UV Protection of Bacteria Under Simulated Martian Conditions

2020 ◽  
Author(s):  
Paul Godin ◽  
Andrew Schuerger ◽  
Casey Moore ◽  
John Moores
Keyword(s):  
Uv Radiation ◽  
Light Transmission ◽  
Uv Protection ◽  
Genus Bacillus ◽  
Short Term ◽  
Planetary Protection ◽  
Microbial Life ◽  
Acidic Conditions ◽  
Acidic Environments ◽  
Martian Regolith

<p>Ultraviolet (UV) irradiation on the surface of Mars is an important factor affecting the survivability of microorganisms on Mars. The possibility of Martian brines made from Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>, MnSO<sub>4</sub>, and MgSO<sub>4</sub> salts providing a habitable niche on Mars via attenuation of UV radiation was investigated on the bacteria Bacillus subtilis and Enterococcus faecalis. Results demonstrated that it is possible for brines containing Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3 </sub>on Mars to provide protection from harmful UV radiation, even at concentrations as low as 0.5%. Brines made from MnSO<sub>4</sub> and MgSO<sub>4</sub>, did not provide significant UV protection and most spores/cells died over the course of short-term experiments.</p> <p>However, Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3 </sub>brines are strongly acidic, and thus, were lethal to E. faecalis. In contrast, B. subtilis, as a spore-forming bacterium resistant to pH extremes, was unaffected by the acidic conditions of the brines and did not experience any significant lethal effects. Any extant microbial life in Martian Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3 </sub>brines (if present) would need to be capable of surviving acidic environments, if these brines are to be considered a possible habitable niche.</p> <p>The results from this work are important to both the search for life on planets with an atmosphere unable to significantly attenuate UV radiation (i.e., like Mars); and for planetary protection, since it is possible that terrestrial bacteria in the genus Bacillus are likely to survive in Fe-sulfate brines on Mars.</p> <p>Furthermore, preliminary work on UV and photosynthetically active radiation (PAR) light transmission and scattering through simulated Martian regolith and rock samples are also presented. Regoliths that block UV but allow for PAR would be likely candidates for supporting bacterial life.</p>

Influence of UV radiation on the light transmission of a polymer optical fiber

1993 ◽  
Vol 59 (1-2) ◽  
pp. 528-532 ◽  
Author(s):  
P. M. Pakhomov ◽  
M. A. Maryukov ◽  
V. M. Levin ◽  
A. S. Chegolya
Keyword(s):  
Optical Fiber ◽  
Uv Radiation ◽  
Light Transmission ◽  
Polymer Optical Fiber

scholarly journals Solar UV radiation and microbial life in the atmosphere

2018 ◽  
Vol 17 (12) ◽  
pp. 1918-1931 ◽  
Author(s):  
Sasha Madronich ◽  
Lars Olof Björn ◽  
Richard L. McKenzie
Keyword(s):  
Uv Radiation ◽  
Seasonal Patterns ◽  
Microbial Life ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Solar Ultraviolet

Many microorganisms are alive while suspended in the atmosphere, but are exposed to solar ultraviolet (UV) radiation from all directions. Geographic and seasonal patterns of DNA-damaging UV doses can be estimated from observations as well as modeling.

scholarly journals Lmo0036, an ornithine and putrescine carbamoyltransferase in Listeria monocytogenes, participates in arginine deiminase and agmatine deiminase pathways and mediates acid tolerance

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3150-3161 ◽  
Author(s):  
Jianshun Chen ◽  
Changyong Cheng ◽  
Ye Xia ◽  
Hanxin Zhao ◽  
Chun Fang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Foodborne Pathogen ◽  
Acid Tolerance ◽  
Arginine Deiminase ◽  
Transcriptional Level ◽  
Acidic Conditions ◽  
Acidic Environments ◽  
Agmatine Deiminase

Listeria monocytogenes is a foodborne pathogen causing listeriosis. Acid is one of the stresses that foodborne pathogens encounter most frequently. The ability to survive and proliferate in acidic environments is a prerequisite for infection. However, there is limited knowledge about the molecular basis of adaptation of L. monocytogenes to acid. Arginine deiminase (ADI) and agmatine deiminase (AgDI) systems are implicated in bacterial tolerance to acidic environments. Homologues of ADI and AgDI systems have been found in L. monocytogenes lineages I and II strains. Sequence analysis indicated that lmo0036 encodes a putative carbamoyltransferase containing conserved motifs and residues important for substrate binding. Lmo0036 acted as an ornithine carbamoyltransferase and putrescine carbamoyltransferase, representing the first example, to our knowledge, that catalyses reversible ornithine and putrescine carbamoyltransfer reactions. Catabolic ornithine and putrescine carbamoyltransfer reactions constitute the second step of ADI and AgDI pathways. However, the equilibrium of in vitro carbamoyltransfer reactions was overwhelmingly towards the anabolic direction, suggesting that catabolic carbamoyltransferase was probably the limiting step of the pathways. lmo0036 was induced at the transcriptional level when L. monocytogenes was subjected to low-pH stress. Its expression product in Escherichia coli exhibited higher catabolic carbamoyltransfer activities under acidic conditions. Consistently, absence of this enzyme impaired the growth of Listeria under mild acidic conditions (pH 4.8) and reduced its survival in synthetic human gastric fluid (pH 2.5), and corresponded to a loss in ammonia production, indicating that Lmo0036 was responsible for acid tolerance at both sublethal and lethal pH levels. Furthermore, Lmo0036 played a possible role in Listeria virulence.

scholarly journals Physiological responses and toxin production ofMicrocystis aeruginosain short-term exposure to solar UV radiation

2018 ◽  
Vol 17 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Marcelo Hernando ◽  
Melina Celeste Crettaz Minaglia ◽  
Gabriela Malanga ◽  
Christian Houghton ◽  
Darío Andrinolo ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Physiological Responses ◽  
Toxin Production ◽  
Short Term ◽  
Solar Uv Radiation ◽  
Short Term Exposure ◽  
Solar Uv

We found a UVBR threshold and different responses were activated depending on the exposure to UVAR or UVBR and their doses. =: no changes; −: decrease; +: increase. The number of signals represents the intensity of the effect.

Synthesis of MnO2 nanoparticles and their effective utilization as UV protectors for outdoor high voltage polymeric insulators used in power transmission lines

2016 ◽  
Vol 18 (48) ◽  
pp. 32876-32890 ◽  
Author(s):  
Dipankar Ghosh ◽  
Subhendu Bhandari ◽  
Dipak Khastgir
Keyword(s):  
Uv Radiation ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Uv Protection ◽  
Power Transmission Lines ◽  
Effective Utilization ◽  
Mno2 Nanoparticles ◽  
Polymeric Insulators ◽  
Outdoor Insulators

The mechanism of the UV protection of polymers by MnO2 where UV radiation is absorbed by MnO2 particles present in the PDMS/EVA–MnO2 composite used in high voltage outdoor insulators for power transmission lines.

scholarly journals Biofilms Confer Resistance to Simulated Extra-terrestrial Geochemical Extremes

2017 ◽  
Author(s):  
Adam H. Stevens ◽  
Delma Childers ◽  
Mark Fox-Powell ◽  
Charles S. Cockell
Keyword(s):  
Planktonic Cells ◽  
Planetary Protection ◽  
Aqueous Environments ◽  
Groundwater Systems ◽  
Acidic Conditions ◽  
High Sulfate ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Over Time

1AbstractBiofilms improve microbes’ resistance to a variety of extreme physical and chemical conditions on Earth. The discovery of putative aqueous environments on other planetary bodies such as Mars motivates an interest in understanding the viability of life, and the potential role of biofilms, in previously unexplored geochemical extremes. We investigated the loss of viability of planktonic cells and biofilms ofSphingomonas desiccabilis(a Gram-negative, desiccation resistant, soil crust-forming organism) to simulated Martian brines. These brines were produced from geochemical modelling of past aqueous environments on Mars, and their high sulfate concentrations make them different to most terrestrial brines, although similar briny environments have been found in locations such as the Basque Lakes in Canada or in deep subsurface groundwater systems. Biofilms grown on basaltic scoria were subjected to the simulated martian brines and the viability of cells was measured over time and compared to equivalent planktonic cultures. Crystal violet assay was used to measure how the biomass of the biofilms changed over time in response to the brines. While certain brines were highly hostile to microbial viability, we found that biofilms that were desiccated prior to being treated with brines maintained viability over a longer treatment period when compared to planktonic cells. Our results show that biofilms confer short-term protection to the harsh osmotic, ionic, and acidic conditions of Mars-relevant brines. However, in the most extreme simulated brines, even biofilms eventually lost viability. By demonstrating that biofilms confer protection to conditions that are potentially analogous to current day recurrent slope lineae (thought to be produced by the flow of briny fluids) on Mars, our results show that contaminant biofilm-forming microorganisms may have a greater chance of surviving in so-called ‘Special Regions’ on Mars, with implications for planetary protection in missions that aim to explore these regions.

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