TY - GEN A1 - des Aulnois, Maxime Georges A1 - Réveillon, Damien A1 - Robert, Elise A1 - Caruana, Amandine A1 - Briand, Enora A1 - Guljamow, Arthur A1 - Dittmann, Elke A1 - Amzil, Zouher A1 - Bormans, Myriam T1 - Salt shock responses of Microcystis revealed through physiological, transcript, and metabolomic analyses T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The transfer of Microcystis aeruginosa from freshwater to estuaries has been described worldwide and salinity is reported as the main factor controlling the expansion of M. aeruginosa to coastal environments. Analyzing the expression levels of targeted genes and employing both targeted and non-targeted metabolomic approaches, this study investigated the effect of a sudden salt increase on the physiological and metabolic responses of two toxic M. aeruginosa strains separately isolated from fresh and brackish waters, respectively, PCC 7820 and 7806. Supported by differences in gene expressions and metabolic profiles, salt tolerance was found to be strain specific. An increase in salinity decreased the growth of M. aeruginosa with a lesser impact on the brackish strain. The production of intracellular microcystin variants in response to salt stress correlated well to the growth rate for both strains. Furthermore, the release of microcystins into the surrounding medium only occurred at the highest salinity treatment when cell lysis occurred. This study suggests that the physiological responses of M. aeruginosa involve the accumulation of common metabolites but that the intraspecific salt tolerance is based on the accumulation of specific metabolites. While one of these was determined to be sucrose, many others remain to be identified. Taken together, these results provide evidence that M. aeruginosa is relatively salt tolerant in the mesohaline zone and microcystin (MC) release only occurs when the capacity of the cells to deal with salt increase is exceeded. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1130 KW - Microcystis aeruginosa KW - microcystin KW - salt stress KW - metabolomic KW - transcript Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472405 SN - 1866-8372 IS - 1130 ER - TY - JOUR A1 - des Aulnois, Maxime Georges A1 - Réveillon, Damien A1 - Robert, Elise A1 - Caruana, Amandine A1 - Briand, Enora A1 - Guljamow, Arthur A1 - Dittmann, Elke A1 - Amzil, Zouher A1 - Bormans, Myriam T1 - Salt shock responses of Microcystis revealed through physiological, transcript, and metabolomic analyses JF - Toxins N2 - The transfer of Microcystis aeruginosa from freshwater to estuaries has been described worldwide and salinity is reported as the main factor controlling the expansion of M. aeruginosa to coastal environments. Analyzing the expression levels of targeted genes and employing both targeted and non-targeted metabolomic approaches, this study investigated the effect of a sudden salt increase on the physiological and metabolic responses of two toxic M. aeruginosa strains separately isolated from fresh and brackish waters, respectively, PCC 7820 and 7806. Supported by differences in gene expressions and metabolic profiles, salt tolerance was found to be strain specific. An increase in salinity decreased the growth of M. aeruginosa with a lesser impact on the brackish strain. The production of intracellular microcystin variants in response to salt stress correlated well to the growth rate for both strains. Furthermore, the release of microcystins into the surrounding medium only occurred at the highest salinity treatment when cell lysis occurred. This study suggests that the physiological responses of M. aeruginosa involve the accumulation of common metabolites but that the intraspecific salt tolerance is based on the accumulation of specific metabolites. While one of these was determined to be sucrose, many others remain to be identified. Taken together, these results provide evidence that M. aeruginosa is relatively salt tolerant in the mesohaline zone and microcystin (MC) release only occurs when the capacity of the cells to deal with salt increase is exceeded. KW - Microcystis aeruginosa KW - microcystin KW - salt stress KW - metabolomic KW - transcript Y1 - 2020 U6 - https://doi.org/10.3390/toxins12030192 SN - 2072-6651 VL - 12 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Pancrace, Claire A1 - Ishida, Keishi A1 - Briand, Enora A1 - Pichi, Douglas Gatte A1 - Weiz, Annika R. A1 - Guljarmow, Arthur A1 - Scalvenzi, Thibault A1 - Sassoon, Nathalie A1 - Hertweck, Christian A1 - Dittmann, Elke A1 - Gugger, Muriel T1 - Unique Biosynthetic Pathway in Bloom-Forming Cyanobacterial Genus Microcystis Jointly Assembles Cytotoxic Aeruginoguanidines and Microguanidines JF - ACS chemical biology N2 - The cyanobacterial genus Microcystis is known to produce an elaborate array of structurally unique and biologically active natural products, including hazardous cyanotoxins. Cytotoxic aeruginoguanidines represent a yet unexplored family of peptides featuring a trisubstituted benzene unit and farnesylated arginine derivatives. In this study, we aimed at assigning these compounds to a biosynthetic gene cluster by utilizing biosynthetic attributes deduced from public genomes of Microcystis and the sporadic distribution of the metabolite in axenic strains of the Pasteur Culture Collection of Cyanobacteria. By integrating genome mining with untargeted metabolomics using liquid chromatography with mass spectrometry, we linked aeruginoguanidine (AGD) to a nonribosomal peptide synthetase gene cluster and coassigned a significantly smaller product to this pathway, microguanidine (MGD), previously only reported from two Microcystis blooms. Further, a new intermediate class of compounds named microguanidine amides was uncovered, thereby further enlarging this compound family. The comparison of structurally divergent AGDs and MGDs reveals an outstanding versatility of this biosynthetic pathway and provides insights into the assembly of the two compound subfamilies. Strikingly, aeruginoguanidines and microguanidines were found to be as widespread as the hepatotoxic microcystins, but the occurrence of both toxin families appeared to be mutually exclusive. Y1 - 2018 U6 - https://doi.org/10.1021/acschembio.8b00918 SN - 1554-8929 SN - 1554-8937 VL - 14 IS - 1 SP - 67 EP - 75 PB - American Chemical Society CY - Washington ER -