Short-term effects of solar UV radiation and NO₃ ^- supply on the accumulation of mycosporine-like amino acids in Pyropia columbina (Bangiales, Rhodophyta) under spring ozone depletion in the sub-Antarctic region, Chile

Abstract

Short-term variations of mycosporine-like amino acids (MAAs) in Pyropia columbina (Montage) W.A. Nelson exposed to nitrate (NO3 -) enrichment under different outdoor light treatments during the spring ozone depletion of 2008 in Punta Arenas (Chile) were investigated. Segments of P. columbina thalli were cultivated under three treatments of solar radiation without or with NO3 - supply (0.38 mmol l-1): PAR (P), PAR+UVA (PA), and PAR+UVA+UVB (PAB). Samples were taken at 8:00 h (initial value), 9:30, 12:30, 15:30, and 18:00 h on November 8 and at 9:00 h on November 9 (recovery period). A complex dynamic of MAAs affected by light quality and NO3 - supply was observed. During the light period, the highest content of MAAs was reached under PAB and NO3 - enrichment, whereas MAAs increased during the recovery period in P and PAB with no NO3 - supply. Five MAAs were identified: porphyra-334, shinorine, asterina-330, palythine, and mycosporine-glycine. The hourly accumulation of each MAA varied mainly according to the time of exposure and NO3 - supply. In general, the percentage of porphrya-334 increased, whereas the other MAAs decreased during the exposure period. These results suggest that MAA content in P. columbina varied in the short-term (hours) and the changes were related to the solar irradiance received and NO3 - availability.

Variación en la concentración de aminoácidos tipo micosporinas en macroalgas de las regiones de Valparaíso y Magallanes, Chile

“…En algas rojas apenas 6 de ellos son los más frecuentes: porphyra-334 ( max = 334nm), shinorina ( max = 334nm), palitinol ( max = 332nm), asterina-330 ( max = 330nm), palitina ( max = 320nm) y micosporina-glicina ( max = 310nm). Se ha reportado que la especie P. columbina posee 5 tipos de MAAs, con un porcentaje superior al 90% de porphya-334 (Navarro et al 2014a). De esta manera, el máximo de absorción estaría en la longitud de onda 334 nm, lo cual concuerda con lo mostrado en la Figura 1.…”

“…Debido a que la concentración de compuestos fotoprotectores puede variar durante el día (Navarro et al 2014a), las diferentes especies fueron recolectadas a la misma hora (11:00 AM). De los ejemplares colectados, se usaron las secciones apicales a modo de evitar la variación intratalo verificada en otras especies (Karsten et al 1999, Höyer et al 2001.…”

“…A medida que se acumula información referente a estos compuestos, se sugiere que no existen patrones claros sobre la inducción de MAAs, indicando además que su inducción, formación y acumulación es un mecanismo muy flexible y especie-específico (Höyer et al 2001, Navarro et al 2014a. Sin embargo, de modo general, se puede mencionar que aquellas algas sujetas a constantes variaciones en los niveles de radiación UV, como las que habitan la región intermareal, tendrían mayores concentraciones de MAAs que aquellas algas del submareal, las cuales no sufren variaciones bruscas en su exposición a la radiación.…”

Sunscreens of red algae from Patagonia: a biotechnological perspective

“…In red algae, MAAs are present in species from different water depths [25,32] and geographical areas, ranging from polar to tropical regions [22] and including the Subantarctic [25,28,58,59] and Antarctic regions [32]. Macroalgae can be classified according to their MAA content into three physiologically different groups: (1) species with no MAA biosynthesis capability, (2) species with a constant and relatively high MAA composition and concentration, and (3) species with a basic MAA concentration that adjusts in relation to changes in the quality and quantity of environmental radiation (e.g., UVA, UVB, and by PAR) [27,28,[60][61][62], as well as in relation to other environmental variables such as salinity, temperature, desiccation [44,63], and N availability [24, 26-28, 59, 64-66].…”

“…the synthesis and accumulation of UV-absorbing compounds such as trihidroxicoumarins in green algae [17], polyphenols in brown algae [15,[18][19][20][21], and mycosporine-like amino acids (MAAs) in red algae species [22][23][24][25][26][27][28].…”