title: Diurnal variation in bacterioplankton composition and DNA damage in the microbial community from an Andean oligotrophic lake.
abstract: Laguna Azul is an oligotrophic lake situated at 4,560 m above sea level and subject to a high level of solar radiation. Bacterioplankton community composition (BCC) was analysed by denaturing gradient gel electrophoresis and the impact of solar ultraviolet radiation was assessed by measuring cyclobutane pyrimidine dimers (CPD). Furthermore, pure cultures of Acinetobacter johnsonii A2 and Rhodococcus sp. A5 were exposed simultaneously and CPD accumulation was studied. Gel analyses generated a total of 7 sequences belonging to Alpha-proteobacteria (1 band), Beta-proteobacteria (1 band), Bacteroidetes (2 bands), Actinobacteria (1 band), and Firmicutes (1 band). DGGE profiles showed minimal changes in BCC and no CPD was detected even though a high level of damage was found in biodosimeters. A. johnsonii A2 showed low level of DNA damage while Rhodococcus sp. A5 exhibited high resistance since no CPD were detected under natural UV-B exposure, suggesting that the bacterial community is well adapted to this highly solar irradiated environment.
authors.affiliation: Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina; Instituto de Microbiología, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Tucumán, Argentina. Electronic address: verozenoff@hotmail.com.
authors.forename: María V
authors.initials: MV
authors.lastname: Fernández-Zenoff
authors.affiliation: Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina.
authors.forename: María C
authors.initials: MC
authors.lastname: Estévez
authors.affiliation: Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina.
authors.forename: María E
authors.initials: ME
authors.lastname: Farías
mesh_terms: D001118:Argentina; D001419:Bacteria / Q000235:genetics*; D002940:Circadian Rhythm; D004249:DNA Damage; D060106:Lakes; D010933:Plankton / Q000235:genetics*; D014871:Water Microbiology
keywords: Andean lakes; CPD; DGGE; Electroforesis en gradiente desnaturalizante; Lagunas andinas; Radiación ultravioleta; Ultraviolet radiation