Naslov
Correlation between ochratoxin A biosynthesis and oxidant/antioxidant modulation in Aspergillus ochraceus

Autori
Punelli, Federico ; Reverberi, Massimo ; Gazzetti, Katia ; Zjalić, Slaven ; Ricelli, Alessandra ; Fanelli, Corrado ; Fabbri, Anna Adele

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

Izvornik
9th Europeean Conference on Fungal Genetics. Meeting abstracts / - , 2008, 139-139

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
ochratoxin ; reactive oxigen species ; hydroperoxides ; oxidant inducers ; reverse PCR

Sažetak
Reactive oxigen species (ROS) and lipoperoxides in Aspergillus parasiticus stimulated aflatoxin production and the expression of transcription factors related to oxidative stress. These factors promoted the transcription of genes encoding antioxidant-related enzymes. In A.parasiticus cell oxidative stress, induced by ROS and lipoperoxides, appeared to be percived by ApyapA (Yap1 orthologue) to primes antioxidant defence activities. Dapyap1 mutant has an altered perception of oxidative stress and presentes a precocious and increased production of aflatoxin in comparison to wilde type (WT). Also in A. ochraceus (MPV 2037 strain-OTA producer) hydroperoxides of linoleic acid are able to modulate ochratoxin A (OTA) production.The correlation between lipoperoxides and OTA biosynthesis was analysed in previous works (Punelli et al., 2007)and a daolox-like (lipoxygenase mutant) presented a delay in the sporulation and Ota production. In this study a correlation among lipoperoxidation, activity of antioxidant defence system and OTA biosynthesis was more deeply evidenced and new approaches were used to analyze the function of oxidative stress in fungak cells. Oxidant inducers like Menadione 0.1 and 0.5 mM, CCl4 0.5% v/v, H2O2 10 mM, tBOOH 100 mM were used to test their effect on OTA production by WT. Furthermore the construction of Daoyao-like mutant was performed to investigate the correlation between oxidative stress and OTA biosynthesis.To Analyze A. ochraceous genome, several primers were used (Aoyao, Aocat, Aosod) The transcription level in WT and mutant was studied by reverse PCR analysis. In A. ochraceus OTA producer a 657 bp sequence of aoyap-like (accession numbet EUO45307 -82% of aa homology with A. fumigatus yap1) a 309 bb Aocat-like (95-100% of aa homology A. clavatus CatA) and 233 bp Cu-Zn Aosod-like (77% of aa homology woth A.fumigatus Cu, Zn SOD) were characterized and partially cloned and the activity and expression of these enzymes were analysed in mycelia. The results obtained show that a delay in the sporulation was observed inthe mutanta and the best antioxidant enzymes stimulator were MENADIONE O.5Mm AND ccL4 0.5% v/v, also the OTA production was affected by oxidant inducers.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Biotehnologija

POVEZANOST RADA