The mxd operon in Shewanella oneidensis MR-1 is induced in response to starvation and regulated by ArcS/ArcA and BarA/UvrY

BMC Microbiology

Research Article

Soni Shukla¹  Jana Müller¹  Kathinka A Jost¹  Alfred M Spormann² 

[1] Department of Civil & Environmental Engineering, Stanford University, 94035-4020, Stanford, CA, USA;Department of Civil & Environmental Engineering, Stanford University, 94035-4020, Stanford, CA, USA;Department of Chemical Engineering, Stanford University, 94035-5025, Stanford, CA, USA;Biomedical Engineering and Science, Stanford University, 94035-5429, Stanford, CA, USA;

关键词: Sodium Lactate;    Lysogeny Broth;    Reporter Strain;    Carbon Starvation;    Planktonic Condition;   

DOI  :  10.1186/1471-2180-13-119

 received in 2013-02-05, accepted in 2013-05-15,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundS. oneidensis MR-1 is a dissimilatory metal-reducing bacterium. Under anoxic conditions S. oneidensis MR-1 attaches to and uses insoluble minerals such as Fe(III) and Mn(IV) oxides as electron acceptors. In the laboratory, S. oneidensis MR-1 forms biofilms under hydrodynamic flow conditions on a borosilicate glass surface; formation of biofilms was previously found to be dependent on the mxd gene cluster (mxdABCD).ResultsThis study revealed environmental and genetic factors regulating expression of the mxd genes in S. oneidensis MR-1. Physiological experiments conducted with a S. oneidensis MR-1 strain carrying a transcriptional lacZ fusion to the mxd promoter identified electron donor starvation as a key factor inducing mxd gene expression. Tn5 mutagenesis identified the ArcS/ArcA two-component signaling system as a repressor of mxd expression in S. oneidensis MR-1 under planktonic conditions. Biofilms of ∆arcS and ∆arcA strains carrying a transcriptional gfp -reporter fused to the mxd promoter revealed a reduced mxd expression, suggesting that ArcS/ArcA are necessary for activation of mxd expression under biofilm conditions. Biofilms of ∆arcS and ∆arcA mutants were unable to form a compact three-dimensional structure consistent with a low level of mxd expression. In addition, BarA/UvrY was identified as a major regulator of mxd expression under planktonic conditions. Interestingly, biofilms of ∆barA and ∆uvrY mutants were able to form three-dimensional structures that were, however, less compact compared to wild type biofilms.ConclusionsWe have shown here that the mxd genes in S. oneidensis MR-1 are controlled transcriptionally in response to carbon starvation and by the ArcS/ArcA and the BarA/UvrY signaling system. BarA might function as a sensor to assess the metabolic state of the cell, including carbon starvation, leading to expression of the mxd operon and therefore control biofilm formation.

【 授权许可】

Unknown   
© Müller et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.