Alternariol monomethyl ether(AME),a mycotoxin produced by Alternaria spp.,yet its microbial degradation mechanisms remain poorly understood.This study investigated the biodegradation of AME by Aspergillus oryzae durin...Alternariol monomethyl ether(AME),a mycotoxin produced by Alternaria spp.,yet its microbial degradation mechanisms remain poorly understood.This study investigated the biodegradation of AME by Aspergillus oryzae during coculture.Three AME-degrading strains were isolated from grapes,with strain A.oryzae PC2 showing the highest efficiency and achieving 92.8%AME degradation within 4 days.The results indicated that intracellular components,rather than cell wall adsorption,were responsible for the degradation by A.oryzae PC2.Protease K and SDS treatments significantly reduced degradation activity,while partial activity remained after heat treat-ment,indicating proteinaceous factors within the intracellular components.The sulfited metabolite,AME-SO_(3)^(-),was detected and qualified via HPLC-MS and Fourier Transform infrared spectroscopy(FTIR).The acute toxi-cology predictions,combined with in vivo evidence from a mealworm model,consistently demonstrated that the toxicity of AME-SO_(3)^(-)was significantly lower than that of the parent AME,as evidenced by markedly improved locomotor activity.Molecular dynamics simulations revealed that AME stably binds within the active site of a 3′-phosphoadenosine 5′-phosphosulfate sulfotransferase(GenBank:KDE85275.1),with CYS112 implicated in SO_(3)^(2-)and·SO_(3)^(-)formation.Quantum chemical analysis indicated that H25 of AME is susceptible to electrophilic attack,while O18 is a likely site for nucleophilic radical attack.Reactive molecular dynamics simulations further showed that hydroxyl and oxygen radicals target H25,forming a radical intermediate(AME·),which subse-quently reacts with·SO_(3)^(-)at O18 to form AME-SO_(3)^(-).These results reveal a novel pathway for the conversion of AME to AME-SO3-via sulfitation,and provide a potential strategy for mycotoxin detoxification using microbial systems.展开更多
基金supported by Natural Science Foundation of Hunan Province(project no.2024JJ5374)National Natural Science Foundation of China(project no.31871858).
文摘Alternariol monomethyl ether(AME),a mycotoxin produced by Alternaria spp.,yet its microbial degradation mechanisms remain poorly understood.This study investigated the biodegradation of AME by Aspergillus oryzae during coculture.Three AME-degrading strains were isolated from grapes,with strain A.oryzae PC2 showing the highest efficiency and achieving 92.8%AME degradation within 4 days.The results indicated that intracellular components,rather than cell wall adsorption,were responsible for the degradation by A.oryzae PC2.Protease K and SDS treatments significantly reduced degradation activity,while partial activity remained after heat treat-ment,indicating proteinaceous factors within the intracellular components.The sulfited metabolite,AME-SO_(3)^(-),was detected and qualified via HPLC-MS and Fourier Transform infrared spectroscopy(FTIR).The acute toxi-cology predictions,combined with in vivo evidence from a mealworm model,consistently demonstrated that the toxicity of AME-SO_(3)^(-)was significantly lower than that of the parent AME,as evidenced by markedly improved locomotor activity.Molecular dynamics simulations revealed that AME stably binds within the active site of a 3′-phosphoadenosine 5′-phosphosulfate sulfotransferase(GenBank:KDE85275.1),with CYS112 implicated in SO_(3)^(2-)and·SO_(3)^(-)formation.Quantum chemical analysis indicated that H25 of AME is susceptible to electrophilic attack,while O18 is a likely site for nucleophilic radical attack.Reactive molecular dynamics simulations further showed that hydroxyl and oxygen radicals target H25,forming a radical intermediate(AME·),which subse-quently reacts with·SO_(3)^(-)at O18 to form AME-SO_(3)^(-).These results reveal a novel pathway for the conversion of AME to AME-SO3-via sulfitation,and provide a potential strategy for mycotoxin detoxification using microbial systems.
