中文摘要：

发菜（Nostoc flagelliforme）是一种陆生固氮蓝藻,为探讨其耐旱的分子机理及对极端干旱环境的适应和保护机制,运用双向电泳技术（2-DE）、凝胶图像分析、MALDI-TOF-TOF/MS质谱鉴定和数据库检索,分析发菜过氧化物氧还蛋白（Peroxiredoxin）在持续干燥48 h和复吸水4 h后的差异表达水平,根据鉴定的过氧化物氧还蛋白已知氨基酸序列设计简并性引物克隆该基因,分析基因和氨基酸序列的同源性及对蛋白质二级结构进行预测,并研究其原核表达.结果表明,发菜过氧化物氧还蛋白在复吸水后的表达量明显高于干燥状态下的表达量。根据简并性引物克隆获得长度为639 bp的过氧化物氧还蛋白基因,GenBank登陆号为HM854286.序列比较分析显示该基因具有较高的保守性,蛋白质二级结构主要由α螺旋、β折叠和随机卷曲构成.将过氧化物氧还蛋白基因在大肠杆菌中表达,获得符合预期的外源重组蛋白（26.5×103）,经Western blotting验证,该外源蛋白为过氧化物氧还蛋白.图10表1参25

英文摘要：

Nostoc flagelliforme is a terrestrial nitrogen-fixing cyanobacteria with strong drought ecological adaptability.In this research,2-DE,gel image analysis and MALDI-TOF-TOF/MS were applied to compare and identify the peroxiredoxin expression level from N.flagelliforme subjected to dehydration and rehydration.Degeneracy primer was designed based on the identified amino acid sequences in order to clone peroxiredoxin gene,to analyze the gene and amino acid sequences,to predict the secondary structure of peroxiredoxin,and to study the prokaryotic expression of the peroxiredoxin gene.The results indicated that peroxiredoxin expression level of N.flagelliforme subjected to rehydration was higher than that to desiccation.Peroxiredoxin gene was cloned and a full length of 639 bp DNA was obtained（GenBank access number： HM854286）.Homology analysis showed that the N.flagelliforme peroxiredoxin gene has high consensus regions.The secondary structure of peroxiredoxin was made up of α helix,β strands and random coil.Peroxiredoxin gene was expressed in E.coli,and a Mr 26.5×103 heterologous protein was obtained.It was confirmed by Western blotting that the protein was peroxiredoxin.The study laid a foundation for in depth research in terms of the drought-resistant molecular mechanism and protection mechanism of N.flagelliforme in extreme arid environment.Fig 10,Tab 1,Ref 25