Acclimation to singlet oxygen stress in Chlamydomonas reinhardtii
Acclimation to singlet oxygen stress in Chlamydomonas reinhardtii
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DOI：
10.1128/ec.00207-06
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发表时间：
2007-06-01
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影响因子：
--
通讯作者：
Niyogi, Krishna K.
中科院分区：
文献类型：
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作者：
Ledford, Heidi K.;Chin, Brian L.;Niyogi, Krishna K.
在有氧环境中，对氧化线索的反应对于生理适应（适应）变化的环境条件至关重要。测试单细胞莱茵衣藻适应特定形式的氧化应激的能力。驯化被定义为亚致死预处理的活性氧激活防御反应，随后提高生存的压力的能力。C.莱茵衣藻对玫瑰红（一种产生单线态氧的光敏染料）表现出强烈的适应反应。这种适应依赖于光敏作用，仅在光照下给予预处理时发生。将细胞从低光转换到高光也增强了对单线态氧的抗性，这表明高光和单线态氧反应途径存在重叠。RNA水平的微阵列分析表明，相对较少的基因对亚致死水平的单线态氧有反应。两个这样的基因，谷胱甘肽过氧化物酶基因和谷胱甘肽S-转移酶基因的组成性过表达，足以增强单线态氧抗性。大肠杆菌和酿酒酵母表现出明确的反应活性氧，但没有适应单线态氧，可能反映了单线态氧胁迫光合生物的相对重要性。
In an aerobic environment, responding to oxidative cues is critical for physiological adaptation (acclimation) to changing environmental conditions. The unicellular alga Chlamydomonas reinhardtii was tested for the ability to acclimate to specific forms of oxidative stress. Acclimation was defined as the ability of a sublethal pretreatment with a reactive oxygen species to activate defense responses that subsequently enhance survival of that stress. C. reinhardtii exhibited a strong acclimation response to rose bengal, a photosensitizing dye that produces singlet oxygen. This acclimation was dependent upon photosensitization and occurred only when pretreatment was administered in the light. Shifting cells from low light to high light also enhanced resistance to singlet oxygen, suggesting an overlap in high-light and singlet oxygen response pathways. Microarray analysis of RNA levels indicated that a relatively small number of genes respond to sublethal levels of singlet oxygen. Constitutive overexpression of either of two such genes, a glutathione peroxidase gene and a glutathione S-transferase gene, was sufficient to enhance singlet oxygen resistance. Escherichia coli and Saccharomyces cerevisiae exhibit well-defined responses to reactive oxygen but did not acclimate to singlet oxygen, possibly reflecting the relative importance of singlet oxygen stress for photosynthetic organisms.d