Aix-Marseille Univ, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France.
Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU Méditerranée Infection, Marseille, France.
Sci Rep. 2019 Feb 28;9(1):3028. doi: 10.1038/s41598-019-39927-3.
The opportunistic pathogen Mycobacterium ulcerans, which is responsible for Buruli ulcer, synthesizes a series of plasmid-encoded macrolide exotoxins termed mycolactones. These toxins destabilize cell membranes and induce apoptosis-associated pleiotropic effects including tissue destruction, analgesic and anti-inflammatory effects. Despite its medical interest, M. ulcerans is primarily an environmental mycobacterium and the primary functions of mycolactones in the natural ecosystems are unknown. High throughput biochemical profiling findings suggested that M. ulcerans may interact with fungi. Here, we report that semi-purified and purified mycolactones significantly enhance spore germination of Scedosporium apiospermum, Fusarium equiseti and Mucor circinelloides; and that M. ulcerans mycolactones significantly attract colonies of M. circinelloides whereas no significant effect was observed on S. apiospermum and F. equiseti. These experimental results suggest that mycolactones exhibit a chemoattractant activity independent of their cytotoxicity. In natural ecosystems, M. ulcerans mycolactones may act as spore germination inducers and chemoattractants for some fungi, suggesting a novel role for this unique class of mycobacterial toxins in natural ecosystems.
机会性病原体溃疡分枝杆菌（Mycobacterium ulcerans）可导致皮肤溃疡，它能合成一系列被称为“菌 落 因”（mycolactones）的质体编码大环内酯外毒素。这些毒素破坏细胞膜并诱导细胞凋亡相关的多效性效应，包括组织破坏、镇痛和抗炎作用。尽管溃疡分枝杆菌具有医学意义，但它主要是一种环境分枝杆菌，其在自然生态系统中的主要功能尚不清楚。高通量生化分析结果表明，溃疡分枝杆菌可能与真菌相互作用。在这里，我们报告称，半纯化和纯化的菌 落 因显著增强了棘孢木霉（Scedosporium apiospermum）、绳状青霉（Fusarium equiseti）和卷枝毛霉（Mucor circinelloides）的孢子萌发；而溃疡分枝杆菌的菌 落 因则显著吸引卷枝毛霉的菌落，而对棘孢木霉和绳状青霉则没有明显影响。这些实验结果表明，菌 落 因表现出一种独立于其细胞毒性的化学引诱活性。在自然生态系统中，溃疡分枝杆菌的菌 落 因可能作为某些真菌的孢子萌发诱导剂和化学引诱剂，这表明这种独特的分枝杆菌毒素在自然生态系统中具有新的作用。
