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Schuerger AC, Moores JE, Smith DJ, Reitz G. A Lunar Microbial Survival Model for Predicting the Forward Contamination of the Moon. ASTROBIOLOGY 2019; 19:730-756. [PMID: 30810338 DOI: 10.1089/ast.2018.1952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The surface conditions on the Moon are extremely harsh with high doses of ultraviolet (UV) irradiation (26.8 W · m-2 UVC/UVB), wide temperature extremes (-171°C to 140°C), low pressure (10-10 Pa), and high levels of ionizing radiation. External spacecraft surfaces on the Moon are generally >100°C during daylight hours and can reach as high as 140°C at local noon. A Lunar Microbial Survival (LMS) model was developed that estimated (1) the total viable bioburden of all spacecraft landed on the Moon as ∼4.57 × 1010 microbial cells/spores at contact, (2) the inactivation kinetics of Bacillus subtilis spores to vacuum as approaching -2 logs per 2107 days, (3) the inactivation of spores on external surfaces due to concomitant low-pressure and high-temperature conditions as -6 logs per 8 h for local noon conditions, and (4) the ionizing radiation by solar wind particles as approaching -3 logs per lunation on external surfaces only. When the biocidal factors of solar UV, vacuum, high-temperature, and ionizing radiation were combined into an integrated LMS model, a -231 log reduction in viable bioburden was predicted for external spacecraft surfaces per lunation at the equator. Results indicate that external surfaces of landed or crashed spacecraft are unlikely to harbor viable spores after only one lunation, that shallow internal surfaces will be sterilized due to the interactive effects of vacuum and thermal cycling from solar irradiation, and that deep internal surfaces would be affected only by vacuum with a degradation rate of -0.02 logs per lunation.
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Affiliation(s)
- Andrew C Schuerger
- 1 Department of Plant Pathology, University of Florida, Gainesville, Florida
| | - John E Moores
- 2 Centre for Research in Earth and Space Science (CRESS), York University, Toronto, ON Canada
| | - David J Smith
- 3 Space Biosciences Division, NASA, Ames Research Center, Moffett Field, California
| | - Günther Reitz
- 4 Department of Radiation Dosimetry, Nuclear Physics Institute of the CAS, Praha, Czech Republic
- 5 Radiation Biology Division, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
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Ha TMH, Yong D, Lee EMY, Kumar P, Lee YK, Zhou W. Activation and inactivation of Bacillus pumilus spores by kiloelectron volt X-ray irradiation. PLoS One 2017; 12:e0177571. [PMID: 28493969 PMCID: PMC5426783 DOI: 10.1371/journal.pone.0177571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 04/28/2017] [Indexed: 11/30/2022] Open
Abstract
In this study, we investigated the inactivation efficacy of endospore-forming bacteria, Bacillus pumilus, irradiated by low-energy X-rays of different beam qualities. The different low-energy X-rays studied had cut-off energies of 50, 100 and 150 keV. Bacillus pumilus spores (in biological indicator strips) were irradiated at step doses between 6.5 to 390 Gy. The resulting bacteria populations were then quantified by a pour plate method. Results showed that X-rays of lower energies were more effective in inactivating bacterial spores. In addition, an increment in bacterial population was observed at doses below 13Gy. We attributed this increase to a radiation-induced activation of bacterial spores. Four kinetic models were then evaluated for their prediction of bacterial spore behavior under irradiation. This included: (i) first-order kinetics model; (ii) Shull model; (iii) Sapru model; and (iv) probabilistic model. From R2 and AIC analyses, we noted that the probabilistic model performed the best, followed by the Sapru model. We highlighted that for simplicity in curve fitting the Sapru model should be used instead of the probabilistic model. A 12-log reduction in bacterial population (corresponding to a sterility assurance level of 10−6 as required in the sterilization of medical devices) was computed to be achievable at doses of 1000, 1600 and 2300 Gy for the three different X-ray cut-off energies respectively. These doses are an order in magnitude lesser than that required in gamma irradiation. This highlights the applicability of cheaper and safer table-top X-ray sources for sterilization application.
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Affiliation(s)
- Thi Mai Hoa Ha
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- * E-mail:
| | - Derrick Yong
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Elizabeth Mei Yin Lee
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Prathab Kumar
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Yuan Kun Lee
- Department of Microbiology, National University of Singapore, Singapore, Singapore
| | - Weibiao Zhou
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
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Modeling the effect of γ-irradiation on reducing total bacterial populations in gochujang intended for consumption by astronauts in space programs. Food Sci Biotechnol 2011. [DOI: 10.1007/s10068-011-0053-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Reitz G, Bucker H, Ruther W, Graul EH, Beaujean R, Enge W, Heinrich W, Mesland DA, Alpatov AM, Ushakov IA. Effects on ontogenesis of Carausius morosus hit by cosmic heavy ions. INTERNATIONAL JOURNAL OF RADIATION APPLICATIONS AND INSTRUMENTATION. PART D, NUCLEAR TRACKS AND RADIATION MEASUREMENTS 2001; 17:145-53. [PMID: 11537514 DOI: 10.1016/1359-0189(90)90197-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Among the biological problems that arise in long duration spaceflights, the effects of weightlessness and ionizing radiation appear to be the two main risk factors. Eggs of the stick insect Carausius morosus were exposed to spaceflight conditions during the 12.56 day Biosatellite mission Cosmos 1887. Five different ages were used, representing different sensitivities to radiation and different capacities for regeneration. During spaceflight the eggs continued their development. Already, in the Spacelab D1 mission in 1985, it has been shown that microgravity leads to a reduced hatching rate of eggs exposed during the early steps of development. When the eggs were hit by a heavy ion, a further but not significant reduction of the hatching rate was observed. Hatching was normal for eggs which were exposed on a 1 g reference centrifuge in space. Heavy ion hits caused body anomalies. The combined action of heavy ions and microgravity resulted in an unexpectedly high rate of anomalies. In the experiment on Cosmos 1887 these results were confirmed. Studies on the embryonic development before hatching showed no major difference between flight and ground control specimen, neither in speed of development nor in morphological anomalies. Hatching therefore seems to be the critical point in insect ontogenesis.
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Affiliation(s)
- G Reitz
- DLR, Insitute for Aerospace Medicine, Biophysics Division, Koln, FRG
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Pugliese M, Durante M, Grossi GF, Monforti F, Orlando D, Ottolenghi A, Scampoli P, Gialanella G. Inactivation of individual mammalian cells by single alpha-particles. Int J Radiat Biol 1997; 72:397-407. [PMID: 9343105 DOI: 10.1080/095530097143176] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To measure clonogenic death of Chinese hamster V79 cells following exposure to a defined number of 4.3 MeV alpha-particles (track-averaged LET = 105 keV/micron). MATERIALS AND METHODS Cells were irradiated at the radiobiological facility installed at the TTT-3 Tandem accelerator in Naples by using a 'Biostack' approach, which allows the positions of incident tracks relative to cells to be carefully determined. Subcellular structure was identified by fluorescence microscopy, while tracks were visualized by LR-115 solid state nuclear track detectors. RESULTS Particle hits in the cytoplasm did not significantly affect cell survival, yet survival probability decreased exponentially as a function of the number of nuclear traversals. Measured probability of surviving to exactly one 4.3 MeV alpha-particle traversal in the cell nucleus was 0.67 +/- 0.10. Inactivation cross-section was substantially higher than expected from conventional survival curves. However, folding of the data with Poisson statistics showed that survival level expected if a mean of one alpha-particle goes through a nucleus is higher than the measured value after exactly one particle traversal. CONCLUSIONS V79 cells have about 67% probability to survive a single alpha-particle traversal in the cell nucleus. Single-particle survival curves are consistent with conventional dose-survival relationships, once Poisson distribution of traversals is taken into account.
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Affiliation(s)
- M Pugliese
- Servizio di Radioprotezione, Università Federico II, Mostra d'Oltremare, Napoli, Italy
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Reitz G, Horneck G, Facius R, Schäfer M. Results of space experiments. RADIATION AND ENVIRONMENTAL BIOPHYSICS 1995; 34:139-44. [PMID: 7480627 DOI: 10.1007/bf01211539] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Life science research in space was started in Europe with the first Biostack experiment flown onboard Apollo 16 in 1972. Biostack was designed to investigate the biological effects of single heavy ions of cosmic radiation. Among several undertakings towards this goal, the Biostack achieved the highest precision in the determination of the spatial correlation of the observed biological response of single test organisms to the passage of single heavy ions, which is the mandatory requirement. It also provided information on the influence of additional spaceflight factors, such as microgravity, on radiation effects and measurements of the spectrum of charge and energy of the cosmic radiation. The experiment was performed as an international cooperation effort. This report gives a summary of the biological data accumulated in this and the follow-on experiments of the Biostack program.
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Affiliation(s)
- G Reitz
- Institute for Aerospace Medicine, Radiation Biology, Köln, Germany
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Abstract
Among the various particulate components of ionizing radiation in space, heavy ions (the so-called HZE particles) have been of special concern to radiobiologists. To understand the ways by which HZE particles of cosmic radiation interact with biological systems, methods have been developed to precisely localize the trajectory of an HZE particle relative to the biological object and to correlate the physical data of the particle with the biological effects observed along its path. In a variety of test systems, injuries were traced back to the traversal of a single HZE particle, such as somatic mutations, and chromosomal aberrations in plant seeds, development disturbances and malformations in insect and salt shrimp embryos, or cell death in bacterial spores. In the latter case, a long-ranging killing effect around the particle's track was observed. Whereas, from spaceflight experiments, substantial infomation has been accumulated on single HZE particle effects in resting systems and in a few embryonic systems, there is a paucity of data on cosmic radiation effects in whole tissues or animals, especially mammalians.
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Affiliation(s)
- G Horneck
- DLR, Institute of Aerospace Medicine, Koln, Germany
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Horneck G, Bucker H, Reitz G. Long-term survival of bacterial spores in space. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1994; 14:41-45. [PMID: 11539977 DOI: 10.1016/0273-1177(94)90448-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
On board of the NASA Long Duration Exposure Facility (LDEF), spores of Bacillus subtilis in monolayers (10(6)/sample) or multilayers (10(8)/sample) were exposed to the space environment for nearly six years and their survival was analyzed after retrieval. The response to space parameters, such as vacuum (10(-6) Pa), solar electromagnetic radiation up to the highly energetic vacuum-ultraviolet range (10(9) J/m2) and/or cosmic radiation (4.8 Gy), was studied and compared to the results of a simultaneously running ground control experiment. If shielded against solar ultraviolet (UV)-radiation, up to 80 % of spores in multilayers survive in space. Solar UV-radiation, being the most deleterious parameter of space, reduces survival by 4 orders of magnitude or more. However, up to 10(4) viable spores were still recovered, even in completely unprotected samples. Substances, such as glucose or buffer salts serve as chemical protectants. With this 6 year study in space, experimental data are provided to the discussion on the likelihood of "Panspermia".
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Affiliation(s)
- G Horneck
- DLR, Institute of Aerospace Medicine, Biophysics Division, Koln, Germany
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Abstract
The scientific career of Prof. Bucker has spanned a very exciting period in the fledgling science of Space Radiation Biology. The capability for placing biological objects in space was developed, and the methods for properly packaging, retrieving and analyzing them were worked out. Meaningful results on the effects of radiation were obtained for the first time. In fact, many of the successful techniques and methodologies for handling biological samples were developed in Prof. Bucker's laboratories, as attested by the extensive Biostack program. He was the first to suggest and successfully carry out experiments in space directly aimed at measuring effects of single tracks of high-energy heavy galactic cosmic rays by specifically identifying whether or not the object had been hit by a heavy particle track. Because the "hit" frequencies of heavy galactic cosmic rays to cell nuclei in the bodies of space travelers will be low, it is expected that any effects to humans on the cellular level will be dominated by single-track cell traversals. This includes the most important generally recognized late effect of space radiation exposure: radiation-induced cancer. This paper addresses the single-track nature of the space radiation environment, and points out the importance of single "hits" in the evaluation of radiation risk for long-term missions occurring outside the earth's magnetic field. A short review is made of biological objects found to show increased effects when "hit" by a single heavy charged-particle in space. A brief discussion is given of the most provocative results from the bacterial spore Bacillus subtilis: experimental evidence that tracks can affect biological systems at much larger distances from the trajectory than previously suspected, and that the resultant inactivation cross section in space calculated for this system is very large. When taken at face value, the implication of these results, when compared to those from experiments performed at ground-based accelerators with beams at low energies in the same LET range, is that high-energy particles can exert their influence a surprising distance from their trajectory and the inactivation cross sections are some 20 times larger than expected. Clearly, beams from high-energy heavy-ion accelerators should be used to confirm these results. For those end points that can also be caused by low-LET beams such as high-energy protons, it is important to measure their action cross sections as well. The ratio of the cross sections for a high-LET beam to that of a low-LET beam is an interesting experimental ratio and, we suggest, of more intrinsic interest than the RBE (Relative Biological Effectiveness). It is a measure of the "biological" importance of one particle type relative to another particle type. This ratio will be introduced and given the name RPPE (Relative Per Particle Effectiveness). Values of RPPE have appeared in the literature and will be discussed. A rather well-known value of this quantity (13,520) has been suggested for the RPPE of high-energy iron ions to high-energy protons. This value was suggested by Letaw et al. Nature 330, 709-710 (1987)] we will call it the Letaw limit. It will be discussed in terms of the importance of the heavy-ion component vs light-ion component of the galactic cosmic rays. It is also pointed out, however, that there may be unique effects from single tracks of heavy ions that do not occur from light-ion tracks. For such effects, the concepts of both RBE and RPPE lose their meaning.
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Affiliation(s)
- S B Curtis
- Lawrence Berkeley Laboratory, University of California 94720, USA
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Takahashi T, Yatagai F, Izumo K. Microdosimetric considerations of effects of heavy ions on E. coli K-12 mutants. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1992; 12:65-68. [PMID: 11537048 DOI: 10.1016/0273-1177(92)90091-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The inactivation cross sections of E. coli K-12 recombination-deficient mutants, JC1553 (recA) and AB2470 (recB), for several MeV/u alpha-particles and N ions have been successfully analyzed by Katz's target theory in which radiosensitivity parameter E0 is assumed to be LET independent and equal to D37 for gamma-rays. For E. coli K-12 wild type, AB1157 (rec+, uvr+), however, it is impossible to interpret the inactivation cross section data by an LET-independent E0-value. In the latter case, as in the case of B. subtilis spore, it is necessary to assume that the radiosensitivity of the target for the core of a heavy ion is higher than that for delta-electrons. As well as Waligorski, Hamm and Katz's dose, the dose around the trajectory of an ion based on Tabata and Ito's energy deposition algorithm for electrons has been used in the course of analysis.
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Affiliation(s)
- T Takahashi
- RIKEN (int. Phys. Chem. Res.), Saitama, Japan
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Horneck G, Brack A. Study of the origin, evolution and distribution of life with emphasis on exobiology experiments in earth orbit. ADVANCES IN SPACE BIOLOGY AND MEDICINE 1992; 2:229-62. [PMID: 1342246 DOI: 10.1016/s1569-2574(08)60023-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- G Horneck
- Institut für Flugmedizin, DLR, Köln, Germany
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