AUTHOR=Fajardo-Cavazos Patricia , Leehan Joshua D. , Nicholson Wayne L. 

TITLE=Alterations in the Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene after Cultivation in the Human Spaceflight Environment

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.00192

DOI=10.3389/fmicb.2018.00192

ISSN=1664-302X

ABSTRACT=<p>The effect of <italic>Bacillus subtilis</italic> exposure to the human spaceflight environment on growth, mutagenic frequency, and spectrum of mutations to rifampicin resistance (Rif<sup>R</sup>) was investigated. <italic>B. subtilis</italic> cells were cultivated in Biological Research in Canister-Petri Dish Fixation Units (BRIC-PDFUs) on two separate missions to the International Space Station (ISS), dubbed BRIC-18 and BRIC-21, with matching asynchronous ground controls. No statistically significant difference in either growth or in the frequency of mutation to Rif<sup>R</sup> was found in either experiment. However, nucleotide sequencing of the Rif<sup>R</sup> regions of the <italic>rpoB</italic> gene from Rif<sup>R</sup> mutants revealed dramatic differences in the spectrum of mutations between flight (FL) and ground control (GC) samples, including two newly discovered <italic>rpoB</italic> alleles in the FL samples (Q137R and L489S). The results strengthen the idea that exposure to the human spaceflight environment causes unique stresses on bacteria, leading to alterations in their mutagenic potential.</p>