Project description:Iron is the fourth most abundant element in the Earth’s crust. However, the poor solubility of iron due to oxidation of ferrous iron to the almost insoluble ferric iron under aerobic conditions constitutes a considerable challenge for living organisms to obtain sufficient amounts of the iron available. In the present study, we set out to characterize the global gene expression of C. glutamicum under iron limitation in comparison to iron-replete conditions.
Project description:Iron is the fourth most abundant element in the Earth’s crust. However, the poor solubility of iron due to oxidation of ferrous iron to the almost insoluble ferric iron under aerobic conditions constitutes a considerable challenge for living organisms to obtain sufficient amounts of the iron available. In the present study, we set out to characterize the global gene expression of C. glutamicum under iron limitation in comparison to iron-replete conditions.
Project description:The response to iron limitation of the Gram-positive soil bacterium Corynebacterium glutamicum was analyzed with respect to proteome during growth in glucose minimal medium. C. glutamicum cells were grown at regular (36 µM) and low (1 µM) iron concentrations and harvested in the late exponential growth phase. Between 1056 and 1357 proteins were detected (1% false discovery rate, FDR) in the measurements of three biological replicates including technical replicates each for low and high iron conditions with a proteomic shotgun analysis using nanoLC-MS/MS, covering in total 1555 proteins. By SWATH-MS measurements, relative levels of 1123 proteins could be quantified. Thereof, 66 proteins exhibited at least two-fold altered ratios with a p-value ≤0.05 in iron-deprived cells compared to the cells cultivated with 36 μM iron. 38 proteins showed a ≥2-fold higher level under iron limitation, 16 of which were members of the DtxR regulon. The levels of 28 proteins were at least 2-fold lower under iron limitation, 10 of which were members of the RipA regulon.
Project description:To identify genes which are differentially expressed in Corynebacterium glutamicum in the cg2460 deletion strain, we performed DNA microarray analyses of C. glutamicum Δcg2460 compared to the WT.
Project description:To identify genes which are differentially expressed in Corynebacterium glutamicum in the cg2699 deletion strain, we performed DNA microarray analyses of C. glutamicum Δcg2699 compared to the WT.
Project description:Pupylation is a posttranslational protein modification in bacteria resembling ubiquitination in eukaryotes. The prokaryotic ubiquitin-like protein Pup is covalently attached to other proteins via an isopeptide bond between its carboxyterminal glutamate residue and a lysine residue in the target. In mycobacteria, pupylation was shown to mark proteins for unfolding by the ATPase Mpa and subsequent degradation by the proteasome. However, the occurrence of pupylation in species without a proteasome like Corynebacterium glutamicum suggests that degradation may not be the only fate of pupylated proteins. The Îpup mutant senses a stronger iron limitation than the wild type. Among the 125 genes showing at least 2-fold changes in transcript levels in the Îpup mutant (p-value ⤠0.05) were 54% of all genes known to be regulated by the master regulator of iron homeostasis DtxR (Brune et al., 2006; Wennerhold and Bott, 2006). Except for ftn, which is activated by DtxR and showed a 2-fold decreased mRNA level, the other DtxR target genes showed increased mRNA levels in the Îpup strain. These included ripA, encoding a transcriptional regulator of iron proteins, which represses a number of prominent iron-containing proteins under iron limitation, such as aconitase or succinate dehydrogenase (Wennerhold et al., 2005). 79% of the known RipA target genes showed decreased mRNA levels in the Îpup strain. DNA microarray analyses were performed to compare the mRNA levels of the C. glutamicum Îpup mutant and its parent wild type under iron-limited conditions. The two strains precultivated in CGXII medium with 4% (w/v) glucose and 1 µM FeSO4 were inoculated into fresh medium to an OD600 of 1, cultured for 2 h, and harvested on ice by centrifugation (5 min at 4,000 g and 4°C). Please note that the GPL16989 array design comprises oligos for 4 different bacterial genomes. In the GPR-files in this study, all IDs/Names (oligonucleotides) which are not from the host C. glutamicum were replaced by the text EMPTY since only C. glutamicum expression was analyzed.
Project description:Metabolically engineered Corynebacterium glutamicum strains were constructed for the enhanced production of L-arginine, and their gene expression profiles were investigated