37 research outputs found
Molecular response of Deinococcus radiodurans to simulated microgravity explored by proteometabolomic approach
Regarding future space exploration missions and long-term exposure experiments, a detailed
investigation of all factors present in the outer space environment and their effects on organisms of
all life kingdoms is advantageous. Influenced by the multiple factors of outer space, the extremophilic
bacterium Deinococcus radiodurans has been long-termly exposed outside the international Space
Station in frames of the tanpopo orbital mission. the study presented here aims to elucidate molecular
key components in D. radiodurans, which are responsible for recognition and adaptation to simulated
microgravity. D. radiodurans cultures were grown for two days on plates in a fast-rotating 2-D clinostat
to minimize sedimentation, thus simulating reduced gravity conditions. Subsequently, metabolites
and proteins were extracted and measured with mass spectrometry-based techniques. our results
emphasize the importance of certain signal transducer proteins, which showed higher abundances
in cells grown under reduced gravity. these proteins activate a cellular signal cascade, which leads to
differences in gene expressions. Proteins involved in stress response, repair mechanisms and proteins
connected to the extracellular milieu and the cell envelope showed an increased abundance under
simulated microgravity. focusing on the expression of these proteins might present a strategy of cells
to adapt to microgravity conditions
Molecular response of Deinococcus radiodurans exposed to vacuum conditions of Low Earth Orbit
The polyextremophile, gram-positive bacterium Deinococcus radiodurans is able to withstand harsh
conditions of real and simulated outer space environment, e.g., extreme temperature fluctuations,
desiccation, UV radiation, and ionizing radiation. A long-term space exposure of D. radiodurans has been
performed in exposure experiments at low Earth orbit in frames of the Tanpopo orbital mission aiming to
investigate the possibility of interplanetary transfer of life. Although it is important to analyse the impact of
space environmental factors simultaneously, it is also crucial to investigate these factors separately under
controlled conditions in order to decipher fundamental response mechanisms involved
Metallosphaera sedula on a Mission – mimicking Mars in frames of the Tanpopo 4 mission
With future long-term space exploration and life detection missions on Mars, understanding the
microbial survival beyond Earth as well as the identification of past life traces on other planetary
bodies becomes increasingly important. The series of the Tanpopo space mission experiments target
a long-term exposure (one to three years) of microorganisms on the KIBO Module of the
International Space Station (ISS) in the low Earth orbit (LEO) (Kawaguchi et al., 2020; Ott et al.,
2020). In the search for possible past and/or present microbial life on Mars, metallophilic archaeal
species are of a special interest due to their inherent extraordinary characteristics.
Chemolithotrophic archaea (e.g., from the order Sulfolobales) employ a number of ancient metabolic
pathways to extract energy from diverse inorganic electron donors and acceptors. Metallosphaera
sedula, an iron- and sulfur-oxidizing chemolithotrophic archaeon, which flourishes under hot and
acidic conditions (optimal growth at 74°C and pH 2.0), was cultivated on genuine extraterrestrial
minerals (Milojevic et al., 2019; Milojevic et al., 2021) as well as synthetic Martian materials (Kölbl
et al., 2017). In all cases, M. sedula cells were able to utilize given mineral materials as the sole
energy source for cellular growth and proliferation. During the growth of M. sedula cells on these
materials, a natural mineral impregnation and encrustation of microbial cells was achieved, followed
by their preservation under the conditions of desiccation (Kölbl et al. 2020). Our studies indicate
that this archaeon, when impregnated and encrusted with minerals, withstand long-term desiccation
and can be even recovered from the dried samples to the liquid cultures (Kölbl et al., 2020). The
achieved preservation of desiccated M. sedula cells facilitated our further survivability studies with
this desiccated microorganism under simulated Mars-like environmental conditions and during the
Tanpopo-4 space exposure experiment. [...
Proteomic and Metabolomic Profiling of Deinococcus radiodurans Recovering After Exposure to Simulated Low Earth Orbit Vacuum Conditions
The polyextremophile, gram-positive bacterium Deinococcus radiodurans can withstand harsh conditions of real and simulated outer space environment, e.g., UV and ionizing radiation. A long-term space exposure of D. radiodurans has been performed in Low Earth Orbit (LEO) in frames of the Tanpopo orbital mission aiming to investigate the possibility of interplanetary life transfer. Space vacuum (10-4–10-7 Pa) is a harmful factor, which induces dehydration and affects microbial integrity, severely damaging cellular components: lipids, carbohydrates, proteins, and nucleic acids. However, the molecular strategies by which microorganisms protect their integrity on molecular and cellular levels against vacuum damage are not yet understood. In a simulation experiment, we exposed dried D. radiodurans cells to vacuum (10-4–10-7 Pa), which resembles vacuum pressure present outside the International Space Station in LEO. After 90 days of high vacuum exposure, survival of D. radiodurans cells was 2.5-fold lower compared to control cells. To trigger molecular repair mechanisms, vacuum exposed cells of D. radiodurans were recovered in complex medium for 3 and 6 h. The combined approach of analyzing primary metabolites and proteins revealed important molecular activities during early recovery after vacuum exposure. In total, 1939 proteins covering 63% of D. radiodurans annotated protein sequences were detected. Proteases, tRNA ligases, reactive oxygen species (ROS) scavenging proteins, nucleic acid repair proteins, TCA cycle proteins, and S-layer proteins are highly abundant after vacuum exposure. The overall abundance of amino acids and TCA cycle intermediates is reduced during the recovery phase of D. radiodurans as they are needed as carbon source. Furthermore, vacuum exposure induces an upregulation of Type III histidine kinases, which trigger the expression of S-layer related proteins. Along with the highly abundant transcriptional regulator of FNR/CRP family, specific histidine kinases might be involved in the regulation of vacuum stress response. After repair processes are finished, D. radiodurans switches off the connected repair machinery and focuses on proliferation. Combined comparative analysis of alterations in the proteome and metabolome helps to identify molecular key players in the stress response of D. radiodurans, thus elucidating the mechanisms behind its extraordinary regenerative abilities and enabling this microorganism to withstand vacuum stress
Space Radiobiology
The study of the biologic effects of space radiation is considered a “hot topic,” with increased interest in the past years. In this chapter, the unique characteristics of the space radiation environment will be covered, from their history, characterization, and biological effects to the research that has been and is being conducted in the field.
After a short introduction, you will learn the origin and characterization of the different types of space radiation and the use of mathematical models for the prediction of the radiation doses during different mission scenarios and estimate the biological risks due to this exposure. Following this, the acute, chronic, and late effects of radiation exposure in the human body are discussed before going into the detailed biomolecular changes affecting cells and tissues, and in which ways they differ from other types of radiation exposure.
The next sections of this chapter are dedicated to the vast research that has been developed through the years concerning space radiation biology, from small animals to plant models and 3D cell cultures, the use of extremophiles in the study of radiation resistance mechanisms to the importance of ground-based irradiation facilities to simulate and study the space environment
Proteomic Response of Deinococcus radiodurans to Short-Term Real Microgravity during Parabolic Flight Reveals Altered Abundance of Proteins Involved in Stress Response and Cell Envelope Functions
Rapidly evolving space exploration makes understanding the short- and long- term effects of microgravity on humans, plants, and microorganisms an important task. The ubiquitous presence of the gravitational force has had an influence on the development of all living entities on Earth, and short- and long-term changes in perceived gravitational force can induce notable changes within cells. Deinococcus radiodurans is the Gram-positive bacterium that is best known for its extreme resistance to UV-C and gamma radiation, oxidation stress, and desiccation. Thus increased interest has been placed on this species in the context of space research. The present study aims to elucidate the short-term proteomic response of this species to real microgravity during parabolic flight. Overnight cultures of D. radiodurans were subjected to microgravity during a single parabola, and metabolic activity was quenched using methanol. Proteins were extracted and subsequently measured using HPLC nESI MS/MS. The results, such as the enrichment of the peptidoglycan biosynthesis pathway with differentially abundant proteins and altered S-layer protein abundance, suggested molecular rearrangements in the cell envelope of D. radiodurans. Altered abundance of proteins involved in energy metabolism and DNA repair could be linked with increased endogenous ROS production that contributes to the stress response. Moreover, changes in protein abundance in response to microgravity show similarities with previously reported stress responses. Thus, the present results could be used to further investigate the complex regulation of the remarkable stress management of this bacterium
“Freezing” Thermophiles: From One Temperature Extreme to Another
New detections of thermophiles in psychrobiotic (i.e., bearing cold-tolerant life forms) marine and terrestrial habitats including Arctic marine sediments, Antarctic accretion ice, permafrost, and elsewhere are continually being reported. These microorganisms present great opportunities for microbial ecologists to examine biogeographical processes for spore-formers and non-spore-formers alike, including dispersal histories connecting warm and cold biospheres. In this review, we examine different examples of thermophiles in cryobiotic locations, and highlight exploration of thermophiles at cold temperatures under laboratory conditions. The survival of thermophiles in psychrobiotic environments provokes novel considerations of physiological and molecular mechanisms underlying natural cryopreservation of microorganisms. Cultures of thermophiles maintained at low temperature may serve as a non-sporulating laboratory model for further exploration of metabolic potential of thermophiles at psychrobiotic temperatures, as well as for elucidating molecular mechanisms behind natural preservation and adaptation to psychrobiotic environments. These investigations are highly relevant for the search for life on other cold and icy planets in the Solar System, such as Mars, Europa and Enceladus
Advances in the Space Station
A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station is an artificial satellite (i.e. a type of orbital spaceflight). Stations must have docking ports to allow other spacecraft to dock to transfer crew and supplies. The purpose of maintaining an orbital outpost varies depending on the program. Space stations have most often been launched for scientific purposes, but military launches have also occurred. As of 2022, there are two fully operational space stations in low Earth orbit (LEO) – the International Space Station (ISS) and China's Tiangong Space Station (TSS). While the ISS has been permanently inhabited since October 2000 with the Expedition 1 crews, the TSS will do so with the Shenzhou 14 crews in June 2022. The ISS is used to study the effects of spaceflight on the human body, as well as to provide a location to conduct a greater number and longer length of scientific studies than is possible on other space vehicles. China's Tiangong Space Station is scheduled to finish its phase 1 construction by the end of 2022 with the addition of two lab modules. India has also proposed to build a space station in the coming decades. There have been numerous decommissioned space stations, including USSR's Salyuts, Russia's Mir, NASA's Skylab, and China's Tiangong 1 and 2