AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens

Issac Abraham Sybiya Vasantha Packiavathy; Arunachalam Kannappan; Sivaprakasam Thiyagarajan; Ramanathan Srinivasan; Danaraj Jeyapragash; John Bosco John Paul; Pazhanivel Velmurugan; Arumugam Veera Ravi

doi:10.3389/fmicb.2021.634593

AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens

Front Microbiol. 2021 Apr 14:12:634593. doi: 10.3389/fmicb.2021.634593. eCollection 2021.

Affiliations

¹ Department of Biotechnology, Karpagam Academy of Higher Education, Coimbatore, India.
² Department of Biotechnology, Alagappa University, Karaikudi, India.
³ Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
⁴ Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
⁵ Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou, China.
⁶ Department of Electronics and Communication Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India.
⁷ Centre for Materials Engineering and Regnerative Medicine, Bharath Institute of Higher Education and Research, Chennai, India.

Abstract

Quorum sensing (QS) is a signaling mechanism governed by bacteria used to converse at inter- and intra-species levels through small self-produced chemicals called N-acylhomoserine lactones (AHLs). Through QS, bacteria regulate and organize the virulence factors' production, including biofilm formation. AHLs can be degraded by an action called quorum quenching (QQ) and hence QQ strategy can effectively be employed to combat biofilm-associated bacterial pathogenesis. The present study aimed to identify novel bacterial species with QQ potential. Screening of Palk Bay marine sediment bacteria for QQ activity ended up with the identification of marine bacterial isolate 28 (MSB-28), which exhibited a profound QQ activity against QS biomarker strain Chromobacterium violaceum ATCC 12472. The isolate MSB-28 was identified as Psychrobacter sp. through 16S-rRNA sequencing. Psychrobacter sp. also demonstrated a pronounced activity in controlling the biofilm formation in different bacteria and biofilm-associated virulence factors' production in P. aeruginosa PAO1. Solvent extraction, heat inactivation, and proteinase K treatment assays clearly evidence the enzymatic nature of the bioactive lead. Furthermore, AHL's lactone ring cleavage was confirmed with experiments including ring closure assay and chromatographic analysis, and thus the AHL-lactonase enzyme production in Psychrobacter sp. To conclude, this is the first report stating the AHL-lactonase mediated QQ activity from marine sediment bacteria Psychrobacter sp. Future work deals with the characterization, purification, and mass cultivation of the purified protein and should pave the way to assessing the feasibility of the identified protein in controlling QS and biofilm-mediated multidrug resistant bacterial infections in mono or multi-species conditions.

Keywords: AHL-lactonase; Pseudomonas aeruginosa; Psychrobacter sp.; marine Palk Bay sediment; quorum quenching.