title: Photoprotection by carotenoid pigments in the yeast Rhodotorula mucilaginosa: the role of torularhodin.
abstract: In this paper we report the relationship between carotenoids and ergosterol and cell UV-B resistance in different strains of the yeast Rhodotorula mucilaginosa. Cell survival was studied using a set of 13 strains; additionally, two mutants (a hyper-producing one and a colourless one) in combination with diphenylamine (DPA), a carotenogenesis inhibitor, were used. A positive correlation between total carotenoids and survival to UV-B radiation was found. However, when individual carotenoid concentrations were tested, only torularhodin was found to be significantly related to UV-B survival. On the contrary, ergosterol did not affect survival. The hyper-pigmented strain showed an enhanced survival (up to 250%) compared to the parental strain, while the survival of the albino mutant was similar to that experienced by the parental strain; however, observed changes in survival were dose dependent. The cyclobutane pyrimidine dimers (CPDs), one of the major forms of DNA damage caused by UV exposure, appears as unrelated to the accumulation of carotenoids and cell survival. These results indicate that bearing higher torularhodin concentrations enhances UV-B survival in yeasts and, thus, the accumulation of this pigment constitutes an important mechanism that improves the resistance of yeasts to UV-B.
authors.affiliation: Laboratorio de Microbiología Aplicada y Biotecnología, Instituto de Investigaciones en Biodiversidad y Medio Ambiente, INIBIOMA (CONICET-UNComahue), Quintral 1250, 8400, San Carlos de Bariloche, Río Negro, Argentina.
authors.forename: Martín
authors.initials: M
authors.lastname: Moliné
authors.forename: María Regina
authors.initials: MR
authors.lastname: Flores
authors.forename: Diego
authors.initials: D
authors.lastname: Libkind
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Diéguez
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Farías
authors.forename: María
authors.initials: M
authors.lastname: van Broock
mesh_terms: D002338:Carotenoids / Q000494:pharmacology / Q000502:physiology*; D002470:Cell Survival; D004249:DNA Damage; D004159:Diphenylamine / Q000494:pharmacology; D004875:Ergosterol / Q000494:pharmacology; D011740:Pyrimidine Dimers / Q000737:chemistry; D012248:Rhodotorula / Q000187:drug effects / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; D002338:Carotenoids; D004159:Diphenylamine; C078923:torularhodin; D004875:Ergosterol