Zinc Accumulation Characteristics of Two Exophiala Strains and Their Antioxidant Response to Zn2+ Stress
Zinc Accumulation Characteristics of Two Exophiala Strains and Their Antioxidant Response to Zn2+ Stress
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DOI：
10.4236/jep.2013.44a003
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
Y. Diao;T. Li;Z. Zhao
中科院分区：
文献类型：
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作者：
Y. Diao;T. Li;Z. Zhao
锌是一种必需元素，在自然环境中，过量的锌对生物体是有毒的。比较研究了耐锌菌株H93 （EC50 = 1010 mg·L-1 Zn2+）和锌敏感菌株B40-3 （EC50 = 26 mg·L-1 Zn2+）的锌积累特性及其对Zn2+胁迫的抗氧化反应。在各自Zn2+中位有效浓度下，H93的吸收锌量是B40-3的2.5倍，累积锌量是B40-3的5.2倍。CaCl2洗脱实验表明，锌主要积聚在两株真菌菌丝的胞内。比较分析了不同Zn2+浓度对两株真菌抗氧化成分和抗氧化酶活性的调节作用。H93的总超氧化物歧化酶、过氧化物酶和谷胱甘肽活性始终高于B40-3，丙二醛含量也高于B40-3。目前的研究结果表明，该菌株对锌的耐受性可能与它们在不同的锌积累速率和抗氧化成分调节下的各种本能行为有关。
Zinc is an essential element, which is toxic for organisms in their natural environments in excessive amounts. The zinc accumulation characteristics of a Zn-tolerant strain (H93, EC50 = 1010 mg·L–1 Zn2+) and a Zn-sensitive strain (B40-3, EC50 = 26 mg·L–1 Zn2+), Exophiala spp. and their antioxidant response to Zn2+ stress were comparatively characterized. Under their respective Zn2+ median effective concentrations, H93 absorbed 2.5-fold and accumulated 5.2-fold more Zn than B40-3. An elution experiment using CaCl2 revealed that Zn mainly accumulated intracellularly in the mycelia of the two fungal strains. The modulation of antioxidant components and antioxidant enzyme activities of the two fungal strains were comparatively analyzed under different Zn2+ concentrations. The activity of the total superoxide dismutase, peroxidase, and glutathione of H93 was always higher than that of B40-3, and the malondialdehyde content in H93 was also higher than that of B40-3. The current results suggested that the Zn tolerance of Exophiala strain may be attributed to their various instinctive behaviors with different rates of Zn accumulation and modulation of antioxidant components.