Shewanella oneidensis MR-1 etrA deletion mutant strain expression profiling determines fine-tuning regulatory role in anaerobic metabolism
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ABSTRACT: Comparisson of expression profiling of a etrA deletion mutant strain (experimental sample) with that of the wild type Shewanella oneidensis MR-1 strain to assess global direct/indirect genetic regulation EtrA in Shewanella oneidensis MR-1 shares 73.6% and 50.8% amino acid sequence identity with the oxygen-sensing regulator Fnr in E. coli and Anr in Pseudomonas aeruginosa, respectively; however, its regulatory role of anaerobic metabolism in Shewanella spp. is complex and not well understood. Whole-genome expression profiling using a etrA gene deletion mutant as the experimental sample and the wild type strain as the reference, determine that EtrA fine-tunes the expression of genes involved in various anaerobic metabolic pathways, including nitrate, fumarate and dimethyl sulfoxide reduction. Moreover, genes involved in prophage activation and and genes implicated in aerobic metabolism were also differentially expressed. In contrast to previous studies that attributed a minor regulatory role to EtrA in Shewanella spp., this study demonstrates that EtrA acts as a global transcriptional regulator and cofers physiological advantages to the strain under certain growth conditions.
Project description:The sumitted data compares gene expression profile of Shewnaella oneidensis MR-1 on two different sets of media conditions (nutritionally rich LB medium and Lactate minimal medium) To explore the effect of various growth phases in Shewanella oneidensis MR-1, the genome-wide transcriptome profiles growth in two sets media was compared to each other. Strain was grown in chemostat at 20% O2 in batch culture. Samples were collected in duplicate from both experiments.
Project description:To identify the transcriptional targets of the DNA-binding response regulator HnoC (SO_2540), mRNA transcript levels in Shewanella oneidensis were measured using whole genome microarray analysis. Transcript levels were compared between WT Shewanella oneidensis and a hnoC deletion strain.
Project description:Investigation of whole genome gene expression level changes in a Shewanella oneidensis MR-1 to Fe nanoparticle decorated anodes, compared to the carbon plate anodes in microbial electrolysis cells. Whole genome microarray analysis of the gene expression showed that the encoding biofilm formation genes were significantly up-regulated as response to nanoparticle decorated anodes which indicated thickness improvements contributed to enhance current density. The increased expression genes related to nanowire, flavins and c-type cytochromes also have partially contributed to enhance current density by Fe nanoparticle decorated anode. The majority of additional differentially expressed genes associated with electron transport, anaerobic metabolism in response to the nanostructured anodes possibly play roles in current density enhancement. A six chip study using total RNA recovered from three separate replicates of biofilm on Fe Nanoparticle decorated anode of Shewanella oneidensis MR-1 and three separate replicates of carbon plate control. Each chip measures the expression level of 4,295 genes .
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.
Project description:Comparison of gene expression and mutant fitness in Shewanella oneidensis MR-1 Expression data for 15 growth conditions in mid-exponential phase and expression data across growth phases for 3 of those conditions
Project description:To identify the transcriptional targets of the DNA-binding response regulator HnoC (SO_2540), mRNA transcript levels in Shewanella oneidensis were measured using whole genome microarray analysis. Transcript levels were compared between WT Shewanella oneidensis and a hnoC deletion strain. Transcript levels of a WT and hnoC deletion strain were measured after 15 hrs growth, 4 independent replicates were performed for each strain
Project description:Pinchuck2010 - Genome-scale metabolic network
of Shewanella oneidensis (iSO783)
This model is described in the article:
Constraint-based model of
Shewanella oneidensis MR-1 metabolism: a tool for data analysis
and hypothesis generation.
Pinchuk GE, Hill EA, Geydebrekht OV,
De Ingeniis J, Zhang X, Osterman A, Scott JH, Reed SB, Romine MF,
Konopka AE, Beliaev AS, Fredrickson JK, Reed JL.
PLoS Comput. Biol. 2010 Jun; 6(6):
e1000822
Abstract:
Shewanellae are gram-negative facultatively anaerobic
metal-reducing bacteria commonly found in chemically (i.e.,
redox) stratified environments. Occupying such niches requires
the ability to rapidly acclimate to changes in electron
donor/acceptor type and availability; hence, the ability to
compete and thrive in such environments must ultimately be
reflected in the organization and utilization of electron
transfer networks, as well as central and peripheral carbon
metabolism. To understand how Shewanella oneidensis MR-1
utilizes its resources, the metabolic network was
reconstructed. The resulting network consists of 774 reactions,
783 genes, and 634 unique metabolites and contains biosynthesis
pathways for all cell constituents. Using constraint-based
modeling, we investigated aerobic growth of S. oneidensis MR-1
on numerous carbon sources. To achieve this, we (i) used
experimental data to formulate a biomass equation and estimate
cellular ATP requirements, (ii) developed an approach to
identify cycles (such as futile cycles and circulations), (iii)
classified how reaction usage affects cellular growth, (iv)
predicted cellular biomass yields on different carbon sources
and compared model predictions to experimental measurements,
and (v) used experimental results to refine metabolic fluxes
for growth on lactate. The results revealed that aerobic
lactate-grown cells of S. oneidensis MR-1 used less efficient
enzymes to couple electron transport to proton motive force
generation, and possibly operated at least one futile cycle
involving malic enzymes. Several examples are provided whereby
model predictions were validated by experimental data, in
particular the role of serine hydroxymethyltransferase and
glycine cleavage system in the metabolism of one-carbon units,
and growth on different sources of carbon and energy. This work
illustrates how integration of computational and experimental
efforts facilitates the understanding of microbial metabolism
at a systems level.
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Project description:To investigate how cell elongation impacts extracellular electron transfer (EET) of electroactive microorganisms (EAMs), the division of model EAM Shewanella oneidensis MR-1 was engineered by reducing the formation of cell divisome. Specially, by blocking the translation of division proteins via anti-sense RNAs or expressing division inhibitors, the cellular length and output power density were all increased. Electrophysiological and transcriptomic results synergistically revealed that the programmed cell elongation reinforced EET by enhancing NADH oxidation, inner-membrane quinone pool, and abundance of c-type cytochromes. Moreover, cell elongation enhanced hydrophobicity due to decreased cell-surface polysaccharide, thus facilitated initial surface adhesion stage in biofilm formation. The output current and power density all increased in positive correction with cellular length. However, inhibition of cell division reduced cell growth, which was then restored by quorum sensing-based dynamic regulation of cell growth and elongation phases. The QS-regulated elongated strain thus enabled a cell length of 143.6 ± 40.3 µm (72.6-fold of that of S. oneidensis MR-1), which resulted in an output power density of 248.0 ± 10.6 mW m-2 (3.41-fold of that of S. oneidensis MR-1) and exhibited superior potential for pollutant treatment. Engineering cellular length paves an innovate avenue for enhancing the EET of EAMs.
Project description:Investigation of whole genome gene expression level changes in a Shewanella oneidensis MR-1 to Fe nanoparticle decorated anodes, compared to the carbon plate anodes in microbial electrolysis cells. Whole genome microarray analysis of the gene expression showed that the encoding biofilm formation genes were significantly up-regulated as response to nanoparticle decorated anodes which indicated thickness improvements contributed to enhance current density. The increased expression genes related to nanowire, flavins and c-type cytochromes also have partially contributed to enhance current density by Fe nanoparticle decorated anode. The majority of additional differentially expressed genes associated with electron transport, anaerobic metabolism in response to the nanostructured anodes possibly play roles in current density enhancement.