Detection of Diverse N-Acyl-Homoserine Lactones in Vibrio alginolyticus and Regulation of Biofilm Formation by N-(3-Oxodecanoyl) Homoserine Lactone In vitro

Abstract

Quorum sensing (QS) is a cell-to-cell communication system based on the exchange of small intercellular signal molecules, such as N-Acyl homoserine lactones (AHLs), which act as cell-density mediators of QS gene expression, and are highly variable both in types and amounts in most Gram-negative Proteobacteria. Understanding the regulation of AHLs may contribute to the elucidation of cell density-dependent phenomena, such as biofilm formation. Vibrio alginolyticus is among the most frequently observed marine opportunistic Vibrio pathogens. However, AHL production of this species and its effects on biofilm formation remain to be understood. Here, our study reported the diverse AHL profiles of 47 marine-isolated V. alginolyticus strains and the effects of exogenous 3-oxo-C10-HSL on biofilm formation under different temperature conditions (16°C and 28°C). A total of 11 detected AHLs were produced by the isolates, of which 3-OH-C4-HSL, 3-oxo-C10-HSL and 3-oxo-C14-HSL comprised the largest proportions. We also observed that moderate levels of exogenous 3-oxo-C10-HSL (10 and 20 μM) could induce or enhance biofilm formation and alter its structure, while high levels (40 and 100 μM) did not significantly improve and even inhibited biofilm formation in V. alginolyticus. Further, regulation by exogenous 3-oxo-C10-HSL was both concentration- and temperature-dependent in V. alginolyticus.

Serine/threonine kinase PpkA coordinates the interplay between T6SS2 activation and quorum sensing in the marine pathogen Vibrio alginolyticus

“…V. alginolyticus pathogenicity is regulated by a V. harveyilike quorum sensing (QS) system, a bacterial cell-cell communication system controled by three sets of autoinducers (AIs) (Liu et al, 2017). LuxO and LuxR play pivotal roles in translating the signals from AIs and other environmental cues, e.g., temperature fluctuations, into regulation of the expression of diverse genes (Wang et al, 2007;Rui et al, 2008;Gu et al, 2016).…”

Quorum Quenching Properties and Probiotic Potentials of Intestinal Associated Bacteria in Asian Sea Bass Lates calcarifer

“…V. harveyi produces a singular signal of AHL type, namely harveyi autoinducer 1 (HAI-1), whereas V. alginolyticus strains produce diverse kinds of AHLs dominantly including 3-oh-C 4 -HSL, 3-oxo-C 10 -HSL, and 3-oxo-C 14 -HSL [42,43]. By comparing the calculated R f values on TLC plates, the studied V. harveyi and V. alginolyticus generated 3-oh-C 4 -HSL and 3-oxo-C 10 -HSL, respectively.…”

“…With the expression of β-galactosidase activity in the presence of 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside (X-Gal), A. tumefaciens NTL4 recognizes substituted (carbonyl or hydroxyl) or unsubstituted AHL-derivatives with side chain lengths from 4 to 12 carbons with the exception of C 4 -AHL [10,67]. The media used for A. tumefaciens NTL4 and C. violaceum CV026 were included with 50 µg/mL of gentamycin and kanamycin, respectively [42]. Pseudomonas fluorescence P3/pME6863 was used as a positive control in AHL degradation assays [26].…”

“…Pseudomonas fluorescence P3/pME6863 was used as a positive control. Given that our objective was the isolation of AHL degrading bacteria incapable of producing any AHLs, the selected isolates were also examined for the production of any exogenous AHLs by cross-feeding assay, as described by Liu et al (2017) [42]. Each isolate was streaked on Luria-Bertani (LB) agar plates alongside two reporter strains (C. violaceum CV026 and A. tumefaciens NTL4) and incubated at 28 • C for 48 h. Prior to using A. tumefaciens NTL4, the plates were overlaid with a new layer agar containing X-Gal for detection of β-galactosidase activity.…”

“…To qualitatively explore the range of AHLs produced by V. harveyi and V. alginolyticus, these bacteria were cross-fed alongside the biosensors C. violaceum CV026 and A. tumefaciens NTL4 as described by Liu et al (2017) [42]. In order to extract the AHLs, V. harveyi and V. alginolyticus were grown in TSB medium supplemented with 2% NaCl to stationary phase (OD 600 2.7).…”