Nanlou Respiratory Diseases Department, Chinese PLA General Hospital, Beijing 100853, China.
BMC Microbiol. 2013 Dec 28;13:304. doi: 10.1186/1471-2180-13-304.
For a long time, Enterococcus faecium was considered a harmless commensal of the mammalian gastrointestinal (GI) tract and was used as a probiotic in fermented foods. In recent decades, E. faecium has been recognised as an opportunistic pathogen that causes diseases such as neonatal meningitis, urinary tract infections, bacteremia, bacterial endocarditis and diverticulitis. E. faecium could be taken into space with astronauts and exposed to the space environment. Thus, it is necessary to observe the phenotypic and molecular changes of E. faecium after spaceflight.
An E. faecium mutant with biochemical features that are different from those of the wild-type strain was obtained from subculture after flight on the SHENZHOU-8 spacecraft. To understand the underlying mechanism causing these changes, the whole genomes of both the mutant and the WT strains were sequenced using Illumina technology. The genomic comparison revealed that dprA, a recombination-mediator gene, and arpU, a gene associated with cell wall growth, were mutated. Comparative transcriptomic and proteomic analyses showed that differentially expressed genes or proteins were involved with replication, recombination, repair, cell wall biogenesis, glycometabolism, lipid metabolism, amino acid metabolism, predicted general function and energy production/conversion.
This study analysed the comprehensive genomic, transcriptomic and proteomic changes of an E. faecium mutant from subcultures that were loaded on the SHENZHOU-8 spacecraft. The implications of these gene mutations and expression changes and their underlying mechanisms should be investigated in the future. We hope that the current exploration of multiple "-omics" analyses of this E. faecium mutant will provide clues for future studies on this opportunistic pathogen.
很长一段时间以来，屎肠球菌被认为是哺乳动物胃肠道（GI）的无害共生菌，并被用作发酵食品中的益生菌。近几十年来，屎肠球菌已被确认为一种机会性病原体，可引起新生儿脑膜炎、尿路感染、菌血症、细菌性心内膜炎和憩室炎等疾病。屎肠球菌可随宇航员带入太空并暴露于太空环境中。因此，有必要观察屎肠球菌在太空飞行后的表型和分子变化。
从神舟八号飞船飞行后的亚培养中获得了与野生型菌株生化特征不同的屎肠球菌突变体。为了了解导致这些变化的潜在机制，使用 Illumina 技术对突变体和 WT 菌株的全基因组进行了测序。基因组比较表明，dprA（一种重组介导基因）和 arpU（与细胞壁生长相关的基因）发生了突变。比较转录组和蛋白质组分析表明，差异表达的基因或蛋白与复制、重组、修复、细胞壁生物合成、糖代谢、脂质代谢、氨基酸代谢、预测的一般功能和能量产生/转换有关。
本研究分析了加载在神舟八号飞船上的屎肠球菌突变体的综合基因组、转录组和蛋白质组变化。未来应进一步研究这些基因突变和表达变化及其潜在机制的意义。我们希望目前对这种屎肠球菌突变体的多种“组学”分析的探索将为未来对这种机会性病原体的研究提供线索。
