Oxidative stress induced by a commercial glyphosate formulation in a tolerant strain of Chlorella kessleri

We studied the toxicity of a glyphosate formulation and provide evidence of metabolic alterations due to oxidative stress caused in a Chlorella kessleri tolerant strain by exposure to the herbicide. After 96h of exposure to increasing concentrations of the herbicide (0-70mgL-1) with alkylaryl polyglycol ether surfactant, growth was inhibited (EC50-96h 55.62mgL-1). Glyphosate increased protein and malondialdehyde content which was significantly higher than in the control at 50-70mgL-1. Superoxide dismutase and catalase activities and reduced glutathione levels increased in a concentration-dependant manner. Morphological studies showed increases in vacuolisation and in cell and sporangia sizes. The glyphosate formulation studied has a cytotoxic effect on C. kessleri through a mechanism that would involve the induction of oxidative stress. Upon glyphosate exposure, oxidative stress parameters such as SOD and CAT activities and MDA level could be more sensitive biomarkers than usually tested growth parameters in C. kessleri. © 2010 Elsevier Inc.Fil: Romero, Delfina Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo; ArgentinaFil: Rios, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo; ArgentinaFil: Juárez, Angela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo; Argentin