Acumulación de aminoácidos tipo micosporina (MAAs): Biosíntesis, fotocontrol y funciones ecofisiológicas

Abstract

The negative effects of UV radiation on aquatic organisms can be diminished by several photo-protective mechanisms such as the accumulation of UV absorbing substances (photoprotectors) and the activation of antioxidant systems. The mycosporine-like amino acids (MAAs) are one of the most known photoprotectors. In this review their photoprotective and antioxidant capabilities are described. The UV screening function of MAAs can be inferred from their photophysic characteristics. It is known that MAAs act as passive screen dissipating the UV energy absorbed as thermal form. The accumulation of MAAs is induced by both UV radiation (UV-A and UV-B) and by blue light in the photosynthetic active radiation part of the spectrum (PAR). On the other hand, there are several reports indicating other physiological functions of the MAAs, antioxidant activity, osmotic regulation and reproduction. Since MAAs are nitrogenous compounds, recently the influence of inorganic nitrogen in combination to UV radiation and/or high irradiance of PAR is being investigated. The ammonium is rapidly mobilized to MAAs, and hence they maybe regarded as a nitrogen reservoir. © 2006 Sociedad de Biología de Chile.