Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions
Ionizing radiation is one of the main factors limiting the survival of microorganisms in extraterrestrial conditions. The survivability of microorganisms under irradiation depends significantly on the conditions, in which the irradiation occurs. In particular, temperature, pressure, oxygen and water...
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MDPI AG
2021-01-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/9/1/198 |
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| author | Vladimir S. Cheptsov Andrey A. Belov Elena A. Vorobyova Anatoli K. Pavlov Vladimir N. Lomasov |
| author_facet | Vladimir S. Cheptsov Andrey A. Belov Elena A. Vorobyova Anatoli K. Pavlov Vladimir N. Lomasov |
| author_sort | Vladimir S. Cheptsov |
| collection | DOAJ |
| description | Ionizing radiation is one of the main factors limiting the survival of microorganisms in extraterrestrial conditions. The survivability of microorganisms under irradiation depends significantly on the conditions, in which the irradiation occurs. In particular, temperature, pressure, oxygen and water concentrations are of great influence. However, the influence of factors such as the radiation intensity (in low-temperature conditions) and the type of mineral matrix, in which microorganisms are located, has been practically unstudied. It has been shown that the radioresistance of bacteria can increase after their exposure to sublethal doses and subsequent repair of damage under favorable conditions, however, such studies are also few and the influence of other factors of extraterrestrial space (temperature, pressure) was not studied in them. The viability of bacteria <i>Arthrobacter polychromogenes</i>, <i>Kocuria rosea</i> and <i>Xanthomonas</i> sp. after irradiation with gamma radiation at a dose of 1 kGy under conditions of low pressure (1 Torr) and low temperature (−50 °C) at different radiation intensities (4 vs. 0.8 kGy/h) with immobilization of bacteria on various mineral matrices (montmorillonite vs. analogue of lunar dust) has been studied. Native, previously non-irradiated strains, and strains that were previously irradiated with gamma radiation and subjected to 10 passages of cultivation on solid media were irradiated. The number of survived cells was determined by culturing on a solid medium. It has been shown that the radioresistance of bacteria depends significantly on the type of mineral matrix, on which they are immobilized, wherein montmorillonite contributes to an increased survivability in comparison with a silicate matrix. Survivability of the studied bacteria was found to increase with decreasing radiation intensity, despite the impossibility of active reparation processes under experimental conditions. Considering the low intensity of radiation on various space objects in comparison with radiobiological experiments, this suggests a longer preservation of the viable microorganisms outside the Earth than is commonly believed. An increase in bacterial radioresistance was revealed even after one cycle of irradiation of the strains and their subsequent cultivation under favourable conditions. This indicates the possibility of hypothetical microorganisms on Mars increasing their radioresistance. |
| first_indexed | 2024-03-09T04:21:16Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-09T04:21:16Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
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| series | Microorganisms |
| spelling | doaj.art-c1ea3379aba642b8b2eb0ff665eb30272023-12-03T13:48:09ZengMDPI AGMicroorganisms2076-26072021-01-019119810.3390/microorganisms9010198Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature ConditionsVladimir S. Cheptsov0Andrey A. Belov1Elena A. Vorobyova2Anatoli K. Pavlov3Vladimir N. Lomasov4Soil Science Faculty, Lomonosov Moscow State University, Leninskie Gory, 1, 12, 119234 Moscow, RussiaSoil Science Faculty, Lomonosov Moscow State University, Leninskie Gory, 1, 12, 119234 Moscow, RussiaSoil Science Faculty, Lomonosov Moscow State University, Leninskie Gory, 1, 12, 119234 Moscow, RussiaIoffe Physical-Technical Institute of the Russian Academy of Sciences, Polytechnicheskaya Street, 26, 194021 Saint-Petersburg, RussiaSTC “Nuclear Physics”, Peter the Great St. Petersburg State Polytechnic University, Polytechnicheskaya Street, 29, 195251 Saint-Petersburg, RussiaIonizing radiation is one of the main factors limiting the survival of microorganisms in extraterrestrial conditions. The survivability of microorganisms under irradiation depends significantly on the conditions, in which the irradiation occurs. In particular, temperature, pressure, oxygen and water concentrations are of great influence. However, the influence of factors such as the radiation intensity (in low-temperature conditions) and the type of mineral matrix, in which microorganisms are located, has been practically unstudied. It has been shown that the radioresistance of bacteria can increase after their exposure to sublethal doses and subsequent repair of damage under favorable conditions, however, such studies are also few and the influence of other factors of extraterrestrial space (temperature, pressure) was not studied in them. The viability of bacteria <i>Arthrobacter polychromogenes</i>, <i>Kocuria rosea</i> and <i>Xanthomonas</i> sp. after irradiation with gamma radiation at a dose of 1 kGy under conditions of low pressure (1 Torr) and low temperature (−50 °C) at different radiation intensities (4 vs. 0.8 kGy/h) with immobilization of bacteria on various mineral matrices (montmorillonite vs. analogue of lunar dust) has been studied. Native, previously non-irradiated strains, and strains that were previously irradiated with gamma radiation and subjected to 10 passages of cultivation on solid media were irradiated. The number of survived cells was determined by culturing on a solid medium. It has been shown that the radioresistance of bacteria depends significantly on the type of mineral matrix, on which they are immobilized, wherein montmorillonite contributes to an increased survivability in comparison with a silicate matrix. Survivability of the studied bacteria was found to increase with decreasing radiation intensity, despite the impossibility of active reparation processes under experimental conditions. Considering the low intensity of radiation on various space objects in comparison with radiobiological experiments, this suggests a longer preservation of the viable microorganisms outside the Earth than is commonly believed. An increase in bacterial radioresistance was revealed even after one cycle of irradiation of the strains and their subsequent cultivation under favourable conditions. This indicates the possibility of hypothetical microorganisms on Mars increasing their radioresistance.https://www.mdpi.com/2076-2607/9/1/198astrobiologyMarsradioresistancesurvivabilitycryopreservationionizing radiation |
| spellingShingle | Vladimir S. Cheptsov Andrey A. Belov Elena A. Vorobyova Anatoli K. Pavlov Vladimir N. Lomasov Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions Microorganisms astrobiology Mars radioresistance survivability cryopreservation ionizing radiation |
| title | Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions |
| title_full | Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions |
| title_fullStr | Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions |
| title_full_unstemmed | Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions |
| title_short | Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions |
| title_sort | effects of radiation intensity mineral matrix and pre irradiation on the bacterial resistance to gamma irradiation under low temperature conditions |
| topic | astrobiology Mars radioresistance survivability cryopreservation ionizing radiation |
| url | https://www.mdpi.com/2076-2607/9/1/198 |
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