Project description:This study examines genome-wide expression of the phenanthrene-degrading Sphingomonas sp. LH128 as a response to short-term starvation stress. For this purpose, the strain was subjected to complete nutrient starvation for 4h after growth on a rich medium. Survival was monitored by plating and transcriptomic response was determined by whole-genome microarray analysis. The data showed no major differences were obsrved in gene expression and the viability of the cells were not affected during short-term incubation time Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 starved for 4h in isotonic solution of 0.01 mM MgS04 was studied using genome-wide gene expression analysis. For this purpose, the strain was pregrown in minimal medium to an OD600 of 0.5, washed twice with 0.01 mM MgS04 and resuspended in the same solution to an OD of 0.5. RNA was extracted both from starved cells and from the initial culture (non-starved cells) and cDNA was synthesized and labeled with Cy3. Transcriptomic response of three replicates were analyzed and compared with the initial inoculum
Project description:This study examines genome-wide expression of the phenanthrene-degrading Sphingomonas sp. LH128 as a response to long-term starvation stress. For this purpose, the strain was subjected to complete nutrient starvation for 6 months after growth on a rich medium. Survival was monitored by plating, physiological response was examined by flow cytometry and FAME analysis, and this response was related to transcriptomic response as determined by whole-genome microarray analysis. The data showed that decreased gene functions involved in ribosomal proteins biosynthesis, decreased chromosomal replication, increased gene functions involved in stringent regulation of gene expression, increased gene functions involved in genetic exchange and recombination, increased efflux systems, increased degradation of rRNA, and increased M-NM-2-oxidation of fatty acids to access stored nutrients. Genes involved in PAH degradations appears to be with decreased expression. Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 starved for 6 month in isotonic solution of 0.01 mM MgS04 was studied using genome-wide gene expression analysis. For this purpose, the strain was pregrown in minimal medium to an OD600 of 0.5, washed twice with 0.01 mM MgS04 and resuspended in the same solution to an OD of 0.5. RNA was extracted both from starved cells and from the initial culture (non-starved cells) and cDNA was synthesized and labeled with Cy3. Transcriptomic response of three replicates were analyzed and compared with the initial inoculum
Project description:This study examines genome-wide expression of the phenanthrene-degrading Sphingomonas sp. LH128 as a response to short-term starvation stress. For this purpose, the strain was subjected to complete nutrient starvation for 4h after growth on a rich medium. Survival was monitored by plating and transcriptomic response was determined by whole-genome microarray analysis. The data showed no major differences were obsrved in gene expression and the viability of the cells were not affected during short-term incubation time
Project description:This study examines the transcriptomic response of biofilms of the PAH-degrading Sphingomonas sp. LH128 on solute stress when actively degrading and growing on the PAH compound. To address the effect of solute stress on bacterial physiology and transcriptomic response, NaCl was used as osmolyte. Both acute and chronic solute stress was invoked to assess differences in short-term and long-term responses.
Project description:This study examines genome-wide expression of the phenanthrene-degrading Sphingomonas sp. LH128 as a response to long-term starvation stress. For this purpose, the strain was subjected to complete nutrient starvation for 6 months after growth on a rich medium. Survival was monitored by plating, physiological response was examined by flow cytometry and FAME analysis, and this response was related to transcriptomic response as determined by whole-genome microarray analysis. The data showed that decreased gene functions involved in ribosomal proteins biosynthesis, decreased chromosomal replication, increased gene functions involved in stringent regulation of gene expression, increased gene functions involved in genetic exchange and recombination, increased efflux systems, increased degradation of rRNA, and increased β-oxidation of fatty acids to access stored nutrients. Genes involved in PAH degradations appears to be with decreased expression.
Project description:This study examines the transcriptomic response of biofilms of the PAH-degrading Sphingomonas sp. LH128 on solute stress when actively degrading and growing on the PAH compound. To address the effect of solute stress on bacterial physiology and transcriptomic response, NaCl was used as osmolyte. Both acute and chronic solute stress was invoked to assess differences in short-term and long-term responses. Transcriptomic response of phenanthrene degrading Sphingomonas sp. LH128 biofilms as a response to short-term and long-term solute (NaCl) stress was studied using genome-wide gene expression analysis. For this purpose, the strain was grown in customized continuous glass flow chambers that contain solid phenanthrene as a sole carbon source and that allow easy recovery of biofilm cells for transcriptomic and physiological analysis. A NaCl stress of 450 mM was imposed on LH128 biofilms growing on phenanthrene crystals coated on glass slides either for 4 hours (acute stress) or for 3 days (chronic stress). RNA was extracted from the biofilm and cDNA was synthesized and labeled with Cy3. Transcriptomic response in the stressed biofilms of three replicates per conditions were analyzed and compared with non-stressed
Project description:Microbial communities that degrade lignocellulosic biomass are typified by high levels of species- and strain-level complexity, as well as synergistic interactions between both cellulolytic and non-cellulolytic microorganisms. Here we deconvoluted a highly efficient cellulose-degrading and methanogenic consortium (SEM1b) that is co-dominated by Clostridium (Ruminiclostridium) thermocellum and multiple heterogenic strains affiliated to C. proteolyticus. A time-series analysis was performed over the entire lifetime span of the microbial community and comprised of metagenomic, metatranscriptomic, metabolomics, metaproteomic and 16S rRNA gene analysis for 8 time points, in triplicate. Metagenomic analysis of SEM1b recovered metagenome-assembled genomes (MAGs) for each constituent population, whereas in parallel two novel strains of C. proteolyticus were isolated and sequenced. Both the recovered MAGs and the isolated strains were used as a database for further functional meta-omics. Absolute quantitative metatranscriptomics was performed thanks the spike-in of an in vitro transcribed RNA as an internal standard and label-free quantification was used for the metaproteomic analysis. The present dataset has been used for several publications. The first aim of the project was to characterize the interactions between uncultured populations in a lignocellulose-degrading community. Furthermore, because of the in-depth multi-omics characterization of the community, the dataset was used to develop new approaches for meta-omics integration as well as to assess the protein-to-RNA ratio of multiple microbial populations simultaneously. Modifications of multi-omics toolkits allowed us to assess the linearity between transcriptome and proteome for each population over time and reveal deeper functional-related trends and integrative co-dependent metabolisms that drive the overall phenotype of microbial communities.
Project description:Members of the bacterial phylum Spirochaetes are primarily studied for their commensal and pathogenic roles in animal hosts. However, Spirochaetes are also frequently detected in anoxic hydrocarbon-contaminated environments but their ecological role in such ecosystems has so far remained unclear. Here we provide a functional trait to these frequently detected organisms with an example of a sulfate-reducing, naphthalene-degrading enrichment culture consisting of a sulfate-reducing deltaproteobacterium Desulfobacterium naphthalenivorans and a novel spirochete Rectinema cohabitans. Using a combination of genomic, proteomic, and physiological studies we show that R. cohabitans grows by fermentation of organic compounds derived from biomass from dead cells (necromass). It recycles the derived electrons in the form of H2 to the sulfate-reducing D. naphthalenivorans, thereby supporting naphthalene degradation and forming a simple microbial loop. We provide metagenomic evidence that equivalent associations between Spirochaetes and hydrocarbon-degrading microorganisms are of general importance in hydrocarbon- and organohalide-contaminated ecosystems. We propose that environmental Spirochaetes form a critical component of a microbial loop central to nutrient cycling in subsurface environments. This emphasizes the importance of necromass and H2-cycling in highly toxic contaminated subsurface habitats such as hydrocarbon-polluted aquifers.