Project description:High-resolution “tiling” expression data for Zymomonas mobilis ZM4 growing in rich and minimal media, heat-shocked, or at high ethanol
Project description:High-resolution “tiling” expression data for Zymomonas mobilis ZM4 growing in rich and minimal media, heat-shocked, or at high ethanol One chip for each growth condition and one “genomic control” array hybridized to genomic DNA
Project description:Background Zymomonas mobilis ZM4 is a capable ethanologenic bacterium with high ethanol productivity and ethanol tolerance. Previous studies indicated that several stress-related proteins and changes in the ZM4 membrane lipid composition may contribute to ethanol tolerance. However, the molecular mechanisms of its ethanol stress response have not been elucidated fully. Methodology/Principal Findings In this study, ethanol stress responses were investigated using systems biology approaches. Medium supplementation with an initial 47 g/L (6% v/v) ethanol reduced Z. mobilis ZM4 glucose consumption, growth rate and ethanol productivity compared to that of untreated controls. A proteomic analysis of early exponential growth identified about one thousand proteins, or approximately 55% of the predicted ZM4 proteome. Proteins related to metabolism and stress response such as chaperones and key regulators were more abundant in the early ethanol stress condition. Transcriptomic studies indicated that the response of ZM4 to ethanol is dynamic, complex and involves many genes from all the different functional categories. Most down-regulated genes were related to translation and ribosome biogenesis, while the ethanol-upregulated genes were mostly related to cellular processes and metabolism. Transcriptomic data were used to update Z. mobilis ZM4 operon models. Furthermore, correlations among the transcriptomic, proteomic and metabolic data were examined. Among significantly expressed genes or proteins, we observe higher correlation coefficients when fold-change values are higher. Conclusions Our study has provided insights into the responses of Z. mobilis to ethanol stress through an integrated “omics” approach for the first time. This systems biology study elucidated key Z. mobilis ZM4 metabolites, genes and proteins that form the foundation of its distinctive physiology and its multifaceted response to ethanol stress. A sixteen array study using total RNA recovered from wild-type cultures of Zymomonas mobilis subsp mobilis ZM4 at different time points of 6, 10, 13.5, and 26h post-inoculation with 6% (v/v) treatment compred to that of control without ethanol supplementation. Two biological replicates for treatment and control condition.
Project description:we aimed to screen candidate kinase genes under the stress of phenolic aldehydes during ethanol fermentation for Zymomonas mobilis ZM4
Project description:Looking at the expression levels of all the genes of Zymomonas mobilis ZM4; and in particular we would like to predict the strengths of the genes located on the native plasmids.
Project description:Background Zymomonas mobilis ZM4 is a capable ethanologenic bacterium with high ethanol productivity and ethanol tolerance. Previous studies indicated that several stress-related proteins and changes in the ZM4 membrane lipid composition may contribute to ethanol tolerance. However, the molecular mechanisms of its ethanol stress response have not been elucidated fully. Methodology/Principal Findings In this study, ethanol stress responses were investigated using systems biology approaches. Medium supplementation with an initial 47 g/L (6% v/v) ethanol reduced Z. mobilis ZM4 glucose consumption, growth rate and ethanol productivity compared to that of untreated controls. A proteomic analysis of early exponential growth identified about one thousand proteins, or approximately 55% of the predicted ZM4 proteome. Proteins related to metabolism and stress response such as chaperones and key regulators were more abundant in the early ethanol stress condition. Transcriptomic studies indicated that the response of ZM4 to ethanol is dynamic, complex and involves many genes from all the different functional categories. Most down-regulated genes were related to translation and ribosome biogenesis, while the ethanol-upregulated genes were mostly related to cellular processes and metabolism. Transcriptomic data were used to update Z. mobilis ZM4 operon models. Furthermore, correlations among the transcriptomic, proteomic and metabolic data were examined. Among significantly expressed genes or proteins, we observe higher correlation coefficients when fold-change values are higher. Conclusions Our study has provided insights into the responses of Z. mobilis to ethanol stress through an integrated “omics” approach for the first time. This systems biology study elucidated key Z. mobilis ZM4 metabolites, genes and proteins that form the foundation of its distinctive physiology and its multifaceted response to ethanol stress.
Project description:We report the genome changes associated with a Zymomonas mobilis sodium acetate-tolerant mutant (AcR). We used comparative genomics, transcriptomics, and genetics to show nhaA over-expression conferred sodium acetate (NaAc) tolerance in Z. mobilis. We observed a synergistic effect for sodium and acetate ions that enhanced toxicity against the wild-type strain (ZM4), which was not observed for similar concentrations of potassium and ammonium acetate under controlled laboratory conditions. We extended our studies and demonstrated that Saccharomyces cerevisiae sodium-proton antiporter genes contribute to NaAc tolerance for this important ethanologen. The application of classical and systems biology tools is a paradigm for industrial strain improvement and combines benefits of few a priori assumptions with detailed, rapid, mechanistic studies. Finally, our studies reinforce the idea that one obtains what one selects for in mutant screens and that a genetic system is important for industrial strain development. ZM4_ACr_NaCl_NaAc_study. Whole-genome expression profiles of exponential and stationary phase cells were analyzed for the wild-type Zymomonas mobilis ZM4 and the acetate-tolerant mutant AcR under 12g/L sodium acetate and same molar concentration of sodium chloride (8.55g/L) control conditions.