RSC Advances
·
2017
·Vol. 7
·期 37
·23021-23026
·
IF 3.108
Jing Zhao,Ling Wang,Dan Xu,Zhisong Lu
Silver nanoparticles (AgNPs) have been extensively studied as antimicrobial materials, but their capability of suppressing aflatoxin production has not been investigated. In this work, AgNPs with an average size of 4.5 nm were synthesized to inhibit the growth of Aspergillus flavus (A. flavus). Based on the anti-fungal assay, the concentration of 5 μg mL−1 was chosen to study the direct inhibiting effects of AgNPs on aflatoxin production. Results show that AgNP treatment could significantly decrease secretion of aflatoxin B1 from A. flavus. Real-time measurements of O2− with an electrochemical sensor reveal that the AgNPs could trigger the release of O2− from fungal mycelia. A mechanism involving O2− release is proposed to explain AgNP-caused depression of aflatoxin production from A. flavus. This is the first attempt to study AgNP-induced inhibition on aflatoxin generation and its possible mechanisms.
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Biomed Research International
·
2016
·
IF 2.134
Jie Liu,Lvhui Sun,Niya Zhang,Jiacai Zhang,Jiao Guo,Chong Li,Shahid Ali Rajput,Desheng Qi
The current study was to better understand the potential factors affecting aflatoxin B1 (AFB1) accumulation varies between different grains. The nutrient composition and contents of defatted substrates were determined; additionally, according to the nutrient content of the substrates, the effects of starch, soluble sugars, amino acids, and trace elements on AFB1 production and mycelial growth in Czapek-Dox medium were examined. These results verified that removal of lipids from ground substrates significantly reduced the substrate’s potential for AFB1 production by Aspergillus flavus. Maltose, glucose, sucrose, arginine, glutamic acid, aspartic acid, and zinc significantly induced AFB1 production up to 1.7- to 26.6-fold. And stachyose more significantly promoted A. flavus growth than the other nutrients. Thus, this study demonstrated that, combined with the nutrients content of grains, in addition to lipids, sucrose, stachyose, glutamic acid, and zinc might play key roles in various grains that are differentially infected by A. flavus. Particularly, two new nutrients (arginine and stachyose) of the grains we found significantly stimulate AFB1 production and A. flavus growth, respectively. The results provide new concepts for antifungal methods to protect food and animal feed from AFB1 contamination.
研究领域:
食品科学
·
微生物学
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Food Frontiers
·
2023
·
IF 9.9
Jiayun Fu,Mei Gu,Honglin Yan,Minhui Zhang,Huali Xie,Xiaofeng Yue,Qi Zhang,Peiwu Li
Microbial toxins are important factors that contribute to human diseases and food losses. Predicting the production of these toxins before they occur is a significant challenge. In this study, we innovatively developed a strategy called targeted acquisition of toxin-related immunogen (TATRI) to identify early diagnostic biomarkers for microbial toxins. Taking Aspergillus flavus as an example, we employed an immunoassay-based screening approach to identify nanobodies that exhibited significant response signals to different toxigenic strains. Subsequently, we isolated and purified the specific immunogen pre-aflatoxin biomarker PAB-01 that bound to the selected nanobody. The results showed that the level of PAB-01 was positively correlated with the toxin-producing ability of A. flavus strains and could be detected before the production of aflatoxins. It met the essential requirements as an early diagnostic biomarker for aflatoxin contamination. Protein identification and bioinformatics analysis revealed that PAB-01 is a glycoprotein that can be secreted into the extracellular space. It is located on chromosome 5 of A. flavus and belongs to the 75 family of glycoside hydrolases. Furthermore, we used 7 g/kg as the critical concentration of PAB-01 to diagnose the risk of aflatoxin contamination in stored peanuts, with an accuracy rate of 75.9% for high-risk samples. In summary, this work provides a promising approach for the identification of protein biomarkers prior to microbial toxin production and the establishment of early diagnostic techniques for microbial toxins.
研究领域:
微生物学
·
毒理学
·
食品安全
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分子生物学
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生物技术
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Foods
·
2021
·Vol. 11
·期 1
·93
·
IF 4.35
Chenling Qu,Zhuozhen Li,Xiupin Wang
Aspergillus flavusis a common contaminant in grain, oil and their products. Its metabolite aflatoxin B1(AFB1) has been proved to be highly carcinogenic. Therefore, it is of great importance to find possible antifungal substances to inhibit the growth and toxin production ofAspergillus flavus. Carvacrol (CV) was reported as a potent antifungal monoterpene derived from plants. In this paper, the antifungal effects and mechanism of CV onAspergillus flavuswere investigated. CV was shown good inhibition on the growth ofAspergillus flavusand the production of AFB1. CV used in concentrations ranging from 0, 50, 100 and 200 μg/mL inhibited the germination of spores, mycelia growth and AFB1production dose-dependently. To explore the antifungal mechanism of CV onAspergillus flavus, we also detected the ergosterol content ofAspergillus flavusmycelia, employed Scanning Electron Microscopy (SEM) to observe mycelia morphology and utilized Ultra-High-Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HRMS) to explore the lipidome profiles ofAspergillus flavus. The results showed that the production of ergosterol of mycelia was reduced as the CV treatment concentration increased. SEM photographs demonstrated a rough surface and a reduction in the thickness of hyphae inAspergillus flavustreated with CV (200 µg/mL). In positive ion mode, 21 lipids ofAspergillus flavusmycelium were downregulated, and 11 lipids were upregulated after treatment with 200-µg/mL CV. In negative ion mode, nine lipids ofAspergillus flavusmycelium were downregulated, and seven lipids upregulated after treatment with 200-µg/mL CV. In addition, the analysis of different lipid metabolic pathways between the control and 200-µg/mL CV-treated groups demonstrated that glycerophospholipid metabolism was the most enriched pathway related to CV treatment.Keywords:Aspergillus flavus;carvacrol;untargeted lipidomics;ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS);antifungal activity
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Microbiology Spectrum
·
2023
·Vol. 11
·期 4
·
IF 3.7
Liuke Liang,Wei Zhang,Jing Hao,Yanyu Wang,Shan Wei,Shuaibing Zhang,Yuansen Hu,Yangyong Lv
A variety of essential oils and edible compounds have been widely recognized for their antifungal activity in recent years. In this study, we explored the antifungal activity of estragole from Pimenta racemosa against Aspergillus flavus and investigated the underlying mechanism of action. The results showed that estragole had significant antifungal activity against A. flavus, with a minimum inhibitory concentration of 0.5 μL/mL against spore germination. Additionally, estragole inhibited the biosynthesis of aflatoxin in a dose-dependent manner, and aflatoxin biosynthesis was significantly inhibited at 0.125 μL/mL. Pathogenicity assays showed that estragole had potential antifungal activity against A. flavus in peanut and corn grains by inhibiting conidia and aflatoxin production. Transcriptomic analysis showed that the differentially expressed genes (DEGs) were mainly related to oxidative stress, energy metabolism, and secondary metabolite synthesis following estragole treatment. Importantly, we experimentally verified reactive oxidative species accumulation following downregulation of antioxidant enzymes, including catalase, superoxide dismutase, and peroxidase. These results suggest that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis. These findings expand our knowledge on the antifungal activity and molecular mechanisms of estragole, and provide a basis for estragole as a potential agent against A. flavus contamination.IMPORTANCE Aspergillus flavus contaminates crops and produces aflatoxins, carcinogenic secondary metabolites which pose a serious threat to agricultural production and animal and human health. Currently, control of A. flavus growth and mycotoxin contamination mainly relies on antimicrobial chemicals, agents with side effects such as toxic residues and the emergence of resistance. With their safety, environmental friendliness, and high efficiency, essential oils and edible compounds have become promising antifungal agents to control growth and mycotoxin biosynthesis in hazardous filamentous fungi. In this study, we explored the antifungal activity of estragole from Pimenta racemosa against A. flavus and investigated its underlying mechanism. The results demonstrated that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis.
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INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Chenggang Song,Wuliang Shi,Jian Yang,Gang Ding,Wei Chen,Chengguo Jia,Mingzhe Zhang,Jianchun Qin
The presence of aflatoxins resulting from Aspergillus flavus infection in food poses a significant threat to human health due to their potent carcinogenicity or hepatotoxicity. Monarda didyma essential oil, with 92.3% thymol as the active ingredient, is effective in inhibiting A. flavus infestation during peanut storage. Thymol was found to inhibit the growth of A. flavus with an IC 50 value of 14.5 µg mL −1 . When exposed to thymol stress, A. flavus experiences disruption of its glycolysis and tricarboxylic acid cycle, leading to the accumulation of reactive oxygen species and resulting in cell membrane damage and apoptosis. Furthermore, thymol leads to the downregulation of multiple genes, including aflA , involved in the aflatoxin biosynthesis, resulting in a reduction in the production of aflatoxins. This demonstrates the potential of M. didyma essential oil and thymol as effective inhibitors of mycotoxins, thereby contributing to the resolution of food safety issues.
研究领域:
食品科学
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微生物学
·
药理学
·
真菌学
·
植物化学
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Kunlong Yang,Yue Luo,Tongzheng Sun,Han Qiu,Qingru Geng,Yongxin Li,Man Liu,Nancy P. Keller,Fengqin Song,Jun Tian
Nitric oxide (NO) is a signaling molecule with diverse roles in various organisms. However, its role in the opportunistic pathogen Aspergillus flavus remains unclear. This study investigates the potential of NO, mediated by metabolites from A. oryzae (AO), as an antifungal strategy against A . flavus . We demonstrated that AO metabolites effectively suppressed A . flavus asexual development, a critical stage in its lifecycle. Transcriptomic analysis revealed that AO metabolites induced NO synthesis genes, leading to increased intracellular NO levels. Reducing intracellular NO content rescued A . flavus spores from germination inhibition caused by AO metabolites. Furthermore, exogenous NO treatment and dysfunction of flavohemoglobin Fhb1, a key NO detoxification enzyme, significantly impaired A . flavus asexual development. RNA-sequencing and metabolomic analyses revealed significant metabolic disruptions within tricarboxylic acid (TCA) cycle upon AO treatment. NO treatment significantly reduced mitochondrial membrane potential (Δψm) and ATP generation. Additionally, aberrant metabolic flux within the TCA cycle was observed upon NO treatment. Further analysis revealed that NO induced S-nitrosylation of five key TCA cycle enzymes. Genetic analysis demonstrated that the S-nitrosylated Aconitase Acon and one subunit of succinate dehydrogenase Sdh2 played crucial roles in A . flavus development by regulating ATP production. This study highlights the potential of NO as a novel antifungal strategy to control A . flavus by compromising its mitochondrial function and energy metabolism.
研究领域:
微生物学
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分子生物学
·
真菌学
·
生物化学
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Food Bioscience
·
2026
·
IF 5.9
Xuran Fu,Jiadi Sun,Honglin Yan,Xiyu Cao,Chuanzhi Jiang,Jin Ye,Wei Wang,Jia-Sheng Wang,Xiulan Sun
Climate change could affect the growth and colonization of Aspergillus flavus (A. flavus) in maize, increasing the risk of mycotoxins in aflatoxins (AFs) and cyclopiazonic acid (CPA). However, changes in ecophysiological characteristics of A. flavus under future climate scenarios remain unclear, particularly under alternating temperatures resulting from day and night variations. This study aims to explore the interactive effects of alternating temperatures (28/20 o C and 33/25 o C) under the photoperiod with 13 h light/11h darkness, CO 2 (400 ppm and 1000 ppm), and different water activities (0.93aw, 0.95aw and 0.99aw). The growth rate, lag phase, conidia production, oxidative stress indicators and related mycotoxins (AFs and CPA) of A. flavus were analyzed under a combination of different climatic factors in maize flour agar (MFA) and potato dextrose agar (PDA) medium. The results indicate that water activity is the primary factor regulating A. flavus growth, conidia production, and mycotoxin production. Its single-factor effects and interactions with other factors exert a highly significant influence on all indicators (p<0.001). Elevated alternating temperatures promote the growth of A. flavus . The impact of CO 2 is relatively limited, with significant effects observed only on conidia and CPA. The interaction between alternating temperature, water activity, and CO 2 concentration have an effect on growth and mycotoxin production in A. flavus . However, mycotoxin production does not fully correlate with gene expression. These findings provide valuable baseline data on the interactions between temperature, water activity, and CO 2 concentration in relation to A. flavus growth and mycotoxin production.
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FOOD CONTROL
·
2021
·
IF 5.548
Dan Xu,Mengqi Wei,Shurui Peng,Haizhen Mo,Lin Huang,Lishan Yao,Liangbin Hu
The contamination of food with Aspergillus flavus has caused serious economic losses and posed a great threat to human and animal health. Cumin , a condiment and flavoring in many dishes, was showed to have great potential to prevent A. flavus contamination in the present study. By using cumin essential oil (CEO), the occurrence of A. flavus contamination on peanuts was prevented during the storage period even up to 9 months. We further identified cuminaldehyde as the predominant component in CEO with great inhibitory activity to both the growth of A. flavus and aflatoxin B 1 (AFB 1 ) biosynthesis. The data showed that the minimum inhibitory concentration (MIC) of cuminaldehyde to conidial growth was 0.64 μL/mL, and the mycelia exposed to 0.80 μL/mL cuminaldehyde reduced AFB 1 production by more than 99% in comparison to the control. RNA-Seq profiles showed that some genes, involving the synthesis pathway of ergosterol and AFB 1 , were significantly down-regulated in the transcription by cuminaldehyde. Further investigation confirmed a significantly reduced cellular ergosterol content in the presence of cuminaldehyde, and the qRT-RCR results were also in agreement with that by RNA-Seq, indicating down-regulated expressions of those genes involving ergosterol and AFB 1 synthesis. Taken together, our study strongly supported cuminaldehyde as a potential agent for the prevention of A. flavus contamination.
研究领域:
微生物学
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食品科学
·
分子生物学
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Food Bioscience
·
2026
·
IF 6.2
Yong-xin Li,Chao Pan,Yuting Sun,Zihan Zhou,Yuanhang Ni,Kunlong Yang,Ling Shen,Jun Tian
Aspergillus flavus is a major foodborne fungus capable of producing aflatoxins that threaten food quality and safety. Nitrogen metabolism is closely associated with fungal development and secondary metabolism; however, the roles of nitrate-responsive regulators in aflatoxin biosynthesis remain unclear. In this study, the biological functions of AfnirA and AfcrnA , two regulators involved in nitrate utilization, were investigated in A. flavus through gene deletion and overexpression analyses. Transcriptional profiling showed that both genes responded to changes in nitrogen sources and were induced under nitrogen imbalance conditions. Functional analyses demonstrated that AfnirA and AfcrnA differentially affected fungal growth, conidiation, conidial germination, and sclerotial development. Deletion of AfnirA abolished sclerotia formation, whereas disruption of AfcrnA significantly increased sclerotia production. In addition, the Δ AfcrnA mutant exhibited enhanced sensitivity to osmotic, oxidative, and cell wall stresses, accompanied by increased intracellular reactive oxygen species accumulation. Notably, deletion of AfcrnA markedly promoted aflatoxin B1 production, with an approximately 2.3-fold, and upregulated the expression of aflatoxin biosynthetic genes, including aflC , aflD , and aflP . Subcellular localization analysis revealed nuclear localization of AfnirA , whereas AfcrnA displayed vacuolar-associated cytoplasmic localization. These findings indicate that AfnirA and AfcrnA play distinct roles in regulating fungal development, oxidative stress adaptation, and aflatoxin biosynthesis in A. flavus .
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INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
·
2021
·
IF 5.277
Di Sun,Jin Mao,Zhijian Wang,Hui Li,Liangxiao Zhang,Wen Zhang,Qi Zhang,Peiwu Li
Peanut is an important resource of edible oil and digestible protein in daily life, which is rich in the nutriments and antioxidants such as vitamins, minerals and polyphenols. However, peanut is susceptible to the contamination of Aspergillus flavus ( A. flavus ), which can produce highly carcinogenic toxins that brings serious threats to human health and food safety. Exploring green and effective methods to control A. flavus is meaningful. Herein, a green and economical way to control A. flavus on peanuts was demonstrated. It was found that the growth of A. flavus hyphae and germination of its spores could be inhibited in the presence of α-Fe 2 O 3 nanorods under sunlight irradiation according to the agar diffusion method , flat colony counting method and fluorescence-based live/dead test. The diameter of inhibition zone was 22.3 ± 0.2 mm and the inhibition rate of spores germination was about 60 ± 5%, when the concentration of α-Fe 2 O 3 was 10 mg/mL for 7 h sunlight irradiation. Most important, α-Fe 2 O 3 showed the photocatalytic inhibition of A. flavus on peanuts under sunlight irradiation with the inhibition rate of about 90 ± 5%, and the production of aflatoxin B 1 and aflatoxin B 2 were reduced by 90 ± 2% and 70 ± 3%, respectively. By comparing the fat contents, protein contents, acid value, peroxide value and antioxidative compositions of peanuts, it was found that there was no obvious effect on the quality of peanuts after inhibition treatment. The findings provide a green, safe and economical strategy to control A. flavus on peanuts, which may be as a promising way to be used in food and agro-food preservation.
研究领域:
食品科学
·
微生物学
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 102
·期 15
·6659-6672
·
IF 3.34
Tian Jun,Gan Yeyun,Pan Chao,Zhang Man,Wang Xueyan,Tang Xudong,Peng Xue
The contamination of food with Aspergillus flavus and subsequent aflatoxins is one of the most serious safety problems in the world. In this study of nerol (NEL)’s antifungal mechanism of action, we observed morphological and physiological changes in Aspergillus flavus. We found that NEL resulted in elevated levels of reactive oxygen species (ROS) and calcium ions (Ca 2+ ). On ROS assays, compared with the controls, the proportion of fluorescent cells treated with concentrations of 0.25, 0.5, 1, and 2 μL/mL NEL increased to 8.4 ± 1.07%, 10.2 ± 1.72%, 13.4 ± 0.50%, and 26.2 ± 4.21%, respectively. Increased mitochondrial dysfunction and oxidative stress induced by the interactions between Ca 2+ and ROS subsequently activate the release of cytochrome c and caspase activity. Characteristic changes of apoptosis were also observed via various detection methods, including phosphatidylserine externalization, nuclear condensation, and DNA fragmentation. Meanwhile, we found that the expression of CaMKs increased significantly in NEL-treated cells. In conclusion, our findings indicate that NEL has great potential as an eco-friendly antifungal agent for food preservation.
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