Bacillaenes: Decomposition Trigger Point and Biofilm Enhancement in Bacillus

Huayue Li; Xiao Han; Yujing Dong; Shanshan Xu; Chao Chen; Yingang Feng; Qiu Cui; Wenli Li

doi:10.1021/acsomega.0c03389

Bacillaenes: Decomposition Trigger Point and Biofilm Enhancement in Bacillus

ACS Omega. 2021 Jan 8;6(2):1093-1098. doi: 10.1021/acsomega.0c03389. eCollection 2021 Jan 19.

Authors

Huayue Li^{1

2}, Xiao Han¹, Yujing Dong¹, Shanshan Xu¹, Chao Chen^{3

4

5}, Yingang Feng^{3

4

5}, Qiu Cui^{3

4

5}, Wenli Li^{1

2}

Affiliations

¹ Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
² Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
³ Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
⁴ Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
⁵ Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.

Abstract

Bacillaenes are a class of poly-unsaturated enamines produced by Bacillus strains that are notoriously unstable toward light, oxygen, and normal temperature. Herein, in an in-depth study of this highly unstable chemotype, the stability and biological function of bacillaenes were investigated. The structure change of the bacillaene scaffold was tracked by time-course ¹H NMR data analysis coupled with the differential analysis of 2D-NMR spectra method, which was demonstrated to be a "domino" effect triggered by 4',5'-cis (2 and 3) configuration rearranged to trans (2a and 3a). These findings provide the possibility for stabilizing the bacillaene scaffold by chemical modification of its trigger points. In the biofilm assay, compounds 1 and 2 accelerated self-biofilm formation in Bacillus methylotrophicus B-9987 at low concentrations of 1.0 and 0.1 μg/mL. Interestingly, bacillaenes play dual roles as antibiotic and biofilm enhancers in a dose-dependent manner, both of which serve in the self-protection of Bacillus.