title: Alterations in architecture and metabolism induced by ultraviolet radiation-B in the carragenophyte Chondracanthus teedei (Rhodophyta, Gigartinales).
abstract: The in vivo effect of ultraviolet radiation-B (UVBR) in apical segments of Chondracanthus teedei was examined. Over a period of 7 days, the segments were cultivated and exposed to photosynthetically active radiation (PAR) at 80 μmol photons m(-2) s(-1) and PAR + UVBR at 1.6 W m(-2) for 3 h per day. The samples were processed for electron microscopy and histochemistry; also was analyzed growth rates, mitochondrial activity, protein levels, content of photosynthetic pigments and photosynthetic performance. UVBR elicited increased cell wall thickness and accumulation of plastoglobuli, changes in mitochondrial organization and destruction of chloroplast internal organization. Compared to controls, algae exposed to PAR + UVBR showed a growth rate reduction of 55%. The content of photosynthetic pigments, including chlorophyll a and phycobiliproteins, decreased after exposure to PAR + UVBR. This result agrees with the decreased photosynthetic performance observed after exposing algae to PAR + UVBR. Irradiation also elicited increased activity of the antioxidant enzyme glutathione peroxidase and decreased mitochondrial NADH dehydrogenase activity, which correlated with the decreased protein content in plants exposed to PAR + UVBR. Taken together, these findings strongly indicate that UVBR negatively affects the architecture and metabolism of the carragenophyte C. teedei.
authors.affiliation: Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, 88049-900, CP 476, Florianópolis, SC, Brazil. edcash@ccb.ufsc.br
authors.forename: Eder C
authors.initials: EC
authors.lastname: Schmidt
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pereira
authors.forename: Carime L Mansur
authors.initials: CL
authors.lastname: Pontes
authors.forename: Rodrigo
authors.initials: R
authors.lastname: dos Santos
authors.forename: Fernando
authors.initials: F
authors.lastname: Scherner
authors.forename: Paulo A
authors.initials: PA
authors.lastname: Horta
authors.forename: Roberta
authors.initials: R
authors.lastname: de Paula Martins
authors.forename: Alexandra
authors.initials: A
authors.lastname: Latini
authors.forename: Marcelo
authors.initials: M
authors.lastname: Maraschin
authors.forename: Zenilda L
authors.initials: ZL
authors.lastname: Bouzon
mesh_terms: D005979:Glutathione Peroxidase / Q000378:metabolism; D008928:Mitochondria / Q000528:radiation effects; D009245:NADH Dehydrogenase / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects; D000461:Rhodophyta / Q000378:metabolism* / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D005979:Glutathione Peroxidase; D009245:NADH Dehydrogenase