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(70-03) Cadmium removal in Tetraselmis suecica cells exposed to cadmium: relation with sulfhydryl groups. Pérez, Mónica1, Torres, Enrique1, Abalde, Julio*,1, Herrero, Concepción1, 1 Lab. Microbiología, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de A Coruña, A Coruña, Spain ABSTRACT- One of the metals whose concentration is increasing in environments is cadmium. This metal has been ranked as one of the major potential metal hazards with acute toxicity to terrestrial and aquatic organisms. Marine microalgae, a renewable natural biomass, have attracted the attention of many investigators for cadmium removal, since some microalgae species are able to grow in polluted environments and possess the capacity to uptake metals from their environment, resulting in an internal concentration greater than that of the surrounding water. The aim of this study was to test the ability of the marine microalga Tetraselmis suecica to remove cadmium. This microalga is easy to culture, usually used in aquaculture systems and have shown high tolerance to cadmium. The removal of this metal was analyzed in cultures exposed to different cadmium concentrations (0.6, 3, 6, 15, 30 and 45 mg/L). The higher proportion of cadmium was accumulated intracellularly in most cultures except in cultures with 45 mg Cd/L, therefore, T. suecica mainly seems to use an internal detoxification mechanism. In fact, a similar pattern between the increase of intracellular cadmium and sulfhydryl groups evolution through time was observed. The correlation between the intracellular cadmium and the content of sulfhydryl groups was highly significant (r2=0.996, p<0.001) being the slope of the regression line 2.16, just as expected from this type of interaction. A common response of microalgae upon exposure to cadmium is the synthesis of class III metallothioneins. These polypeptides present the general structure ( Key words: microalga, Tetraselmis suecica, bioaccumulation, sulfhydryl groups |
-Glu-Cys)n-Gly. Cadmium is bound to ?SH groups of Cys. This is one of the mechanisms because microalgae cells can bioaccumulate cadmium.