Induction and Repair of DNA Double-Strand Breaks under Irradiation and Microgravity

Pross, H. D.; Casares, A.; Kiefer, Jürgen

doi:10.1667/0033-7587(2000)153[0521:iarodd]2.0.co;2

Cited by 35 publications

(20 citation statements)

References 19 publications

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“…This can cause mutation in DNA sequences and subsequent morphological changes, though no such observations have been reported (8). Thus we used not only morphological indications, but also molecular biological techniques for species identification.…”

Section: Discussionmentioning

confidence: 99%

Fungal Flora on Board the Mir‐Space Station, Identification by Morphological Features and Ribosomal DNA Sequences

Makimura

Hanazawa

Takatori

et al. 2001

Microbiology and Immunology

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This report is on the morphological and molecular biological identification, using 18S-and ITSI-rDNA sequences, of the "space fungi" isolated on board the Russian Mir-Space Station as the major constituents of the fungal flora. The six fungal strains were isolated from air by using an air sampler or from condensation. Strains were identified as Penicillium chrysogenum, Aspergillus versicolor, or Penicillium sp, by both methods. The species of space fungi were common saprophytic fungi in our living environment, potential pathogens, and aUergens. This study concluded that the environment on board the space station Mir allows the growth of potentially pathogenic fungi as true in residential areas on the earth. Therefore, to prevent infection or other health disorders caused by these fungi, easy and reliable methods should be established to survey the fungal flora in a space station.Key words: Mir-Space Station, Fungal flora, DNA Sequences, Identification Space science is a new field of study that will inevitably progress in the early part of this century. Several long-term manned space missions have already been scheduled to the International Space Station, of which the completion is expected to be 2006. Humans in space are exposed both to space radiation and microgravity. Moreover, astronauts will face a variety of microorganisms, especially fungi, as partially reported in English abstracts of Russian papers (12)(13)(14) in the cases of Salyut-6 and Mir-Space Stations. It is possible that these fungi can cause unexpected infections or allergic diseases in astronauts whose immune systems are disturbed by radiation effects under the condition of microgravity or another environment of space. These "space fungi" also damaged electronic equipment on the MirSpace Station by biodeterioration. It is therefore important to study space microbiology, especially the field of medical mycology. We report here the morphological and molecular biological identification, using 18S-and ITS I-rONA sequences, of these space fungi isolated on Materials and MethodsSampling fungal strains. Six fungal strains were isolated from air by using an air sampler (Millipore, 21.1 em', 0.45 11m filter; AI-II, AI-21, BI-6, B2-1O, and B2-24), or from condensation (WI-C4) on board the Russian Mir-Space Station (Mission: JIMM, Mir-Station, 2110-3/2, 1997, National Space Development Agency, Japan). The isolation was done at the Department of Microbiology, Gifu University School of Medicine, and strains were delivered to Teikyo University Institute of Medical Mycology. Air samples were cultured with yeast and mold broth (Millipore) at room temperature (20-25 C) for one to two weeks, and condensation was cultured with Sabouraud dextrose agar (SDA; %, w/v; peptone 1, glucose 1, with agar 1.5) at 30 C for two weeks.Morphological observations. The colonial characAbbreviations: EDTA, ethylenediaminetetraacetic acid; ITS, internal transcribed spacer; peR, polymerase chain reaction; rONA, ribosomal DNA; SDA, Sabouraud dextrose agar.

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Section: Discussionmentioning

confidence: 99%

Fungal Flora on Board the Mir‐Space Station, Identification by Morphological Features and Ribosomal DNA Sequences

Makimura

Hanazawa

Takatori

et al. 2001

Microbiology and Immunology

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“…By measuring the amount of remaining, unrepaired breaks, researchers demonstrated that there was no difference in double-strand break repair between the flight and ground control samples, suggesting no significant impact of the real microgravity condition on this process. 47 While these studies on bacteria and yeast did not show impaired DNA repair in microgravity, studies on more complex organisms and human cells have yielded very different results. For instance, a study on Caenorhabditis elegans showed that several DDR genes were differentially expressed during the 16.5-day Shenzhou-8 space mission, suggesting possible enhanced DDR under microgravity.…”

Section: Spaceflight Studiesmentioning

confidence: 99%

Interplay of space radiation and microgravity in DNA damage and DNA damage response

et al. 2017

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In space, multiple unique environmental factors, particularly microgravity and space radiation, pose constant threat to the DNA integrity of living organisms. Specifically, space radiation can cause damage to DNA directly, through the interaction of charged particles with the DNA molecules themselves, or indirectly through the production of free radicals. Although organisms have evolved strategies on Earth to confront such damage, space environmental conditions, especially microgravity, can impact DNA repair resulting in accumulation of severe DNA lesions. Ultimately these lesions, namely double strand breaks, chromosome aberrations, micronucleus formation, or mutations, can increase the risk for adverse health effects, such as cancer. How spaceflight factors affect DNA damage and the DNA damage response has been investigated since the early days of the human space program. Over the years, these experiments have been conducted either in space or using ground-based analogs. This review summarizes the evidence for DNA damage induction by space radiation and/or microgravity as well as spaceflight-related impacts on the DNA damage response. The review also discusses the conflicting results from studies aimed at addressing the question of potential synergies between microgravity and radiation with regard to DNA damage and cellular repair processes. We conclude that further experiments need to be performed in the true space environment in order to address this critical question.

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“…Using an on-board radiation source, Pross et al (207) showed, using cells of Saccharomyces cerevisiae rad 54-3, that in microgravity both the number of radiation-induced DNA DSBs and the efficiency of their repair did not differ from those under terrestrial conditions. Therefore, the synergistic effects of microgravity and radiation in biological systems that have been observed in several instances, e.g., embryonic systems (reviewed in references 92 and 93), can probably not be explained by a disturbance of intracellular repair in microgravity.…”

Section: Interactions Of Microgravity and Radiation In Microorganismsmentioning

confidence: 99%

Space Microbiology

Horneck

Klaus

Mancinelli

2010

Microbiol Mol Biol Rev

557

489

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SUMMARY The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis.

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Induction and Repair of DNA Double-Strand Breaks under Irradiation and Microgravity

Cited by 35 publications

References 19 publications

Fungal Flora on Board the Mir‐Space Station, Identification by Morphological Features and Ribosomal DNA Sequences

Fungal Flora on Board the Mir‐Space Station, Identification by Morphological Features and Ribosomal DNA Sequences

Interplay of space radiation and microgravity in DNA damage and DNA damage response

Space Microbiology

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