查找使用阿拉丁产品的科研文献

Cuminaldehyde in cumin essential oils prevents the growth and aflatoxin B1 biosynthesis of Aspergillus flavus in peanuts

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.

Inhibitory effect of (E)-2-hexenal as a potential natural fumigant on Aspergillus flavus in stored peanut seeds

Weibin Ma,Luling Zhao,Yanli Xie

The efficacy of eight kinds of green leaf volatiles (GLVs) was investigated as potential natural antifungal agents against Aspergillus flavus in this study. Based on the in vitro assay, volatile phase inhibitory effects of the selected eight GLVs were consistently more effective on A. flavus growth than contact phase inhibitory effects, and ( E )-2-hexenal exhibited the highest efficacy as it could totally inhibited growth of A. flavus at concentrations of 0.032   μL/mL air and 1.6   μL/mL under vapor and contact conditions, respectively. Furthermore, results obtained from the in vivo assay demonstrated that ( E )-2-hexenal possessed potent fumigant activity in reducing A. flavus infection in stored peanut seeds, as it could completely inhibit colonization of A. flavus at 0.32   μL/mL air. Both in vitro and in vivo assay results provided convincing evidence that ( E )-2-hexenal, one of the GLVs that is naturally present in many plants, can potentially be used as a highly efficient and eco-friendly antifungal fumigant to protect peanut seeds from contamination of A. flavus during storage.

Electrochemical analysis of specific catalase activity during development of Aspergillus flavus and its correlation with aflatoxin B1 production

Yanjing Yun,Zhisong Lu,Jing Yang,Taotao Liang,Gang Xiao,Yan Qiao,Yang Liu

Aflatoxin B 1 (AFB 1 ) contamination causes huge economic losses. To explore the correlation between catalase (CAT) and AFB 1 production during fungal development, we fabricated an electrochemical CAT-activity sensor by measuring residual H 2 O 2 after enzymatic degradation. The sensor made by palladium nanoparticles/carbonized bacterial cellulose nanocomposites exhibits a linear range over 0.5–3.5 U/mL and a detection limit of 0.434 U/mL. Both dry weight and CAT activity of mycelia continuously increase. But, the latter shows a greater increase than the former after three days. Specific CAT activity in crude enzyme extract of A. flavus was quantified. It maintains at ~25.00 U/mg for 3 days and enhances to 28.91 and 45.30 U/mg, respectively, on days 4 and 5. AFB 1 production follows the same trend. On days 4 and 5, AFB 1 concentration reaches 201.35 and 767.9 ng/mL, respectively. The positive correlation between specific CAT activity and AFB 1 production suggests that CAT is involved in AFB 1 biosynthesis.

Antifungal mechanisms of binary combinations of volatile organic compounds produced by lactic acid bacteria strains against Aspergillus flavus

Yi Zhang,Bin Li,Mingze Fu,Zhirong Wang,Kewei Chen,Muying Du,Zsolt Zalán,Ferenc Hegyi,Jianquan Kan

Aspergillus flavus（A. flavus）, a common humic fungus known for its ability to infect agricultural products, served as the subject of investigation in this study. The primary objective was to assess the antifungal efficacy and underlying mechanisms of binary combinations of five volatile organic compounds (VOCs) produced by lactic acid bacteria, specifically in their inhibition of A. flavus . This assessment was conducted through a comprehensive analysis, involving biochemical characterization and transcriptomic scrutiny. The results showed that VOCs induce notable morphological abnormalities in A. flavus conidia and hyphae. Furthermore, they disrupt the integrity of the fungal cell membrane and cell wall, resulting in the leakage of intracellular contents and an increase in extracellular electrical conductivity. In terms of cellular components, VOC exposure led to an elevation in malondialdehyde content while concurrently inhibiting the levels of total lipids, ergosterol, soluble proteins, and reducing sugars. Additionally, the impact of VOCs on A. flavus energy metabolism was evident, with significant inhibition observed in the activities of key enzymes, such as Na + /K + -ATPase, malate dehydrogenase, succinate dehydrogenase, and chitinase. And they were able to inhibit aflatoxin B 1 synthesis. The transcriptomic analysis offered further insights, highlighting that differentially expressed genes (DEGs) were predominantly associated with membrane functionality and enriched in pathways about carbohydrate and amino acid metabolism. Notably, DEGs linked to cellular components and energy-related mechanisms exhibited down-regulation, thereby corroborating the findings from the biochemical analyses. In summary, these results elucidate the principal antifungal mechanisms of VOCs, which encompass the disruption of cell membrane integrity and interference with carbohydrate and amino acid metabolism in A. flavus .

Antifungal efficacy of paeonol on Aspergillus flavus and its mode of action on cell walls and cell membranes

Qian Li,Ying Zhao,Xiaoman Zhu,Yanli Xie

Aspergillus flavus ( A. flavus ) contaminates agricultural products and endangers human health. Plant-derived natural compounds are potential antifungal agents that are superior to chemical fungicides. Paeonol can effectively inhibit A. flavus growth , and its potential antifungal actions were investigated by examining a series of phenotypic changes. The damage to cell walls was visualized by surface ultrastructural characterization and quantified by the decreases in β-1,3-glucan and chitin content. The integrity of the cell membranes was damaged, as indicated by propidium iodide (PI) staining, cell constituent release, relative conductivity, pH values, and the contents of extracellular metal ions (e.g., K + and Na + ). Furthermore, paeonol decreased the content of total lipids, induced lipid peroxidation, altered glycerol content, and destroyed trehalose . Finally, paeonol also reduced the pathogenicity of A. flavus in both peanuts and corn kernels. This study proposes paeonol as a new antifungal agent for use against A. flavus and provides new insights into the mechanism underlying the alterations in A. flavus in response to paeonol.

o-Vanillin, a promising antifungal agent, inhibits Aspergillus flavus by disrupting the integrity of cell walls and cell membranes

Li Qian,Zhu Xiaoman,Xie Yanli,Zhong Yue

Abstract o -Vanillin is a natural product that has been widely applied in the food and pharmaceutical industries. In this study, we determined that o -vanillin can strongly inhibit the growth of Aspergillus flavus mycelia. However, the inhibition mechanism of o -vanillin is still elusive. The ultrastructural morphology of mycelia was injured, and the cell walls were destroyed. The OH functional groups on cell walls were altered, and the content of protein in mycelial cell walls was reduced by o -vanillin. The content of β-1,3-glucan in cell walls was significantly ( P < 0.05) reduced by o -vanillin in a dose-dependent manner, while chitin was not markedly affected. Moreover, o -vanillin led to an increase in the permeability of cell membranes. o -Vanillin also exhibited a promising antifungal effect on contaminated corn kernels. Therefore, o -vanillin inhibited the growth of mycelia by disrupting the integrity of cell walls and cell membranes. This study not only sheds light on the antifungal mechanism of o -vanillin but also indicates that it is a promising agent for the control of A. flavus infection. Key points o -Vanillin has strong inhibitory effects on A. flavus. o -Vanillin destroyed the integrity of cell walls and cell membranes. o -Vanillin could effectively inhibit the growth of A. flavus on corn kernels.

PP2C phosphatases Ptc1 and Ptc2 dephosphorylate PGK1 to regulate autophagy and aflatoxin synthesis in the pathogenic fungus Aspergillus flavus

Zhuo Zhu,Mingkun Yang,Guang Yang,Bei Zhang,Xiaohong Cao,Jun Yuan,Feng Ge,Shihua Wang

(E)-2-Hexenal, as a Potential Natural Antifungal Compound, Inhibits Aspergillus flavus Spore Germination by Disrupting Mitochondrial Energy Metabolism

Weibin Ma,Luling Zhao,Wenhong Zhao,Yanli Xie

Fungal contamination imposes threats to agriculture and food production and human health. A method to safely and effectively restrict fungal contamination is still needed. Here, we report the effect and mode of action of (E)-2-hexenal, one of the green leaf volatiles (GLVs), on the spore germination of Aspergillus flavus, which can contaminate a variety of crops. The EC50 value, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC) of (E)-2-hexenal were 0.26, 1.0, and 4.0 μL/mL, respectively. As observed by scanning electron microscopy (SEM), the surface morphology of A. flavus spores did not change after treatment with the MIC of (E)-2-hexenal, but the spores were shrunken and depressed upon treatment with the MFC of (E)-2-hexenal. The MIC and MFC of (E)-2-hexenal induced evident phosphatidylserine (PS) externalization of A. flavus spores as detected by double staining with Annexin V-FITC and propidium iodide, indicating that early apoptosis was potentially induced. Furthermore, sublethal doses of (E)-2-hexenal disturbed pyruvate metabolism and reduced the intracellular soluble protein content of A. flavus spores during the early stage of germination, and MIC treatment decreased acetyl-CoA and ATP contents by 65.7 ± 3.7% and 53.9 ± 4.0% (P < 0.05), respectively. Additionally, the activity of mitochondrial dehydrogenases was dramatically inhibited by 23.8 ± 2.2% (P < 0.05) at the MIC of (E)-2-hexenal. Therefore, the disruption of mitochondrial energy metabolism and the induction of early apoptosis are involved in the mechanism of action of (E)-2-hexenal against A. flavus spore germination.

Effect of Aspergillus flavus Fungal Elicitor on the Production of Terpenoid Indole Alkaloids in Catharanthus roseus Cambial Meristematic Cells

Chuxin Liang,Chang Chen,Pengfei Zhou,Lv Xu,Jianhua Zhu,Jincai Liang,Jiachen Zi,Rongmin Yu

This study reported the inducing effect ofAspergillus flavusfungal elicitor on biosynthesis of terpenoid indole alkaloids (TIAs) inCatharanthus roseuscambial meristematic cells (CMCs) and its inducing mechanism. According to the results determined by HPLC and HPLC-MS/MS, the optimal condition of theA. flavuselicitor was as follows: after suspension culture ofC. roseusCMCs for 6 day, 25 mg/LA. flavusmycelium elicitor were added, and the CMC suspensions were further cultured for another 48 h. In this condition, the contents of vindoline, catharanthine, and ajmaline were 1.45-, 3.29-, and 2.14-times as high as those of the control group, respectively. Transcriptome analysis showed thatD4H,G10H,GES,IRS,LAMT,SGD,STR,TDC, andORCA3were involved in the regulation of this induction process. The results of qRT-PCR indicated that the increasing accumulations of vindoline, catharanthine, and ajmaline inC. roseusCMCs were correlated with the increasing expression of the above genes. Therefore,A. flavusfungal elicitor could enhance the TIA production ofC. roseusCMCs, which might be used as an alternative biotechnological resource for obtaining bioactive alkaloids.Keywords:Catharanthus roseus;cambial meristematic cells;Aspergillus flavus;terpenoid indole alkaloids;biosynthesis

Biocontrol potential of 1-pentanal emitted from lactic acid bacteria strains against Aspergillus flavus in red pepper (Capsicum annuum L.)

Bin Li,Zhirong Wang,Gang Yang,Shan Huang,Shenglan Liao,Kewei Chen,Muying Du,Zsolt Zalán,Ferenc Hegyi,Jianquan Kan

Aflatoxin contamination poses a significant threat to world health and has caused huge economic losses to countries worldwide. The application of volatile organic compounds (VOCs) has emerged as one of the most promising strategies for the prevention and control of fungal contamination. In this work, first, VOCs produced by six lactic acid bacteria (LAB) strains exhibited excellent inhibition activity against the growth of Aspergillus flavus . Then, gas chromatograph-mass spectrometry (GC-MS) identified 32 compounds from captured VOCs of LAB. In addition, partial least square (PLS) analysis revealed that 1-pentanal, 1-pentanol, glycidol, 1- hexanol and 1-heptanol are the compounds most related to antifungal effect in volatile profiles, demonstrating excellent inhibition against A. flavus on both potato dextrose agar (PDA) plates and red pepper powder in next antifungal assay. In vitro experiments revealed 1-pentanal to have the highest antifungal activity of the five VOCs, with a minimal inhibitory concentration (MIC) of 40 μL/L. Scanning electron microscopy (SEM) proved that exposure to 1-pentanal caused A. flavus to exhibit mycelial shriveling and failed conidia formation. Meanwhile, our results showed that fumigation with 1-pentanal had no adverse effect on the quality of red pepper powder. These results indicate that 1-pentanal, identified as the component with the highest antifungal activity in this study, is a promising bio-preservative with the potential to prevent A. flavus contamination of red pepper.

Antifungal Activity of Essential Oil Compounds (Geraniol and Citral) and Inhibitory Mechanisms on Grain Pathogens (Aspergillus flavus and Aspergillus ochraceus)

Xi Tang,Ye-Lin Shao,Ya-Jie Tang,Wen-Wen Zhou

The grain contamination byAspergillusspp. has been a serious issue. This study exhibited the excellent antifungal effects of the essential oil compounds (EOCs) geraniol and citral against common grain pathogens (A. flavusandA. ochraceus) in vitro and in situ. The inhibitory mechanisms were also evaluated from the perspective of cell membrane permeability, reactive oxygen species (ROS) generation, andAspergillusspp. growth-related gene expression. Meanwhile, the combined effects of EOCs in the vapor phase and modified atmosphere packaging (MAP) were examined to find an alternative preservation method for controllingAspergillusspp. The results indicated that citral exhibited the antifungal activity mainly by downregulating the sporulation- and growth-related genes for both pathogens. Geraniol displayed inhibitory effectiveness againstA. flavuspredominantly by inducing the intracellular ROS accumulation and showed toxicity againstA. ochraceusprincipally by changing cell membrane permeability. Furthermore, the synthetic effects of EOCs and MAP (75% CO2and 25% N2) induced better grain quality than the current commercial fumigant AlP. These findings reveal that EOCs have potential to be a novel grain preservative for further application.Keywords:antifungal activity;geraniol;citral;Aspergillus;relative electric conductivity;reactive oxygen species;gene expression;modified atmosphere packaging

Insights into the antifungal and antiaflatoxin efficacy of Citrus limon leaf essential oil against Aspergillus flavus based on multi-omics

Huanyan Liang,Xueyun Tang,Chenghua Luo,Mengting Xian,Qian Li,Lei Zhang,Xiangsheng Zhao

Citrus limon leaf essential oil (LLEO) inhibits Aspergillus flavus growth. • (R)-(+)-citronellal is the major antifungal component of LLEO. • LLEO induces membrane damage, disrupts metabolism and modulates oxidative stress. • LLEO reduces aflatoxin B 1 accumulation in postharvest Arecae Semen and peanuts. Agricultural food commodities are highly susceptible to fungal contamination and mycotoxin accumulation, with aflatoxin B 1 (AFB 1 ), produced by Aspergillus species being the most toxic. Given the urgent demand for eco-friendly treatments, this study investigated the antifungal and antiaflatoxin activities of Citrus limon leaf essential oil (LLEO) against Aspergillus flavus , as well as its underlying mechanisms. LLEO significantly inhibited A. flavus growth and AFB 1 accumulation. SPME-GC-MS analysis identified (R)-(+)-citronellal as the major antifungal component of LLEO, with other minor constituents potentially contributing synergistically. Mechanistically, LLEO reduced ergosterol content, modulated oxidative stress, and disrupted energy metabolism. Integrative multi-omics analysis further revealed that LLEO suppressed mycelial growth and aflatoxin production by modulating primary metabolism, peroxisome function, and AF synthesis pathways. Notably, LLEO effectively inhibited A. flavus infection in Arecae Semen and peanuts when applied as vapors in the headspace of sealed samples. Collectively, these findings demonstrate that LLEO is a promising natural preservative for the postharvest control and safety of agricultural commodities.