Survey of Alternaria Toxins and Other Mycotoxins in Dried Fruits in China

Self Cite

Alternaria alternata is an important phytopathogen causing fruit black rot and also producing a variety of mycotoxins, such as alternariol (AOH) and alternariol monomethyl ether (AME) as two main contaminants. This could lead to economic losses of agricultural products as well as human health risks. In this study, magnolol extracted from the traditional Chinese herb, Mangnoliaofficinalis, exhibited an obvious antifungal property and could completely suppress the mycelial growth at 100 μM. Morphological differences of A. alternata were observed to be significantly shrunk and wrinkled after the exposure to magnolol. Furthermore, AOH and AME were no longer produced in response to 50 μM of magnolol. To uncover the antifungal and antimycotoxigenic mechanisms, the transcriptomic profiles of A. alternata—treated with or without magnolol—were evaluated. The clustered genes responsible for AOH and AME biosynthesis were obviously less transcribed under magnolol stress and this was further confirmed by qRT-PCR. The global regulators of carbon and nitrogen utilization, such as CreA and NmrA, were significantly down-regulated and this possibly caused the reduction in mycotoxins. In addition, fatty acid β-oxidation was regarded to contribute to polyketide mycotoxin production for the supply of precursor acetyl-CoA while the expression of these related genes was inhibited. The response to magnolol led to the marked alteration of oxidative stress and the down-expression of the mitogen-activated protein kinase (MAPK) signaling pathway from the transcriptome data and the determination of peroxidase (POD), superoxide dismutase (SOD) and glutathione (GSH) assays. This above might be the very reason for the growth supression and mycotoxin production of A. alternata by magnolol. This study provides new insights into its potential as an important active ingredient for the control of A. alternata and its mycotoxins in fruits and their products.

Section: Introductionmentioning

confidence: 99%

Transcriptomic Insights into the Antifungal Effects of Magnolol on the Growth and Mycotoxin Production of Alternaria alternata

Wang

Yuan

et al. 2020

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“…Literature data concerning mycotoxins stability in organic solvents and extracts are scattered and devoted to a single or several selected representatives of mycotoxins. The current trend towards the development of multi-analyte methods, however, demands the confirmation of standard solutions stability for dozens of analytes: the whole spectrum of regulated mycotoxins [5,6] or a broad range of fungal metabolites [7][8][9]. Common factors affecting the stability of standard solution are the solvents ability to degrade analyte and to get evaporated, temperature and UV-irradiation.…”

Section: Introductionmentioning

confidence: 99%

Stability of Mycotoxins in Individual Stock and Multi-Analyte Standard Solutions

Kiseleva¹,

Chalyy²,

Седова³

et al. 2020

Standard solutions of mycotoxins prepared in RP HPLC solvents from neat standards are usually used for analytical method development. Multi-mycotoxin HPLC-MS/MS methods necessitate stability estimation for the wide spectrum of fungal metabolites. The stability of individual diluted stock standard solutions of mycotoxins in RP-HPLC solvents and multi-analyte HPLC-MS/MS calibrants was evaluated under standard storage and analysis conditions. Individual stock standard solutions of aflatoxins, sterigmatocystin, A-and B-trichothecenes, zearalenone and its analogues, ochratoxin A, fumonisins, Alternaria toxins, enniatins and beauvericin, moniliformin, citrinin, mycophenolic, cyclopiazonic acids and citreoviridin were prepared in RP-HPLC solvents and stored at −18 • C for 14 months. UV-spectroscopy was utilized to monitor the stability of analytes, excluding fumonisins. The gradual degradation of α-, β-zearalenol and α-, β-zearalanol in acetonitrile was detected. Aflatoxins and sterigmatocystin, zearalenone, Alternaria toxins, enniatins and beauvericin, citrinin, mycophenolic, cyclopiazonic acids and citreoviridin can be referred to as stable. The concentration of the majority of trichothecenes should be monitored. Diluted multi-mycotoxin standard in water/methanol (50/50 v/v) solutions acidified with 0.1% formic acid proved to be stable in silanized glass at 23 • C exposed to light for at least 75 h (CV ≤ 10%). An unexpected manifestation of MS/MS signal suppression/enhancement was discovered in the course of multi-mycotoxin standard solution stability evaluation. Key Contribution:The stability of the wide spectrum of mycotoxins in individual standard solutions in RP-HPLC solvents and multi-analyte HPLC-MS/MS calibrants under standard storage and analysis conditions is discussed basing on experimental and literature data.

“…Acid-treated durian peel is a promising waste material for mycotoxin decontamination.Toxins 2020, 12, 108 2 of 17 occurring in food and feedstuffs are aflatoxins, ochratoxins, zearalenone, deoxynivalenol, and fumonisins [4,5]. Contamination by mycotoxins is common in primary agricultural commodities such as maize, rice, wheat, cereal products, meat, and dried fruits [5][6][7][8]. Multi-mycotoxin contamination of food and feedstuffs depends on environmental conditions and type of substrate [9].…”

mentioning

confidence: 99%

The Effectiveness of Durian Peel as a Multi-Mycotoxin Adsorbent

Adunphatcharaphon

Petchkongkaew

Greco

et al. 2020

Durian peel (DP) is an agricultural waste that is widely used in dyes and for organic and inorganic pollutant adsorption. In this study, durian peel was acid-treated to enhance its mycotoxin adsorption efficacy. The acid-treated durian peel (ATDP) was assessed for simultaneous adsorption of aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), and fumonisin B1 (FB1). The structure of the ATDP was also characterized by SEM–EDS, FT–IR, a zetasizer, and a surface-area analyzer. The results indicated that ATDP exhibited the highest mycotoxin adsorption towards AFB1 (98.4%), ZEA (98.4%), and OTA (97.3%), followed by FB1 (86.1%) and DON (2.0%). The pH significantly affected OTA and FB1 adsorption, whereas AFB1 and ZEA adsorption was not affected. Toxin adsorption by ATDP was dose-dependent and increased exponentially as the ATDP dosage increased. The maximum adsorption capacity (Qmax), determined at pH 3 and pH 7, was 40.7 and 41.6 mmol kg−1 for AFB1, 15.4 and 17.3 mmol kg−1 for ZEA, 46.6 and 0.6 mmol kg−1 for OTA, and 28.9 and 0.1 mmol kg−1 for FB1, respectively. Interestingly, ATDP reduced the bioaccessibility of these mycotoxins after gastrointestinal digestion using an in vitro, validated, static model. The ATDP showed a more porous structure, with a larger surface area and a surface charge modification. These structural changes following acid treatment may explain the higher efficacy of ATDP in adsorbing mycotoxins. Hence, ATDP can be considered as a promising waste material for mycotoxin biosorption.