Amorphous calcium carbonate enhances osteogenic differentiation and myotube formation of human bone marrow derived mesenchymal stem cells and primary skeletal muscle cells under microgravity conditions

Astronauts are exposed to severely stressful physiological conditions due to microgravity and increased space radiation. Space environment affects every organ and cell in the body and the significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton (spaceflight osteopenia). Amorphous Calcium Carbonate (ACC) emerges as a promising candidate for prevention of these effects, owing to its unique physicochemical properties and its potential to address the intricately linked nature of bone-muscle crosstalk. Reported here are two studies carried out on the International Space Station (ISS). The first, performed in 2018 as a part of the Ramon-Spacelab project, was a preliminary experiment, in which stromal murine cells were differentiated into osteoblasts when ACC was added to the culture medium. A parallel experiment was done on Earth as a control. The second study was part of Axiom-1's Rakia project mission launched to the ISS on 2022 utilizing organ-on-a-chip methodology with a specially designed autonomous module. In this experiment, human bone-marrow derived mesenchymal stem cells (hBM-MSCs) and human primary muscle cells were cultured in the presence or absence of ACC, in duplicates. The results showed that ACC enhanced differentiation of human primary skeletal muscle cells into myotubes. Similarly, hBM-MSCs were differentiated significantly better into osteocytes in the presence of ACC leading to increased calcium deposits. The results, combined with previous data, support the use of ACC as an advantageous supplement for preventing muscle and bone deterioration in outer space conditions, facilitating extended extraterrestrial voyages and colonization.

Comparative genomic analysis of Cohnella hashimotonis sp. nov. isolated from the International Space Station

A single strain from the family Paenibacillaceae was isolated from the wall behind the Waste Hygiene Compartment aboard the International Space Station (ISS) in April 2018, as part of the Microbial Tracking mission series. This strain was identified as a gram-positive, rod-shaped, oxidase-positive, catalase-negative motile bacterium in the genus Cohnella, designated as F6_2S_P_1^T. The 16S sequence of the F6_2S_P_1^T strain places it in a clade with C. rhizosphaerae and C. ginsengisoli, which were originally isolated from plant tissue or rhizosphere environments. The closest 16S and gyrB matches to strain F6_2S_P_1^T are to C. rhizosphaerae with 98.84 and 93.99% sequence similarity, while a core single-copy gene phylogeny from all publicly available Cohnella genomes places it as more closely related to C. ginsengisoli. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values to any described Cohnella species are <89 and <22%, respectively. The major fatty acids for strain F6_2S_P_1^T are anteiso-C_15:0 (51.7%), iso-C_16:0 (23.1%), and iso-C_15:0 (10.5%), and it is able to metabolize a wide range of carbon compounds. Given the results of the ANI and dDDH analyses, this ISS strain is a novel species within the genus Cohnella for which we propose the name Cohnella hashimotonis, with the type strain F6_2S_P_1^T (=NRRL B-65657^T and DSMZ 115098^T). Because no closely related Cohnella genomes were available, this study generated the whole-genome sequences (WGSs) of the type strains for C. rhizosphaerae and C. ginsengisoli. Phylogenetic and pangenomic analysis reveals that F6_2S_P_1^T, C. rhizosphaerae, and C. ginsengisoli, along with two uncharacterized Cohnella strains, possess a shared set of 332 gene clusters which are not shared with any other WGS of Cohnella species, and form a distinct clade branching off from C. nanjingensis. Functional traits were predicted for the genomes of strain F6_2S_P_1^T and other members of this clade.

Conducting Plant Experiments in Space and on the Moon

The growth and development of plants during spaceflight have important implications for both basic and applied research supported by NASA and other international space agencies. While there have been many reviews of plant space biology, this chapter attempts to fill a gap in the literature on the actual process and methods of performing plant research in the spaceflight environment. One of the authors (JZK) has been a principal investigator on eight spaceflight projects. These experiences include using the U.S. Space Shuttle, the former Russian Space Station Mir, and the International Space Station, utilizing the Space Shuttle and Space X as launch vehicles. While there are several ways to fly an experiment into space and to obtain a spaceflight opportunity, this review focuses on using the NASA peer-reviewed sciences approach to get an experiment manifested for flight. Three narratives for the implementation of plant space biology experiments are considered from rapid turn around of a few months to a project with new hardware development that lasted 6 years. The many challenges of spaceflight research include logistical and resource constraints such as crew time, power, cold stowage, data downlinks, among others. Additional issues considered are working at NASA centers, hardware development, safety concerns, and the engineering versus science culture in space agencies. The difficulties of publishing the results from spaceflight research based on such factors as the lack of controls, limited sample size, and the indirect effects of the spaceflight environment also are summarized. Lessons learned from these spaceflight experiences are discussed in the context of improvements for future space-based research projects with plants. We also will consider new opportunities for Moon-based research via NASA's Artemis lunar exploration program.

How plants grow under gravity conditions besides 1 g: perspectives from hypergravity and space experiments that employ bryophytes as a model organism

Plants have evolved and grown under the selection pressure of gravitational force at 1 g on Earth. In response to this selection pressure, plants have acquired gravitropism to sense gravity and change their growth direction. In addition, plants also adjust their morphogenesis in response to different gravitational forces in a phenomenon known as gravity resistance. However, the gravity resistance phenomenon in plants is poorly understood due to the prevalence of 1 g gravitational force on Earth: not only it is difficult to culture plants at gravity > 1 g(hypergravity) for a long period of time but it is also impossible to create a < 1 genvironment (μg, micro g) on Earth without specialized facilities. Despite these technical challenges, it is important to understand how plants grow in different gravity conditions in order to understand land plant adaptation to the 1 g environment or for outer space exploration. To address this, we have developed a centrifugal device for a prolonged duration of plant culture in hypergravity conditions, and a project to grow plants under the μg environment in the International Space Station is also underway. Our plant material of choice is Physcomitrium (Physcomitrella) patens, one of the pioneer plants on land and a model bryophyte often used in plant biology. In this review, we summarize our latest findings regarding P. patens growth response to hypergravity, with reference to our on-going "Space moss" project. In our ground-based hypergravity experiments, we analyzed the morphological and physiological changes and found unexpected increments of chloroplast size and photosynthesis rate, which might underlie the enhancement of growth and increase in the number of gametophores and rhizoids. We further discussed our approaches at the cellular level and compare the gravity resistance in mosses and that in angiosperms. Finally, we highlight the advantages and perspectives from the space experiments and conclude that research with bryophytes is beneficial to comprehensively and precisely understand gravitational responses in plants.

A Microbial Monitoring System Demonstrated on the International Space Station Provides a Successful Platform for Detection of Targeted Microorganisms

Closed environments such as the International Space Station (ISS) and spacecraft for other planned interplanetary destinations require sustainable environmental control systems for manned spaceflight and habitation. These systems require monitoring for microbial contaminants and potential pathogens that could foul equipment or affect the health of the crew. Technological advances may help to facilitate this environmental monitoring, but many of the current advances do not function as expected in reduced gravity conditions. The microbial monitoring system (RAZOR^® EX) is a compact, semi-quantitative rugged PCR instrument that was successfully tested on the ISS using station potable water. After a series of technical demonstrations between ISS and ground laboratories, it was determined that the instruments functioned comparably and provided a sample to answer flow in approximately 1 hour without enrichment or sample manipulation. Post-flight, additional advancements were accomplished at Kennedy Space Center, Merritt Island, FL, USA, to expand the instrument’s detections of targeted microorganisms of concern such as water, food-borne, and surface microbes including Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa, Escherichia coli, and Aeromonas hydrophilia. Early detection of contaminants and bio-fouling microbes will increase crew safety and the ability to make appropriate operational decisions to minimize exposure to these contaminants.

Genomic and Functional Characterization of Enterococcus faecalis Isolates Recovered From the International Space Station and Their Potential for Pathogenicity

Enterococcus faecalis is a multidrug resistant, opportunistic human pathogen and a leading cause of hospital acquired infections. Recently, isolates have been recovered from the air and surfaces onboard the International Space Station (ISS). Pangenomic and functional analyses were carried out to assess their potential impact on astronaut health. Genomes of each ISS isolate, and both clinical and commensal reference strains, were evaluated for their core and unique gene content, acquired antibiotic resistance genes, phage, plasmid content, and virulence traits. In order to determine their potential survival when outside of the human host, isolates were also challenged with three weeks of desiccation at 30% relative humidity. Finally, pathogenicity of the ISS strains was evaluated in the model organism Caenorhabditis elegans. At the culmination of this study, there were no defining signatures that separated known pathogenic strains from the more commensal phenotypes using the currently available resources. As a result, the current reliance on database information alone must be shifted to experimentally evaluated genotypic and phenotypic characteristics of clinically relevant microorganisms.

No Effect of Microgravity and Simulated Mars Gravity on Final Bacterial Cell Concentrations on the International Space Station: Applications to Space Bioproduction

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.

Validating an Automated Nucleic Acid Extraction Device for Omics in Space Using Whole Cell Microbial Reference Standards

NASA has made great strides in the past five years to develop a suite of instruments for the International Space Station in order to perform molecular biology in space. However, a key piece of equipment that has been lacking is an instrument that can extract nucleic acids from an array of complex human and environmental samples. The Omics in Space team has developed the μTitan (simulated micro(μ) gravity tested instrument for automated nucleic acid) system capable of automated, streamlined, nucleic acid extraction that is adapted for use under microgravity. The μTitan system was validated using a whole cell microbial reference (WCMR) standard comprised of a suspension of nine bacterial strains, titrated to concentrations that would challenge the performance of the instrument, as well as to determine the detection limits for isolating DNA. Quantitative assessment of system performance was measured by comparing instrument input challenge dose vs recovery by Qubit spectrofluorometry, qPCR, Bioanalyzer, and Next Generation Sequencing. Overall, results indicate that the μTitan system performs equal to or greater than a similar commercially available, earth-based, automated nucleic acid extraction device. The μTitan system was also tested in Yellowstone National Park (YNP) with the WCMR, to mimic a remote setting, with limited resources. The performance of the device at YNP was comparable to that in a laboratory setting. Such a portable, field-deployable, nucleic extraction system will be valuable for environmental microbiology, as well as in health care diagnostics.

Quantitative evaluation of bioaerosols in different particle size fractions in dust collected on the International Space Station (ISS)

Exposure to bioaerosols can adversely influence human health through respiratory tract, eye, and skin irritation. Bioaerosol composition is unique on the International Space Station (ISS), where the size distribution of particles in the air differs from those on Earth. This is due to the lack of gravitational settling and sources of biological particles. However, we do not understand how microbes are influenced by particle size in this environment. We analyzed two types of samples from the ISS: (1) vacuum bag debris which had been sieved into five different size fractions and (2) passively collected particles on a tape substrate with a passive aerosol sampler. Using quantitative polymerase chain reaction (qPCR), the highest concentration of fungal spores was found in the 106-150 μm-sized sieved dust particles, while the highest concentration of bacterial cells was found in the 150-250 μm-sized sieved dust particles. Illumina MiSeq DNA sequencing revealed that particle size was associated with bacterial and fungal communities and statistically significant (p = 0.035, p = 0.036 respectively). Similar fungal and bacterial species were found within the passive aerosol sample and the sieved dust samples. The most abundant fungal species identified in the aerosol and sieved samples are commonly found in food and plant material. Abundant bacterial species were most associated with the oral microbiome and human upper respiratory tract. One limitation to this study was the suboptimal storage conditions of the sieved samples prior to analysis. Overall, our results indicate that microbial exposure in space may depend on particle size. This has implications for ventilation and filtration system design for future space vehicles and habitats.

Polar auxin transport is essential to maintain growth and development of etiolated pea and maize seedlings grown under 1 g conditions: Relevance to the international space station experiment

We conducted "Auxin Transport" space experiments in 2016 and 2017 in the Japanese Experiment Module (JEM) on the International Space Station (ISS), with the principal objective being integrated analyses of the growth and development of etiolated pea (Pisum sativum L. cv Alaska) and maize (Zea mays L. cv Golden Cross Bantam) seedlings under true microgravity conditions in space relative to auxin dynamics. Etiolated pea seedlings grown under microgravity conditions in space for 3 days showed automorphogenesis. Epicotyls and roots bent ca. 45° and 20° toward the direction away from the cotyledons, respectively, whereas those grown under artificial 1 g conditions produced by a centrifuge in the Cell Biology Experimental Facility (CBEF) in space showed negative and positive gravitropic response in epicotyls and in roots, respectively. On the other hand, the coleoptiles of 4-day-old etiolated maize seedlings grew almost straight, but the mesocotyls curved and grew toward a random direction under microgravity conditions in space. In contrast, the coleoptiles and mesocotyls of etiolated maize seedlings grown under 1 g conditions on Earth were almost straight and grew upward or toward the direction against the gravity vector. The polar auxin transport activity in etiolated pea epicotyls and in maize shoots was significantly inhibited and enhanced, respectively, under microgravity conditions in space as compared with artificial 1 g conditions in space or 1 g conditions on Earth. An inhibitor of polar auxin transport, 2,3,5-triiodobenzoic acid (TIBA) substantially affected the growth direction and polar auxin transport activity in etiolated pea seedlings grown under both artificial 1 g and microgravity conditions in space. These results strongly suggest that adequate polar auxin transport is essential for gravitropic response in plants. Possible mechanisms enhancing polar auxin transport in etiolated maize seedlings grown under microgravity conditions in space are also proposed.

Media Exchange Performance Test Using the Bradford Assay in an Automated Bioreactor Engineering Model for Space Experiments

Life science research has been actively carried out in space for a long time using bioreactor equipment, in anticipation of manned space exploration and space tourism. Such studies have reported that the microgravity environment has a negative effect on the human body, including the musculoskeletal system, nervous system, and endocrine system. Bone loss and muscular atrophy are issues that need to be resolved before long-term exposure of the human body to a space environment. To address this problem, Y. K. Kim et al. designed a system in 2015 and performed an evaluation of an automated bioreactor development model (DM) for space experiments. In this study, we developed an automated bioreactor engineering model (EM) based on the previous literature, and conducted media exchange performance testing using the Bradford assay. We used a novel method that allowed quantitative assessment of the media exchange rate versus the conventional assessment method using visual observation with a camera. By measuring the media exchange rate of the automated bioreactor EM, we attempted to verify applicability for the system for space experiments. We expect that the experimental method proposed in this study is useful for logical determination of liquid exchange or circulation in different closed systems.

The Utilization of Plant Facilities on the International Space Station-The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions

In the preparation for missions to Mars, basic knowledge of the mechanisms of growth and development of living plants under microgravity (micro-g) conditions is essential. Focus has centered on the g-effects on rigidity, including mechanisms of signal perception, transduction, and response in gravity resistance. These components of gravity resistance are linked to the evolution and acquisition of responses to various mechanical stresses. An overview is given both on the basic effect of hypergravity as well as of micro-g conditions in the cell wall changes. The review includes plant experiments in the US Space Shuttle and the effect of short space stays (8-14 days) on single cells (plant protoplasts). Regeneration of protoplasts is dependent on cortical microtubules to orient the nascent cellulose microfibrils in the cell wall. The space protoplast experiments demonstrated that the regeneration capacity of protoplasts was retarded. Two critical factors are the basis for longer space experiments: a. the effects of gravity on the molecular mechanisms for cell wall development, b. the availability of facilities and hardware for performing cell wall experiments in space and return of RNA/DNA back to the Earth. Linked to these aspects is a description of existing hardware functioning on the International Space Station.