Nickel accumulation and nickel effects on cellular growth, respiration, photosynthesis, ascorbate peroxidase (APX) activity, and levels of thiols, histidine and phosphate-molecules were determined in Euglena gracilis. Cells incubated with 0.5–1 mM NiCl₂ showed impairment of O₂ consumption, photosynthesis, Chl a + b content and APX activity whereas cellular integrity and viability were unaltered. Nickel accumulation was depressed by Mg²⁺ and Cu²⁺, while Ca²⁺, Co²⁺, Mn²⁺ and Zn²⁺ were innocuous. The growth half-inhibitory concentrations for Ni²⁺ in the culture medium supplemented with 2 or 0.2 mM Mg²⁺ were 0.43 or 0.03 mM Ni²⁺, respectively. Maximal nickel accumulation (1,362 mg nickel/Kg DW) was achieved in cells exposed to 1 mM Ni²⁺ for 24 h in the absence of Mg²⁺ and Cu²⁺; accumulated nickel was partially released after 72 h. GSH polymers content increased or remained unchanged in cells exposed to 0.05–1 mM Ni²⁺; however, GSH, cysteine, γ-glutamylcysteine, and phosphate-molecules all decreased after 72 h. Histidine content increased in cells stressed with 0.05 and 0.5 mM Ni²⁺ for 24 h but not at longer times. It was concluded that E. gracilis can accumulate high nickel levels depending on the external Mg²⁺ and Cu²⁺ concentrations, in a process in which thiols, histidine and phosphate-molecules have a moderate contribution.

中文翻译：

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像绿藻一样的Euglena gracilis积累的镍

测定了裸藻（Euglena gracilis）中镍的积累和镍对细胞生长，呼吸，光合作用，抗坏血酸过氧化物酶（APX）活性以及硫醇，组氨酸和磷酸盐分子水平的影响。用0.5–1 mM NiCl ₂孵育的细胞显示O ₂消耗，光合作用，Chl a + b含量和APX活性受损，而细胞完整性和活力未改变。Mg ²⁺和Cu ²⁺抑制了镍的积累，而Ca 2 ⁺，Co 2 ⁺，Mn ²⁺和Zn ²⁺则无害。Ni ²⁺的生长半抑制浓度补充有2或0.2 mM Mg ²⁺的培养基中的Ni ²⁺分别为0.43或0.03 mM Ni ²⁺。在没有Mg ²⁺和Cu ²⁺的情况下，在暴露于1 mM Ni ^2+的电池中放置24 h可获得最大的镍累积量（1,362 mg镍/ Kg DW）；72小时后，部分释放出了积聚的镍。在暴露于0.05–1 mM Ni ^2+的细胞中，GSH聚合物的含量增加或保持不变。然而，GSH，半胱氨酸，γ-谷氨酰半胱氨酸和磷酸盐分子在72小时后均下降。在用0.05和0.5 mM Ni ²⁺胁迫的细胞中，组氨酸含量增加24小时，但没有更长的时间。得出的结论是，小肠埃希氏菌硫醇，组氨酸和磷酸盐分子的贡献中等，可根据外部Mg ²⁺和Cu ^2+的浓度累积高水平的镍。