Isolation of rpoB Mutations Causing Rifampicin Resistance in Bacillus subtilis Spores Exposed to Simulated Martian Surface Conditions

Astrobiology ◽  
2008 ◽  
Vol 8 (6) ◽  
pp. 1159-1167 ◽  
Author(s):  
Amy E. Perkins ◽  
Andrew C. Schuerger ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Rifampicin Resistance ◽  
Martian Surface ◽  
Surface Conditions

Extended survival of several organisms and amino acids under simulated martian surface conditions

Icarus ◽  
2011 ◽  
Vol 211 (2) ◽  
pp. 1162-1178 ◽  
Author(s):  
A.P. Johnson ◽  
L.M. Pratt ◽  
T. Vishnivetskaya ◽  
S. Pfiffner ◽  
R.A. Bryan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Martian Surface ◽  
Surface Conditions ◽  
Extended Survival

scholarly journals Persistence of Biomarker ATP and ATP-Generating Capability in Bacterial Cells and Spores Contaminating Spacecraft Materials under Earth Conditions and in a Simulated Martian Environment

2008 ◽  
Vol 74 (16) ◽  
pp. 5159-5167 ◽  
Author(s):  
Patricia Fajardo-Cavazos ◽  
Andrew C. Schuerger ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Pumilus ◽  
Surface Radiation ◽  
Dominant Factor ◽  
Bacterial Cells ◽  
Gas Composition ◽  
Martian Surface ◽  
Full Spectrum ◽  
Planetary Protection ◽  
Surface Conditions ◽  
Uv C

ABSTRACTMost planetary protection research has concentrated on characterizing viable bioloads on spacecraft surfaces, developing techniques for bioload reduction prior to launch, and studying the effects of simulated martian environments on microbial survival. Little research has examined the persistence of biogenic signature molecules on spacecraft materials under simulated martian surface conditions. This study examined how endogenous adenosine-5′-triphosphate (ATP) would persist on aluminum coupons under simulated martian conditions of 7.1 mbar, full-spectrum simulated martian radiation calibrated to 4 W m−2of UV-C (200 to 280 nm), −10°C, and a Mars gas mix of CO2(95.54%), N2(2.7%), Ar (1.6%), O2(0.13%), and H2O (0.03%). Cell or spore viabilities ofAcinetobacter radioresistens, Bacillus pumilus, andB. subtiliswere measured in minutes to hours, while high levels of endogenous ATP were recovered after exposures of up to 21 days. The dominant factor responsible for temporal reductions in viability and loss of ATP was the simulated Mars surface radiation; low pressure, low temperature, and the Mars gas composition exhibited only slight effects. The normal burst of endogenous ATP detected during spore germination inB. pumilusandB. subtiliswas reduced by 1 or 2 orders of magnitude following, respectively, 8- or 30-min exposures to simulated martian conditions. The results support the conclusion that endogenous ATP will persist for time periods that are likely to extend beyond the nominal lengths of most surface missions on Mars, and planetary protection protocols prior to launch may require additional rigor to further reduce the presence and abundance of biosignature molecules on spacecraft surfaces.

scholarly journals Transport processes induced by metastable boiling water under Martian surface conditions

2016 ◽  
Vol 9 (6) ◽  
pp. 425-428 ◽  
Author(s):  
M. Massé ◽  
S. J. Conway ◽  
J. Gargani ◽  
M. R. Patel ◽  
K. Pasquon ◽  
...  
Keyword(s):  
Transport Processes ◽  
Boiling Water ◽  
Martian Surface ◽  
Surface Conditions

Spectral reflectance properties of minerals exposed to martian surface conditions: Implications for spectroscopy-based mineral detection on Mars

2021 ◽  
pp. 105377
Author(s):  
Nathalie Turenne ◽  
Alexis Parkinson ◽  
Daniel M. Applin ◽  
Paul Mann ◽  
Edward A. Cloutis ◽  
...  
Keyword(s):  
Spectral Reflectance ◽  
Martian Surface ◽  
Surface Conditions ◽  
Mineral Detection

scholarly journals Protective Role of Spore Structural Components in Determining Bacillus subtilis Spore Resistance to Simulated Mars Surface Conditions

2012 ◽  
Vol 78 (24) ◽  
pp. 8849-8853 ◽  
Author(s):  
Ralf Moeller ◽  
Andrew C. Schuerger ◽  
Günther Reitz ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Dipicolinic Acid ◽  
Protective Role ◽  
Structural Components ◽  
Wild Type ◽  
Content Type ◽  
Surface Conditions ◽  
Bacillus Subtilis Spore ◽  
Spore Resistance

ABSTRACTSpores of wild-type and mutantBacillus subtilisstrains lacking various structural components were exposed to simulated Martian atmospheric and UV irradiation conditions. Spore survival and mutagenesis were strongly dependent on the functionality of all of the structural components, with small acid-soluble spore proteins, coat layers, and dipicolinic acid as key protectants.

The Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene Depends on the Growth Environment

2021 ◽  
Author(s):  
Joss D. Leehan ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Growth Condition ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Target Gene ◽  
Rpob Gene ◽  
Relative Fitness ◽  
Rifampicin Resistance ◽  
Resistance Mutations ◽  
Growth Environment

Results from previous investigations into spontaneous rifampicin-resistance (Rif R ) mutations in the Bacillus subtilis rpoB gene suggested that the spectrum of mutations may depend on the growth environment. However, these studies were limited by low sample numbers, allowing for the potential distortion of the data by the presence of ‘jackpot’ mutations which may have arisen early in the growth of a population. Here we addressed this issue by performing fluctuation analyses to assess both the rate and spectrum of Rif R mutations in two distinct media: LB, a complete laboratory medium and SMM Asn , a minimal medium utilizing L-asparagine as the sole carbon source. We cultivated 60 separate populations under each growth condition and determined that the mutation rate to Rif R to be slightly but significantly higher in LB cultures. We then sequenced the relevant regions of rpoB to map the spectrum of Rif R mutations under each growth condition. We found a distinct spectrum of mutations in each medium; LB cultures were dominated by the H482Y mutation (27/53 or 51%) whereas SMM Asn cultures were dominated by the S487L mutation (24/51 or 47%). Furthermore, we found through competition experiments that the relative fitness of the S487L mutant was significantly higher in SMM Asn than in LB medium. We therefore conclude that both the spectrum of Rif R mutations in the B. subtilis rpoB gene and the fitness of resulting mutants to be influenced by the growth environment. Importance The rpoB gene encodes the beta subunit of RNA polymerase, and mutations in rpoB are key determinants of resistance to the clinically important antibiotic rifampicin. We show here that the spectrum of mutations in Bacillus subtilis rpoB depends on the medium in which the cells are cultivated. The results show that not only does the growth environment play a role in natural selection and fitness, but it also influences the probability of mutation at particular bases within the target gene.

Sign in / Sign up

Export Citation Format

Share Document