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Patterned hydrophobic domains in the exopolymer matrix of Shewanella oneidensis MR-1 biofilms.

ABSTRACT: Water-dispersible amphiphilic surface-engineered quantum dots (QDs) were found to be strongly accumulated within discrete zones of the exopolymer network of Shewanella oneidensis MR-1 biofilms, but not on the cell surfaces. These microdomains showed a patterned distribution in the exopolymer matrix, which led to a restricted diffusion of the amphiphilic nanoparticles.

SUBMITTER: Aldeek F

PROVIDER: S-EPMC3568607 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

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Patterned hydrophobic domains in the exopolymer matrix of Shewanella oneidensis MR-1 biofilms.

Aldeek Fadi F Schneider Raphaël R Fontaine-Aupart Marie-Pierre MP Mustin Christian C Lécart Sandrine S Merlin Christophe C Block Jean-Claude JC

Applied and environmental microbiology 20121207 4

Water-dispersible amphiphilic surface-engineered quantum dots (QDs) were found to be strongly accumulated within discrete zones of the exopolymer network of Shewanella oneidensis MR-1 biofilms, but not on the cell surfaces. These microdomains showed a patterned distribution in the exopolymer matrix, which led to a restricted diffusion of the amphiphilic nanoparticles. ...[more]

PMID: 23220957

Similar Datasets

Spatiometabolic stratification of Shewanella oneidensis biofilms.

Project description:Biofilms, or surface-attached microbial communities, are both ubiquitous and resilient in the environment. Although much is known about how biofilms form, develop, and detach, very little is understood about how these events are related to metabolism and its dynamics. It is commonly thought that large subpopulations of cells within biofilms are not actively producing proteins or generating energy and are therefore dead. An alternative hypothesis is that within the growth-inactive domains of biofilms, significant populations of living cells persist and retain the capacity to dynamically regulate their metabolism. To test this, we employed unstable fluorescent reporters to measure growth activity and protein synthesis in vivo over the course of biofilm development and created a quantitative routine to compare domains of activity in independently grown biofilms. Here we report that Shewanella oneidensis biofilm structures reproducibly stratify with respect to growth activity and metabolism as a function of size. Within domains of growth-inactive cells, genes typically upregulated under anaerobic conditions are expressed well after growth has ceased. These findings reveal that, far from being dead, the majority of cells in mature S. oneidensis biofilms have actively turned-on metabolic programs appropriate to their local microenvironment and developmental stage.

| S-EPMC1636161 | biostudies-literature

Redox and pH microenvironments within Shewanella oneidensis MR-1 biofilms reveal an electron transfer mechanism.

Project description:The goal of this research was to quantify the variations in redox potential and pH in Shewanella oneidensis MR-1 biofilms respiring on electrodes. We grew S. oneidensis MR-1 on a graphite electrode, which was used to accept electrons for microbial respiration. We modified well-known redox and pH microelectrodes with a built-in reference electrode so that they could operate near polarized surfaces and quantified the redox potential and pH profiles in these biofilms. In addition, we used a ferri-/ferrocyanide redox system in which electrons were only transferred by mediated electron transfer to explain the observed redox potential profiles in biofilms. We found that regardless of the polarization potential of the biofilm electrode, the redox potential decreased toward the bottom of the biofilm. In a fully redox-mediated control system (ferri-/ferrocyanide redox system), the redox potential increased toward the bottom when the electrode was the electron acceptor. The opposite behavior of redox profiles in biofilms and the redox-controlled system is explained by S. oneidensis MR-1 biofilms not being redox-controlled when they respire on electrodes. The lack of a significant variation in pH implies that there is no proton transfer limitation in S. oneidensis MR-1 biofilms and that redox potential profiles are not caused by pH.

| S-EPMC3238545 | biostudies-literature

Quantitative proteome of Shewanella oneidensis MR-1

Project description:We investigated the anode-specific responses of Shewanella oneidensis MR-1, an exoelectroactive ammaproteobacterium, using for the first time iTRAQ and 2D-LC MS/MS driven membrane proteomics to compare protein abundances in S. oneidensis when generating power in MFCs, and growing in a continuous culture.

2016-12-08 | PXD004090 | Pride

Iron triggers ?So prophage induction and release of extracellular DNA in Shewanella oneidensis MR-1 biofilms.

Project description:Prophages are ubiquitous elements within bacterial chromosomes and affect host physiology and ecology in multiple ways. We have previously demonstrated that phage-induced lysis is required for extracellular DNA (eDNA) release and normal biofilm formation in Shewanella oneidensis MR-1. Here, we investigated the regulatory mechanisms of prophage ?So spatiotemporal induction in biofilms. To this end, we used a functional fluorescence fusion to monitor ?So activation in various mutant backgrounds and in response to different physiological conditions. ?So induction occurred mainly in a subpopulation of filamentous cells in a strictly RecA-dependent manner, implicating oxidative stress-induced DNA damage as the major trigger. Accordingly, mutants affected in the oxidative stress response (?oxyR) or iron homeostasis (?fur) displayed drastically increased levels of phage induction and abnormal biofilm formation, while planktonic cells were not or only marginally affected. To further investigate the role of oxidative stress, we performed a mutant screen and identified two independent amino acid substitutions in OxyR (T104N and L197P) that suppress induction of ?So by hydrogen peroxide (H2O2). However, ?So induction was not suppressed in biofilms formed by both mutants, suggesting a minor role of intracellular H2O2 in this process. In contrast, addition of iron to biofilms strongly enhanced ?So induction and eDNA release, while both processes were significantly suppressed at low iron levels, strongly indicating that iron is the limiting factor. We conclude that uptake of iron during biofilm formation triggers ?So-mediated lysis of a subpopulation of cells, likely by an increase in iron-mediated DNA damage sensed by RecA.

| S-EPMC4136115 | biostudies-literature

Transcript map of Shewanella oneidensis MR-1

Project description:High-resolution tiling analysis of the MR-1 transcriptome in defined lactate minimal medium

2012-07-19 | GSE39468 | GEO

Transcript map of Shewanella oneidensis MR-1

Project description:High-resolution tiling analysis of the MR-1 transcriptome under diverse growth conditions The conditions include aerobic growth in Luria-Bertani broth (LB), aerobic growth in defined lactate minimal medium, anaerobic growth in defined lactate minimal medium with 20mM dimethyl sulfoxide as the electron acceptor, anaerobic growth in defined lactate minimal medium with 10mM iron (III) citrate as the electron acceptor, 10 minutes post heat shock at 42oC see GSE39468 for tiling data on lactate minimal media

2013-03-18 | GSE45217 | GEO

Transcript structures in Shewanella oneidensis MR-1

Project description:5' RNASeq of mRNA from S. oneidensis MR-1 grown aerobically in Luria-Bertani broth (LB) and defined lactate minimal medium

2013-03-21 | GSE45313 | GEO

dRNA-seq of Shewanella oneidensis MR-1

Project description:We combined high-resolution tiling microarrays and 5'-end RNA sequencing to obtain a genome-wide map of transcription start sites (TSSs) for Shewanella oneidensis MR-1. To test the reliability of these TSSs, we compared our result to those from differential RNA sequencing (dRNA-seq), which discriminates primary and processed ends of transcripts. We found that our identified TSSs tend to have significantly more mapped reads in the TEX(+) sample than the TEX(-) sample. Overall, the dRNA-seq results support the validity of our predictions for TSS.

2014-06-12 | GSE58292 | GEO

Transcript structures in Shewanella oneidensis MR-1

Project description:5' RNA-Seq of mRNA from S. oneidensis MR-1 grown aerobically in defined lactate medium

2012-07-19 | GSE39474 | GEO

Observation of dielectric universalities in albumin, cytochrome C and Shewanella oneidensis MR-1 extracellular matrix.

Project description:The electrodynamics of metals is well understood within the Drude conductivity model; properties of insulators and semiconductors are governed by a gap in the electronic states. But there is a great variety of disordered materials that do not fall in these categories and still respond to external field in an amazingly uniform manner. At radiofrequencies delocalized charges yield a frequency-independent conductivity ? 1(?) whose magnitude exponentially decreases while cooling. With increasing frequency, dispersionless conductivity starts to reveal a power-law dependence ? 1(?)?? s with s?<?1 caused by hopping charge carriers. At low temperatures, such Universal Dielectric Response can cross over to another universal regime with nearly constant loss ????1/??=?const. The powerful research potential based on such universalities is widely used in condensed matter physics. Here we study the broad-band (1-1012?Hz) dielectric response of Shewanella oneidensis MR-1 extracellular matrix, cytochrome C and serum albumin. Applying concepts of condensed matter physics, we identify transport mechanisms and a number of energy, time, frequency, spatial and temperature scales in these biological objects, which can provide us with deeper insight into the protein dynamics.

| S-EPMC5691187 | biostudies-literature

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