Amicoumacins from a desert bacterium: quorum sensing inhibitor against Chromobacterium violaceum

Abstract

In our study, the anti-quorum sensing (QS) activity of fermentation broth from TRM B-02, a bacterium isolated from Taklimakan desert, was investigated using the biosensor bioassay on Chromobacterium violaceum ATCC12472. TRM B-02 was 100% similar to Bacillus subtilis subsp. Inaquosorum KCTC 13429^(T) by genotypic and phenotypic analyses. Based on anti-QS activity tracking, six known amicoumacins, named as AI-77-H (1), AI-77-F (2), amicoumacin B (3), amicoumacin C (4), AI-77-C (5) and bacilosarcins D (6), were isolated and identified. Among them, compounds 1–3 exhibited a better inhibitory effect on C. violaceum ATCC12472. Further research suggested that compounds 1–3 could significantly down-regulate the expressions of violacein operon A (vioA), vioB, vioD and vioE and up-regulate vioC. Docking experiments indicated that compounds 1–3 may act as an inhibitor of violacein biosynthetic pathway competitively inhibiting the binding of flavin adenine dinucleotide (FAD) with the vioD enzyme.

Keywords:

• Quorum sensing inhibitor
• Bacillus subtilis
• amicoumacins

Disclosure statement

There was no conflict of interest in all the authors.

Author contributions

Zhong-Bo Zhou and Chuan-Xing Wan designed the experiment and performed the statistical analysis. Wen-Pan Shi carried out the study and Hong Zeng drafted the manuscript. All authors read and approved the final version of the manuscript.

Additional information

Funding

This work was supported by National Science Foundation [grant no.U1703236], the Projects of Engineering Laboratory of Chemical Resources Utilization in South Xinjiang of Xinjiang Production and Construction Corps [grant no. CRUZD1901] and the Innovation Team Project in Key Field of Xinjiang Production & Construction Corps [grant no. 2017CB014].