Inhibition of Aflatoxin Biosynthesis by Organophosphorus Compounds

The effect of a range of organophosphorus and various other compounds on production of aflatoxin by Aspergillus flavus was investigated. Five organophosphorus compounds - Chlormephos, Ciodrin, Naled, Phosdrin and Trichlorphon- at concentrations of 20 and 100 μg/ml of culture fluid were found to have activity similar to Dichlorvos, in that they lowered the level of aflatoxin produced and caused formation of several anthraquinone pigments. Two of these pigments have not previously been described, one was named Versicol and a suggested structure is presented, whilst the other compound was shown to be its acetate derivative. A rationale is suggested for the required elements of structure, which are necessary for an organophosphorus compound to have Dichlorvos-type activity. Two unrelated compounds, ammonium nitrate and Tridecanone were also found to elicit Dichlorvos-type activity. It is likely that tridecanone or its breakdown products competitively inhibit enzymes involved in aflatoxin biosynthesis. It is possible that this inhibition effect explains the lowering of aflatoxin production in lipid-rich commodities infected by A. flavus.

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NsdC and NsdD Affect Aspergillus flavus Morphogenesis and Aflatoxin Production

Eukaryotic Cell ◽

10.1128/ec.00069-12 ◽

2012 ◽

Vol 11 (9) ◽

pp. 1104-1111 ◽

Cited By ~ 66

Author(s):

Jeffrey W. Cary ◽

Pamela Y. Harris-Coward ◽

Kenneth C. Ehrlich ◽

Brian M. Mack ◽

Shubha P. Kale ◽

...

Keyword(s):

Aspergillus Flavus ◽

Strong Association ◽

Aflatoxin Production ◽

Expression Data ◽

Aflatoxin Biosynthesis ◽

Wild Type ◽

Content Type ◽

Conidium Formation ◽

In The Wild ◽

Type Gene

ABSTRACT The transcription factors NsdC and NsdD are required for sexual development in Aspergillus nidulans . We now show these proteins also play a role in asexual development in the agriculturally important aflatoxin (AF)-producing fungus Aspergillus flavus . We found that both NsdC and NsdD are required for production of asexual sclerotia, normal aflatoxin biosynthesis, and conidiophore development. Conidiophores in nsdC and nsdD deletion mutants had shortened stipes and altered conidial heads compared to those of wild-type A. flavus . Our results suggest that NsdC and NsdD regulate transcription of genes required for early processes in conidiophore development preceding conidium formation. As the cultures aged, the Δ nsdC and Δ nsdD mutants produced a dark pigment that was not observed in the wild type. Gene expression data showed that although AflR is expressed at normal levels, a number of aflatoxin biosynthesis genes are expressed at reduced levels in both nsd mutants. Expression of aflD , aflM , and aflP was greatly reduced in nsdC mutants, and neither aflatoxin nor the proteins for these genes could be detected. Our results support previous studies showing that there is a strong association between conidiophore and sclerotium development and aflatoxin production in A. flavus.

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Comparison of the Antifungal and Antiaflatoxigenic Potential of Liquid and Vapor Phase of Thymus vulgaris Essential Oil Against Aspergillus flavus

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-016 ◽

2019 ◽

Vol 82 (12) ◽

pp. 2044-2048

Author(s):

FEI TIAN ◽

SANG YOO LEE ◽

HYANG SOOK CHUN

Keyword(s):

Liquid Phase ◽

Essential Oil ◽

Aspergillus Flavus ◽

Vapor Phase ◽

Substantial Reduction ◽

Brown Rice ◽

Aflatoxin Production ◽

Thymus Vulgaris ◽

Aflatoxin Biosynthesis ◽

Fungal Contamination

ABSTRACT The antifungal and antiaflatoxigenic activity of Thymus vulgaris essential oil (EO) against Aspergillus flavus was evaluated over a range of concentrations in vapor- and liquid-phase contact tests. Total reduction in mycelial growth in the vapor- and liquid-phase tests was detected at EO concentrations of 20 and 400 μg/mL, respectively. Treatment with 10 μg/mL EO reduced aflatoxin production by 97.0 and 56.4% in the vapor- and liquid-phase tests, respectively. Greater inhibition of the expression of both fungal development–related genes (brlA, abaA, and wetA) and aflatoxin biosynthesis–related genes (aflR, aflD, and aflK) was also observed in the vapor-phase test. A substantial reduction in aflatoxin production was also observed in brown rice (72.7%) and white rice (18.0%). Our results indicate that the way this EO contacts fungal cells significantly affects its antifungal activity and that T. vulgaris EO in vapor phase might be a good strategy to control fungal contamination. HIGHLIGHTS

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aflN Is Involved in the Biosynthesis of Aflatoxin and Conidiation in Aspergillus flavus

Toxins ◽

10.3390/toxins13110831 ◽

2021 ◽

Vol 13 (11) ◽

pp. 831

Author(s):

Kunzhi Jia ◽

Lijuan Yan ◽

Yipu Jia ◽

Shuting Xu ◽

Zhaoqi Yan ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Aspergillus Flavus ◽

Prevention And Control ◽

Reactive Oxygen Species Generation ◽

Reactive Oxygen ◽

Hyphal Growth ◽

Aflatoxin Production ◽

Oxygen Species ◽

Aflatoxin Biosynthesis ◽

And Control

Aspergillus flavus poses a threat to society economy and public health due to aflatoxin production. aflN is a gene located in the aflatoxin gene cluster, but the function of AflN is undefined in Aspergillus flavus. In this study, aflN is knocked out and overexpressed to study the function of AflN. The results indicated that the loss of AflN leads to the defect of aflatoxin biosynthesis. AflN is also found to play a role in conidiation but not hyphal growth and sclerotia development. Moreover, AlfN is related to the response to environmental oxidative stress and intracellular levels of reactive oxygen species. At last, AflN is involved in the pathogenicity of Aspergillus flavus to host. These results suggested that AflN played important roles in aflatoxin biosynthesis, conidiation and reactive oxygen species generation in Aspergillus flavus, which will be helpful for the understanding of aflN function, and will be beneficial to the prevention and control of Aspergillus flavus and aflatoxins contamination.

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Inhibitory effects of three monoterpenes from ginger essential oil on growth and aflatoxin production of Aspergillus flavus and their gene regulation in aflatoxin biosynthesis

Applied Biological Chemistry ◽

10.1007/s13765-018-0352-x ◽

2018 ◽

Vol 61 (2) ◽

pp. 243-250 ◽

Cited By ~ 3

Author(s):

Young-Sun Moon ◽

Hoi-Seon Lee ◽

Sung-Eun Lee

Keyword(s):

Gene Regulation ◽

Essential Oil ◽

Aspergillus Flavus ◽

Aflatoxin Production ◽

Aflatoxin Biosynthesis ◽

Inhibitory Effects

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Suppression of Aflatoxin Production by Essential Oil and Lactobacillus rhamnosus and Molecular Detection of Aflatoxin Biosynthesis aflR Gene Expression in Aspergillus flavus

Egyptian Journal of Microbiology ◽

10.21608/ejm.2015.235 ◽

2015 ◽

Vol 50 (1) ◽

pp. 61-82

Keyword(s):

Gene Expression ◽

Essential Oil ◽

Aspergillus Flavus ◽

Molecular Detection ◽

Lactobacillus Rhamnosus ◽

Aflatoxin Production ◽

Aflatoxin Biosynthesis

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Organic acids suppress aflatoxin production via lowering expression of aflatoxin biosynthesis-related genes in Aspergillus flavus

Food Control ◽

10.1016/j.foodcont.2018.01.017 ◽

2018 ◽

Vol 88 ◽

pp. 207-216 ◽

Cited By ~ 8

Author(s):

Young-Sun Moon ◽

Hyeong-Mi Kim ◽

Hyang Sook Chun ◽

Sung-Eun Lee

Keyword(s):

Organic Acids ◽

Aspergillus Flavus ◽

Aflatoxin Production ◽

Aflatoxin Biosynthesis

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Ssu72 Regulates Fungal Development, Aflatoxin Biosynthesis and Pathogenicity in Aspergillus flavus

Toxins ◽

10.3390/toxins12110717 ◽

2020 ◽

Vol 12 (11) ◽

pp. 717

Author(s):

Guang Yang ◽

Xiaohong Cao ◽

Ling Qin ◽

Lijuan Yan ◽

Rongsheng Hong ◽

...

Keyword(s):

Rna Polymerase Ii ◽

Aspergillus Flavus ◽

Pathogenic Fungus ◽

Aflatoxin Production ◽

Regulation Of Transcription ◽

Aflatoxin Biosynthesis ◽

Fungal Development ◽

Oxidative Stresses ◽

Novel Strategy ◽

Phosphatase Ssu72

The RNA polymerase II (Pol II) transcription process is coordinated by the reversible phosphorylation of its largest subunit-carboxy terminal domain (CTD). Ssu72 is identified as a CTD phosphatase with specificity for phosphorylation of Ser5 and Ser7 and plays critical roles in regulation of transcription cycle in eukaryotes. However, the biofunction of Ssu72 is still unknown in Aspergillus flavus, which is a plant pathogenic fungus and produces one of the most toxic mycotoxins-aflatoxin. Here, we identified a putative phosphatase Ssu72 and investigated the function of Ssu72 in A. flavus. Deletion of ssu72 resulted in severe defects in vegetative growth, conidiation and sclerotia formation. Additionally, we found that phosphatase Ssu72 positively regulates aflatoxin production through regulating expression of aflatoxin biosynthesis cluster genes. Notably, seeds infection assays indicated that phosphatase Ssu72 is crucial for pathogenicity of A. flavus. Furthermore, the Δssu72 mutant exhibited more sensitivity to osmotic and oxidative stresses. Taken together, our study suggests that the putative phosphatase Ssu72 is involved in fungal development, aflatoxin production and pathogenicity in A. flavus, and may provide a novel strategy to prevent the contamination of this pathogenic fungus.

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Aspergillus Goes Viral: Ecological Insights from the Geographical Distribution of the Mycovirome within an Aspergillus flavus Population and Its Possible Correlation with Aflatoxin Biosynthesis

Journal of Fungi ◽

10.3390/jof7100833 ◽

2021 ◽

Vol 7 (10) ◽

pp. 833

Author(s):

Francesca Degola ◽

Giorgio Spadola ◽

Marco Forgia ◽

Massimo Turina ◽

Lucia Dramis ◽

...

Keyword(s):

Aspergillus Flavus ◽

Aflatoxin Production ◽

Fungal Species ◽

Natural Environments ◽

The Novel ◽

Aflatoxin Biosynthesis ◽

Biological Variables ◽

Pattern Distribution ◽

Toxigenic Strains

Microbial multi-level interactions are essential to control the success of spreading and survival of most microbes in natural environments. Phytopathogenic mycotoxigenic fungal species, such as Aspergillus flavus, represent an important issue in food safety. Usually, non-toxigenic strains are exploited for biocontrol strategies to mitigate infections by toxigenic strains. To comprehend all the biological variables involved in the aflatoxin biosynthesis, and to possibly evaluate the interplay between A. flavus toxigenic and non-toxigenic strains during intraspecific biocompetition, the “virological” perspective should be considered. For these reasons, investigations on mycoviruses associated to A. flavus populations inhabiting specific agroecosystems are highly desirable. Here, we provide the first accurate characterization of the novel mycovirome identified within an A. flavus wild population colonizing the maize fields of northern Italy: a selection of A. flavus strains was biologically characterized and subjected to RNAseq analysis, revealing new mycoviruses and a peculiar geographic pattern distribution in addition to a 20% rate of infection. More interestingly, a negative correlation between viral infection and aflatoxin production was found. Results significantly expanded the limited existent data about mycoviruses in wild A. flavus, opening new and intriguing hypotheses about the ecological significance of mycoviruses.

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Investigation of the Antifungal and Anti-Aflatoxigenic Potential of Plant-Based Essential Oils against Aspergillus flavus in Peanuts

Journal of Fungi ◽

10.3390/jof6040383 ◽

2020 ◽

Vol 6 (4) ◽

pp. 383

Author(s):

Premila Narayana Achar ◽

Pham Quyen ◽

Emmanuel C. Adukwu ◽

Abhishek Sharma ◽

Huggins Zephaniah Msimanga ◽

...

Keyword(s):

Essential Oils ◽

Aspergillus Flavus ◽

High Performance ◽

Opportunistic Infections ◽

Aflatoxin Production ◽

The United States ◽

Microscopy Study ◽

Aspergillus Species ◽

Gas Chromatography Mass Spectrometry ◽

Ammonia Vapor

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts.

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