Astronauts have been previously shown to exhibit decreased salivary lysozyme and increased dental calculus and gingival inflammation in response to space flight host factors that could contribute to oral diseases such as caries and periodontitis. However the specific physiological response of caries-causing bacteria such as Streptococcus mutans to space flight and/or ground-based simulated microgravity has not been extensively investigated. In this study High Aspect Ratio Vessel (HARV) S. mutans simulated microgravity and normal gravity cultures were assessed for changes in metabolite and transcriptome profiles H2O2 resistance and competence in sucrose-containing biofilm media. Stationary phase S. mutans simulated microgravity cultures displayed increased killing by H2O2 compared to normal gravity control cultures but competence was not affected. RNA-seq analysis revealed that expression of 153 genes was up-regulated >= 2-fold and 94 genes down-regulated >= 2-fold during simulated microgravity HARV growth. These included a number of genes located on extrachromosomal elements as well as genes involved in carbohydrate metabolism translation and stress responses. Collectively these results suggest that growth under microgravity analog conditions promotes changes in S. mutans gene expression and physiology that may translate to an altered cariogenic potential of this organism during space flight missions. Overall design: Differential gene expression was compared between RNA from S. mutans grown in normal gravity HARVs (n=3 independent cultures) and RNA from S. mutans grown in simulated microgravity HARVs (n=3 independent cultures)

['Microgravity is one of the most important features in spaceflight. Previous evidence has shown that significant changes to the musculoskeletal and immune systems occurred under microgravity. The present study was undertaken to explore the change in protein abundance in human colon colorectal cells that were incubated for 48 or 72 h either in normal conditions and µG simulated conditions. The comparative proteomic method based on the 18O labeling technique was applied to investigate the up-regulated proteins and down-regulated proteins in SH-SY5Y under simulated microgravity.']

Spaceflight is a unique environment with profound effects on biological systems including tissue redistribution and musculoskeletal stresses. However the more subtle biological effects of spaceflight on cells and organisms are difficult to measure in a systematic unbiased manner. Here we test the utility of the molecularly barcoded yeast deletion collection to provide a quantitative assessment of the effects of microgravity on a model organism. We developed robust hardware to screen in parallel the complete collection of ~4800 homozygous and ~5900 heterozygous (including ~1100 single-copy deletions of essential genes) yeast deletion strains each carrying unique DNA that acts as strain identifiers. We compared strain fitness for the homozygous and heterozygous yeast deletion collections grown in spaceflight and ground as well as plus and minus hyperosmolar sodium chloride providing a second additive stressor. The genome-wide sensitivity profiles obtained from these treatments were then queried for their similarity to a compendium of drugs whose effects on the yeast collection have been previously reported. We found that the effects of spaceflight have high concordance with the effects of DNA-damaging agents and changes in redox state suggesting mechanisms by which spaceflight may negatively affect cell fitness.

Spaceflight is a unique environment with profound effects on biological systems including tissue redistribution and musculoskeletal stresses. However the more subtle biological effects of spaceflight on cells and organisms are difficult to measure in a systematic unbiased manner. Here we test the utility of the molecularly barcoded yeast deletion collection to provide a quantitative assessment of the effects of microgravity on a model organism. We developed robust hardware to screen in parallel the complete collection of ~4800 homozygous and ~5900 heterozygous (including ~1100 single-copy deletions of essential genes) yeast deletion strains each carrying unique DNA that acts as strain identifiers. We compared strain fitness for the homozygous and heterozygous yeast deletion collections grown in spaceflight and ground as well as plus and minus hyperosmolar sodium chloride providing a second additive stressor. The genome-wide sensitivity profiles obtained from these treatments were then queried for their similarity to a compendium of drugs whose effects on the yeast collection have been previously reported. We found that the effects of spaceflight have high concordance with the effects of DNA-damaging agents and changes in redox state suggesting mechanisms by which spaceflight may negatively affect cell fitness.

While it has been shown that astronauts suffer immune disorders after spaceflight the underlying causes are still poorly understood and there are many variables to consider when investigating the immune system in a complex environment. Additionally there is growing evidence that suggests that not only is the immune system being altered but the pathogens that infect the host are significantly influenced by spaceflight and ground-based spaceflight conditions. In this study we demonstrate that Serratia marcescens (strain Db11) was significantly more lethal to Drosophila melanogaster after growth on the International Space Station than ground-based controls but that the host immune system is not significantly altered amongst known immune genes. High-throughput sequencing of wild-type (w1118) adult hosts infected with either space or ground-reared S. marcescens revealed few changes in gene expression with 11 genes significantly differentially expressed (q-values <0.05) and only one gene related to the immune system. This data supports the main findings of the paper which state that both spaceflight and low-shear modeled microgravity conditions increase the virulence of this pathogen independent of the host immune system. This data which shows that there are no significant immune-related changes to the host when infected with space-grown sample compared to ground-grown sample provides further evidence that there are likely phenotypic changes to the pathogen itself that is causing increased virulence in spaceflight and in low-shear modeled microgravity. RNA was extracted in triplicate from 2 pooled adult (2-3 day old female) Drosophila melanogaster (w1118) per treatment with 4 total treatment groups (no injection control sham injection with PBS ground bacteria-injected and space bacteria-injected) with poly(A)+ RNA libraries. Samples were multiplexed and sequenced 100bp paired-end ready were sequenced on one lane of the Illumina HiSeq-4000.

The introduction of generally recognized as safe (GRAS) probiotic microbes into the spaceflight food system has the potential for use as a safe non-invasive daily countermeasure to crew microbiome and immune dysregulation. However the microgravity effects on the stress tolerances and genetic expression of probiotic bacteria must be determined to confirm translation of strain benefits and to identify potential for optimization of growth survival and strain selection for spaceflight. The work presented here demonstrates the translation of characteristics of a GRAS probiotic bacteria to a microgravity analog environment. Lactobacillus acidophilus ATCC 4356 was grown in the low shear modeled microgravity (LSMMG) orientation and the control orientation in the rotating wall vessel (RWV) to determine the effect of LSMMG on the growth survival through stress challenge and gene expression of the strain. No differences were observed between the LSMMG and control grown L. acidophilus suggesting that the strain will behave similarly in spaceflight and may be expected to confer Earth-based benefits.

Spaceflight imposes numerous adaptive challenges for terrestrial life. The reduction in gravity or microgravity represents a novel environment that can disrupt homeostasis of many physiological processes. Additionally it is becoming increasingly clear that an organism s microbiome is critical for host health and examining its resiliency in microgravity represents a new frontier for space biology research. In this study we examine the impact of microgravity on the interactions between the squid Euprymna scolopes and its beneficial symbiont Vibrio fischeri which form a highly specific binary mutualism. First animals inoculated with V. fischeri aboard the space shuttle showed effective colonization of the host light organ the site of the symbiosis during spaceflight. Second RNA-Seq analysis of squid exposed to modeled microgravity conditions exhibited extensive differential gene expression in the presence and absence of the symbiotic partner. Transcriptomic analyses revealed in the absence of the symbiont during modeled microgravity there was an enrichment of genes and pathways associated with the innate immune and oxidative stress response. The results suggest that V. fischeri may help modulate the host stress responses under modeled microgravity. This study provides a window into the adaptive responses that the host animal and its symbiont use during modeled microgravity.

This study s goal was to examine if any salivary microbiome changes were observed in astronauts as a result of spaceflight. In addition this study looked for any microbiome signature that may be associated with viral reactivation in humans

Data were generated as part of a NASA-funded study (Turek F (PI) et al. Effects of Spaceflight on Gastrointestinal Microbiota in Mice: Mechanisms and Impact on Multi-System. NASA NRA: NRA NNH14ZTT002N). As part of the study, we requested and received samples from RR1. We generated 16S rRNA gene amplicon sequence data from DNA extracted from fecal samples, and compared these data to similar data generated on shuttle mission STS-135 and from ground-based studies of radiation. We assessed effect of flight conditions and radiation.

While it has been shown that astronauts suffer immune disorders after spaceflight, the underlying causes are still poorly understood and there are many variables to consider when investigating the immune system in a complex environment. Additionally, there is growing evidence that suggests that not only is the immune system being altered, but the pathogens that infect the host are significantly influenced by spaceflight and ground-based spaceflight conditions. In this study, we demonstrate that Serratia marcescens (strain Db11) was significantly more lethal to Drosophila melanogaster after growth on the International Space Station than ground-based controls, but that the host immune system is not significantly altered amongst known immune genes. High-throughput sequencing of wild-type (w1118) adult hosts infected with either space or ground-reared S. marcescens revealed few changes in gene expression, with 11 genes significantly differentially expressed (q-values less than 0.05) and only one gene related to the immune system. This data supports the main findings of the paper, which state that both spaceflight and low-shear modeled microgravity conditions increase the virulence of this pathogen, independent of the host immune system. This data, which shows that there are no significant immune-related changes to the host when infected with space-grown sample compared to ground-grown sample, provides further evidence that there are likely phenotypic changes to the pathogen itself that is causing increased virulence in spaceflight and in low-shear modeled microgravity. RNA was extracted in triplicate from 2 pooled adult (2-3 day old female) Drosophila melanogaster (w1118) per treatment, with 4 total treatment groups (no injection control, sham injection with PBS, ground bacteria-injected, and space bacteria-injected) with poly(A)+ RNA libraries. Samples were multiplexed and sequenced 100bp paired-end ready were sequenced on one lane of the Illumina HiSeq-4000.