title: Microcystins do not necessarily lower the sensitivity of Microcystis aeruginosa to tannic acid.
abstract: Different phytoplankton strains have been shown to possess varying sensitivities towards macrophyte allelochemicals, yet the reasons for this are largely unknown. To test whether microcystin (MC) is responsible for strain-specific sensitivities of Microcystis aeruginosa to macrophyte allelochemicals, we compared the sensitivity of 12 MC- and non-MC-producing M. aeruginosa strains, including an MC-deficient mutant and its wild type, to the polyphenolic allelochemical tannic acid (TA). Non-MC-producing strains showed a significantly higher sensitivity to TA than MC-producing strains, both in Chlorophyll a concentrations and quantum yields of photosystem II. In contrast, an MC-deficient mutant displayed a higher fitness against TA compared to its wild type. These results suggest that the resistance of M. aeruginosa to polyphenolic allelochemicals is not primarily related to MCs per se, but to other yet unknown protective mechanisms related to MCs.
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany Marine Science and Technology Center, Klaipėda University, H. Manto 84, 92294 Klaipėda, Lithuania algirdas.svanys@jmtc.ku.lt.
authors.forename: Algirdas
authors.initials: A
authors.lastname: Švanys
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany Leibniz-Institute for Baltic Sea Research Warnemünde, Department of Biological Oceanography, Seestraße 15, D-18119 Rostock, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Eigemann
authors.affiliation: Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes, Alte Fischerhütte 2, D-16775 Stechlin, Germany Potsdam University, Institute of Biochemistry and Biology, Maulbeerallee 10, D-14469 Potsdam, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Grossart
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Hilt
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D008826:Microbial Sensitivity Tests; D052998:Microcystins / Q000378:metabolism*; D046931:Microcystis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013634:Tannins / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D052998:Microcystins; D013634:Tannins; D002734:Chlorophyll; C078588:microcystin; D000077194:Chlorophyll A
keywords: Microcystis aeruginosa; allelopathy; microcystin; tannic acid; ΔmcyB mutant