelli, Alessandra ; payne, Garry ; Fabbri, Anna A. ; Fanelli, Corrado

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
9th Europeean conference on fungal genetics. Meeting abstracts / - , 2008, 140-140

Skup
9th Europeean conference on fungal genetics

Mjesto i datum
Edinburgh, Ujedinjeno Kraljevstvo, 05.04.2008. - 08.04.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
aflatoxins; oxidative stress; lipid metabolism; peroxisomes

Sažetak
Oxidative stress represents a trigger for different metabolic events in all organisms and occurs during oxidative process in the cell such as glucose oxidation and beta-oxidation of fatty acids. In aflatoxigenic fungi these process are able to supply the aflatoxin building blocks i.e. the acetyl-CoA and sn oxidative cell environment, which is necessary for the transformation of precursors of aflatoxins. In fact among the several enzyme-catalysed reactions in aflatoxin biosynthesis, at last 6 are represented by oxidative transformnations. In order to demonstrate a correlation between cell redox ballance, lipid metabolism and aflatoxin synthesis the WT and mutant strains of Aspergillus parasiticus (NRL 2999) and A. flavus (NRRL 3357), aflatoxin producers were used. A null mutant approach was used for studying the involvment of the oxidative stress related transcription factor ApyapA (yap1 ortholog) in toxin biosynthesis by A. parasiticus. To study how lipid metabolism is related to aflatoxin formation, a gene (controlled by the Cu, Zn sod promoter of A. flavus) encoding for viral (Cymbidium Ringspot Virus) protein P33, which is able to induce peroxisome proliferation, lipid metabolism and aflatoxin biosynthesis, and in silico analysis of the promoter of the promoter of the aflatoxin gene regulator AflR using N_SITE tool of softberry software (www.softberry.com) was carried out. In A. parasiticus, oxidative stress via the activation of the oxidative stress related trancriptional factor ApyapA, regulates conidiogenesis and aflatoxin synthesis whereas an up-regulation of the lipid metabolism (FFA beta -oxidation and TG accumulation) induces a hyperoxidant status and aflatoxin biosynthesis enhancement in A. flavus. In silico (N_SITE analysis indicates the presence of regulatory elements (RE) responsive to CREB (cAMP), SREBP-ADD1 (lipid and glucose metabolism) AP1 (human ortholog of Yap1 and ApyapA) PPAR (lipid metabolism) binding factors. It emerges a scenario in which carbon source aviability, the turnover of lipids and the cell redox balance can modulate aflatoxin synthesis by affecting aflR transcription, furnishing acetate blocks and creating an oxidative cell environment.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Biotehnologija

POVEZANOST RADA