Molecular repertoire of Deinococcus radiodurans after 1 year of exposure outside the International Space Station within the Tanpopo mission

Abstract

Background The extraordinarily resistant bacterium Deinococcus radiodurans withstands harsh environmental conditions present in outer space. Deinococcus radiodurans was exposed for 1 year outside the International Space Station within Tanpopo orbital mission to investigate microbial survival and space travel. In addition, a ground-based simulation experiment with conditions, mirroring those from low Earth orbit, was performed. Methods We monitored Deinococcus radiodurans cells during early stage of recovery after low Earth orbit exposure using electron microscopy tools. Furthermore, proteomic, transcriptomic and metabolomic analyses were performed to identify molecular mechanisms responsible for the survival of Deinococcus radiodurans in low Earth orbit. Results D. radiodurans cells exposed to low Earth orbit conditions do not exhibit any morphological damage. However, an accumulation of numerous outer-membrane-associated vesicles was observed. On levels of proteins and transcripts, a multi-faceted response was detected to alleviate cell stress. The UvrABC endonuclease excision repair mechanism was triggered to cope with DNA damage. Defense against reactive oxygen species is mirrored by the increased abundance of catalases and is accompanied by the increased abundance of putrescine, which works as reactive oxygen species scavenging molecule. In addition, several proteins and mRNAs, responsible for regulatory and transporting functions showed increased abundances. The decrease in primary metabolites indicates alternations in the energy status, which is needed to repair damaged molecules. Conclusion Low Earth orbit induced molecular rearrangements trigger multiple components of metabolic stress response and regulatory networks in exposed microbial cells. Presented results show that the non-sporulating bacterium Deinococcus radiodurans survived long-term low Earth orbit exposure if wavelength below 200 nm are not present, which mirrors the UV spectrum of Mars, where CO2 effectively provides a shield below 190 nm. These results should be considered in the context of planetary protection concerns and the development of new sterilization techniques for future space missions.

Shotgun metagenomic analysis of kombucha mutualistic community exposed to Mars‐like environment outside the International Space Station

“…In the era of deep space exploration, it is crucial to understand the effects of exposure to stressful space and/or Mars conditions on microbial organisms. Effects of spaceflight have been mostly investigated on microbial monocultures (Horneck et al ., 2010; de Vera et al ., 2019; Dey, 2019; Ott et al ., 2020). Nonetheless, most species thrive in multispecies consortia, and exploration of multispecies communities remains an interesting area of investigation due to the multiple mechanisms of spaceflight tolerance (May et al ., 2019; Podolich et al ., 2019; Sobisch et al ., 2019), such as the formation of protective biofilm and cooperative sustainability of multispecies consortium structure.…”

To Other Planets With Upgraded Millennial Kombucha in Rhythms of Sustainability and Health Support

“…Rather than being sent from Earth, EMVs could be produced on-site, which would circumvent issues related to long-term conservation. This could be facilitated by the fact that bacterial EMV production seems to be intensified in space (Zea et al, 2017;Ott et al, 2020). EMVs from ground control and space-flown KMC samples did not exhibit signs of cyto-, endo-or neurotoxicity (Podolich et al, 2019), and neither did EMVs of the dominant kombucha community member Komagataeibacter oboediens (Podolich et al, 2020): membrane alterations occurred but did not lead to toxicity for eukaryotic cells in vitro.…”

Scientific Targets of Tanpopo: Astrobiology Exposure and Micrometeoroid Capture Experiments at the Japanese Experiment Module Exposed Facility of the International Space Station

“…(3) The mutations of D. radiodurans R1 were evaluated by mutation analysis of the rpoB gene of rifampicin resistance (Fujiwara et al, 2021). Transcriptome and proteome analyses of the recovery phase of D. radiodurans R1 exposed to space were performed to clarify which genes (proteins) and biological pathways are important for the survival of spaceexposed microbes (Ott et al, 2020). b The mutant strain deficient in condensed nucleoid-dependent end joining pathway (CNDEJ) owing to a mutation in the pprA gene.…”

“…The survival slopes of the DNA-deficient mutant strains were similar to each other, with the exception of D. radiodurans UVS78 that had an accelerated survival slope relative to other strains exposed to sunlight. This suggests that nucleotide excision repair (NER) and/or UV-damage excision repair (UVER) pathways, which are deficient in UV78 strain, are important to repair the damaged DNA suffered during space exposure under sunlight (Kawaguchi et al, 2020;Ott et al, 2020). Kawaguchi et al (2020) also suggested that cell pellets with a diameter of 1 mm will be protected from UV light and were estimated to survive for 2-8 years in the space environment by extrapolating the survival curve and taking the lighting efficiency of the space experiments into account.…”

“…b Reported inFujiwara et al (2021). c Reported inOtt et al (2020). d Only first-year samples were analyzed (reported inYamagishi et al, 2018).SCIENCE OF TANPOPO EXPERIMENT ON ISS…”