In this study, a simple and rapid DAPI-based protocol was developed and optimized to visualize polyphosphates (polyPs) in the cyanobacterium Synechocystis sp. PCC 6803. The optimum dye concentration and incubation time were determined, and formaldehyde fixation was shown to significantly improve polyP detection in Synechocystis cells. Using the developed protocol, for the first time, it was shown that 80% of Synechocystis cells under phosphate overplus were able to accumulate phosphorus as polyP 3 min after the addition of KHPO. After 1 h, the number of cells with polyP began to decrease, and after 24 h, polyP granules were detected in only 30% of the cells. Thus, the Synechocystis cells appeared to be heterogeneous in their ability to accumulate and mobilize polyP. Like other photosynthetic organisms, Synechocystis synthesized less polyP in the dark than in the light. The accumulation of polyP was not inhibited under conditions of cold and heat stresses, and some cells were even able to synthesize polyP at a temperature of approximately 0 °C.
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http://dx.doi.org/10.1007/s00709-019-01374-2 | DOI Listing |
Metab Eng
January 2025
Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden. Electronic address:
Acetate is a biological anion with many applications in the chemical and food industries. In addition to being a common microbial fermentative end-product, acetate can be produced by photosynthetic cyanobacteria from CO using solar energy. Using wild-type cells of the unicellular model cyanobacterium Synechocystis PCC 6803 only low levels of acetate are observed outside the cells.
View Article and Find Full Text PDFLight-driven biotransformations in recombinant cyanobacteria benefit from the atom-efficient regeneration of reaction equivalents like NADPH from water and light by oxygenic photosynthesis. The self-shading of photosynthetic cells throughout the reaction volume, along with the need for extended light paths, limits adequate light supply and significantly restricts the potential for upscaling. Here, we present a flat panel photobioreactor (1 cm optical path length) as a scalable system to provide efficient illumination at high cell densities.
View Article and Find Full Text PDFGenes Genomics
January 2025
Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, 106 91, Stockholm, Sweden.
Background: Cyanobacteria, particularly Synechocystis sp. PCC 6803, serve as model organisms for studying acclimation strategies that enable adaptation to various environmental stresses. Understanding the molecular mechanisms underlying these adaptations provides insight into how cells adjust gene expression in response to challenging conditions.
View Article and Find Full Text PDFArch Microbiol
January 2025
Department of Botany, CMS College Kottayam, Kottayam, Kerala, 686001, India.
Among all photosynthetic life forms, cyanobacteria exclusively possess a water-soluble, light-sensitive carotenoprotein complex known as orange carotenoid proteins (OCPs), crucial for their photoprotective mechanisms. These protein complexes exhibit both structural and functional modularity, with distinct C-terminal (CTD) and N-terminal domains (NTD) serving as light-responsive sensor and effector regions, respectively. The majority of cyanobacterial genomes contain genes for OCP homologs and related proteins, highlighting their essential role in survival of the organism over time.
View Article and Find Full Text PDFBiotechnol Bioeng
December 2024
Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, The Netherlands.
Cyanobacteria have been genetically modified to convert CO into biochemical products, but efficient genetic engineering tools, including CRISPR-Cas systems, remain limited. This is primarily due to the polyploid nature of cyanobacteria, which hinders their effectiveness. Here, we address the latter by specifically (i) modifying the RSF1010-based replicative plasmid to simplify cloning efforts while maintaining high conjugation efficiency; (ii) improving the design of the guide RNA (gRNA) to facilitate chromosomal cleavage; (iii) introducing template DNA fragments as pure plasmids via natural transformation; and (iv) using sacB to facilitate replicative plasmid curing.
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