Effects Of Simulated Microgravity Research Articles

3D-clinorotation induces specific alterations in metabolite profiles of germinating Brassica napus L. seeds

During the whole history of their life on Earth, higher plants evolved under the constant gravity stimulus. Therefore, plants developed efficient mechanisms of gravity perception, underlying their ability to adjust the direction of growth to the gravity vector, i.e. the phenomenon of gravitropism. In this context, alterations in the magnitude and vector of the gravity field might compromise plant growth and development. This aspect was successfully addressed in gravity fields of low intensity (microgravity). On the other hand, microgravity can be simulated on the Earth by clinorotation, i.e. rotation of the experimental plant along one or several axes. This approach is routinely used for studies of gravity-related responses of crop plants, although the effect of simulated microgravity on the most sensitive ontogenetic stages — germination and seedling development — is still not sufficiently characterized. Recently, we addressed the effects of clinorotation on the proteome of germinating oilseed rape (Brassica napus) seeds. Here we extend this study to the seedling primary metabolome and address its changes in the presence of 3D-clinorotation. GC-MS analysis revealed essential alterations in patterns of sugars and sugar phosphates (specifically glucose-6-phosphate), methionine and glycerol. Thereby, abundances of individual metabolites showed high dispersion, indicating high lability and plasticity of the seedling metabolome.

The Effect of Short-and Long-Term Simulated Microgravity on Immune Cells

Long-term space flight will be a major mission for International Space Administration. However, it has been shown that exposure to space flight result in immune system dysfunction. Therefore, understand the mechanism of immun... | Find, read and cite all the research you need on Tech Science Press

Combined Effects of Low-Dose Proton Radiation and Simulated Microgravity on the Mouse Retina and the Hematopoietic System.

The purpose of the current study was to characterize the effects of simulated microgravity and radiation-induced changes in retina and retinal vasculature, and to assess the accompanying early changes in immune cells and hematological parameters. To better understand the effects of spaceflight, we used a combination of treatments designed to simulate both the radiation and low-gravity aspects of space conditions. To simulate the broad energy spectrum of a large solar particle event (SPE) and galactic cosmic ray (GCR) radiation, male C57BL/6J mice were exposed to whole-body irradiation using fully modulated beams of 150-MeV protons containing particles of energy from 0 to 150 MeV and a uniform dose-vs.-depth profile. The mice were also hindlimb-unloaded (HLU) by tail suspension. Mice were unloaded for 7 days, exposed to 50 cGy, unloaded for an additional 7 days and then sacrificed for tissue isolation at days 4 and 30 after the combined treatments. Increases in the number of apoptotic cells were observed in the endothelial cells of mice that received radiation alone or with HLU compared to controls at both days 4 and 30 (P < 0.05). Endothelial nitric oxide synthase (eNOS) levels were significantly elevated in the retina after irradiation only or combined with HLU compared to controls at the 30-day time point (P < 0.05). The most robust changes were observed in the combination group, suggesting a synergistic response to radiation and unloading. For hematopoietic parameters, our analysis indicated the main effects for time and radiation at day 4 after treatments (day 11 postirradiation) (P < 0.05), but a smaller influence of HLU for both white blood cell and lymphocyte counts. The group treated with both radiation and HLU showed greater than 50% reduction in lymphocyte counts compared to controls. Radiation-dependent differences were also noted in specific lymphocyte subpopulations (T, B, natural killer cells). This study shows indications of an early effect of low-dose radiation and spaceflight conditions on retina and immune populations.

Investigation on rat intestinal homeostasis alterations induced by 7-day simulated microgravity effect based on a proteomic approach

The present study aims at investigating alterations of rat intestinal homeostasis induced by 7-day simulated microgravity (SMG) effect through a proteomic approach. Tail-suspension model was used to simulate microgravity effect and a label-free quantitative proteomic strategy was employed to determine proteins in rat intestine. As a result, 717 differently expressed proteins were identified and 29 proteins were down-regulated while 688 proteins were up-regulated. 283 out of 717 proteins were categorized into 7 clusters with DAVID (version 6.8). The three highest enrichment scores were annotation cluster I about cell-cell adhesion (46 proteins with enrichment score of 16.67), annotation cluster II about carbohydrate metabolism (32 proteins with enrichment score of 6.17) and annotation cluster III about activity of pepdtidase (17 proteins with enrichment score of 4.74). Results of rat intestine proteomics indicate that SMG might disrupt intestinal homeostasis, which possibly resulted in opening of intestinal epithelial barrier (IEB), potentially leading to risk of systemic inflammatory response (SIR) and inflammatory bowel diseases (IBD). The present results also provide some useful information for mechanism and countermeasures of intestine injuries induced by microgravity.

Effects of simulated microgravity on the expression profiles of RNA during osteogenic differentiation of human bone marrow mesenchymal stem cells.

ObjectivesExposure to microgravity induces many adaptive and pathological changes in human bone marrow mesenchymal stem cells (hBMSCs). However, the underlying mechanisms of these changes are poorly understood. We revealed the gene expression patterns of hBMSCs under normal ground (NG) and simulated microgravity (SMG), which showed an interpretation for these changes by gene regulation and signal pathways analysis.Materials and methodsIn this study, hBMSCs were osteogenically induced for 0, 2, 7 and 14 days under normal ground gravity and simulated microgravity, followed by analysis of the differences in transcriptome expression during osteogenic differentiation by RNA sequencing and some experimental verification for these results.ResultsThe results indicated that 837, 399 and 894 differentially expressed genes (DEGs) were identified in 2, 7 and 14 days samples, respectively, out of which 13 genes were selected for qRT‐PCR analysis to confirm the RNA‐sequencing results. After analysis, we found that proliferation was inhibited in the early stage of induction. In the middle stage, osteogenic differentiation was inhibited, whereas adipogenic differentiation benefited from SMG. Moreover, SMG resulted in the up‐regulation of genes specific for tumorigenesis in the later stage.ConclusionOur data revealed that SMG inhibits the proliferation and inhibits the differentiation towards osteoblasts but promotes adipogenesis. SMG also selects highly tumorigenic cells for survival under prolonged SMG.

Effects of RCCS simulated microgravity on proliferation and cell cytoskeleton of human HaCaT keratinocyte

Objective To investigate the effects of simulated microgravity by RCCS on proliferation and cell cytoskeleton of human HaCaT keratinocyte. Methods The rotary cell culture system (RCCS) was used to simulate the microgravity environment, and human HaCaT keratinocytes were divided randomly(random number) into the simulated microgravity group (SMG) and normal gravity group (NG). HaCaT cells in the two groups were harvested respectively after 32, 36 and 42 h culture. The HaCaT cells proliferation and cycles were detected by flow cytometry, the concentration of hb-EGF in supernatant was detected by ELISA, and the cell cytoskeleton was observed after 42 hours’ culture under laser confocal microscope with FITC-labeled technique. SPSS 23.0 statistical software was used for statistical analysis, and P <0.05 was considered statistically significant. Results The flow cytometry showed that the proportions of human HaCaT keratinocytes in G1 and G2/M phases were increased while the proportion of HaCaT cells in S stage was decreased significantly after 32, 36 and 42 h RCCS culture compared with those in the normal gravity group. The HaCaT cells in G1 stage were declined along with incubation time. ELISA results showed that the hb-EGF concentration in HaCaT supernatant under simulated microgravity culture for 24 and 36 h was lower than that in the normal control group (P<0.01). The laser confocal microscope revealed that the HaCaT fluorescence intensity was decreased, and there were disordered microfilaments, structural ambiguity, pseudopodia reduction and irregular shape among FITC-labeled HaCaT cells cultured 42 h in RSSC compared with the normal gravity group. Conclusions RCCS simulated microgravity environment could inhibit the cell cycle transformation and proliferation of human HaCaT keratinocyte, affect the keratinocyte-secreting function, and induce alterations of the cell cytoskeleton. Key words: Simulated microgravity; RCCS; Keratinocyte; HaCaT cell line; Proliferation; Cell cycle; hb-EGF; Cytoskeleton

Effect of simulated microgravity on the circadian rhythm of Drosophila melanogaster

Biological interactions and environmental constraints alter life-history traits, modifying organismal performances. Trematode parasites often impact their hosts by inducing parasitic castration, frequently correlated with increased body size in the host (i.e., gigantism hypothesis), which is postulated to reflect the re-allocation of energy released by the reduction in the reproductive process. In this study, we compared the effect of a trematode species on shell size and morphology in adult individuals of the intertidal mussels Perumytilus purpuratus (>20 mm) collected from two local populations of contrasting environmental regimes experienced in central-southern Chile. Our field data indicates that in both study locations, parasitized mussels evidenced higher body sizes (shell length, total weight and volume) as compared with non-parasitized. In addition, parasitized mussels from the southern location evidenced thinner shells than non-parasitized ones and those collected from central Chile, suggesting geographical variation in shell carbonate precipitation across intertidal habitats of the Chilean coast. In laboratory conditions, mussels collected from a local population in central Chile were exposed to two temperature treatments (12 and 18 °C). Parasitized mussels showed higher growth rates than non-parasitized, regardless of the seawater temperature treatments. However, the metabolic rate was not influenced by the parasite condition or the temperature treatments. Our field and laboratory results support the parasite-induced gigantism hypothesis, and suggest that both the thermal environment and geographic location explain only a portion of the increased body size, while the parasitic condition is the most plausible factor modulating the outcome of this host-parasite interaction.

Effects of miR-503-5p on apoptosis of human pulmonary microvascular endothelial cells in simulated microgravity.

Recent studies have shown that microRNA (miRNAs) can play important roles in the regulation of endothelial cell (EC) function. However, the expression profile of miRNAs and their effects on the apoptosis of ECs under microgravity conditions remains unclear. In this study, the apoptosis of human pulmonary microvascular endothelial cells (HPMECs) under simulated microgravity was identified by Annexin V and propidium iodide double staining and transmission electron microscopy. miRNA microarray assay was used to screen the differentially expressed miRNAs in HPMECs under simulated microgravity, and eight differentially expressed miRNAs were identified. Specifically, miR-503-5p, which was found to be most significantly upregulated in both microarray and quantitative reverse-transcription polymerase chain reaction assays, was selected for further functional investigation. Overexpression of miR-503-5p induced apoptosis of HPMECs under normal gravity and aggravated the negative effects of simulated microgravity on HPMECs. Furthermore, silencing of miR-503-5p expression effectively attenuated the negative effects of simulated microgravity on HPMECs. Further experiments showed that the mRNA and protein expression of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2), which has been confirmed as a direct target of miR-503-5p, was inhibited by the upregulation of miR-503-5p and increased by the downregulation of miR-503-5p. Taken together, our findings demonstrate, for the first time, that miR-503-5p can induce apoptosis of HPMECs under simulated microgravity through, at least in part, inhibiting the expression of Bcl-2.

Microgravity-Induced Alterations of Inflammation-Related Mechanotransduction in Endothelial Cells on Board SJ-10 Satellite.

Endothelial cells (ECs) are mechanosensitive cells undergoing morphological and functional changes in space. Ground-based study has provided a body of evidences about how ECs can respond to the effect of simulated microgravity, however, these results need to be confirmed by spaceflight experiments in real microgravity. In this work, we cultured EA.hy926 ECs on board the SJ-10 Recoverable Scientific Satellite for 3 and 10 days, and analyzed the effects of space microgravity on the ECs. Space microgravity suppressed the glucose metabolism, modulated the expression of cellular adhesive molecules such as ICAM-1, VCAM-1, and CD44, and depressed the pro-angiogenesis and pro-inflammation cytokine secretion. Meanwhile, it also induced the depolymerization of actin filaments and microtubules, promoted the vimentin accumulation, restrained the collagen I and fibronectin deposition, regulated the mechanotransduction through focal adhesion kinase and Rho GTPases, and enhanced the exosome-mediated mRNA transfer. Unlike the effect of simulated microgravity, neither three-dimensional growth nor enhanced nitric oxide production was observed in our experimental settings. This work furthers the understandings in the effects and mechanisms of space microgravity on ECs, and provides useful information for future spaceflight experimental design.

Long-Term Effects of Simulated Microgravity and Vibration Exposure on Skeletal Development in Zebrafish.

Most studies utilizing fish to study the effects of simulated microgravity (SMG) only observe the effects during the first week of development. They also do not take into account the potential impact on development of vibrations caused by the equipment. In this study we analyze the effects of both SMG and vibration on development of the skeleton. We analyze three different exposure durations and starting points that coincide with cranial neural crest cell migration. We use a combination of bone staining and morphometrics to analyze the effects. Our data show that both vibration and SMG affect vertebra number and body size; however, not all vertebrae are equally affected by each treatment. We also show that delayed ossification manifests during development, particularly after SMG exposure, and this translates into buckled and bent bones in adults. This study highlights the large impact of even very short exposure periods when they coincide with critical time points of development.

The subsequent biological effects of simulated microgravity on endothelial cell growth in HUVECs

PurposeMicrogravity is known to cause endothelium dysfunction in astronauts returning from spaceflight. We aimed to reveal the regulatory mechanism in alterations of human endothelial cells after simulated microgravity (SMG). MethodsWe utilized the rotary cell culture system (RCCS-1) to explore the subsequent effects of SMG on human umbilical vein endothelial cells (HUVECs). ResultsSMG-treated HUVECs appeared obvious growth inhibition after return to normal gravity, which might be attributed to a set of responses including alteration of cytoskeleton, decreased cell adhesion capacity and increased apoptosis. Expression levels of mTOR and its downstream Apaf-1 were increased during subsequent culturing after SMG. miR-22 was up-regulated and its target genes SRF and LAMC1 were down-regulated at mRNA levels. LAMC1 siRNAs reduced cell adhesion rate and inhibited stress fiber formation while SRF siRNAs caused apoptosis. ConclusionSMG has the subsequent biological effects on HUVECs, resulting in growth inhibition through mTOR signaling and miR-22-mediated mechanism.

Hindlimb Unloading Effects on β-Endorphin Receptor in Rats

Background: Space is a harsh environment that affects the body in many ways. Humans venturing into the environment of space can have negative effects on the body. Objectives: This study focused on the effects of simulated microgravity on β-endorphin receptor concentration. Methods: Rats (n = 16) were divided in two groups (n = 8/group), freely moving (control group) and hindlimb unloading. A rat-tail suspension model was used in experiment groups for 14 days to explore the effect of simulated microgravity on the β-endorphin receptor concentration in the hippocampus, brain stem, and prefrontal cortex. Results: The results showed that the concentration of β-endorphin receptor in the brain stem and prefrontal cortex, but not in hippocampus, was significantly higher in hindlimb unloading rats than controls. Conclusions: It is possible that simulated microgravity may increase the β-endorphin receptor expression in the prefrontal cortex and brain stem in the rat.

The combined effects of real or simulated microgravity and red-light photoactivation on plant root meristematic cells.

Red light is able to compensate for deleterious effects of microgravity on root cell growth and proliferation. Partial gravity combined with red light produces differential signals during the early plant development. Light and gravity are environmental cues used by plants throughout evolution to guide their development. We have investigated the cross-talk between phototropism and gravitropism under altered gravity in space. The focus was on the effects on the meristematic balance between cell growth and proliferation, which is disrupted under microgravity in the dark. In our spaceflight experiments, seedlings of three Arabidopsis thaliana genotypes, namely the wild type and mutants of phytochrome A and B, were grown for 6days, including red-light photoactivation for the last 2days. Apart from the microgravity and the 1g on-board control conditions, fractional gravity (nominally 0.1g, 0.3g, and 0.5g) was created with on-board centrifuges. In addition, a simulated microgravity (random positioning machine, RPM) experiment was performed on ground, including both dark-grown and photostimulated samples. Photoactivated samples in spaceflight and RPM experiments showed an increase in the root length consistent with phototropic response to red light, but, as gravity increased, a gradual decrease in this response was observed. Uncoupling of cell growth and proliferation was detected under microgravity in darkness by transcriptomic and microscopic methods, but red-light photoactivation produced a significant reversion. In contrast, the combination of red light and partial gravity produced small but consistent variations in the molecular markers of cell growth and proliferation, suggesting an antagonistic effect between light and gravity signals at the early plant development. Understanding these parameters of plant growth and development in microgravity will be important as bioregenerative life support systems for the colonization of the Moon and Mars.

Effects of simulated microgravity on rice (MR219) growth and yield

Rice (Oryza sativa L.) is a staple food in many Asian countries with an ever increasing demand. However, the production of high quality rice seeds is insufficient to meet this demand. Research on plant growth in space related to the exposure of a microgravity environment are rare, costly and time-limited. Similar experiments can be conducted on the ground to simulate the microgravity condition using a 2-D clinostat which compensates for the unilateral influence of gravity. This study was conducted to establish a simple and cost effective technique to enhance the quality of the Malaysian rice seed variety MR 219 by using a 2-D clinostat and to determine the effects of simulated microgravity on the growth and yield of the rice seeds. The experiments were performed at different rotation speeds (2 rpm and 10 rpm) for 10 days at room temperature. The rice growth and yield parameters were measured every 2 weeks and at harvest time (day 110), respectively. The data were analysed using the MINITAB statistical software package. The mean value estimates of the parameters obtained under different conditions were compared using analysis of variance (ANOVA) with the Tukey test for multiple comparisons using a 0.05 significance level. Significant differences in the number of tiller, stem width , chlorophyll content , weight of grains and panicles and total grain weight per plant were identified at rotation speed 10 rpm when compared to rotation speed 2 rpm and control. The highest means were mainly obtained under 10 rpm clinorotated rice seeds. In general, plants grown from 10 rpm clinorotated seeds are also more resistant to rice diseases (rice blast disease, rice tungro disease and hopper burn). These results suggest that simulated microgravity using a 2-D clinostat affected several rice (MR219) growth and yield parameters significantly.

Effects of simulated microgravity on seed germination, growth, development and accumulated secondary compounds of Hibiscus sagittifolius Kurz. cultured in vitro

In the present study, Hibiscus sagittifolius Kurz. seeds were used as the plant materials for studying on the effects of simulated microgravity (on a 2D clinostat) on seed germination, shoot multiplication, growth, development and secondary metabolite accumulation. After surface sterilization, seeds were cultured on MS medium supplemeted with 30 g/l sucrose and 9 g/l agar in Petri dishes (9 seeds per dish, the seed to seed distance of 1.5 cm and kept in the same direction), and maintained in a Clinostat (2 rpm). The results showed that simulated microgravity inhibited the growth and development of Hibiscus sagittifolius roots with root length of 11.83 cm, fresh and dry weight of 58.28 and 5.23 mg, respectively but it made an increase in germination rate (87%) and accumulation of secondary metabolites (the total saponins content of 53.00 mg/g and the total coumarin content of 25.67 mg/g) after 3 weeks of culture. In addition, the simulated microgravity also resulted in positive shoot multiplication (shoot height of 3.07 cm, 6.33 nodes per shoot, 3.33 shoots per explant, and the fresh and dry weight of 401.33 and 37.00 mg, respectively), and growth and development of Hibiscus sagittifolius shoots (plant height of 12.17 cm with 5.67 leaves per shoot together with the average root length of 1.77 cm, and the fresh and dry weight of 419.00 and 36.00 mg) after 4 weeks of culture. The results from this study could be attributed to future perspectives in research on plant breeding and accumulation of secondary metabolites in medicinal plants.

Effect of simulated microgravity on peripheral oxygen saturation in rats

To study the effect of microgravity on peripheral oxygen saturation (SpO 2) in rats, tail-suspended rats were applied to simulate microgravity environment. SpO 2 and arterial oxygen saturation (SaO 2) were measured by pulse oximeter and arterial blood gas analyzer (ABGA) respectively on the 14th day, 21st day and 28th day in tail-suspended group and control group. Paired t-test shows that SpO 2 was significantly lower than SaO 2 in tail-suspended group on the 14th day ( P < 0.05), the 21st day ( P < 0.05) and the 28th day ( P < 0.01). The ANOVA results shows that modeling time had significant effect on SpO 2 value but no effect on SaO 2 value in tail-suspended group. These results indicate that pulse oximeter may be not suitable for oxygen saturation test in microgravity environment.

Regulation of the Response of Caenorhabditis elegans to Simulated Microgravity by p38 Mitogen-Activated Protein Kinase Signaling

The in vivo function of p38 mitogen-activated protein kinase (MAPK) signaling in regulating the response to simulated microgravity is still largely unclear. Using Caenorhabditis elegans as an assay system, we investigated the in vivo function of p38 MAPK signaling in regulating the response of animals to simulated microgravity and the underlying molecular mechanism. Simulated microgravity treatment significantly increased the transcriptional expressions of genes (pmk-1, sek-1, and nsy-1) encoding core p38 MAPK signaling pathway and the expression of phosphorylated PMK-1/p38 MAPK. The pmk-1, sek-1, or nsy-1 mutant was susceptible to adverse effects of simulated microgravity. The intestine-specific activity of PMK-1 was required for its function in regulating the response to simulated microgravity, and the entire p38 MAPK signaling pathway could act in the intestine to regulate the response to simulated microgravity. In the intestine, SKN-1 and ATF-7, two transcriptional factors, were identified as downstream targets for PMK-1 in regulating the response to simulated microgravity. Therefore, the activation of p38 MAPK signaling may mediate a protection mechanism for nematodes against the adverse effects of simulated microgravity. Additionally, our results highlight the potential crucial role of intestinal cells in response to simulated microgravity in nematodes.

Simulated Microgravity Condition Alters the Gene Expression of some ECM and Adhesion Molecules in Adipose Derived Stem Cells.

Adipose- derived stem cells (ADSCs) are widely used for tissue engineering and regenerative medicine. The beneficial effects of ADSCs on wound healing have already been reported. Remodeling of extracellular matrix (ECM) is the most important physiological event during wound healing. ECM is sensitive to mechanical stresses and the expression of its components can be therefore influenced. The aim of this study was to investigate the effect of simulated microgravity on gene expression of some ECM and adhesion molecules in human ADSCs. After isolation and characterization of ADSCs, cells were exposed to simulated microgravity for 1, 3 and 7 days. Real-time PCR, fluorescence immunocytochemistry, and MTT assay were performed to evaluate the alterations of integrin subunit beta 1 (ITGB1), collagen type 3 (ColIII), matrix metalloproteinase-1 (MMP1), CD44, fibrillin (FBN1), vimentin (VIM) genes, and ColIII protein levels as well as cells viability. Microgravity simulation increased the expression of ITGB1, ColIII, MMP1, and CD44 and declined the expression of FBN1 and VIM genes. ColIII protein levels also increased. There were no significant changes in the viability of cells cultured in microgravity. Since the high expression of ECM components is known as one of the fibroblast markers, our data suggest that pretreatment of ADSCs by simulated microgravity may increase their differentiation capacity towards fibroblastic cells. Microgravity had not adversely affected the viability of ADSCs, and it is likely to be used alone or in combination with biochemical inducers for cell manipulation.

Effect of Simulated Microgravity Conditions on Differentiation of Adipose Derived Stem Cells towards Fibroblasts Using Connective Tissue Growth Factor.

Background: Mesenchymal stem cells (MSCs) are multipotent cells able to differentiating into a variety of mesenchymal tissues including osteoblasts, adipocytes and several other tissues. Objectives: Differentiation of MSCs into fibroblast cells in vitro is an attractive strategy to achieve fibroblast cell and use them for purposes such as regeneration medicine. The goal of this study was investigate the simulated microgravity effect on differentiation of Adipose Derived Stem Cells (ADSCs) to fibroblasts. Materials and Methods: To fibroblast differentiation 100 ng.mL-1 of connective tissue growth factor (CTGF), and for simulation microgravity, 2D clinostat was used. After isolation the human ADSCs from adipose, cells were passaged, and at passages 3 they were used for characterization and subsequent steps. After 7 days of CTGF and simulated microgravity treatment, proliferation, and differentiation were analyzed collectively by MTT assay, quantitative PCR analyses, and Immunocytochemistry staining. Results: MTT assay revealed that CTGF stimulate the proliferation but simulated microgravity didn't have statistically significant effect on cell proliferation. In RNA level the expression of these genes are investigated: collagen type I (COLI), elastin (ELA), collagen type III (ColIII), Matrix Metalloproteinases I(MMP1), Fibronectin 1 (FN1), CD44, Fibroblast Specific protein (FSP-1), Integrin Subunit Beta 1 (ITGB1), Vimentin (VIM) and Fibrillin (FBN). We found that expression of ELN, FN1, FSP1, COL1A1, ITGB1, MMP1 and COL3A1 in both condition, and VIM and FBN1 just in differentiation medium in normal gravity increased. In protein level the expression of COL III and ELN in simulated microgravity increased. Conclusions: These findings collectively demonstrate that the simulated microgravity condition alters the marker fibroblast gene expression in fibroblast differentiation process.

The effect of simulated microgravity on the Brassica napus seedling proteome.

The magnitude and the direction of the gravitational field represent an important environmental factor affecting plant development. In this context, the absence or frequent alterations of the gravity field (i.e. microgravity conditions) might compromise extraterrestrial agriculture and hence space inhabitation by humans. To overcome the deleterious effects of microgravity, a complete understanding of the underlying changes on the macromolecular level is necessary. However, although microgravity-related changes in gene expression are well characterised on the transcriptome level, proteomic data are limited. Moreover, information about the microgravity-induced changes in the seedling proteome during seed germination and the first steps of seedling development is completely missing. One of the valuable tools to assess gravity-related issues is 3D clinorotation (i.e. rotation in two axes). Therefore, here we address the effects of microgravity, simulated by a two-axial clinostat, on the proteome of 24- and 48-h-old seedlings of oilseed rape (Brassica napus L.). The liquid chromatography-MS-based proteomic analysis and database search revealed 95 up- and 38 downregulated proteins in the tryptic digests obtained from the seedlings subjected to simulated microgravity, with 42 and 52 annotations detected as being unique for 24- and 48-h treatment times, respectively. The polypeptides involved in protein metabolism, transport and signalling were annotated as the functional groups most strongly affected by 3-D clinorotation.