Effect of UV Radiation on the Synthesis of UV-Absorbing Compounds in Eleven Cyanobacteria Acclimated to Different Salinities.

MEDINA, C.D.; ALBARRACÍN V.H.; FARIAS M.E.

Córdoba

Congreso; 16th INTERNATIONAL CONGRESS ON PHOTOBIOLOGY; 2014

High-Altitude Andean Lakes HAAL serves as ideal environments to study the cyanobacterial diversity of a terrestrial, hypersaline system that has a potential value for bioprospecting [1]. In this work, we performed isolation of novel cyanobacteria from diverse lakes and samples from the HAAL. In addition, effects of three doses (15, 30 and 60 Wm−2) of UV radiation on the synthesis of UV-absorbing compounds in the isolated cyanobacteria acclimated to four salinities (i.e., 0, 10, 30 and 60 psu) were investigated. We isolated representative strains from eleven genera (Anabaena, Nostoc, Symplocastrum, Leptolyngbya, Phormidium, Synechococcus, Pseudoanabaena, Nodularia, Synechocystis, Chroococcus and Cyanosarcina). Increase of salinity (i.e., to 0 from 60 psu) affects the growth rate of cultures. Combined effect of both salinity and UV radiation resulted in lower biomass. Subsequent acclimation from short period (less than 6 h) of UV radiation to subsequent duration of treatment (more than 6 h) resulted in an increase of Chl-a content. The production of UV-absorbing compounds such as scytonemin and mycosporine-like amino acids (MAAs) were studied. At an intermediate salinity (i.e., 10 psu) and after 3 h of exposure to UV we observed the greatest accumulation of UV-absorbing compounds. The detected UV-absorbing compounds may play a dual role as passive sunscreens and as osmotic protectant, providing efficient tolerance mechanisms to original hard conditions impairing on the HAAL. Acknowledgments This work was supported by Agencia Nacional de Promoción Científica y Tecnológica - ANPCyT [1] Farias ME, Rascovan N, Toneatti DM, Albarracin VH, Flores MR, et al. (2013) The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes. PLoS ONE 8(1)