Callone Alan I, Carignan Mario, Montoya Nora G, Carreto José I
Instituto Nacional de Investigación y Desarrollo Pesquero, Paseo Victoria Ocampo No. 1, 7600 Mar del Plata, Argentina.
J Photochem Photobiol B. 2006 Sep 1;84(3):204-12. doi: 10.1016/j.jphotobiol.2006.03.001. Epub 2006 May 12.
Changes in mycosporine-like amino acids (MAAs) induced by the increase of photosynthetically active radiation (PAR) were studied in the toxic dinoflagellate Alexandrium tamarense. Cultures of A. tamarense were maintained at exponential growth under low (25 micromol quanta m(-2)s(-1)) PAR irradiance. The cultures were nutrient enriched and one day later exposed to higher irradiance (150 micromol quanta m(-2)s(-1)). The content of MAAs was determined by means of high performance liquid chromatography (HPLC). Eleven MAAs, including some partially characterized compounds, were identified. The MAAs synthesis induction can be described as a two-stage process. The first one involves the net synthesis of the MAAs bi-substituted by amino acids. In the second stage these compounds were transformed into other secondary MAAs. The two most prominent changes were observed in the concentration of porphyra-334 and palythene. The cellular concentration of porphyra-334 increased during the first 2h of exposure to higher irradiance and then decreased rapidly. In contrast, the cellular concentration of palythene showed a continuous accumulation since the beginning of the exposure. In A. tamarense the main route of MAAs transformation has porphyra-334 as a precursor of a sequential conversion resulting in the accumulation of palythene.
在有毒甲藻塔玛亚历山大藻中，研究了光合有效辐射（PAR）增加诱导的类菌孢素氨基酸（MAAs）变化。塔玛亚历山大藻培养物在低PAR辐照度（25微摩尔光量子·米⁻²·秒⁻¹）下维持指数生长。培养物进行营养强化，一天后暴露于更高辐照度（150微摩尔光量子·米⁻²·秒⁻¹）。通过高效液相色谱（HPLC）测定MAAs含量。鉴定出11种MAAs，包括一些部分表征的化合物。MAAs合成诱导可描述为一个两阶段过程。第一阶段涉及氨基酸双取代的MAAs的净合成。在第二阶段，这些化合物转化为其他二级MAAs。在紫菜-334和聚苔色胺的浓度上观察到两个最显著的变化。紫菜-334的细胞浓度在暴露于更高辐照度的前2小时内增加，然后迅速下降。相反，聚苔色胺的细胞浓度自暴露开始以来持续积累。在塔玛亚历山大藻中，MAAs转化的主要途径以紫菜-334为顺序转化的前体，导致聚苔色胺的积累。
