Project description:Exploring molecular details of carbon utilization trade-offs in galactose-evolved yeast Adaptively evolved yeast mutants on galactose for around 400 generations showed diminished growth and carbon uptake rates on glucose. Genome-scale approaches were applied to characterize the molecular genetic basis of these trade-offs in carbon source utilization. Engineered mutants showing trade-offs in a specific carbon uptake rate between both carbons were used as controls. The transcriptional responses of the evolved mutants were almost identical during growth on both carbon sources. These carbon-independent conserved patterns were clearly observed in specific pathways and genes. Up-regulation of PGM2, a confirmed beneficial genetic change for improving galactose utilization was preserved on both carbons. In addition, HXK1, GLK1 and genes involved in reserve carbohydrate metabolism were up-regulated, while HXK2 was down-regulated. Genes that have a transcription factor binding site for Gis1p, Rph1p, Msn2/4p and Nrg1p were up-regulated. These results indicated changes in the metabolic pathways involved in metabolism of both carbons and in nutrient signaling pathway. The concentration profile of trehalose and glycogen supported these findings. Mutations in RAS2 and ERG5 genes were selected because of their beneficial and neutral effect on galactose utilization, respectively in our previous study. Site-directed mutants containing galactose-beneficial mutations in RAS2 only resulted in a significant decrease in glucose utilization. Integration of all these analyses clearly suggest an antagonistic pleiotropic trade-off in carbon source utilization caused by changes in regulatory region, and we hereby demonstrate how systems biology can be used to gain insight into evolutionary processes at the molecular level. Yeast galactose evolved mutants having improved galactose availability were grown on aerobic batch with glucose as carbon source
Project description:Exploring molecular details of carbon utilization trade-offs in galactose-evolved yeast Adaptively evolved yeast mutants on galactose for around 400 generations showed diminished growth and carbon uptake rates on glucose. Genome-scale approaches were applied to characterize the molecular genetic basis of these trade-offs in carbon source utilization. Engineered mutants showing trade-offs in a specific carbon uptake rate between both carbons were used as controls. The transcriptional responses of the evolved mutants were almost identical during growth on both carbon sources. These carbon-independent conserved patterns were clearly observed in specific pathways and genes. Up-regulation of PGM2, a confirmed beneficial genetic change for improving galactose utilization was preserved on both carbons. In addition, HXK1, GLK1 and genes involved in reserve carbohydrate metabolism were up-regulated, while HXK2 was down-regulated. Genes that have a transcription factor binding site for Gis1p, Rph1p, Msn2/4p and Nrg1p were up-regulated. These results indicated changes in the metabolic pathways involved in metabolism of both carbons and in nutrient signaling pathway. The concentration profile of trehalose and glycogen supported these findings. Mutations in RAS2 and ERG5 genes were selected because of their beneficial and neutral effect on galactose utilization, respectively in our previous study. Site-directed mutants containing galactose-beneficial mutations in RAS2 only resulted in a significant decrease in glucose utilization. Integration of all these analyses clearly suggest an antagonistic pleiotropic trade-off in carbon source utilization caused by changes in regulatory region, and we hereby demonstrate how systems biology can be used to gain insight into evolutionary processes at the molecular level.
Project description:Adaptively evolved mutants of yeast on galactose were characterized by feremtation physiology and tools from systems biology. Three evolved mutants of yeast grown on aerobic batch with galactose as carbon source
Project description:Trade-offs often occurs during experimental evolution. For example, the degeneration of growth in glucose was found in a galactose adapted yeast. Here, we isolated one Lactococcus lactis mutant using experimental on maltose. The mutant grows normally on glucose, but faster than the wild-type on maltose and galactose. DNA microarray analysis and whole genome re-sequencing were applied to disclose the crucial points that determine the phenotype.
Project description:We report high-throughput RNA sequencing of Δcrp and five adaptively evolved mutants of Δcrp in the batch exponential phase, IG116-Δcrp in batch exponential phase and Δcrp and two adaptively evolved mutants of Δcrp in chemostat cultivations
Project description:Efficient utilization of lignocellulosic biomass-derived sugars is essential to improve the economics of biorefinery. While Pseudomonas putida is a promising microbial host, its usage is limited because this strain cannot utilize xylose or galactose as a sole carbon source. To address this issue, we heterologously introduced a xylose utilizing gene (xylD) from Caulobacter crescentus and a galactose operon (galETKM) from E. coli MG1655. To improve the utilization further, we evolved the engineered strains in minimal medium conditions. After the evolution, they acquired better fitnesses on the non-native sugars. To understand transcriptional changes after the evolution, the transcriptomes of few evolved isolates were analyzed.
Project description:In order to understand LBG derived galacto-manno-oligosaccharides utilization by a probiotic bacterium, Lactobacillus plantarum WCFS1, we have grown Lactobacillus plantarum WCFS1 (in duplicates) till mid log phase (OD600nm ~0.5, 10 h) in carbon free MRS (de Man, Rogosa Sharpe ) media containing either galacto-manno-oligosaccharides, mannose, glucose or galactose (1% w/v) as the sole carbon source.
Project description:This study was aimed to further illustrate the expression files of REN between glucose and raffinose in MRS broth. Transcriptomic analysis combined with mutants of the key genes based on homologous recombination technology indicated that galA1 gene cluster plays an important role in raffinose metabolism. Gene rafP and galA1 are responsible for raffinose transport and α-galactoside hydrolysis, followed by galactose hydrolysis by galKTE and sucrose hydrolysis by scrB. Lactobacillus salivarius Ren expanded the carbon utilization spectrum to adapt the fluctuating carbohydrate sources in the environment and shifted its carbohydrate metabolism to mixed-acid fermentation and then generated extra energy to bacterial growth when exposed to raffinose.
Project description:The evolutionary transition of multicellular life initially involves growth in groups of undifferentiated cells followed by differentiation into soma and germ-like cells. This is facilitated by trade-offs between traits determining survival and reproduction, favoring the coexistence of cells with extreme trait values and a convex trade-off curve as the multicellular state dominates. However, these transitions remain poorly characterized at the ecological and genetic level. Here, we studied the evolution of cell groups in ten isogenic lines of the unicellular green algae Chlamydomonas reinhardtii with prolonged exposure to a rotifer predator. We confirmed that this trait was heritable and characterized by a convex trade-off curve between reproduction and survival. Identical mutations evolved in all cell group isolates which were linked to survival and reducing associated cell costs. Overall, we show that just 500 generations of predator selection is sufficient to lead to a convex trade-off and incorporate evolved changes into the prey genome.