Knowledge of how microorganisms respond and adapt to low-pressure (LP) environments is limited. Previously, Bacillus subtilis strain WN624 was grown at the near-inhibitory LP of 5 kPa for 1,000 generations and strain WN1106, which exhibited increased relative fitness at 5 kPa, was isolated. Genomic sequence differences between ancestral strain WN624 and LP-evolved strain WN1106 were identified using whole-genome sequencing. LP-evolved strain WN1106 carried amino acid-altering mutations in the coding sequences of only seven genes (fliI, parC, ytoI, bacD, resD, walK, and yvlD) and a single 9-nucleotide in-frame deletion in the rnjB gene that encodes RNase J2, a component of the RNA degradosome. By using a collection of frozen stocks of the LP-evolved culture taken at 50-generation intervals, it was determined that (i) the fitness increase at LP occurred rapidly, while (ii) mutation acquisition exhibited complex kinetics. A knockout mutant of rnjB was shown to increase the competitive fitness of B. subtilis at both LP and standard atmospheric pressure.
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http://dx.doi.org/10.1128/AEM.01690-15 | DOI Listing |
Astrobiology
September 2021
Space Life Sciences Lab, Department of Microbiology and Cell Science, University of Florida, Kennedy Space Center, Florida, USA.
To determine microbial evolutionary strategies to low-pressure (LP; 5 kPa) growth, an environmental condition not experienced on Earth until ∼20 km in altitude, a previously described evolutionary experiment was conducted. The resulting LP evolved strain WN1106, isolated from the terminus of the experiment, was shown to have several genomic mutations absent in the ancestral strain, WN624. Three of the mutations were in regulatory genes: , , and .
View Article and Find Full Text PDFAppl Environ Microbiol
November 2015
Department of Microbiology and Cell Science, University of Florida, Merritt Island, Florida, USA
Knowledge of how microorganisms respond and adapt to low-pressure (LP) environments is limited. Previously, Bacillus subtilis strain WN624 was grown at the near-inhibitory LP of 5 kPa for 1,000 generations and strain WN1106, which exhibited increased relative fitness at 5 kPa, was isolated. Genomic sequence differences between ancestral strain WN624 and LP-evolved strain WN1106 were identified using whole-genome sequencing.
View Article and Find Full Text PDFAstrobiology
March 2012
Department of Microbiology and Cell Science, University of Florida, Kennedy Space Center, 32899, USA.
The atmospheric pressure on Mars ranges from 1-10 mbar, about 1% of Earth pressure (∼1013 mbar). Low pressure is a growth-inhibitory factor for terrestrial microorganisms on Mars, and a putative low-pressure barrier for growth of Earth bacteria of ∼25 mbar has been postulated. In a previous communication, we described the isolation of a strain of Bacillus subtilis that had evolved enhanced growth ability at the near-inhibitory low pressure of 50 mbar.
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