Gomes-Junior R A, Moldes C A, Delite F S, Gratão P L, Mazzafera P, Lea P J, Azevedo R A
Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba 13418-900, SP, Brazil.
Plant Physiol Biochem. 2006 May-Jun;44(5-6):420-9. doi: 10.1016/j.plaphy.2006.06.002. Epub 2006 Jun 13.
The antioxidant responses of coffee (Coffea arabica L.) cell suspension cultures to nickel (Ni) were investigated. Ni was very rapidly accumulated in the cells and the accumulation could be directly correlated with the increase of NiCl(2) concentration in the medium. At 0.05 mM NiCl(2) growth was stimulated, but at 0.5 mM NiCl(2), the growth rate was reduced. An indication of alterations in the presence of reactive oxygen species was detected by an increase in lipid peroxidation at 0.5 mM NiCl(2). Catalase (CAT; EC 1.11.1.6), glutathione reductase (GR; EC 1.6.4.2), ascorbate peroxidase (APX; EC 1.11.1.11), guaiacol peroxidase (GOPX; EC 1.11.1.7) and superoxide dismutase (SOD; EC 1.15.1.1) activities were increased, particularly at earlier NiCl(2) exposure times and the activities were higher at 0.5 mM NiCl(2) for most of exposure times tested. Non-denaturing PAGE revealed one CAT isoenzyme, nine SOD isoenzymes and four GR isoenzymes. The SOD isoenzymes were differentially affected by NiCl(2) treatment and one GR isoenzyme was increased by NiCl(2). NiCl(2) at 0.05 mM did not induce lipid peroxidation and the main response appeared to be via the induction of SOD, CAT, GOPX and APX activities for the removal of the reactive oxygen species and through the induction of GR to ensure the availability of reduced glutathione.
研究了咖啡（阿拉比卡咖啡）细胞悬浮培养物对镍（Ni）的抗氧化反应。镍在细胞中迅速积累，且这种积累与培养基中NiCl₂浓度的增加直接相关。在0.05 mM NiCl₂时生长受到刺激，但在0.5 mM NiCl₂时，生长速率降低。在0.5 mM NiCl₂时，脂质过氧化增加，这表明活性氧存在时发生了变化。过氧化氢酶（CAT；EC 1.11.1.6）、谷胱甘肽还原酶（GR；EC 1.6.4.2）、抗坏血酸过氧化物酶（APX；EC 1.11.1.11）、愈创木酚过氧化物酶（GOPX；EC 1.11.1.7）和超氧化物歧化酶（SOD；EC 1.15.1.1）的活性增加，特别是在早期NiCl₂暴露时间，并且在大多数测试的暴露时间下，0.5 mM NiCl₂时的活性更高。非变性聚丙烯酰胺凝胶电泳显示一种CAT同工酶、九种SOD同工酶和四种GR同工酶。SOD同工酶受NiCl₂处理的影响不同，一种GR同工酶因NiCl₂而增加。0.05 mM的NiCl₂不会诱导脂质过氧化，主要反应似乎是通过诱导SOD、CAT、GOPX和APX的活性来去除活性氧，并通过诱导GR来确保还原型谷胱甘肽的可用性。
