Fotoprotección antioxidante no-enzimática contra el potencial daño inducido por UVBR en una diatomea antártica (Thalassiosira sp.) Non-enzymatic antioxidant photoprotection against potential UVBR-induced damage in an Antarctic diatom (Thalassiosira sp.)

• Main Authors: Marcelo Hernando, Gabriela Malanga, Susana Puntarulo, Gustavo Ferreyra
• Format: Article in Journal/Newspaper
• Language: English; Spanish
• Published: Escuela de Ciencias del Mar, Facultad de Recursos Naturales, Pontificia Universidad Católica de Valparaíso 2011
• Subjects: β-caroteno; α-tocopherol; tasa de crecimiento; diatomeas; MAAs; fotoprotección; Antártida; β-carotene; growth rate; diatoms; photoprotection; Antarctica; Aquaculture. Fisheries. Angling; SH1-691; Oceanography; GC1-1581; Biology (General); QH301-705.5; Antarctic; Potter Cove; Antarc*; Antártica
• Online Access: https://doaj.org/article/db229ab0d964422c95e00e680fc51451

In January 1999, unialgal cultures of the diatom Thalassiosira sp., solate from natural phyto-plankton assemblages from Potter Cove, Antarctica, were exposed to solar ultraviolet radiation (UVR, 280400 nm) in order to study the long-term acclimation of this species. Ultraviolet radiation B (UVBR, 280-315 nm) inhibited the growth rate during the first and second days of exposure. No UVBR inhibition was observed on the third day. The initial content of α-tocopherol (13 pmol (10(4) cell)-1) showed a marked decrease during the exponential growth phase (4 pmol (10(4) cell-1) by day 3). The initial content of β-carotene (3 pmol (10(4) cell)-1) did not show significant differences over time in cells exposed to UVBR. Two mycosporine-like amino acids (MAAs) were identified: porphyra-334 and shinorine. Cellular concentrations of MAAs increased significantly on days 2 and 3, and exposure of the algae to UVBR significantly enhanced this value. The relative importance of MAAs concentration was significant (P < 0.05) in relation to the α-tocopherol content. A positive correlation was shown between cellular MAAs concentration and growth rate. Our results suggest that photoprotection against UV-induced damage is characterized by short-term consumption of α-tocopherol and longer-term synthesis of MAAs. The UVBR damage/repair ratio during long-term exposure involves the combined action of several endogenous factors within the cell, with MAAs synthesis being the most effective factor related to photoprotection. Durante enero 1999, cultivos unialgales de una diatomea Thalassiosira sp., aislada de poblaciones fitoplanctónicas naturales de Caleta Carlos Potter, Antártida, fueron expuestos a radiación solar ultravioleta (UVR, 280-400 nm) con el objetivo de estudiar su aclimatación a largo plazo. La radiación ultravioleta B (UVBR, 280-315 nm) inhibió la tasa de crecimiento durante el primer y segundo día de exposición. No se observó inhibición por UVBR durante el tercer día. El contenido inicial de α-tocopherol (13 pmol (10(4) ...