Menadione-Induced Oxidative Stress Re-Shapes the Oxylipin Profile of Aspergillus flavus and Its Lifestyle

Abstract

Aspergillus flavus is an efficient producer of mycotoxins, particularly aflatoxin B1, probably the most hepatocarcinogenic naturally-occurring compound. Although the inducing agents of toxin synthesis are not unanimously identified, there is evidence that oxidative stress is one of the main actors in play. In our study, we use menadione, a quinone extensively implemented in studies on ROS response in animal cells, for causing stress to A. flavus. For uncovering the molecular determinants that drive A. flavus in challenging oxidative stress conditions, we have evaluated a wide spectrum of several different parameters, ranging from metabolic (ROS and oxylipin profile) to transcriptional analysis (RNA-seq). There emerges a scenario in which A. flavus activates several metabolic processes under oxidative stress conditions for limiting the ROS-associated detrimental effects, as well as for triggering adaptive and escape strategies.

Influence of “Vitakorm-BSR-Forte” preparation on the antioxidant and cytoprotective processes in the mucosa of small intestine under the action of aflatoxin B1

“…Отримані дані вказують на високу сприйнятливість досліджуваних клітин до впливу AFB1 як прооксиданта, що стимулює процеси ПОЛ за умов надходження в організм тварин. Ці результати узгоджуються з даними літератури, згідно з якими афлатоксин В1, як і деякі інші природні токсини, індукує утворення АФО у клітинах [2,24]. За умов застосування препарату "Вітакорм-БСР-форте" тваринам, які зазнавали впливу AFB1, вміст ТБК-активних продуктів у СОТК зменшувався на 37 % (р<0,01; табл.…”

“…Особливо шкідливим є афлатоксин В1 (AFB1), який має імунотоксичну, мутагенну і канцерогенну дію [3,5,9,23]. У механізмах токсичного впливу афлатоксинів суттєву роль відіграють прооксидантні ефекти [4] і провокування оксидативного стресу [24], який розвивається у клітинах слизової оболонки тонкого кишечника (СОТК) тварин. Цей стан супроводжується утворенням вільних Biol.…”

Tramesan Elicits Durum Wheat Defense against the Septoria Disease Complex

“…In Aspergillus flavus, a mycotoxigenic fungus, the presence of Tramesan strongly inhibits aflatoxin biosynthesis, without significantly influencing fungal growth. Aflatoxin biosynthesis is a response to oxidative stress in fungal cells [21]. The presence of Tramesan enhances the expression of AfyapA, an oxidative stress-related transcriptional factor, thus maintaining oxidant/antioxidant balance and downregulating aflatoxin synthesis.…”

Aflatoxins: biosynthesis, prevention and eradication

“…The regulation of the AF biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be connected to reactive oxygen species (ROS) formation and oxidative stress responses (Zaccaria et al, 2015). The AF biosynthesis is not only regulated by intracellular ROS of different origins (Reverberi et al, 2006;Grintzalis et al, 2014), but the AF biosynthetic pathway itself may serve as a source of ROS due to involvement of P450 enzymes (Roze et al, Tab.…”

“…The transcription of the AF pathway genes can be activated when the AflR protein binds to the palindromic sequence 5´-TCGN 5 CGA-3´ in the promoter region of the AF pathway genes. (Yu et al, 2004), (Zaccaria et al, 2015) aflS aflS interacts with aflR. (Yu et al, 2004) Global regulators veA Global regulator VeA interacts with other velvet domain-containing proteins to regulate the expression of several key genes required for the mycotoxins synthesis, including AF, cyclopiazonic acid, and aflatrem.…”