Canini Antonella, Leonardi Donatella, Caiola Maria Grilli
Department of Biology, University of Rome 'Tor Vergata', Via della Ricerca Scientifica I-00133 Rome, Italy.
New Phytol. 2001 Oct;152(1):107-116. doi: 10.1046/j.0028-646x.2001.00244.x.
• The presence of superoxide dismutase (SOD) enzymes and the response of SOD after in vitro induction and decay of a surface bloom are shown in cultures of the cyanobacterium Microcystis aeruginosa. • The SOD enzymes of surface blooms, early degenerate and completely degenerate cultures were assayed by staining for SOD activity, immunoblotting and immunogold labelling. • One band of Mn- and three bands of Fe-SOD were detected in cell extracts. During surface bloom formation, Fe-SOD activity increased fivefold compared with that in control cells; no variation was detected in Mn-SOD activity. However, in early degenerate cultures, Fe-SOD activity decreased to that seen in control cultures, while activity disappeared in completely degenerate cultures. Immunogold labelling showed that Fe-SOD was localized in the cytoplasmic and thylakoid membranes of Microcystis. The extent of labelling paralleled the course of Fe-SOD activity with an increase in particles in surface blooming cells. • The results suggest Fe-SOD increased due to photooxidative stress. However, under prolonged photooxidative stress, high concentrations of active oxygen species could directly, or indirectly, inactivate and degrade Fe-SOD.
• 铜绿微囊藻培养物中显示了超氧化物歧化酶（SOD）的存在以及体外诱导和表面水华衰减后SOD的反应。
• 通过SOD活性染色、免疫印迹和免疫金标记对表面水华、早期衰退和完全衰退培养物中的SOD酶进行了检测。
• 在细胞提取物中检测到一条锰超氧化物歧化酶带和三条铁超氧化物歧化酶带。在表面水华形成期间，铁超氧化物歧化酶活性与对照细胞相比增加了五倍；锰超氧化物歧化酶活性未检测到变化。然而，在早期衰退培养物中，铁超氧化物歧化酶活性降至对照培养物中的水平，而在完全衰退培养物中活性消失。免疫金标记显示铁超氧化物歧化酶定位于微囊藻的细胞质和类囊体膜中。标记程度与铁超氧化物歧化酶活性变化过程平行，表面水华细胞中的颗粒增加。
• 结果表明，铁超氧化物歧化酶因光氧化应激而增加。然而，在长期光氧化应激下，高浓度的活性氧可直接或间接使铁超氧化物歧化酶失活并降解。
