- Background: Candida albicans is an opportunistic pathogenic yeast, which could become pathogenic in various stressful environmental factors including the spaceflight environment. - albicans were increased in the spaceflight group compared to the control group. - Proteomic analysis identified 548 up-regulated proteins involved in the ribosome, DNA replication, base excision repair and sulfur metabolism in the spaceflight group. - Conclusions: Mechanisms that could explain the results in the phenotypic experiment of C. - It has been known that microorganisms such as bacteria and fungi have widely existed in the Inter- national Space Station [1]. - albicans may change with the changes in the external environment [3]. - albicans pro- liferate more rapidly in the International Space Station [4, 5], thereby multiplying the risk of onboard cross- contamination, colonization, and infection. - After exposure to the spaceflight environment, C.. - albicans was recovered in the sabouraud-dextrose broth (SDB) medium and their survival was evaluated by OD 600 measurement. - 1A, the growth lag period of the spaceflight group was about 8 h after inoculated into medium, which was shorter than that of the control group (about 10 h). - The mean specific growth rate of the. - The OD 600 of spaceflight group was significantly higher than that of control group ( P <. - spaceflight group was 0.44/h, which was faster than that of the control group (0.35/h, P = 0.018). - albicans in the spaceflight group was rougher and the wrinkles at the edges were increased when compared to the control group. - The amount of biofilm formation was signifi- cantly increased in the spaceflight group (Fig. - albicans through scanning electron microscope (SEM), while grape-like clusters with sparse cell connections were observed in the control group (Fig. - The environ- mental resistance evaluation result showed that the survival rate of the spaceflight group was higher than that of the control group in the SDB medium con- taining hydrogen peroxide (Fig. - The result of virulence experiment (Additional file 2: Figure S2) showed that the spaceflight group had a lower max- imum and a more significant decrease of the normal- ized cell index (NCI) compared to the control group, which indicates that spaceflight group has stronger cytotoxicity. - albicans were increased after exposure to the space- flight environment.. - In total, 3670 proteins were identified and 3499 proteins were quantified in the spaceflight group and control group of C. - This resulted in 548 significantly up-regulated and 332 significantly down-regulated proteins in the spaceflight group compared with the control group (Additional file 5: Table S2), which were shown in Fig. - The result showed that the spaceflight group and control group are clearly separated, which reflected the significant change of protein expression in C. - albicans after exposure to the spaceflight environment.. - Among the 548 up-regulated proteins in spaceflight group,. - In addition, base excision re- pair was also enriched, which related to DNA damage repair and may explain the increased antioxidant cap- acity of the spaceflight group. - Sulfur metabolism was enriched in up-regulated proteins. - While metabolic pro- cesses such as carbon metabolism, biosynthesis of sec- ondary metabolites, glyoxylate and dicarboxylate metabolism, propanoate metabolism, phenylalanine me- tabolism, tyrosine metabolism, and fatty acid degrad- ation were significantly enriched in the down-regulated proteins. - In total, 1465 peaks were identified in the spaceflight group and control group of C. - Out of these five metabolites, 5′-Methylthioadenosine and ade- nylsuccinic acid were significantly up-regulated in the spaceflight group (Fig. - Consistent with the metabolome result, adenylosuccinate synthetase, which catalyzes IMP and L-aspartate to generate ade- nylsuccinic acid, was also up-regulated (P = 0.0001, fold change = 1.17) in spaceflight group from prote- ome data. - We found MTA was up-regulated in the spaceflight group with metabolomics analysis. - While S-methyl-5′- thioadenosine phosphorylase (MEU1), which involved in the breakdown of MTA and responsible for the first step in the methionine salvage pathway after MTA has been generated from S-adenosylmethionine [12], was significantly up-regulated in spaceflight group of proteomics.. - Mean- while, Jiang et al. - Altenburg et al. - The red points represented 548 proteins that were up- regulated in spaceflight group (adjusted P <. - The blue points represented 332 proteins that were down-regulated in spaceflight group (adjusted P value <. - d Enriched KEGG pathways in up-regulated (red) and down-regulated (blue) proteins of spaceflight group. - albicans in simulated microgravity results in an in- crease in filamentous forms of the organism, which is consistent with enhanced pathogenicity. - albicans in the space environment might be threated to the health of astro- nauts. - albicans after exposure to the spaceflight environment. - albicans were increased in the spaceflight group. - Crabbé et al. - However, Hammond et al. - The difference between their results and ours may because their experiment was done in the International Space Station with 48 h, while our spaceflight environment was low earth orbit flight for 12 days. - a Scatter plots of two up-regulated metabolites in the spaceflight group. - b Scatter plots of three down-regulated metabolites in the spaceflight group. - On the one hand, we found that S-adenosylmethionine synthase (SAM2), which catalyzes the formation of S-adenosylmethionine from methionine, was increased in spaceflight group. - However, the expression of MEU1, which involved in the methionine salvage pathway by breakdown MTA, was increased in the spaceflight group.. - Mean- while, 5-methyltetrahydropteroyltriglutamate homocysteine methyltransferase (MET6), which involved in the formation of methionine, was also up-regulated (adjust P <. - On the other hand, bifunctional cysteine synthase (MET15) [19], which has cysteine synthase activity and may synthase cysteine from serine, was increased in spaceflight group. - Meanwhile, aspartate aminotransferase (AAT21) and aspartate transaminase (AAT1), which may play roles in catalyzes cysteine [20], were down-regulated in spaceflight group. - So we concluded that cysteine and me- thionine were accumulated in the spaceflight group of C.. - Besides, methionine and cysteine are sulfur- containing amino acids, and proteins involved in sulfur me- tabolism such as sulfite reductase subunit alpha (MET10), sulfite reductase beta subunit, sulfate adenylyltransferase (MET3) and adenylyl-sulfate kinase (MET14) were simul- taneously up-regulated in spaceflight group. - In addition, Li et al. - In- creased proliferation rate, biofilm formation, antioxidant capacity, cytotoxicity, and filamentous morphology were observed in the spaceflight group of C. - albicans com- pared to the control group. - Enrichment analysis with DEPs indicated that proteins in the ribosome, DNA replication, base excision repair, and sulfur metabolism were significantly up-regulated, while proteins in many metabolic processes were signifi- cantly down-regulated. - After incubated at 30 °C for 30 h, half of the samples were cultured in space for 12 days carried by the “SJ-10” satellite. - And the rest samples were cul- tured at the ground as control. - Due to the lim- itations of the cycle and conditions of spaceflight experi- ments, all replicates were obtained by the recovery of experimental strain.. - albicans in the spaceflight group and control group were recovered on the SDB medium at 30 °C overnight, respectively. - Samples were inoculated into SDB liquid medium and incubated at 150 rpm at 30 °C. - The initial OD 600 measurement is measured every 2 h at the beginning of the lag phase and is mea- sured every 1 h in the exponential phase. - Δtime in the exponential phase.. - In the end, the samples were dehydrated with dryer and coated with gold-palladium. - Recovered samples were inoculated into SDB li- quid medium and incubated at 150 rpm at 30 °C until the exponential phase (OD 600 = 1). - After centrifugation again, the precipitation was resuspended with DMEM- F12 medium at the concentration of 4.5 × 107 CFU/mL.. - albicans in spaceflight group and control group were recovered on SDB solid medium at 30 °C overnight, re- spectively. - Recovered samples were inoculated into SDB liquid medium and incubated at 150 rpm at 30 °C and grown to an OD 600 of 1. - Samples were resuspended with lysate buffer (7 M urea, 2 M thiourea, 40 mM DTT, 1 mM PMSF [24]) and were sonicated (1 s/1 s intervals, 80 W power) for 3 min. - Then iodoacetamide was added to the solution with the final concentration of 50 mM and incubated for 40 min at room temperature in the dark.. - The mass spectrometer was operated in the data-dependent mode with positive polarity at electrospray voltage of 2 kV. - Full scan MS spectra (m/z 300–1600) were acquired in the orbitrap with the resolution as 70 K, the automatic gain control (AGC) target was 1e6 and the maximum injection time was 80 ms. - Recovered Candida albicans was added into LoVo cells and the samples were detected with real time cell analyzer. - The red color represented proteins or metabolites that were up-regulated in spaceflight group. - The blue color represented proteins or metabolites that were down-regulated in spaceflight group.. - List of differentially expressed proteins between the spaceflight and control group.. - List of differentially expressed metabolites between the spaceflight and control group.. - The funding bodies played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.. - Novikova N, De Boever P, Poddubko S, et al. - Rosenzweig JA, Abogunde O, Thomas K, et al. - Sugita T, Yamazaki T, Makimura K, et al. - Comprehensive analysis of the skin fungal microbiota of astronauts during a half-year stay at the international Space Station [J]. - Effects of the space flight environment on the immune system [J]. - Crucian B, Stowe RP, Mehta S, et al. - Li L, Liao Z, Yang Y, et al. - Avila MA, Garcia-Trevijano ER, Lu SC, et al. - Pirkov I, Norbeck J, Gustafsson L, et al. - A complete inventory of all enzymes in the eukaryotic methionine salvage pathway [J]. - Jiang W, Xu B, Yi Y, et al. - Crabbe A, Nielsen-Preiss SM, Woolley CM, et al. - Hammond TG, Stodieck L, Birdsall HH, et al. - Viaene J, Tiels P, Logghe M, et al. - Cooper AJ, Bruschi SA, Iriarte A, et al. - Li DD, Wang Y, Dai BD, et al. - Garcia-Sanchez S, Aubert S, Iraqui I, et al. - Li J, Zhang B, Ma T, et al. - Fiorini A, Rosado FR, Bettega EM, et al. - Wisniewski JR, Zougman A, Nagaraj N, et al. - Tyanova S, Temu T, Sinitcyn P, et al
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