Next Article in Journal
Design and Production of a Recombinant Hybrid Toxin to Raise Protective Antibodies against Loxosceles Spider Venom
Next Article in Special Issue
Multiple CH/π Interactions Maintain the Binding of Aflatoxin B1 in the Active Cavity of Human Cytochrome P450 1A2
Previous Article in Journal
A Recurrent Motif: Diversity and Evolution of ShKT Domain Containing Proteins in the Vampire Snail Cumia reticulata
Previous Article in Special Issue
Biological System Responses of Dairy Cows to Aflatoxin B1 Exposure Revealed with Metabolomic Changes in Multiple Biofluids
Article Menu
Issue 2 (February) cover image

Export Article

Open AccessArticle

Inhibition of Aflatoxin Production by Paraquat and External Superoxide Dismutase in Aspergillus flavus

Department of Biosciences, Teikyo University, 1-1 Toyosatodai, Utsunomiya 320-8551, Japan
Author to whom correspondence should be addressed.
Toxins 2019, 11(2), 107;
Received: 15 January 2019 / Revised: 11 February 2019 / Accepted: 12 February 2019 / Published: 12 February 2019
(This article belongs to the Collection Aflatoxins)
PDF [1999 KB, uploaded 18 February 2019]


Aflatoxin contamination of crops is a worldwide problem, and elucidation of the regulatory mechanism of aflatoxin production, for example relative to the oxidative–antioxidative system, is needed. Studies have shown that oxidative stress induced by reactive oxygen species promotes aflatoxin production. However, superoxide has been suggested to have the opposite effect. Here, we investigated the effects of the superoxide generator, paraquat, and externally added superoxide dismutase (SOD) on aflatoxin production in Aspergillus flavus. Paraquat with an IC50 value of 54.9 µM inhibited aflatoxin production without affecting fungal growth. It increased cytosolic and mitochondrial superoxide levels and downregulated the transcription of aflatoxin biosynthetic cluster genes, including aflR, a key regulatory protein. The addition of bovine Cu/ZnSOD to the culture medium suppressed the paraquat-induced increase in superoxide levels, but it did not fully restore paraquat-inhibited aflatoxin production because bovine Cu/ZnSOD with an IC50 value of 17.9 µg/mL itself inhibited aflatoxin production. Externally added bovine Cu/ZnSOD increased the SOD activity in fungal cell extracts and upregulated the transcription of genes encoding Cu/ZnSOD and alcohol dehydrogenase. These results suggest that intracellular accumulation of superoxide impairs aflatoxin production by downregulating aflR expression, and that externally added Cu/ZnSOD also suppresses aflatoxin production by a mechanism other than canonical superoxide elimination activity. View Full-Text
Keywords: aflatoxin production; Aspergillus flavus; superoxide; paraquat; superoxide dismutase aflatoxin production; Aspergillus flavus; superoxide; paraquat; superoxide dismutase

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Furukawa, T.; Sakuda, S. Inhibition of Aflatoxin Production by Paraquat and External Superoxide Dismutase in Aspergillus flavus. Toxins 2019, 11, 107.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Toxins EISSN 2072-6651 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top