Despite being chromium tolerance not related to the induction of phytochelatins, the tolerance to this metal seems strictly connected to sulfur metabolism (Pereira et al., 2008; Schiavon et al., 2008). In the freshwater green alga Scenedesmus acutus sulfur starvation induces a transient increase of Cr(VI) tolerance both in the wild type and in a Cr-tolerant strain (Gorbi et al 2007). This transient increase is lost after 2-day recovery in standard medium. Studies based on microarray analysis showed that in Chlamydomonas reinhardtii sulfur starvation induces the expression of numerous genes, among which plasma membrane sulfate transporters, many enzymes of the sulfate assimilation pathway and enzymes involved in the antioxidative response, such as superoxide dismutase (SOD), GPX, FSD and SHMT (Zhang et al 2004). In order to verify if differences in SOD expression are involved in the observed transient increase in Cr-tolerance, as well in the differential sensitivity shown by the two S. acutus strains, we analysed SOD protein levels after different time of Cr(VI) exposure. No changes was observed in MnSOD or in Cu/ZnSOD following Cr treatment. On the contrary, immunoassays showed in the Cr-tolerant strain treated with Cr(VI) 1mg/l significantly higher levels of FeSOD than in the wild type. A 3-day sulfur starvation enhances FeSOD levels in both strains, though remaining significantly higher in the Cr-tolerant strain. At the present, it is not clear if the enhancement of FeSOD levels could be directly involved in the transient tolerance induced by S-sarvation. Nonetheless, these results suggest the existence of a different threshold of oxidative stress perception that may induce a prompter response of the Cr-tolerant strain to Cr exposure. Gorbi et al., 2007, Aquat. Toxicol. 84:457-464 Pereira et al., 2008, Toxicol Sci 106(2): 400-412 Schiavon et al., 2008, J. Environ. Qual. 37: 1536-1545 Zhang et al. 2004 Eukariotic Cell Vol.3 , No.5: 1331-1348

Different FeSOD levels are associated with different Cr(VI) tolerance in two strains of Scenedesmus acutus / Sardella, Alessio; Bertazzini, Michele; Marieschi, Matteo; Zanni, Corrado; Forlani, Giuseppe; Torelli, Anna. - (2014), pp. 31-31. ((Intervento presentato al convegno Annual meeting of the Italian Phycological Group (SBI) in conjunction with the Annual General Meeting (AGM) of the Federation of European Phycological Society (FEPS) tenutosi a Padova nel 14-15 Novembre 2014.

Different FeSOD levels are associated with different Cr(VI) tolerance in two strains of Scenedesmus acutus

MARIESCHI, Matteo;ZANNI, Corrado;TORELLI, Anna
2014-01-01

Abstract

Despite being chromium tolerance not related to the induction of phytochelatins, the tolerance to this metal seems strictly connected to sulfur metabolism (Pereira et al., 2008; Schiavon et al., 2008). In the freshwater green alga Scenedesmus acutus sulfur starvation induces a transient increase of Cr(VI) tolerance both in the wild type and in a Cr-tolerant strain (Gorbi et al 2007). This transient increase is lost after 2-day recovery in standard medium. Studies based on microarray analysis showed that in Chlamydomonas reinhardtii sulfur starvation induces the expression of numerous genes, among which plasma membrane sulfate transporters, many enzymes of the sulfate assimilation pathway and enzymes involved in the antioxidative response, such as superoxide dismutase (SOD), GPX, FSD and SHMT (Zhang et al 2004). In order to verify if differences in SOD expression are involved in the observed transient increase in Cr-tolerance, as well in the differential sensitivity shown by the two S. acutus strains, we analysed SOD protein levels after different time of Cr(VI) exposure. No changes was observed in MnSOD or in Cu/ZnSOD following Cr treatment. On the contrary, immunoassays showed in the Cr-tolerant strain treated with Cr(VI) 1mg/l significantly higher levels of FeSOD than in the wild type. A 3-day sulfur starvation enhances FeSOD levels in both strains, though remaining significantly higher in the Cr-tolerant strain. At the present, it is not clear if the enhancement of FeSOD levels could be directly involved in the transient tolerance induced by S-sarvation. Nonetheless, these results suggest the existence of a different threshold of oxidative stress perception that may induce a prompter response of the Cr-tolerant strain to Cr exposure. Gorbi et al., 2007, Aquat. Toxicol. 84:457-464 Pereira et al., 2008, Toxicol Sci 106(2): 400-412 Schiavon et al., 2008, J. Environ. Qual. 37: 1536-1545 Zhang et al. 2004 Eukariotic Cell Vol.3 , No.5: 1331-1348
Different FeSOD levels are associated with different Cr(VI) tolerance in two strains of Scenedesmus acutus / Sardella, Alessio; Bertazzini, Michele; Marieschi, Matteo; Zanni, Corrado; Forlani, Giuseppe; Torelli, Anna. - (2014), pp. 31-31. ((Intervento presentato al convegno Annual meeting of the Italian Phycological Group (SBI) in conjunction with the Annual General Meeting (AGM) of the Federation of European Phycological Society (FEPS) tenutosi a Padova nel 14-15 Novembre 2014.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2785154
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