Abstract Fusaric acid (FA) is a secondary metabolite produced by several Fusarium species that commonly is isolated from maize and maize-based foods and feeds, and is toxic to some plants and animals, most notably cotton. Fusarinolic acid (FnA) is closely related to FA and is enzymatically derived from it, but much less is known about its toxicity to humans and other animals. We determined the effects of water activity (aW – 0.95, 0.98 and 0.995), temperature (15°, 25° and 30 °C), incubation time (7, 14, 21 and 28 days) and their interactions on FA and FnA production by two strains of F. temperatum isolated from maize growing on sterile maize grain. The amount of FA and FnA accumulated was measured by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). Both compounds were accumulated by both strains of F. temperatum under all evaluated conditions. The amount of FnA produced always exceeded the amount of FA produced (max 50,000 ng/g and 4,500 ng/g, respectively). Temperature, aW, incubation time, and the two- and three-way interactions amongst them all significantly impacted FA and FnA accumulation. Factors favouring fungal growth and mycotoxin production include insect damage, high humidity, delays in harvest, and improper (wet) storage. Grain colonization by F. temperatum begins in the field, but fungal growth and mycotoxin production can easily continue in storage if conditions are right. Thus, from a toxicological point of view, F. temperatum represents a risk for maize under both field and storage conditions. Our data enable better risk estimates and strategies to reduce FA and FnA in the food and feed chains. The highest level of FA was detected at 0.995aW and was independent of temperature and length of incubation, suggesting that there is a limit to the amount of FA that can be accumulated by F. temperatum growing under laboratory conditions. Strikingly high amounts of FnA were observed under all incubation conditions, often exceeding FA levels by 20× to 200× . This result suggests that FnA is more important to the fungus than is FA, and that FA might be little more than an intermediate in a pathway to FnA. The role of the accumulated FnA is unknown, but its role as a toxin may have been discounted since studies to date report limited toxicity. However, if FnA is tested for toxicity at higher levels, such as those identified in this study, then it could have significant toxicological, or other effects that have not previously been considered.

中文翻译：

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水分活度和温度对温度镰刀菌产镰刀菌酸和镰刀菌酸的影响

摘要 Fusaric acid (FA) 是几种镰刀菌属物种产生的次生代谢物，通常从玉米和玉米类食物和饲料中分离出来，对一些植物和动物有毒，尤其是棉花。Fusarinolic acid (FnA) 与 FA 密切相关，是从它酶促衍生的，但对其对人类和其他动物的毒性知之甚少。我们确定了水分活度（aW – 0.95、0.98 和 0.995）、温度（15°、25° 和 30 °C）、孵育时间（7、14、21 和 28 天）及其对 FA 和 FnA 生产的相互作用的影响通过从生长在不育玉米粒上的玉米中分离出的两株 F. tempatum。FA 和 FnA 的积累量通过高效液相色谱法与电喷雾电离串联质谱法 (HPLC/ESI-MS/MS) 相结合进行测量。在所有评估条件下，两种化合物均由两种 F. tempatum 菌株积累。产生的 FnA 量总是超过产生的 FA 量（最大分别为 50,000 ng/g 和 4,500 ng/g）。温度、aW、孵育时间以及它们之间的双向和三向相互作用都显着影响了 FA 和 FnA 的积累。有利于真菌生长和霉菌毒素产生的因素包括昆虫损害、高湿度、收获延迟和不当（湿）储存。F. tempatum 的谷物定植始于田间，但如果条件合适，真菌生长和霉菌毒素的产生很容易在储存中继续。因此，从毒理学的角度来看，F. tempatum 代表了在田间和储存条件下对玉米的风险。我们的数据有助于更好地评估风险并制定策略，以减少食品和饲料链中的 FA 和 FnA。在 0.995aW 处检测到最高水平的 FA，并且与温度和孵育时间无关，这表明在实验室条件下生长的 F. tempatum 可以积累的 F​​A 量是有限的。在所有孵育条件下都观察到了惊人的大量 FnA，通常超过 FA 水平 20 到 200 倍。这一结果表明 FnA 对真菌比 FA 更重要，并且 FA 可能只是 FnA 途径中的中间体。累积的 FnA 的作用尚不清楚，但由于迄今为止的研究报告毒性有限，因此它作为毒素的作用可能被低估了。但是，如果 FnA 在更高水平上进行毒性测试，例如本研究中确定的那些，