Atoui A, Mitchell D, Mathieu F, Magan N, Lebrihi A
Département Bioprocédés et Systèmes Microbiens, Laboratoire de Génie Chimique UMR5503 (CNRS/INPT/UPS), Ecole Nationale Supérieure Agronomique de Toulouse, Institut National Polytechnique de Toulouse, Castanet Tolosan, France.
J Appl Microbiol. 2007 Oct;103(4):961-8. doi: 10.1111/j.1365-2672.2007.03320.x.
Aspergillus carbonarius is an important ochratoxin A (OTA)-producing fungus which is responsible for toxin contamination of grapes and wine. The objectives of this study were to examine the partitioning of OTA in mycelium and conidia of a range of A. carbonarius strains on artificial grape juice and defined media, to determine the excretion patterns of OTA from these spores, and the effect of organic acids used in wine production on OTA excretion from conidia.
The results showed that 60-70% of the OTA was accumulated in the conidia of a number of different isolates of A. carbonarius. Calculations showed that on different defined media, an amount of 0.011- to 0.1-pg OTA was present per conidium. The OTA in spores was found to be rapidly excreted into the medium during the initial few hours after conidial germination leading to an increase of OTA in must during maceration for wine production. The presence of tartaric acid inhibited OTA production, but malic acid enhanced this production during mycelial growth. These acids were also shown to affect the time course of germination and the rate of OTA excretion from conidia during germination.
This study is the first to examine and show the partitioning of OTA into spores of strains of A. carbonarius and that rapid excretion of OTA from spores could be a reason for OTA accumulation in musts during wine production.
Conidia of A. carbonarius could be a major source of OTA contamination of grapes used in wine production. This information could help in the development of effective prevention strategies to minimize wine contamination with this important mycotoxin.
黑曲霉是一种重要的产赭曲霉毒素A（OTA）的真菌，它会导致葡萄和葡萄酒的毒素污染。本研究的目的是研究一系列黑曲霉菌株在人工葡萄汁和特定培养基上OTA在菌丝体和分生孢子中的分配情况，确定这些孢子中OTA的排泄模式，以及葡萄酒生产中使用的有机酸对分生孢子中OTA排泄的影响。
结果表明，60%-70%的OTA积累在多种不同的黑曲霉菌株的分生孢子中。计算表明，在不同的特定培养基上，每个分生孢子中存在0.011至0.1皮克的OTA。发现孢子中的OTA在分生孢子萌发后的最初几个小时内迅速排泄到培养基中，导致葡萄酒生产浸渍过程中葡萄汁中OTA含量增加。酒石酸的存在抑制了OTA的产生，但苹果酸在菌丝体生长过程中增强了这种产生。这些酸还被证明会影响萌发的时间进程以及分生孢子萌发过程中OTA的排泄速率。
本研究首次检测并表明OTA在黑曲霉菌株的孢子中的分配情况，并且孢子中OTA的快速排泄可能是葡萄酒生产过程中葡萄汁中OTA积累的一个原因。
黑曲霉的分生孢子可能是葡萄酒生产中使用的葡萄受OTA污染的主要来源。这些信息有助于制定有效的预防策略，以尽量减少这种重要霉菌毒素对葡萄酒的污染。
