INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Bioaccumulation and potencial origin of photoprotective compounds (Mycosporine like amino-acids) in freshwater copepods from Patagonia.
Autor/es:
4. GARCÍA, P. E.; M. C. DIEGUÉZ. ; FERRARO, M. A.; ZAGARESE, H. E. Y PÉREZ, A. P.
Lugar:
TORRES, BRASIL
Reunión:
Workshop; GLEON 10; 2010
Resumen:
García, P.
E.1; Diéguez, M. C.1; Ferraro, M. A.2;
Zagarese, H. E2 and Pérez, A. P.1
Bioaccumulation
and potential origin of photoprotective compounds (Mycosporine-like Amino Acids)
in freshwater copepods from Patagonia
1Laboratorio de Fotobiología. UNC. IMIBIOMA. Bariloche (Argentina).
2Laboratorio de ecología y
fotobiología acuática. IIB-INTECH. Chascomus (Argentina).
Abstract
Mycosporine-like
amino acids (MAAs) are common photoprotective compounds occurring in certain
groups of freshwater and marine organisms. These compounds act as sunscreen or
antioxidants and thus provide protection against harmful ultraviolet radiation
(UVR). MAAs can be synthesized by a wide variety of organisms including
bacteria, fungi and algae and their synthesis and bioaccumulation is inducible
by UVR and visible light. Animals appear to acquire MAAs from their diet and/or
from symbiotic organisms. The synthesis of MAAs involves the shikimic acid
pathway, which as far as we know, has not been found in metazoans. The
bioaccumulation of MAAs in three species of calanoid copepods endemic to Patagonia (Boeckella
antiqua, B. gracilis and B. breviucaudata) correlates with UVR exposure, supporting
their role as photoprotective compounds and revealing a common mechanism in Boeckella spp to withstand the high
levels of UV experienced in their natural environments. Concomitantly, temperature
appears as a factor regulating the process of bioaccumulation of MAAs and the survivorship
of cold-adapted species of Boeckella as
well. Peaks of MAAs bioaccumulation in Boeckella spp. were recorded between 12 ºC and 16ºC. Experiments performed
with B. antiqua fed with algae devoid
of MAAs resulted in higher levels of MAAs implying that the process may rely in
an alternative source of these compounds such as endosimbiotic bacteria. Batch culture experiments testing the effect
of bacteria suppression on MAAs accumulation showed
a decrease in the bioaccumulation of these compounds cultures treated with the basteriostatic
Chloramphenicol. This result points out that prokaryotic biota likely
contributes to the bioaccumulation of MAAs in Boeckella spp. Furthermore, experimental analyses testing for the
incidence of actual MAAs concentration on the uptake rate of MAAs in B. antiqua indicated that individuals bearing
high levels of MAAs do not accumulate or even loss these compounds.