GqqA, a novel protein in Komagataeibacter europaeus involved in bacterial quorum quenching and cellulose formation

Abstract

BackgroundWe report on the functional screening and identification of an active quorum quenching (QQ) gene in the Komagataeibacter europaeus strain CECT 8546, which is a member of the acetic acid bacteria (AAB).ResultsUsing a previously published screening protocol (Schipper et al., in Appl Environ Microbiol 75:224–233, 2009. doi: 10.1128/AEM.01389-08) for QQ genes, we identified a single gene, designated gqqA, that interfered strongly with bacterial quorum sensing (QS) in various reporter strains. It encodes for a 281-amino acid protein with a molecular mass of 30 kDa. Although the GqqA protein is similar to predicted prephenate dehydratases, it does not complement Escherichia coli mutants of the pheA gene, thus indicating a potentially different function. Recombinant GqqA protein attenuated QS-dependent pyocyanin production and swarming motility in the Pseudomonas aeruginosa strain PAO1. Moreover, GqqA quenched the QS response of the Agrobacterium tumefaciens NTL4 and the Chromobacterium violaceum CV026 reporter strains. Interestingly, the addition of recombinant GqqA protein to growing cultures of the Komagataeibacter europaeus strain CECT 8546 altered the cellulose production phenotype of CECT 8546 and other AAB strains. In the presence of GqqA protein, cells were planktonic, and no visible cellulose biofilms formed. The addition of low levels of N-acylhomoserine lactones maintained the biofilm formation phenotype.ConclusionsOur data provide evidence for an interconnection between QS and AAB cellulose biofilm formation as well as QQ activity of the GqqA protein.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0482-y) contains supplementary material, which is available to authorized users.

Physicochemical characterization of high-quality bacterial cellulose produced by Komagataeibacter sp. strain W1 and identification of the associated genes in bacterial cellulose production

“…16 A recent study showed that gqqA encoded a novel protein involving in bacterial quorum quenching and cellulose formation, indicating more attention should be paid to BC synthesis mechanisms in bacteria. 17 Since BC production is naturally occurring, most BCproducing bacteria are oen isolated from the carbohydratecontaining substances such as rotten fruits, kombucha and vinegar. 16,18,19 In the present study, a bacterium belonging to the genus Komagataeibater was rstly isolated from a famous vinegar factory located in Yongchun, Quanzhou, China.…”

Aii810, a Novel Cold-Adapted N-Acylhomoserine Lactonase Discovered in a Metagenome, Can Strongly Attenuate Pseudomonas aeruginosa Virulence Factors and Biofilm Formation

“…The method used was described previously, with some modifications ( Ishida et al, 1998 ; Tang et al, 2015 ; Valera et al, 2016 ). Briefly, P. aeruginosa PAO1, which was grown overnight in LB, was diluted to 10 6 CFU/ml in a 12-well cell culture plate with different concentrations of sterile Aii810 (0.05, 0.5, or 5 U/ml).…”

“…AHL-lactonases degrade AHLs by breaking the lactone bond ( Dong et al, 2000 ); AHL-acylases hydrolyze AHLs by degrading the amide linkage and separating the AHL into homoserine lactone and fatty acid ( Lin et al, 2003 ); AHL-oxidases degrade signal molecules by oxidizing the u-1, u-2, and u-3 carbons of the acyl chain of AHL ( Chowdhary et al, 2007 ). Furthermore, some enzymes have shown anti-QS activity against P. aeruginosa infection ( Bijtenhoorn et al, 2011a ; Migiyama et al, 2013 ; Tang et al, 2015 ; Valera et al, 2016 ). Very few reports are available on lactonases with novel characteristics, such as cold adaptation and high hydrolytic activity, because such enzymes are rare.…”

Molecular aspects of bacterial nanocellulose biosynthesis

“…Recently, a novel cellulose biosynthesis regulator, the quorum‐quenching protein GqqA, has been described. The addition of recombinant GqqA protein to growing cultures of the Komagataeibacter europaeus CECT8546 exerted a strong impact on cellulose production (Valera et al ., ). The density of the culture increased overtime in the presence of the GqqA protein, whereas the control cultures did not display any altered behaviour.…”

“…(Valera et al . () suggested that this effect is attributable to alterations in the produced AHL molecules.…”