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目的对搭载神舟八号飞船的屎肠球菌进行突变株筛选,并鉴定和分析差异表达的蛋白质。方法利用Biolog生化反应板从搭载神舟八号飞船飞行后屎肠球菌中筛选突变株,提取突变株蛋白质并进行SDS-PAGE电泳检测,用BCA法测定总蛋白浓度后,采用同重同位素相对与绝对定量(isobaric tags for relative and absolute quantitation,iTRAQ)方法分析空间环境诱变屎肠球菌突变株和地面对照株之间的差异表达蛋白,并进行统计、分析和注释。结果通过Biolog表型筛选获得空间环境诱导屎肠球菌突变株LCT-EF20,该菌株能利用肌酐和L-苹果酸,而不能利用对羟基苯乙酸。差异蛋白组学分析发现了124个蛋白质表达的改变,其中50个蛋白表达上调,74个蛋白表达下调。结论太空环境可改变屎肠球菌的生物学特性,并影响大量蛋白质的表达,差异表达蛋白主要分布在代谢相关过程。
Objective To screen mutants of Enterococcus faecium carrying Shenzhou VIII spacecraft and identify and analyze the differentially expressed proteins. Methods Mutant strains of Enterococcus faecium were collected from the spacecraft carrying Shenzhou No. 8 using Biolog biochemical reaction plate. Proteins of the mutants were extracted and analyzed by SDS - PAGE. Total protein concentration was determined by BCA method. The relative and absolute Quantitative (isobaric tags for relative and absolute quantitation, iTRAQ) method was used to analyze the differentially expressed proteins between mutagenic strains of Enterococcus faecium in space environment and ground control strains. The statistical analysis, analysis and annotation were performed. Results The space-environment-induced Enterococcus faecium mutant LCT-EF20 was obtained by Biolog phenotype screening, which can utilize creatinine and L-malic acid, but not p-hydroxyphenylacetic acid. Differential proteomic analysis revealed 124 protein changes, of which 50 were up-regulated and 74 were down-regulated. Conclusion The space environment can change the biological characteristics of Enterococcus faecium and affect the expression of a large number of proteins. The differentially expressed proteins are mainly distributed in the metabolism-related processes.