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Background and Aims The aim of this study was to explore the effects of space flight on Klebsiella pneumoniae . Methods A strain of K. pneumoniae was sent to space for 398 h aboard the ShenZhou VIII spacecraft during November 1, 2011–November 17, 2011. At the same time, a ground simulation with similar temperature conditions during the space flight was performed as a control. After the space mission, the flight and control strains were analyzed using phenotypic, genomic, transcriptomic and proteomic techniques. Results The flight strains LCT-KP289 exhibited a higher cotrimoxazole resistance level and changes in metabolism relative to the ground control strain LCT-KP214. After the space flight, 73 SNPs and a plasmid copy number variation were identified in the flight strain. Based on the transcriptomic analysis, there are 232 upregulated and 1879 downregulated genes, of which almost all were for metabolism. Proteomic analysis revealed that there were 57 upregulated and 125 downregulated proteins. These differentially expressed proteins had several functions that included energy production and conversion, carbohydrate transport and metabolism, translation, ribosomal structure and biogenesis, posttranslational modification, protein turnover, and chaperone functions. At a systems biology level, the ytfG gene had a synonymous mutation that resulted in significantly downregulated expression at both transcriptomic and proteomic levels. Conclusions The mutation of the ytfG gene may influence fructose and mannose metabolic processes of K. pneumoniae during space flight, which may be beneficial to the field of space microbiology, providing potential therapeutic strategies to combat or prevent infection in astronauts. [ABSTRACT FROM AUTHOR]

Abstract: The microgravity environment of spaceflight expeditions has been associated with altered microbial responses. This study explores the characterization of Serratia marcescensis grown in a spaceflight environment at the phenotypic, transcriptomic and proteomic levels. From November 1, 2011 to November 17, 2011, a strain of S. marcescensis was sent into space for 398h on the Shenzhou VIII spacecraft, and ground simulation was performed as a control (LCT-SM213). After the flight, two mutant strains (LCT-SM166 and LCT-SM262) were selected for further analysis. Although no changes in the morphology, post-culture growth kinetics, hemolysis or antibiotic sensitivity were observed, the two mutant strains exhibited significant changes in their metabolic profiles after exposure to spaceflight. Enrichment analysis of the transcriptome showed that the differentially expressed genes of the two spaceflight strains and the ground control strain mainly included those involved in metabolism and degradation. The proteome revealed that changes at the protein level were also associated with metabolic functions, such as glycolysis/gluconeogenesis, pyruvate metabolism, arginine and proline metabolism and the degradation of valine, leucine and isoleucine. In summary S. marcescens showed alterations primarily in genes and proteins that were associated with metabolism under spaceflight conditions, which gave us valuable clues for future research. [Copyright &y& Elsevier]