Project description:Recent functional genomics and genome-scale modeling approaches indicated that B12 production in Lactobacillus reuteri could be improved by medium optimization. Here we show that a series of systematic single amino acid omissions could significantly modulate the production of B12 from nearly undetectable levels (by isoleucine omission) to 20-fold higher than previously reported through omission of cysteine. We analyzed by cDNA microarray experiments the transcriptional response of L. reuteri to the medium lacking cysteine. These results supported the observed high B12 production and provided new avenues for future improvement of production of vitamin B12. Keywords: cell type comparison loop design
Project description:Recent functional genomics and genome-scale modeling approaches indicated that B12 production in Lactobacillus reuteri could be improved by medium optimization. Here we show that a series of systematic single amino acid omissions could significantly modulate the production of B12 from nearly undetectable levels (by isoleucine omission) to 20-fold higher than previously reported through omission of cysteine. We analyzed by cDNA microarray experiments the transcriptional response of L. reuteri to the medium lacking cysteine. These results supported the observed high B12 production and provided new avenues for future improvement of production of vitamin B12. Keywords: cell type comparison
Project description:Lactobacillus reuteri is a heterofermentative lactic acid bacterium best known for its ability to co-ferment glucose and glycerol. Its genome sequence has recently been deduced enabling the implementation of genome-wide analysis. In this study we developed a dedicated cDNA microarray platform and a genome-scale metabolic network model of L. reuteri and use them to revisit the co-fermentation of glucose and glycerol. The model was used to simulate experimental conditions and to visualize and integrate experimental data in particular the global transcriptional response of L. reuteri to the presence of glycerol. We show how the presence of glycerol affects cell physiology and triggers specific regulatory mechanisms allowing simultaneously a better yield and more efficient biomass formation. Furthermore we were able to predict and demonstrate for this well-studied condition the involvement of previously unsuspected metabolic pathways for instance related to amino acids and vitamins. These could be used as leads in future studies aiming at the increased production of industrially relevant compounds such as vitamin B12 or 1 3- propanediol. Keywords: cell type comparison Dye swap
Project description:Lactobacillus reuteri is a heterofermentative lactic acid bacterium best known for its ability to co-ferment glucose and glycerol. Its genome sequence has recently been deduced enabling the implementation of genome-wide analysis. In this study we developed a dedicated cDNA microarray platform and a genome-scale metabolic network model of L. reuteri and use them to revisit the co-fermentation of glucose and glycerol. The model was used to simulate experimental conditions and to visualize and integrate experimental data in particular the global transcriptional response of L. reuteri to the presence of glycerol. We show how the presence of glycerol affects cell physiology and triggers specific regulatory mechanisms allowing simultaneously a better yield and more efficient biomass formation. Furthermore we were able to predict and demonstrate for this well-studied condition the involvement of previously unsuspected metabolic pathways for instance related to amino acids and vitamins. These could be used as leads in future studies aiming at the increased production of industrially relevant compounds such as vitamin B12 or 1 3- propanediol. Keywords: cell type comparison Loop design
Project description:Lactobacillus reuteri is a heterofermentative lactic acid bacterium best known for its ability to co-ferment glucose and glycerol. Its genome sequence has recently been deduced enabling the implementation of genome-wide analysis. In this study we developed a dedicated cDNA microarray platform and a genome-scale metabolic network model of L. reuteri and use them to revisit the co-fermentation of glucose and glycerol. The model was used to simulate experimental conditions and to visualize and integrate experimental data in particular the global transcriptional response of L. reuteri to the presence of glycerol. We show how the presence of glycerol affects cell physiology and triggers specific regulatory mechanisms allowing simultaneously a better yield and more efficient biomass formation. Furthermore we were able to predict and demonstrate for this well-studied condition the involvement of previously unsuspected metabolic pathways for instance related to amino acids and vitamins. These could be used as leads in future studies aiming at the increased production of industrially relevant compounds such as vitamin B12 or 1 3- propanediol. Keywords: cell type comparison
Project description:Lactobacillus reuteri is a heterofermentative lactic acid bacterium best known for its ability to co-ferment glucose and glycerol. Its genome sequence has recently been deduced enabling the implementation of genome-wide analysis. In this study we developed a dedicated cDNA microarray platform and a genome-scale metabolic network model of L. reuteri and use them to revisit the co-fermentation of glucose and glycerol. The model was used to simulate experimental conditions and to visualize and integrate experimental data in particular the global transcriptional response of L. reuteri to the presence of glycerol. We show how the presence of glycerol affects cell physiology and triggers specific regulatory mechanisms allowing simultaneously a better yield and more efficient biomass formation. Furthermore we were able to predict and demonstrate for this well-studied condition the involvement of previously unsuspected metabolic pathways for instance related to amino acids and vitamins. These could be used as leads in future studies aiming at the increased production of industrially relevant compounds such as vitamin B12 or 1 3- propanediol. Keywords: cell type comparison
Project description:Lactobacillus reuteri has been shown to encode a vitamin B12 biosynthesis pathway that is phylogenetically related to the one present in some representatives of gamma-proteobacteria such as Salmonella and Yersinia. Here we present evidence supporting that the similarities between these otherwise unrelated organisms extend to their regulatory mechanisms. Keywords: cell type comparison
Project description:Lactobacillus reuteri has been shown to encode a vitamin B12 biosynthesis pathway that is phylogenetically related to the one present in some representatives of gamma-proteobacteria such as Salmonella and Yersinia. Here we present evidence supporting that the similarities between these otherwise unrelated organisms extend to their regulatory mechanisms. Keywords: cell type comparison Loop design