Liuzzi Vania C, Fanelli Francesca, Tristezza Mariana, Haidukowski Miriam, Picardi Ernesto, Manzari Caterina, Lionetti Claudia, Grieco Francesco, Logrieco Antonio F, Thon Michael R, Pesole Graziano, Mulè Giuseppina
Institute of Sciences of Food Production, National Research Council Bari, Italy.
Institute of Sciences of Food Production, National Research Council Lecce, Italy.
Front Microbiol. 2017 Jan 9;7:2162. doi: 10.3389/fmicb.2016.02162. eCollection 2016.
Ochratoxin A (OTA) is a nephrotoxic and potentially carcinogenic mycotoxin produced by several species of and , contaminating grapes, wine and a variety of food products. We recently isolated from OTA contaminated soil vineyard a novel free-living strain of sp. , ITEM 17016, able to degrade OTA into the non-toxic catabolic product ochratoxin α. Biochemical studies suggested that the degradation reaction proceeds via peptide bond hydrolysis with phenylalanine (Phe) release. In order to identify genes responsible for OTA degradation we performed a differential gene expression analysis of ITEM 17016 grown in the presence or absence of the toxin. Among the differentially expressed genes, six peptidases up-regulated at 6 h were identified. The degrading activity of the carboxypeptidase PJ_1540 was confirmed in a heterologous system. The enrichment analysis for Gene Ontology terms confirmed that OTA degradation proceeds through peptidase activities and revealed the over-representation of pathways related to Phe catabolism. These results indicate that Phe may represent an energy source for this sp. strain and that OTA degrading reaction triggers the modulation of further catabolic activities.
赭曲霉毒素A（OTA）是由几种曲霉属和青霉属真菌产生的具有肾毒性且有潜在致癌性的霉菌毒素，它会污染葡萄、葡萄酒及多种食品。我们最近从受OTA污染的葡萄园土壤中分离出一种新型的自由生活的曲霉属菌株，ITEM 17016，它能够将OTA降解为无毒的分解代谢产物赭曲霉毒素α。生化研究表明，降解反应通过肽键水解并释放苯丙氨酸（Phe）来进行。为了鉴定负责OTA降解的基因，我们对在有或没有该毒素存在的情况下生长的ITEM 17016进行了差异基因表达分析。在差异表达的基因中，鉴定出了6种在6小时时上调的肽酶。羧肽酶PJ_1540的降解活性在异源系统中得到了证实。基因本体术语的富集分析证实，OTA降解是通过肽酶活性进行的，并揭示了与苯丙氨酸分解代谢相关途径的过度富集。这些结果表明，苯丙氨酸可能是这种曲霉属菌株的能量来源，并且OTA降解反应触发了进一步分解代谢活动的调节。
