空间环境诱导屎肠球菌突变株LCT-EF18的蛋白组学分析

Proteomics of space Enterococcus faecium mutant strain LCT-EF18

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 identify the proteins and analyze their differential expressions in space Enterococcus faecium （E.faecium） ,mutant loaded in Shenzhou 8 spacecraft. Methods E.faecium mutant loaded in Shenzhou 8 spacecraft was isolated with Biolog biochemical reaction plate. Total protein was extracted from E.faecium mutant and quantified by SDS-PAGE. After the total protein was measured by BCA, the differential expressions of proteins in space E.faecium mutant and ground control strain were analyzed by isobaric tags for relative and absolute quantitation （iTRAQ）. Results The space mutant stain LCT-EF20 was obtained by screening its phenotype, which can use inosine and L-malic acid but cannot utilize p-hydroxy phenylacetic acid. Differential proteomic analysis showed that the expression was up-regulated in 50 and down-regulated in 74 out of the 124 proteins with their expression changed. Conclusion Space environment can affect the biological features of E. faecium mutants and the expression of proteins. The differentially expressed proteins are mainly involved in the bacterial metabolic process.