A1S_2811, a CheA/Y-like hybrid two-component regulator from Acinetobacterbaumannii ATCC17978, is involved in surface motility and biofilm formation in this bacterium.

Rong Chen,Ruifu Yang,Ruichen Lv,Zongmin Du,Yafang Tan,Min Wang,Yanfeng Yan,Lisheng Xiao,Yajun Song,Yanping Luo,Yujun Cui

doi:10.1002/mbo3.510

Rong Chen, Ruifu Yang + Show 9 more

Open Access

https://doi.org/10.1002/mbo3.510

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Abstract

Two‐component systems in Acinetobacter baumannii are associated with its virulence, drug resistance, motility, biofilm formation, and other characteristics. In this study, we used RecAb, a genetic engineering method, to investigate the function of A1S_2811 in A. baumannii strain ATCC17978. A1S_2811, a hypothetical hybrid sensor histidine kinase/response regulator, has four histidine‐containing phosphotransfer domains, a CheA‐like regulatory domain, and a CheY‐like receiver domain at its C terminus. Compared with the ATCC17978 strain, both surface motility and biofilm formation at the gas–liquid interface decreased significantly in the A1S_2811 knock‐out strain. The number of pilus‐like structures and the amount of extrapolymeric substances on the cell surface also decreased in the A1S_2811 null strain. Transcription of abaI, which encodes an N‐acylhomoserine lactone synthase in A. baumannii , decreased significantly in the A1S_2811 null strain, and supplementation with synthetic N‐(3‐oxodecanoyl) homoserine‐l‐lactone rescued the surface motility and biofilm formation phenotype in the null mutant. We speculate that A1S_2811 regulates surface motility and biofilm formation, not by regulating type IV pili‐associated genes expression, but by regulating the chaperone/usher pili‐associated csuA/ABCDE operon and the AbaI‐dependent quorum‐sensing pathway‐associated A1S_0112‐0119 operon instead.

Highlights

Acinetobacter baumannii, a ubiquitous, nonfermentative gram-negative bacterium, is an important infectious, nosocomial pathogen with an extraordinary ability to acquire antibiotic resistance determinants and adapt to hospital environments (Gonzalez-Villoria & Valverde- Garduno, 2016)
We have shown that deleting A1S_2811 decreased the surface motility and biofilm formation of A. baumannii ATCC17978
We found that the motility and biofilm formation phenotypes of ATCC17978 were closely related

Summary

| INTRODUCTION

Acinetobacter baumannii, a ubiquitous, nonfermentative gram-negative bacterium, is an important infectious, nosocomial pathogen with an extraordinary ability to acquire antibiotic resistance determinants and adapt to hospital environments (Gonzalez-Villoria & Valverde- Garduno, 2016). CheA in Escherichia coli and its homolog chpA in Pseudomonas aeruginosa, which are components of the chemotactic signal transduction system in these bacteria, have been investigated in detail (Baker, Wolanin, & Stock, 2006; Elowitz, Surette, Wolf, Stock, & Leibler, 1999; Li, Swanson, Simon, & Weis, 1995; Stewart, 1997; Whitchurch et al, 2004) Both of them are TCSs. It was reported that cheA/Y in E. coli and chpA/Y in P. aeruginosa play regulatory roles in controlling bacterial motility via flagella or type IV pili (Alon et al, 1998; Baker et al, 2006; Bertrand, West, & Engel, 2010; Elowitz et al, 1999; Li et al, 1995; Whitchurch et al, 2004); A1S_2811 in A. baumannii has not been studied as yet. Investigating the A1S_2811 hypothetical chemotactic signal transduction system component in A. baumannii ATCC17978 has potential to contribute to better understanding of the function of TCSs in A. baumannii and to elucidate its motility mechanism

| MATERIALS AND METHODS

Findings

| DISCUSSION