Grant Agency of the Czech Republic
Project Info
- Name: Early Phase of Photosystem I Biogenesis: an Unexpected Role of the PsaK Subunit and Function of Accessory Protein Factors
- Registration Number: GA24-10227S
- Period: 2024 - 2026
- Total Subsidity (CZK):
Project leader for MBÚ AV ČR Třeboň
Project description
Photosystem I (PSI) is the key energy-converting machine of oxygenic photosynthesis, containing a large number of protein subunits, pigments and other cofactors. The initial phase ofthe biogenesis of this complex remains largely unknown. The ground-breaking isolation of the individual large protein subunits PsaA and PsaB has only recently allowed us to identify in our laboratory new auxiliary factors involved in PSI formation, while also revealing the unexpected involvement of small PsaK subunit already at the early stage of PSI assembly in the cyanobacterium Synechocystis. The project will elucidate mechanisms by which PsaK and the auxiliary protein factors regulate PSI biogenesis. This will be done by constructing and characterizing specific mutants with missing and tagged PSI subunits and auxiliary factors, and by the isolation, characterization and 3D structure determination of the tagged auxiliary factors bound to PSI complexes. We will also use high-resolution confocal microscopy to localize the fluorescently labeled auxiliary factors in the cell.
Project Info
- Name: EPIC - Indukce cyanopeptidů působením epibiontů
- Registration Number: GA24-10743S
- Period: 2024 -
- Total Subsidity (CZK):
Project leader for MBÚ AV ČR Třeboň
Project description
Project Info
- Name: How to cope with a fluctuating environment: Cell-to-cell heterogeneity versus acclimation in cyanobacteria
- Registration Number: GA24-11363S
- Period: 2024 - 2026
- Total Subsidity (CZK): 9 519 000
Project leader for MBÚ AV ČR Třeboň
Project description
The effects of global warming and ocean acidification on aquatic ecosystems have been intensely studied in the last decades. However, little attention has been put to the effects of short-term fluctuations, i.e. heat waves as well as CO2 and pH variations, which are also expected to intensify. A range of recent studies have revealed large phenotypic heterogeneity among single cells of cyanobacteria. Postulating that such cell-to-cell heterogeneity may present an advantage under rapidly fluctuating conditions, we propose to systematically investigate the contribution of cell-to-cell heterogeneity as well as physiological acclimation to phenotypic plasticity of cyanobacterial populations. We will investigate cultures grown under different environmentally relevant scenarios of fluctuating temperatures and CO2 levels and validate our findings in mesocosm experiments with natural communities. The analysis will involve detailed physiological characterization, advanced techniques with single-cell resolution (e.g. nanoSIMS) and an innovative combination of FACS and transcriptomics.
Project Info
- Name: The biological role of molecules with the carbon-phosphorus bond in a model eukaryote
- Registration Number: GA24-12396S
- Period: 2024 - 2026
- Total Subsidity (CZK): 8 244 000
Project leader for MBÚ AV ČR Třeboň
- Mgr. Jan Janouškovec, Ph.D., Laboratory of Photosynthesis
- RNDr. Eva Horáková, Ph.D., Laboratory of Photosynthesis
Project description
Molecules with carbon-phosphorus (C-P) bonds are found on the surface of many cells but their biological role is not known. In Tetrahymena thermophila, 60% of phosphorus in the flagellar lipid is covalently bound to carbon as 2-aminoethylphosphonate (AEP). This makes T. thermophila an ideal model to understand the cellular role of AEP as the most common natural C-P molecule. Our preliminary data and the literature posit that AEP synthesis is linked to core mitochondrial metabolism and cell surface interactions. In this project, we aim to identify the interactome of AEP biosynthesis and its importance for mitochondrial function and cell physiology. To do this, we will generate knockout and knockdown mutants in AEP biosynthesis, identify interacting proteins, and dissect how AEP synthesis links to mitochondrial metabolism and phenotype changes in mutant physiology and behaviour. The findings will connect early biochemical studies on AEP with molecular genetics and help to understand the strikingly neglected role of C-P molecules in cells and cell evolution.
Project Info
- Name: Mechanisms and importance of functional heterogeneity in unicellular nitrogen fixing cyanobacteria
- Registration Number: GA23-06593S
- Pro roky: 2023 -2025
- Total Subsidity (CZK): 7 075 000,00
Project leader for MBÚ AV ČR Třeboň
Project description
The availability of nitrogen is the critical factor limiting aquatic primary production. Nitrogen fixers convert the inert N2 gas to bioavailable ammonium and play an essential role as a nitrogen supplier. Recently, we have found that only about half of cells fix N2 for two clone unicellular N2 fixers. Further estimation predicted that having heterogeneity save the energy as a community and consequently extend the depth distribution. In the project we aim to 1) evaluate how environmental stress affects the level of heterogeneity (ratio of N2 fixing cells and non-N2 fixing cells), 2) quantify how heterogeneity in N2 fixation influence community and ecosystem, and 3) elucidate the mechanisms of N2 fixation regulation. To visualize N2 fixation at the gene expression level, we will challenge establishing a reporter system. The possibility of genetic engineering for the proposed strains will open the possibility of directly analyze the physiological mechanism of environmentally important marine N2 fixers.
Project Info
- Name: Phosphonate biosynthesis and degradation - a new mitochondrial pathway involved in the global phosphorus cycle?
- Registration Number: GA21-19798M
- Period: 2021 -2025
- Total Subsidity (CZK): 22 392 000,00
Project leader for MBÚ AV ČR Třeboň
Project description
Phosphorus is a core, limiting macronutrient, but its global turnover is still little understood. For example, one quarter of all phosphorus in the ocean occurs as phosphonates, whose metabolism has only been thoroughly studied in bacteria. We identified unexpectedly widespread phosphonate enzymes in eukaryotic genomes and predict that they comprise a novel mitochondrial pathway. To test this, we will computationally map phosphonate enzyme distribution, expression, and cellular localization in all eukaryotes, then localize them subcellularly in two distantly related protists, Perkinsus and Capsaspora. We will next use labeled precursors to track phosphonate metabolism in both species, and measure the ability of a wide range of algae to utilize phosphonate substrates for growth. We will also reconstruct the evolutionary history of all phosphonate enzymes and how they relate to eukaryogenesis. Our findings will illuminate mitochondrial metabolism, eukaryotic evolution, and phosphorus turnover in cells and ecosystems, and identify new enzymes of potential commercial interest.
Project Info
- Name: Mechanistic insight into the photoprotection of Photosystem II by LHC-like proteins
- Registration Number: GA22-030925
- Period: 2022-2024
- Total Subsidity (CZK): 7 441 000,00
Project leader for MBÚ AV ČR Třeboň
Project description
Oxygenic photosynthesis requires two large, chlorophyll-protein complexes, called photosystem I and II (PSI, PSII). PSII is much more prone to photo-inhibition than PSI and a repertoire of mechanisms evolved to protect PSII against excess of light. Light harvesting complexes (LHCs) collect photons for PSII in algae and plants but are also capable to dissipate excitation energy as heat (quenching). Evolutionary related LHC-like proteins, as well as they cyanobacterial homologues Hlips, are probably involved only in photoprotection. The cyanobacterium Synechocystis 6803 contains four Hlips (HliA-D) and our new data show that HliA/C and HliB/C pairs bind to the CP47 PSII subunit and quench PSII assembly intermediates. We will explain the mechanism of PSII photoprotection by solving the structure of RCCII-Hlips complex using cryo-EM and by utilizing ultra-fast spectroscopy and mutagenesis of Hlips. We further explore the physiological role of HliA/B proteins using Synechocystis mutants and a broad set of techniques including protein radiolabeling, 2D gels and protein pull-down assays.
Project Info
- Name: Cell cycle and growth in green algae – interplay of organelles
- Registration Number: GA22-21450S
- Period: 2022-2024
- Total Subsidity (CZK): 6 495 000,00
Project leader for MBÚ AV ČR Třeboň
Project description
The cell cycle progression is intricately intertwined with cell growth. In all organisms, including green algae divided by multiple division, growth is coordinated with cell cycle entry. In autotrophically growing green algae, growth almost exclusively depends on the function, and growth, of chloroplast. Thus, the coordination between growth and cell cycle must also include a coordination between the two compartments, nuclear and chloroplast. Green algae cells contain a single chloroplast, so the coordination is necessary both for growth and for division of chloroplasts and cells. This suggests there are feedback mechanisms coordinating both compartments. Yet, information on them is limited and at molecular level, it is de facto missing. The objectives of project are to: 1) analyze coordination between nuclear and chloroplast compartments in conditions with different requirements on chloroplast function (inorganic or organic carbon source), 2) study effect of chloroplast growth on cell cycle entry, 3) determine if chloroplast DNA replication extent affects cell cycle progression.
Project Info
- Name: Iron monopolization versus community service: the two faces of cyanobacterial beta-hydroxy aspartate lipopeptides
- Registration Number: GA22-05478S
- Period: 2022-2024
- Total Subsidity (CZK): 13 584 000, 00
Project leader for MBÚ AV ČR Třeboň
Project description
Iron is an essential nutrient, yet generally present in poorly bioavailable form (Fe3+) on Earth´s surface. Siderophores are low molecular compounds that scavenge the precipitated Fe, providing an advantage in resource competition on one side and important community service (Fe2+ supply) on the other side. We have recently found siderophores with a double beta-OH-Asp Fe-chelating motif in cyanobacteria and postulated their wide occurrence by genome mining. Hereby, we aim to assess the occurrence of these siderophores in natural communities by targeted field sampling followed by analytical and metagenomics survey. Microbial strains isolated from the samples will be co-cultivated with beta-OH-Asp siderophore producers under manipulated UV treatment and Fe2+/Fe3+ source to determine the ratio between Fe monopolization and benefit provided to other microbes. Bioengineered biosynthetic gene clusters will be assembled to generate structural varia.
Project Info
- Name: Discovery of promissing chemotherapeutic candidates in cyanobacteria using high-throughput screening: mode of action and molecular targets.
- Registration Number: GA21-05649K
- Period: 2021-2024
- Total Subsidity (CZK): 8 193 000,00
Project leader for MBÚ AV ČR Třeboň
Project description
Cancer is a one of the main causes of death worldwide. There is a sustained need for development of new therapeutics due to poor prognosis and acquired resistance. Microorganisms are an extremely valuable source of bioactive compounds with many having clinical applications. To explore drug-induced changes of the transcriptome, the cancer cell line of interest will be exposed to selected hits at half-maximal concentrations. Nostatin A is highly potent against cancer cells of breast and colon origin while sparing primary cells. The second part builds on the previously conducted high-throughput screening (HTS) of cyanobacteria-derived fraction library from which we obtained a number of promising hits with potent anticancer activity. The combination of molecular biology, genomics, metabolomics and analytical chemistry, most notably, thermal proteome profiling and genome wide CRISPR-Cas9 screening, will be employed to reveal molecular targets of nostatin A and the most potent HTS hits. The acquired knowledge will be essential for future preclinical testing.
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