title: Effects of elevated ultraviolet radiation on primary metabolites in selected alpine algae and cyanobacteria.
abstract: Extremophilic green algae and cyanobacteria are the most abundant species in high mountain habitats, where rough climate conditions such as temperature differences, limited water retention and high ultraviolet (UV) radiation are the cause for a restricted biological diversity in favor of a few specialized autotrophic microorganisms. In this study, we investigated four algal species from alpine habitat in a sun simulator for their defense strategies in response to UV-A radiation (315-400nm) up to 13.4W/m(2) and UV-B radiation (280-315nm) up to 2.8W/m(2). Besides changes in pigment composition we discovered that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly produced when the organisms are exposed to elevated UV radiation. Respective compounds were isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated. Our results show that especially tyrosine and guanosine were found to be generally two to three times upregulated in the UV-B exposed samples compared to the non-treated control.
authors.affiliation: Institute of Pharmacy, Pharmacognosy, University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Anja
authors.initials: A
authors.lastname: Hartmann
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Center Munich, 85764 Neuherberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Albert
authors.affiliation: Institute of Pharmacy, Pharmacognosy, University of Innsbruck, 6020 Innsbruck, Austria. Electronic address: markus.ganzera@uibk.ac.at.
authors.forename: Markus
authors.initials: M
authors.lastname: Ganzera
mesh_terms: D000460:Chlorophyta / Q000378:metabolism / Q000528:radiation effects*; D000458:Cyanobacteria / Q000378:metabolism / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D017753:Ecosystem; D014466:Ultraviolet Rays
keywords: Alpine algae; Cyanobacteria; Nucleosides; Primary metabolites; Sun simulator; UV-exposure