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Title: Tolerance and stress response of Macrolepiota procera to nickel
Authors: Baptista, Paula
Ferreira, Sílvia
Soares, Maria Elisa
Coelho, Valentim
Bastos, Maria de Lourdes
Keywords: Macrolepiota procera
Ni2+ tolerance
Ni2+ accumulation
Hydrogen peroxide
Antioxidant enzymes
Issue Date: 2009
Publisher: ACS Publications
Citation: Baptista, Paula; Ferreira, Sílvia; Soares, Elisa; Coelho, Valentim; Bastos, Maria de Lourdes (2009) - Tolerance and stress response of Macrolepiota procera to nickel. Journal of Agricultural and Food Chemistry. ISSN 0021-8561. 57:15, p. 7145–7152
Abstract: Nickel (Ni) is an essential element for many organisms; however, it is very toxic at high concentrations and also depending on the species. In macrofungi the mechanisms underlying their Ni tolerance are poorly documented. This study examines, for the first time, the participation of the antioxidative system in Macrolepiota procera exposed to different Ni2+ concentrations and their relation with Ni tolerance. The effect of the pH on Ni tolerance was also evaluated. The fungus was cultivated on solid medium with different NiCl2 concentrations (0.05, 0.2, 0.8 mM) at pH 4, 6, and 8, and fungi growth and Ni uptake were determined. The antioxidative enzymes catalase (CAT) and superoxide dismutase (SOD) and the production of hydrogen peroxide (H2O2) were evaluated on fungal submerged cultures within the first hours of Ni2+ exposure. Results showed that M. procera growth decreased when Ni2+ concentrations increased, reaching a maximum growth inhibition (>80%) up to 0.2 mM of NiCl2. Ni uptake increased proportionally to Ni increase in the medium. Both Ni tolerance and Ni accumulation were affected by medium pH. Microscope observations showed differences in the size of spores produced by fungi at different Ni concentrations. Ni exposure induced oxidative stress, as indicated by the production of H2O2, the levels of which seem to be regulated by the antioxidant enzymes SOD and CAT. The time variation pattern of SOD and CAT activities indicated that the former has a greater role in alleviating the stress. The results obtained suggested that tolerance of M. procera to Ni2+ is associated with the ability of this macrofungus to initiate an efficient antioxidant defense system
Peer review: yes
ISSN: 0021-8561
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Appears in Collections:BB - Artigos em Revistas Indexados ao ISI/Scopus

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