Cinnamaldehyde inhibits fungal growth and aflatoxin B1 biosynthesis by modulating the oxidative stress response of Aspergillus flavus

2015 ◽  
Vol 100 (3) ◽  
pp. 1355-1364 ◽  
Author(s):  
Qi Sun ◽  
Bo Shang ◽  
Ling Wang ◽  
Zhisong Lu ◽  
Yang Liu
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Fungal Growth ◽  
Oxidative Stress Response

scholarly journals Piperine inhibits aflatoxin B1 production in Aspergillus flavus by modulating fungal oxidative stress response

2017 ◽  
Vol 107 ◽  
pp. 77-85 ◽  
Author(s):  
Isaura Caceres ◽  
Rhoda El Khoury ◽  
Sylviane Bailly ◽  
Isabelle P. Oswald ◽  
Olivier Puel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Oxidative Stress Response

scholarly journals The bZIP Transcription Factor AflRsmA Regulates Aflatoxin B1 Biosynthesis, Oxidative Stress Response and Sclerotium Formation in Aspergillus flavus

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 271
Author(s):  
Xiuna Wang ◽  
Wenjie Zha ◽  
Linlin Liang ◽  
Opemipo Esther Fasoyin ◽  
Lihan Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Stress Response ◽  
Secondary Metabolites ◽  
Secondary Metabolism ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Opportunistic Pathogen ◽  
Oxidative Stress Response ◽  
Bzip Transcription Factor

Fungal secondary metabolites play important roles not only in fungal ecology but also in humans living as beneficial medicine or harmful toxins. In filamentous fungi, bZIP-type transcription factors (TFs) are associated with the proteins involved in oxidative stress response and secondary metabolism. In this study, a connection between a bZIP TF and oxidative stress induction of secondary metabolism is uncovered in an opportunistic pathogen Aspergillus flavus, which produces carcinogenic and mutagenic aflatoxins. The bZIP transcription factor AflRsmA was identified by a homology research of A. flavus genome with the bZIP protein RsmA, involved in secondary metabolites production in Aspergillus nidulans. The AflrsmA deletion strain (ΔAflrsmA) displayed less sensitivity to the oxidative reagents tert-Butyl hydroperoxide (tBOOH) in comparison with wild type (WT) and AflrsmA overexpression strain (AflrsmAOE), while AflrsmAOE strain increased sensitivity to the oxidative reagents menadione sodium bisulfite (MSB) compared to WT and ΔAflrsmA strains. Without oxidative treatment, aflatoxin B1 (AFB1) production of ΔAflrsmA strains was consistent with that of WT, but AflrsmAOE strain produced more AFB1 than WT; tBOOH and MSB treatment decreased AFB1 production of ΔAflrsmA compared to WT. Besides, relative to WT, ΔAflrsmA strain decreased sclerotia, while AflrsmAOE strain increased sclerotia. The decrease of AFB1 by ΔAflrsmA but increase of AFB1 by AflrsmAOE was on corn. Our results suggest that AFB1 biosynthesis is regulated by AflRsmA by oxidative stress pathways and provide insights into a possible function of AflRsmA in mediating AFB1 biosynthesis response host defense in pathogen A. flavus.

scholarly journals Antifungal and antiaflatoxigenic activities of coumarinyl thiosemicarbazides against Aspergillus flavus NRRL 3251

2017 ◽  
Vol 68 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Tihomir Kovač ◽  
Marija Kovač ◽  
Ivica Strelec ◽  
Ante Nevistić ◽  
Maja Molnar
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Antifungal Activity ◽  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Oxidative Stress Response ◽  
Oxidative Status ◽  
Biochemical Assays ◽  
Effect Estimation ◽  
Activity Estimation

Abstract The antifungal and antiaflatoxigenic effects of two series of coumarinyl thiosemicarbazides on Aspergillus flavus NRRL 3251 were studied. Fungi were grown in YES medium for 72 h at 29 °C in the presence of 0, 0.1, 1, and 10 μg mL-1 of coumarinyl thiosemicarbazides: one series with substitution in position 7 and another with substitution in position 4 of the coumarin core. Dry mycelia weight determination was used for antifungal activity estimation, while the aflatoxin B1 content in YES media, determined by the dilute and shoot LC-MS/MS technique, was used for the antiaflatoxigenic effect estimation. Standard biochemical assays were used for oxidative status marker (TBARS, SOD, CAT, and GPX) determination in A. flavus NRRL 3251 mycelia. Results show that 7-substituted-coumarinyl thiosemicarbazides possess a better antifungal and antiaflatoxigenic activity than 4-substituted ones. The most prominent substituted compound was the compound 3, N-(4-chlorophenyl)-2-(2-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)acetyl)hydrazine-1-carbothioamide, which completely inhibited aflatoxin production at the concentration of 10 μg mL-1. Oxidative stress response of A. flavus exposed to the selected compounds points to the modulation of oxidative stress as a possible reason of aflatoxin production inhibition.

scholarly journals VeA Is Associated with the Response to Oxidative Stress in the Aflatoxin Producer Aspergillus flavus

2014 ◽  
Vol 13 (8) ◽  
pp. 1095-1103 ◽  
Author(s):  
Sachin Baidya ◽  
Rocio M. Duran ◽  
Jessica M. Lohmar ◽  
Pamela Y. Harris-Coward ◽  
Jeffrey W. Cary ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Complex Formation ◽  
Osmotic Stress ◽  
Signaling Pathway ◽  
Aspergillus Flavus ◽  
Fungal Species ◽  
Oxidative Stress Response ◽  
Content Type ◽  
Osmotic Stress Response

ABSTRACT Survival of fungal species depends on the ability of these organisms to respond to environmental stresses. Osmotic stress or high levels of reactive oxygen species (ROS) can cause stress in fungi resulting in growth inhibition. Both eukaryotic and prokaryotic cells have developed numerous mechanisms to counteract and survive the stress in the presence of ROS. In many fungi, the HOG signaling pathway is crucial for the oxidative stress response as well as for osmotic stress response. This study revealed that while the osmotic stress response is only slightly affected by the master regulator veA , this gene, also known to control morphological development and secondary metabolism in numerous fungal species, has a profound effect on the oxidative stress response in the aflatoxin-producing fungus Aspergillus flavus . We found that the expression of A. flavus homolog genes involved in the HOG signaling pathway is regulated by veA . Deletion of veA resulted in a reduction in transcription levels of oxidative stress response genes after exposure to hydrogen peroxide. Furthermore, analyses of the effect of VeA on the promoters of cat1 and trxB indicate that the presence of VeA alters DNA-protein complex formation. This is particularly notable in the cat1 promoter, where the absence of VeA results in abnormally stronger complex formation with reduced cat1 expression and more sensitivity to ROS in a veA deletion mutant, suggesting that VeA might prevent binding of negative transcription regulators to the cat1 promoter. Our study also revealed that veA positively influences the expression of the transcription factor gene atfB and that normal formation of DNA-protein complexes in the cat1 promoter is dependent on AtfB.

scholarly journals Mimosa tenuiflora Aqueous Extract: Role of Condensed Tannins in Anti-Aflatoxin B1 Activity in Aspergillus flavus

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 391
Author(s):  
Christopher Hernandez ◽  
Laura Cadenillas ◽  
Anwar El Maghubi ◽  
Isaura Caceres ◽  
Vanessa Durrieu ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aqueous Extract ◽  
Aflatoxin B1 ◽  
Condensed Tannins ◽  
Fungal Growth ◽  
Oxidation Reactions ◽  
Expression Of Genes ◽  
Dependent Inhibition ◽  
Interesting Candidate ◽  
Mimosa Tenuiflora

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.

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