School of Biological Sciences, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand.
School of Biological Sciences, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand; Luxembourg Institute of Science and Technology (LIST), 5 rue Bommel, Z.A.E. Robert Steichen, L-4940 Hautcharage, Luxembourg.
Fungal Genet Biol. 2022 Jan;158:103646. doi: 10.1016/j.fgb.2021.103646. Epub 2021 Nov 24.
Antimicrobial volatile organic compounds (VOCs) may provide fungi an advantage over other competing microorganisms. As these defensive metabolites are often produced in response to microbial competitors, they are easily overlooked in axenic cultures. We used media supplemented with spent medium from Candida albicans to induce the expression of a broad-spectrum antimicrobial response in a previously uncharacterised white-rot fungus, Scytinostroma sp. Crude extractions of Scytinostroma sp. metabolites were found to be cytotoxic to fibroblast cells and antimicrobial to filamentous fungi, yeasts and Gram-positive bacteria. Volatile antimicrobial activity was observed for Scytinostroma sp. cultures and metabolite extracts using antimicrobial assays in bi-compartmentalised plates. Culture headspace analysis using solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) revealed a pronounced shift in Scytinostroma sp. VOCs when cultured on media supplemented with C. albicans spent medium. We observed a significant increase in the levels of 45 identified VOCs, including 7 metabolites with reported antimicrobial activity. Using preparative HPLC combined with GC-MS, we determined that isovelleral is likely to be the main broad-spectrum antimicrobial metabolite produced by Scytinostroma sp. Isovelleral is a sesquiterpene dialdehyde with both antibiotic and antifeedant properties, previously detected in fruit bodies of other Basidiomycetes.
抗菌挥发性有机化合物 (VOCs) 可能使真菌相对于其他竞争微生物具有优势。由于这些防御性代谢物通常是在应对微生物竞争时产生的，因此在无菌培养物中很容易被忽视。我们使用补充了白色念珠菌废培养基的培养基来诱导以前未被描述的白腐真菌 Scytinostroma sp. 表达广谱抗菌反应。Scytinostroma sp. 代谢物的粗提取物被发现对成纤维细胞具有细胞毒性，并且对丝状真菌、酵母和革兰氏阳性细菌具有抗菌作用。使用双隔间板中的抗菌测定法，观察到 Scytinostroma sp. 培养物和代谢物提取物的挥发性抗菌活性。使用固相微萃取 (SPME) 结合气相色谱-质谱 (GC-MS) 对培养物顶空进行分析，结果表明当在补充有白色念珠菌废培养基的培养基上培养时，Scytinostroma sp. 的 VOCs 发生了明显变化。我们观察到 45 种鉴定出的 VOC 水平显著增加，其中包括 7 种具有报道的抗菌活性的代谢物。使用制备型 HPLC 结合 GC-MS，我们确定异戊二醛很可能是 Scytinostroma sp. 产生的主要广谱抗菌代谢物。异戊二醛是一种具有抗生素和抗食性的倍半萜二醛，先前在其他担子菌的子实体中检测到过。
