OxyR-controlled surface polysaccharide production and biofilm formation in Acinetobacter oleivorans DR1
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The genomes of several Acinetobacter species possess three distinct polysaccharide-producing operons [two poly-N-acetyl glucosamine (PNAG) and one K-locus]. Using a microfluidic device, an increased amount of polysaccharides and enhanced biofilm formation were observed following continuous exposure to H2O2 and removal of the H2O2-sensing key regulator, OxyR, in Acinetobacter oleivorans DR1 cells. Gene expression analysis revealed that genes located in PNAG1, but not those in PNAG2, were induced and that genes in the K-locus were expressed in the presence of H2O2. Interestingly, the expression of the K-locus gene was enhanced in the PNAG1 mutant and vice versa. The absence of either OxyR or PNAG1 resulted in enhanced biofilm formation, higher surface hydrophobicity, and increased motility, implying that K-locus-driven polysaccharide production in both the oxyR and PNAG1 deletion mutants may be related to these phenotypes. Both the oxyR and K-locus deletion mutants were more sensitive to H2O2 compared with the wildtype and PNAG1 mutant strains. Purified OxyR binds to the promoter regions of both polysaccharide operons with a higher affinity toward the K-locus promoter. Although oxidized OxyR could bind to both promoter regions, the addition of dithiothreitol further enhanced the binding efficiency of OxyR, suggesting that OxyR might function as a repressor for controlling these polysaccharide operons.
KeywordsAcinetobacter OxyR Exopolysaccharides Poly-N-acetyl glucosamine Capsular polysaccharides Biofilm
This work was supported by grants from the National Research Foundation of Korea (No. NRF-2019R1A2C1088452).
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Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Arakawa Y, Wacharotayankun R, Nagatsuka T, Ito H, Kato N, Ohta M (1995) Genomic organization of the Klebsiella pneumoniae cps region responsible for serotype K2 capsular polysaccharide synthesis in the virulent strain Chedid. J Bacteriol 177(7):1788–1796. https://doi.org/10.1128/jb.177.7.1788-1796.1995 CrossRefPubMedPubMedCentralGoogle Scholar
- Cywes-Bentley C, Skurnik D, Zaidi T, Roux D, Deoliveira RB, Garrett WS, Lu X, O'Malley J, Kinzel K, Zaidi T, Rey A, Perrin C, Fichorova RN, Kayatani AK, Maira-Litran T, Gening ML, Tsvetkov YE, Nifantiev NE, Bakaletz LO, Pelton SI, Golenbock DT, Pier GB (2013) Antibody to a conserved antigenic target is protective against diverse prokaryotic and eukaryotic pathogens. Proc Natl Acad Sci U S A 110(24):2209–2218. https://doi.org/10.1073/pnas.1303573110 CrossRefGoogle Scholar
- Goller C, Wang X, Itoh Y, Romeo T (2006) The cation-responsive protein NhaR of Escherichia coli activates pgaABCD transcription, required for production of the biofilm adhesin poly-β-1,6-N-acetyl-D-glucosamine. J Bacteriol 188(23):8022–8032. https://doi.org/10.1128/JB.01106-06 CrossRefPubMedPubMedCentralGoogle Scholar
- He X, Lu F, Yuan F, Jiang D, Zhao P, Zhu J, Cheng H, Cao J, Lu G (2015) Biofilm formation caused by clinical Acinetobacter baumannii isolates is associated with overexpression of the AdeFGH efflux pump. Antimicrob Agents Chemother 59(8):4817–4825. https://doi.org/10.1128/AAC.00877-15 CrossRefPubMedPubMedCentralGoogle Scholar
- Heo YJ, Chung IY, Cho WJ, Lee BY, Kim JH, Choi KH, Lee JW, Hassett DJ, Cho YH (2010) The major catalase gene (katA) of Pseudomonas aeruginosa PA14 is under both positive and negative control of the global transactivator OxyR in response to hydrogen peroxide. J Bacteriol 192(2):381–390. https://doi.org/10.1128/JB.00980-09 CrossRefPubMedGoogle Scholar
- Hu D, Liu B, Dijkshoorn L, Wang L, Reeves PR (2013) Diversity in the major polysaccharide antigen of Acinetobacter baumannii assessed by DNA sequencing, and development of a molecular serotyping scheme. PLoS One 8(7):e70329. https://doi.org/10.1371/journal.pone.0070329 CrossRefPubMedPubMedCentralGoogle Scholar
- Kim HJ, Eom HJ, Park C, Jung J, Shin B, Kim W, Chung N, Choi IG, Park W (2016) Calcium carbonate precipitation by Bacillus and Sporosarcina strains isolated from concrete and analysis of the bacterial community of concrete. J Microbiol Biotechnol 26(3):540–548. https://doi.org/10.4014/jmb.1511.11008 CrossRefPubMedGoogle Scholar
- LeBlanc JJ, Brassinga AK, Ewann F, Davidson RJ, Hoffman PS (2008) An ortholog of OxyR in Legionella pneumophila is expressed postexponentially and negatively regulates the alkyl hydroperoxide reductase (ahpC2D) operon. J Bacteriol 190(10):3444–3455. https://doi.org/10.1128/JB.00141-08 CrossRefPubMedPubMedCentralGoogle Scholar
- Little DJ, Pfoh R, Le Mauff F, Bamford NC, Notte C, Baker P, Guragain M, Robinson H, Pier GB, Nitz M, Deora R, Sheppard DC, Howell PL (2018) PgaB orthologues contain a glycoside hydrolase domain that cleaves deacetylated poly-β-(1,6)-N-acetylglucosamine and can disrupt bacterial biofilms. PLoS Pathog 14(4):e1006998. https://doi.org/10.1371/journal.ppat.1006998 CrossRefPubMedPubMedCentralGoogle Scholar
- Reid AN, Whitfield C (2005) Functional analysis of conserved gene products involved in assembly of Escherichia coli capsules and exopolysaccharides: evidence for molecular recognition between Wza and Wzc for colanic acid biosynthesis. J Bacteriol 187(15):5470–5481. https://doi.org/10.1128/JB.187.15.5470-5481.2005 CrossRefPubMedPubMedCentralGoogle Scholar
- Wang X, Dubey AK, Suzuki K, Baker CS, Babitzke P, Romeo T (2005) CsrA post-transcriptionally represses pgaABCD, responsible for synthesis of a biofilm polysaccharide adhesin of Escherichia coli. Mol Microbiol 56(6):1648–1663. https://doi.org/10.1111/j.1365-2958.2005.04648.x CrossRefPubMedGoogle Scholar
- Wang Y, Andole Pannuri A, Ni D, Zhou H, Cao X, Lu X, Romeo T, Huang Y (2016) Structural basis for translocation of a biofilm-supporting exopolysaccharide across the bacterial outer membrane. J Biol Chem 291(19):10046–10057. https://doi.org/10.1074/jbc.M115.711762 CrossRefPubMedPubMedCentralGoogle Scholar
- Whitfield C (2006) Biosynthesis and assembly of capsular polysaccharides in Escherichia coli. Annu Rev Biochem 75:39–68. https://doi.org/10.1146/annurev.biochem.75.103004.142545 CrossRefPubMedGoogle Scholar