一株海洋真菌Penicillium sp.QF046的细菌群体感应抑制剂的分离和鉴定

Isolation and Identification of Quorum Sensing Inhibitors from a Strain of Marine Fungus Penicillium sp. QF046

目的:从海洋真菌中筛选得到新型群体感应抑制剂,并对其进行活性评价。方法:首先利用紫色杆菌CV026指示菌株对真菌发酵粗提物进行活性筛选。其次通过18S r DNA序列比对进行菌种鉴定,同时采用硅胶柱色谱、凝胶柱色谱和高效液相色谱等技术并结合活性追踪检测分离纯化的活性化合物,再通过核磁质谱分析确定其结构。最后利用定量测定方法检测其在亚抑菌浓度下对紫色杆菌紫色菌素产量影响以及RT-PCR检测与QS调控相关基因的m RNA表达的影响。结果:从海藻共生菌中筛选到一株具有紫色杆菌群体感应抑制活性的海洋真菌Penicillium sp.QF046,其次级代谢产物中纯化到的活性化合物根据结构鉴定为一种星形曲霉毒素(asteltoxin)。该化合物对于紫色杆菌群体感应抑制浓度低于阳性对照化合物呋喃酮C30,同时抑制了群体感应相关基因m RNA水平的表达。结论:从海洋真菌Penicillium sp.QF046代谢产物中发现了一种抑制紫色杆菌群体感应的星形曲霉毒素,为进一步通过结构改造研发新型抗菌药物提供良好的前体化合物。

Objective： The purpose of this article is to find new quorum sensing inhibitors（QSI） from strains of marine fungus and analyze the inhibitory activity. Methods： Quorum sensing inhibitory activity of crude extracting from this strain was monitored by Chromobacterium violaceum CV026 and the purpose strain was identified based on phylogenetic analysis of 18 S r DNA sequences. The bioactivator with anti-QS activity was separated by bioactivity-guided fractionation from the crude extract, using silica-gel column chromatography, Sephadex LH-20 gel column chromatography and HPLC, and was identified based on spectroscopic analysis. Its QS inhibitory activity was measured by quantifying QS-controlled violacein production, and the effect of m RNA of QS-regulated gene was measured by RT-PCR. Results： A marine fungus strain Penicillium sp.QF046 from seaweed symbiotic was found to have significant C.violaceum QS inhibitory activity. The QSI in the secondary metabolites was purified and identified as a kind of asteltoxin. It significantly reduced violacein production in a lower concentration than furanone C30 and the m RNA level of QS-related genes, indicating inhibition of QS. Conclusions： An asteltoxin from marine fungi strain Penicillium sp. QF046 can inhibit QS in C. violaceum, and could be a precursor compound for further study of novel antibacterial based on structural modification.