20.500.12556/DiRROS-20404-a3a2b5d3-f42e-0ee1-e3cc-d63d849302ca UVB radiation as a potential selective factor favoring microcystin producing bloom forming cyanobacteria Due to the stratospheric ozone depletion, several organisms will become exposed to increased biologically active UVB (280-320 nm) radiation, not only at polar but also at temperate and tropical latitudes. Bloom forming cyanobacteria are exposed to UVB radiation on a mass scale, particularly during the surface bloom and scum formation that can persist for long periods of time. All buoyant species of cyanobacteria are at least periodically exposed to higher irradiation during their vertical migration to the surface that usually occurs several times a day. The aim of this study is to assess the influence on cyanobacteria of UVB radiation at realistic environmental intensities. The effects of two UVB intensities of 0.5 and 0.99 W/m2 in up to 0.5 cm water depth were studied in vitro on Microcystis aeruginosa strains, two microcystin producing and one non-producing. After UVB exposure their ability to proliferate was estimated by cell counting, while cell fitness and integrity were evaluated using light microscopy, autofluorescence and immunofluorescence. Gene damage was assessed by TUNEL assay and SYBR Green staining of the nucleoide area. We conclude that UVB exposure causes damage tothe genetic material, cytoskeletal elements, higher sedimentation rates and consequent cell death. In contrast to microcystin producers (PCC7806 and FACHB905), the microcystin non-producing strain PCC7005 is more susceptible tothe deleterious effects of radiation, with weak recovery ability. The ecological relevance of the results is discussed using data from eleven yearsʼcontinuous UVB radiation measurements within the area of Ljubljana city (Slovenia, Central Europe). Our results suggest that increased solar radiationin temperate latitudes can have its strongest effect during cyanobacterial bloom formation in spring and early summer. UVB radiation in this period may significantly influence strain composition of cyanobacterial blooms in favor of microcystin producers. microcystin cyanobacteria true false true Angleški jezik Ni določen Neznano 2024-09-06 11:39:58 2024-09-06 11:39:59 2024-09-10 13:59:43 0000-00-00 00:00:00 2013 0 0 Popis vira z dne 16. 9. 2013; str. e73919 issue 9 Vol. 8 2013 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2013-09-13 577 1932-6203 10.1371/journal.pone.0073919 2888271 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0073919 1 0091e386-6c34-11ef-9ebd-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=28705 RAZ_Ding_Yi_2013.pdf RAZ_Ding_Yi_2013.pdf 1 C1FEB36D09F219951465F51702BC29D6 0ebc29a0e1c94e42e48fad33990e8ecc1cf65f6e04fcfd9e377c353af4a91bd9 184355c6-6c34-11ef-9ebd-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=28706 Nacionalni inštitut za biologijo 0 0 0