The role of sucrose in cyanobacteria is still not fully understood. It is generally considered a salt-response molecule, and particularly, in Synechocystis sp. strain PCC 6803, it is referred as a secondary osmolyte. We showed that sucrose accumulates transiently in Synechocystis cells at early stages of a salt shock, which could be ascribed to salt activation of sucrose-phosphate synthase (SPS, UDP-glucose: D-fructose-6-phosphate 2-alpha-D-glucosyltransferase; EC 2.4.1.14), the key enzyme in sucrose synthesis pathway, and to an increase of the expression of the SPS encoding gene. Experiments with a mutant strain impaired in sucrose biosynthesis showed that sucrose is essential in stationary phase cells to overcome a later salt stress. Taken together, these results led us to suggest a more intricate function for sucrose than to be an osmoprotectant compound.
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http://dx.doi.org/10.1016/j.plaphy.2005.01.008 | DOI Listing |
Appl Microbiol Biotechnol
January 2025
Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
One strategy for CO mitigation is using photosynthetic microorganisms to sequester CO under high concentrations, such as in flue gases. While elevated CO levels generally promote growth, excessively high levels inhibit growth through uncertain mechanisms. This study investigated the physiology of the cyanobacterium Synechocystis sp.
View Article and Find Full Text PDFPhysiol Plant
January 2025
Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary.
Cyanobacteria are important model organisms for studying the process of photosynthesis and the effects of environmental stress factors. This study aimed to identify the inhibitory sites of NaCl in the whole photosynthetic electron transport in Synechocystis sp. PCC 6803 WT cells by using multiple biophysical tools.
View Article and Find Full Text PDFMetab 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 PDFInt J Mol Sci
January 2025
College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124, China.
Cyanobacterial cytochrome c6 (Cyt c6) is crucial for electron transfer between the cytochrome b6f complex and photosystem I (PSI), playing a key role in photosynthesis and enhancing adaptation to extreme environments. This study investigates the high-resolution crystal structures of Cyt c6 from PCC 7942 and PCC 6803, focusing on its dimerization mechanisms and functional implications for photosynthesis. Cyt c6 was expressed in using a dual-plasmid co-expression system and characterized in both oxidized and reduced states.
View Article and Find Full Text PDFSheng Wu Gong Cheng Xue Bao
January 2025
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China.
Formate is an important solar fuel, with large application potential in bioconversion. Especially, the win-win collaboration is achieved when formate is applied to the cultivation of microalgae, which combines the advantages from both artificial and natural photosynthesis. However, the inhibition of formate on the photosynthetic electron transport hinders the application of formate at high concentrations.
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