Molecular Mechanisms of Microbial Survivability in Outer Space: A Systems Biology Approach.

Tetyana Milojevic,Wolfram Weckwerth

doi:10.3389/fmicb.2020.00923

Abstract

Since the dawn of space exploration, the survivability of terrestrial life in outer space conditions has attracted enormous attention. Space technology has enabled the development of advanced space exposure facilities to investigate in situ responses of microbial life to the stress conditions of space during interplanetary transfer. Significant progress has been made toward the understanding of the effects of space environmental factors, e.g., microgravity, vacuum and radiation, on microorganisms exposed to real and simulated space conditions. Of extreme importance is not only knowledge of survival potential of space-exposed microorganisms, but also the determination of mechanisms of survival and adaptation of predominant species to the extreme space environment, i.e., revealing the molecular machinery, which elicit microbial survivability and adaptation. Advanced technologies in –omics research have permitted genome-scale studies of molecular alterations of space-exposed microorganisms. A variety of reports show that microorganisms grown in the space environment exhibited global alterations in metabolic functions and gene expression at the transcriptional and translational levels. Proteomic, metabolomic and especially metabolic modeling approaches as essential instruments of space microbiology, synthetic biology and metabolic engineering are rather underrepresented. Here we summarized the molecular space-induced alterations of exposed microorganisms in terms of understanding the molecular mechanisms of microbial survival and adaptation to drastic outer space environment.

Highlights

The outer space environment, which is characterized by a high vacuum and an intense radiation, provides hostile conditions to any form of life
Exploring the relevant mechanisms underlying metabolic and physiological changes which microorganisms experience during exposure to outer space, the omics-based approach integrates the different fragments of biological information to understand the flow of information from genomes, mRNA, proteins to metabolites (Weckwerth, 2011a; Ott et al, 2017, 2019b,a), and explains how the microorganisms adapt to this extreme environment
Transcriptomic analysis of R. rubrum (Mastroleo et al, 2009) cultivated aboard spacecraft, B. subtilis (Nicholson et al, 2012) and B. pumilus (Vaishampayan et al, 2012) spores exposed to outer space conditions and Salmonella in low-shear modeled microgravity (LSMMG) conditions (Wilson et al, 2002) revealed a wide repertoire of transcriptional regulators involved in response to a longterm exposure to outer space

Summary

Introduction

The outer space environment, which is characterized by a high vacuum and an intense radiation, provides hostile conditions to any form of life. Global alterations in gene expression at the translational and transcriptional levels induced by adaptation of exposed microorganisms to radiationand microgravity-filled space environment have been confirmed by proteomic and transcriptomic analyses (Figure 2), while genomics techniques revealed a number of mutant microbial strains after spaceflight (Vaishampayan et al, 2010; Chang et al, 2013a,b; Li et al, 2014; Zhang et al, 2015).

Results

Conclusion