Perspective: Time to face the fungal threat

Wu, Felicia

doi:10.1038/516s7a

Cited by 57 publications

(33 citation statements)

References 10 publications

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“…It is more important to notice that this fungus can produce aflatoxins (AFs), the most potent natural carcinogen and toxic compounds ever characterized (Da Rocha et al, 2014). In 1993, AFs are classified as a Class 1 carcinogen by the (International Agency for Research on Cancer [IARC], 1993[IARC], , 2002, and were estimated to induce up to 28% of the total global cases of hepatocellular carcinoma (HCC) (Wu, 2014;Liu et al, 2017). AFs are mainly produced by A. flavus and Aspergillus parasiticus, and the former is the predominant aflatoxigenic species of contaminated foods and feeds in China (Xing et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Ethanol Inhibits Aflatoxin B1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes

et al. 2020

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As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B 1 (AFB 1) is primarily biosynthesized by Aspergillus flavus and Aspergillus parasiticus. Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB 1 production by A. flavus in a dose-dependent manner. Then, the ethanol's molecular mechanism of action on AFB 1 biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for aflC in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of aflK and aflLa may be correlated with the down-regulation of the transcription regulator genes aflR and aflS in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including aflR, aflD, aflM, and aflP may also be associated with the decreased expression of the global regulator gene veA. In particular, ethanol exposure caused the decreased expression of stress response transcription factor srrA and the overexpression of bZIP transcription factor ap-1, C 2 H 2 transcription factors msnA and mtfA, together with the enhanced levels of anti-oxidant enzymatic genes including Cat, Cat1, Cat2, CatA, and Cu, Zn superoxide dismutase gene sod1. Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB 1 biosynthesis by A. flavus via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in A. flavus and to provide solid evidence for its use in controlling AFB 1 contamination.

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Section: Introductionmentioning

confidence: 99%

Ethanol Inhibits Aflatoxin B1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes

et al. 2020

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“…Elevated MC in dried products enables the growth of both microorganisms associated with spoilage and insects that damage stored commodities (Fontana, 2007;Murdock et al, 2012;Roberts, 1972). In addition, sufficient drying prevents the growth of fungi that produce mycotoxins (e.g., aflatoxin) in stored commodities, particularly maize (Zea mays L.) and peanuts or groundnuts (Arachis hypogaea L.) (Wu, 2014;Wu et al, 2014). Thus, the ability to measure and therefore manage MC of seeds and dry commodities is critical to maintaining their postharvest quality.…”

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confidence: 99%

Using Relative Humidity Indicator Paper to Measure Seed and Commodity Moisture Contents

Bradford

Dahal

Bello

2016

Agricultural & Env Letters

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T he longevity of seeds in storage is highly sensitive to their moisture content (MC) and temperature (Ellis and Roberts, 1981). In general, the duration of seed viability (germination capacity) in storage is reduced by half for every 1% increase in MC (fresh weight basis) or 6°C increase in temperature (Ellis and Roberts, 1980;Harrington, 1972). Controlling storage temperature on a large scale is costly, particularly in tropical climates, and often is not economically feasible in developing countries; however, drying (and hermetic packaging) is a low-cost approach to extend seed longevity (Ellis, 1988;IIVR, 2016). Maintaining viability is not an issue for stored dry commodities (e.g., grains, pulses, dried fruits or herbs), but storage at low MC is still critical for the preservation of quality and prevention of spoilage. Elevated MC in dried products enables the growth of both microorganisms associated with spoilage and insects that damage stored commodities (Fontana, 2007;Murdock et al., 2012;Roberts, 1972). In addition, sufficient drying prevents the growth of fungi that produce mycotoxins (e.g., aflatoxin) in stored commodities, particularly maize (Zea mays L.) and peanuts or groundnuts (Arachis hypogaea L.) (Wu, 2014;Wu et al., 2014). Thus, the ability to measure and therefore manage MC of seeds and dry commodities is critical to maintaining their postharvest quality.Seeds and commodities are hygroscopic, and their MC will change in response to the relative humidity (RH) of the air to which they are exposed. The MC of a commodity at a given RH decreases as the temperature or the oil content of the commodity increases. Thus, while the MC of commodities will differ at a given RH and temperature due primarily to differences in oil content (Cromarty et al., 1982), MC and equilibrium RH are related uniquely for a given commodity at a constant temperature, a relationship known as an isotherm (Fig. 1). The growth of both fungal and insect storage pests is prevented at RH percentages less than 70% (fungi) or 35% (insects) Agricultural & Environmental Letters Research LetterAbstract: Declines of seed viability in storage and losses of stored commodities due to fungal spoilage and insect pests are promoted by high moisture content. However, measuring seed or grain moisture content in the field can be difficult, particularly in rural locations in developing countries. Because seed/commodity moisture content is uniquely related to equilibrium relative humidity at a given temperature, moisture content can be estimated by measuring the relative humidity of a sample enclosed in a sealed container. Relative humidity can be measured using electronic meters, or even more inexpensively using indicator paper that changes color in response to relative humidity. We describe this method and provide a spreadsheet to convert relative humidity to moisture content for many common seeds and commodities. This simple method can be used in the field for quickly estimating seed or commodity moisture content to determine whether further ...

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“…The great diversity in their chemical structure can be correlated with the variability on their toxicities and target organs 2 . Aflatoxin is most frequently produced by Aspergillus flavus and A. parasiticus [3][4] , and in addition to liver cancer, it has been associated with acute poisoning, immune-system dysfunction and stunted growth in children 5 . Approximately 18 aflatoxins analogues are known, being the most toxic analogues the B1, B2, G1 and G2, although all aflatoxins have carcinogenic, teratogenic, mutagenic and immunosuppressive effects 6 .…”

Section: Introductionmentioning

confidence: 99%

Analysis of aflatoxin B1 in Brazil nuts: method optimization and validation

2018

JCBSC

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A method for the determination of aflatoxin B1 was validated according to criteria by SANTÉ 11945/2015. The samples were extracted with acetonitrile and the cleaning step was not performed. Quantification was made by liquid chromatography with fluorescence detector and pre-column derivatization with trifluoroacetic acid. No matrix effect was observed and linearity was obtained in the range of 5-80 µg L-1. The recoveries ranged from 73% to 85% with a coefficient of variation of less than 5%. The quantification limit was 6 µg kg-1 and the measurement uncertainty was ± 0.18 µg kg-1 for this level. This method was applied to 14 real samples purchased in the local market and contamination was found in one sample above the limit tolerated by the legislation (59 µg kg-1). It is a low cost method with good sensitivity and easy to execute.

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Perspective: Time to face the fungal threat

Cited by 57 publications

References 10 publications

Ethanol Inhibits Aflatoxin B1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes

Ethanol Inhibits Aflatoxin B1 Biosynthesis in Aspergillus flavus by Up-Regulating Oxidative Stress-Related Genes

Using Relative Humidity Indicator Paper to Measure Seed and Commodity Moisture Contents

Analysis of aflatoxin B1 in Brazil nuts: method optimization and validation

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