A Molecular Genetic Basis Explaining Altered Bacterial Behavior in Space

PLoS One. 2016 Nov 2;11(11):e0164359. doi: 10.1371/journal.pone.0164359. eCollection 2016.


Bacteria behave differently in space, as indicated by reports of reduced lag phase, higher final cell counts, enhanced biofilm formation, increased virulence, and reduced susceptibility to antibiotics. These phenomena are theorized, at least in part, to result from reduced mass transport in the local extracellular environment, where movement of molecules consumed and excreted by the cell is limited to diffusion in the absence of gravity-dependent convection. However, to date neither empirical nor computational approaches have been able to provide sufficient evidence to confirm this explanation. Molecular genetic analysis findings, conducted as part of a recent spaceflight investigation, support the proposed model. This investigation indicated an overexpression of genes associated with starvation, the search for alternative energy sources, increased metabolism, enhanced acetate production, and other systematic responses to acidity-all of which can be associated with reduced extracellular mass transport.

MeSH terms

  • Bacterial Physiological Phenomena / genetics*
  • Energy Metabolism
  • Escherichia coli / physiology
  • Gene Expression
  • Gene Expression Regulation, Bacterial
  • Genetic Association Studies*
  • Hydrogen-Ion Concentration
  • Space Flight*
  • Weightlessness

Grant support

The data analysis effort for this investigation was funded under Grant Agreement (GA-2014-146) as part of the International Space Station (ISS) National Laboratory through the Center for the Advancement of Science in Space, Inc. (CASIS) in accordance with NASA Cooperative Agreement No. NNH11CD70A (http://www.iss-casis.org/). LZ's work in Germany was funded by the German Academic Exchange Service (DAAD) and the German Aerospace Center (DLR) for their support through the DAAD Research Fellowship for Doctoral Candidates and Young Scientists (https://www.daad.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.