Helmholtz Centre for Infection Research, Department of Microbial Drugs, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
J Agric Food Chem. 2014 Apr 23;62(16):3525-30. doi: 10.1021/jf500153d. Epub 2014 Apr 14.
The sooty blotch and flyspeck (SBFS) syndrome of apples and other fruits is caused by a complex consortium of epiphytic fungi that colonize the fruit cuticula. SBFS fungal strains isolated from apples were screened for growth inhibition of the phytopathogen Colletotrichum fioriniae in dual culture tests. Extracts of 11 isolates of SBFS fungi (Microcyclospora malicola, Microcyclospora pomicola, Microcyclospora tardicrescens, and Microcyclosporella mali) inhibited growth of the test strains and were studied for production of antibiotics. A strain of Microcyclospora tardicrescens strongly inhibited growth and was cultivated on a larger scale to characterize its secondary metabolites. Bioassay-guided fractionation and subsequent structure elucidation by spectroscopic and spectrometric methods (NMR, HRMS) yielded trichothecolone acetate (1) and its novel derivative (S)-7-hydroxytrichothecolone acetate (2) as active principles. Microcyclospora tardicrescens was thus identified as a producer of the hazardous trichothecene type mycotoxins for the first time, which should give reason to monitor these foodborne fungi more carefully in the future.
苹果和其他水果的煤污斑点和蝇粪斑（SBFS）综合征是由定殖在果实表皮的一组复杂的附生真菌引起的。从苹果中分离出的 SBFS 真菌菌株在双培养试验中被筛选出对病原菌胶孢炭疽菌（Colletotrichum fioriniae）的生长抑制作用。11 株 SBFS 真菌（Microcyclospora malicola、Microcyclospora pomicola、Microcyclospora tardicrescens 和 Microcyclosporella mali）的提取物抑制了测试菌株的生长，并对其产生抗生素的能力进行了研究。一株 Microcyclospora tardicrescens 强烈抑制了生长，并在更大规模上进行了培养，以对其次生代谢物进行了表征。生物测定指导的分离和随后通过光谱和光谱方法（NMR、HRMS）的结构阐明，得到了曲酸醋酸酯（1）及其新型衍生物（S）-7-羟基曲酸醋酸酯（2）作为活性成分。因此，Microcyclospora tardicrescens 被首次鉴定为产生危害健康的曲霉菌毒素的真菌，这应该促使我们在未来更加仔细地监测这些食源性真菌。
