Project description:We installed and optimized a genetic tool that allows control over protein stability in a model cyanobacterium. This tool has potential uses for the fundamental study of cyanobacterial genes, and may be useful for the design of more sophisticated, bioindustrial cyanobacterial strains.
Project description:The catalytic core of the RNA polymerase of most eubacteria is composed of two α subunits and β, β’ and ω subunits. In Escherichia coli, the ω subunit (encoded by the rpoZ gene) has been suggested to assist β’ during RNA polymerase core assembly. The function of the ω subunit is particularly interesting in cyanobacteria because the cyanobacterial β’ is split to N-terminal γ and C-terminal β’ subunits. The ∆rpoZ strain of the cyanobacterium Synechocystis sp. PCC 6803 grew well in standard conditions although the mutant cells showed low light-saturated photosynthetic activity, low Rubisco content and accumulated high quantities of protective carotenoids and α-tocopherol. The ∆rpoZ strain contained 15% less of the primary σ factor, SigA, than the control strain, and recruitment of SigA to the RNA polymerase core was inefficient in ∆rpoZ. Thus, a cyanobacterial RNA polymerase holoenzyme lacking the ω subunit contains less frequently the primary σ factor. A DNA microarray analysis revealed that this leads to specific down-regulation of highly expressed genes, like genes encoding subunits for Rubisco, ATP synthase, NADH-dehydrogenase and carbon concentrating mechanisms. On the contrary, many genes showing only low or moderate expression in the control strain were up-regulated in ∆rpoZ. A conserved -10 region was detected in promoters showing up or down-regulation in ∆rpoZ, but -35 regions of down-regulated genes completely differed from -35 regions of up-regulated genes.
Project description:The study aims to identify the metabolic differences between two promising fast-growing, non-model cyanobacterial strains, S. elongatus PCC 11801 and PCC 11802. To this end, experiments were carried out to measure metabolite levels in the two cyanobacterial strains grown in shake flasks at a similar light intensity of approx. 300-350 µmole photons.m-2. s-1. The samples for metabolomics analysis were collected during the exponential growth phase at an optical cell density of 0.5-0.6. Isotopic ratio method was utilized to compare the metabolite levels and delineate the differences in their metabolic pathways.
Project description:The study aims to identify the metabolic differences between two promising fast-growing, non-model cyanobacterial strains, S. elongatus PCC 11801 and PCC 11802. To this end, dynamic 13C-labeling experiments were carried out in the two cyanobacterial strains grown in shake flasks at a similar light intensity of approx. 300-350 µmole photons.m-2. s-1. The samples for metabolomics analysis were collected during the exponential growth phase at an optical cell density of 0.5-0.6. The detailed protocol for experiment can be found in the protocol file.
