Firms' exposures on COVID-19 and stock price crash risk: Evidence from China.

This study examines the impact of firms' exposures on COVID-19 sentiment on the stock price crash risk. We show the exposure on COVID-19 sentiment related to the medical, travelling and uncertain aspects significantly increases the stock price crash risk, while the exposure on COVID-19 sentiment related to vaccines significantly decreases the risk of stock price crash. Furthermore, our findings are stronger for non-state-owned firms and firms with low information transparency. Overall, we provide timely policy implication for economic impacts of the COVID-19 on the stock market.

The role of WSC domain-containing protein encoding gene AOL_s00043g401 in the growth and nematode trapping of Arthrobotrys oligospora.

Arthrobotrys oligospora is a model nematode-trapping fungus that has been extensively investigated to understand the interactions between fungi and nematodes. Nematode capture by A. oligospora is a complex process in which recognition of nematodes is generally believed to be mediated by lectins from the fungi. Lectins are a group of carbohydrate-binding proteins that widely exist in microorganisms and contain specific glycosylation recognition domains. In this work, we report the effect of a putative WSC domain-containing protein encoding gene AOL_s00043g401 (g401) on the growth and nematode-trapping of A. oligospora. The g401 gene was knocked out using the homologous recombination approach, and the △g401 mutant strain was then evaluated for its growth rate, conidial yield and germination rate, adaptation to environmental stresses, and nematocidal activity. Interestingly, the deletion of the putative lectin gene g401 had no significant effect on saprophytic growth, conidial yield and germination rate, responses to high salt, surfactant, and strong oxidative environments, as well as nematode-trapping efficiency of A. oligospora. We speculate that this phenomenon might have been caused by an intrinsic genetic compensation of the g401 in this fungus. For instance, more copies of WSC domain encoding genes or PQQ-DH domain encoding genes were found in the genome of A. oligospora. These findings provide further experimental evidence on the effect of lectin-related functional proteins in A. oligospora on nematode capture and will help further analyze their potential roles in the biological control of nematodes in the future.

A putative F-box-domain-encoding gene AOL_s00076g207 regulates the development and pathogenicity of Arthrobotrys oligospora.

F-box protein is a key component of the Skp1-cullin-F-box-type ubiquitin ligase complex (SCF-ULC) that marks its target proteins with ubiquitin for proteasomal degradation. In this study, we explored the potential role of AOL_s00076g207 (Aog207) in Arthrobotrys oligospora, a model fungus for studying nematodes-fungi interactions. The Aog207 gene encodes a putative F-box protein of the SCF-ULC. Deletion of Aog207 could inhibit mycelial growth in TYGA and PDA media. More importantly, the conidial germination rate of ΔAog207 mutants was remarkably declined compared to that of wild-type (WT) strain, and the mutant strains were more sensitive toward chemical stressors than the WT strain. In addition, ΔAog207 mutants generated fewer traps and captured fewer nematodes than WT strain. In summary, Aog207 disruption significantly affected the pathogenicity, mycelial growth, conidial germination, environmental adaptation and trap formation of A. oligospora. These findings may facilitate a better understanding of the nematode predation mechanism of A. oligospora and provide an experimental basis for developing biological control agents against nematodes.

Purification and antioxidant and anti-Inflammatory activity of extracellular polysaccharopeptide from sanghuang mushroom, Sanghuangporus lonicericola.

BACKGROUND: Sanghuang mushrooms are medicinal fungi widely used in eastern Asia. In this study, the antioxidant and anti-inflammatory activity of a novel extracellular polysaccharopeptide, sanghuang extracellular polysaccharopeptide (SePSP) was investigated. The SePSP was purified from the submerged fermentation broth of a sanghuang mycelium, Sanghuangporus lonicericola strain CBS17, which was isolated from a wild sanghuang fruiting body. RESULTS: The SePSP was extracted using an ethanol precipitation procedure, followed by diethylaminoethanol (DEAE) anion-exchange and size-exclusion chromatography. The mass ratio of the polysaccharide and peptide components in the purified SePSP was approximately 4.87:1. By determining its free radical scavenging abilities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), the hydroxyl free radical, and the superoxide anion free radical, as well as its total reducing power, SePSP was shown to have strong concentration-dependent antioxidant activity in vitro. Further, SePSP effectively alleviated dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice. Administration of 200 mg kg-1 SePSP by gavage for 7 days prevented body weight loss; significantly reduced the mRNA levels of proinflammatory cytokines, including TNF-α and IL-1ß; increased mRNA level of the anti-inflammatory cytokine IL-10 in the colon, and decreased the malondialdehyde concentration from 6.42 to 4.82 µmol L-1 in the blood in UC mice. CONCLUSION: The SePSP had strong concentration-dependent antioxidant activity in vitro and effectively alleviated DSS-induced UC in mice. The in vivo therapeutic efficacy in DSS-induced UC may be mediated by modulating the expression of inflammatory cytokines and inhibiting oxidative stress. The findings provide a scientific rationale for the use of bioactive nutraceuticals from sanghuang mushrooms to develop functional foods for the prevention and treatment of UC. © 2020 Society of Chemical Industry.

A novel fungal beta-propeller phytase from nematophagous Arthrobotrys oligospora: characterization and potential application in phosphorus and mineral release for feed processing.

Phytases are widely utilized in feed industry to increase the utilization of phosphorus, minerals, and amino acids for improvement of animal and human nutrition. At present, all known ß-propeller phytases (BPP) have been generated from bacteria, particularly Bacillus. In this work we report for the first time a new fungal-derived BPP phytase. We identified a phytase highly differentially expressed only in the parasitic stage of a nematophagous fungus, Arhtrobotrys oliogospora, during the development of the 3D traps. We found that this phytase was homologous to the known bacterial BPP phytase, thus we referred the new phytase to Aophytase. The heterologous expression of codon-optimized Aophytase gene in Pichia pastoris was successfully investigated to yield recombinant Aophytase (r-Aophytase) with high specific enzyme activity of 74.71 U/mg, much higher than those of recombinant BPP phytases derived bacteria. The kinetic parameters of the r-Aophytase, the optimum pH and temperature, as well as the effects of surfactant, EDTA and different ions on its enzyme activity were further investigated. The potential utilization of r-Aophytase in feed processing was finally explored. We found that the optimal pH value was about 7.5, and the optimal temperature was 50 °C.; r-Aophytase significantly increased the release of inorganic phosphorus from soybean meal, and improved the release of soluble minerals from the durum wheat flour and finger millet flour. The findings indicate its potential utilization in the feed processing to ameliorate nutritional value of cereals and animal feed in the future.

Microalgae cultivation and nutrients removal from sewage sludge after ozonizing in algal-bacteria system.

The feasibility of growing algae in concentrated wastewater generated from sludge ozonation for simultaneous nutrients removal and biomass production was studied. The effects of bacteria addition into microalgae on nutrients removal, biomass yield and settleability, the growth rate of algae and concentrations of extracellular polymeric substances (EPS) and soluble microbial products (SMP) were investigated. The results showed that the growth rate of algae in algal-bacteria system (0.2182) was improved than in algae-only system (0.1852), while both of them are comparable with others reported previously. And the addition of bacteria enhanced COD, NH4+-N, TN and TP removal rate by 23.9 ±â€¯3.3%, 27.7 ±â€¯3.6%, 16.6 ±â€¯1.8% and 14.9 ±â€¯2.2%, respectively. And 32.8 ±â€¯0.7% of the TN and 50.3 ±â€¯1.8% of the TP were recycled from ozonated sludge-supernatant (OSS) being absorbed into algal-bacterial biomass. The algal-bacteria system also demonstrated advantages on biomass settleability and heavy metals removal. Finally, the mechanism involving matter exchange and algal-bacteria system on OSS treatment in this study were discussed through evaluation of nutrients, SMP and EPS contents, nitrogen and phosphorus balance.

Biochar induces different responses of intracellular and extracellular antibiotic resistance genes and suppresses horizontal transfer during lincomycin fermentation dregs composting.

This study aims to indicate the influence of biochar on extracellular and intracellular ARGs (e/iARGs) variation and proliferation during lincomycin fermentation dregs (LFDs) compost. Biochar addition made iARGs keep reducing but eARGs increase to the maximum at the middle thermophilic phase and reduce at the end of the compost. Compared to control 3.15-log and 5.42-log reduction of iARGs and eARGs were observed, respectively. Biochar addition, bacterial community, and MGEs were the major contributors to iARGs and eARGs removal, with the contribution percentages of 38.4%, 31.0%, 23.7%, and 27.2%, 29.1%, and 34.9%, respectively. Moreover, biochar significantly inhibited eARGs transformation and RP4 plasmid conjugative transfer among E. coli DH5α and Pseudomonas aeruginosa HLS-6. The underlying mechanism involved in broken cell membranes of bacteria, and altered expression of oxidative stress genes and save our souls (SOS) response-related genes. The results indicated that biochar addition in composting could limit the dissemination of ARGs.

Behavior Analysis With Integrated Visual-Motor Tracking for Developmental Coordination Disorder.

Developmental coordination disorder (DCD) is a motor learning disability with a prevalence of 5%-6% in school-aged children, which may seriously affect the physical and mental health of affected children. Behavior analysis of children helps explore the mechanism of DCD and develop better diagnosis protocols. In this study, we investigate the behavioral pattern of children with DCD in the gross movement using a visual-motor tracking system. First, visual components of interest are detected and extracted using a series of intelligent algorithms. Then, the kinematic features are defined and calculated to describe the children behavior, including eye movement, body movement, and interacting object trajectory. Finally, statistical analysis is conducted both between groups with different motor coordination abilities and between groups with different task outcomes. The experimental results show that groups of children with different coordination abilities differ significantly both in the duration of eye gaze focusing on the target and in the degree of concentration during aiming, which can serve as behavioral markers to distinguish children with DCD. This finding also provides precise guidance for the interventions for children with DCD. In addition to increasing the amount of time spent on concentrating, we should focus on improving children's attention levels.

Alleviation effects of grape seed proanthocyanidin extract on inflammation and oxidative stress in a D-galactose-induced aging mouse model by modulating the gut microbiota.

Grape seed proanthocyanidin extract (GSPE) that prevents and alleviates the degenerative changes associated with aging has been receiving extensive attention. In our present work, the ageing model was induced by injection of 500 mg kg-1D-galactose daily for a period of eight weeks. The D-galactose-induced ageing mice model was used for evaluating the effect of GSPE on oxidative stress, inflammation levels and gut microbiota composition. D-Galactose induced oxidative damage and inflammation with a significant increase in malondialdehyde contents, myeloperoxidase activities and the levels of TNF-α and IL-1ß, as well as a reduction in the activities of glutathione peroxidase and reduced glutathione. Treatment with different doses of GSPE could significantly improve the antioxidant capacity and inflammation levels in the liver and brain, which is accompanied by increased Lachnospiraceae_NK4A136, Lactobacillus, Bifidobacterium, and Akkermansia, as well as decreased Helicobacter and Alistipes. In addition, the high-dose GSPE group exhibited greater potential to delay the ageing process than the low-dose group. Our results also showed that GSPE administration could downregulate the NLRP3 inflammasome signaling pathway for inhibiting inflammation levels in the brain tissue. This study provided a novel strategy to target the gut microbiota with regard to the effect of GSPE administration on alleviating aging-induced alterations via the gut microbiota-liver axis and gut microbiota-brain axis.

Investigation of construction and characterization of carboxymethyl chitosan - sodium alginate nanoparticles to stabilize Pickering emulsion hydrogels for curcumin encapsulation and accelerating wound healing.

Limitations in compatibility and effectiveness in delivering bioactive compounds often make it prohibitively difficult to apply Pickering emulsions in wound dressing. In this research, we prepared Pickering emulsion composite hydrogels based on carboxymethyl chitosan - sodium alginate (CMCS-SA) nanoparticles (NPs) stabilized Pickering emulsions, poloxamer 407 (PLX), and curcumin (CUR). CMCS-SA NPs were prepared and used to stabilize Pickering emulsion. The stability of Pickering emulsion improved with the increase of the concentration of NPs, and was highly sensitive to ionic strength change. This Pickering emulsion remained stable at various temperatures. After curcumin were introduced into the emulsion, 0.6% CMCS-SA NPs Pickering emulsion showed controlled release of curcumin in vitro. The CMCS-SA-PLX-CUR hydrogels also exhibited smooth surface and dense structure. This composite hydrogels has antibacterial properties against Escherichia coli and Staphylococcus aureus. Moreover, the CMCS-SA-PLX-CUR hydrogels improved wound healing and increased expression of Ki67 and CD31. RT-qPCR results indicated that the mRNA levels of α-SMA and TGF-ß1 in the CMCS-SA-PLX-CUR group were downregulated, while the mRNA levels of TGF-ß3 increased. The present study suggests that the potentials of CMCS-SA-PLX-CUR hydrogels are promising in protecting bioactive components and wound care management.

The fucose-specific lectin gene AOL_s00054g276 affects trap formation and nematocidal activity of the nematophagous fungus Arthrobotrys oligospora.

Nematode-trapping fungi are natural enemies of nematodes in nature. Arthrobotrys oligospora, a typical nematode-trapping fungus with a clear genetic background, can capture and infect nematodes by forming adhesive three-dimensional networks. Lectins, a class of glycoproteins containing glycosyl-specific recognition domains, play an important role in biological recognition. However, the fucose-specific lectins have rarely been studied regarding the process of preying on nematodes. In this study, we characterized the biological role of the fucose-specific lectin-encoding gene AOL_s00054g276 (g276) in A. oligospora. The gene g276 was first deleted based on homologous recombination, then the phenotype and nematocidal activity of the Δg276 mutant was evaluated. The results showed that the deletion of gene g276 delayed trap formation and weakened its nematocidal activity; however, mycelial growth, conidia production, conidial germination rates and adaption to environmental stresses were not affected. Our results suggest that the fucose-specific lectin-encoding gene g276 might be associated with the morphogenesis of this fungus, and its deletion resulted in a significantly low density of three-dimensional traps (P < 0.05) and a significantly low nematode-trapping efficiency (P < 0.001). These findings provide a basis for further elucidating the mechanism of A. oligospora preying on nematodes and lay a foundation for the development and utilization of fungal-derived lectins for nematode control in the future.

Probiotic Bacillus cereus Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice through Improvement of the Intestinal Barrier Function, Anti-Inflammation, and Gut Microbiota Modulation.

Dysbiosis leads to continuous progress of inflammatory bowel disease (IBD). However, current therapeutic approaches for IBD have limited efficacy and are associated with various side effects. This study focused on exploring the positive effect of a new Bacillus cereus (B. cereus) strain (HMPM18123) in a colitis mouse model and elucidate the underlying molecular mechanisms. The colitis symptoms were alleviated by the B. cereus administration as evidenced by decreased body weight loss, colon length shortening, disease activity index score, and histopathological score. The B. cereus mitigated intestinal epithelial barrier damage by upregulating tight junction protein expression. Moreover, B. cereus exerted anti-inflammatory effects by regulating macrophage polarization and suppressing the TLR4-NF-κB-NLRP3 inflammasome signaling pathways. B. cereus also rebalanced the damaged gut microbiota. Thus, the molecular mechanism of alleviating colitis by B. cereus treatment involved the regulation of the TLR4-NF-κB-NLRP3 inflammasome signaling pathways in intestinal mucosal barriers by modulating gut microbiota composition.

The role of Jacalin-related lectin gene AOL_s00083g511 in the development and pathogenicity of the nematophagous fungus Arthrobotrys oligospora.

Arthrobotrys oligospora is a model species of nematophagous fungi and has great potential for the biological control of nematode diseases. Lectin is a protein that binds to carbohydrates and their complexes with high specificity, which mediates recognition events in various physiological and pathological processes. This study aimed to investigate the role of the Jacalin-related lectin (JRL) gene, AOL_s00083g511, in A. oligospora development. Through a homology recombination approach, we obtained the AOL_s00083g511 knockout mutant strain (Ag511). Next, the biological characteristics of the Ag511 mutant strain, including growth rate, conidia germination rate, adaptation to environmental stresses, and nematocidal activity, were compared with those of the wild-type (WT) strain. The results showed that the JRL gene AOL_s00083g511 did not affect fungal growth, conidia germination, 3D-trap formation, and the ability of A. oligospora to prey on nematodes significantly. We speculate that this phenomenon may be caused by a loss of the key ß1-ß2 loops in the AOL_ s00083g511-encoded JRL domain and an intrinsic genetic compensation of AOL_s00083g511 in this fungus. The growth rates of both strains on high salt or surfactant media were similar; however, in the strong oxidation medium, the growth rate of the Ag511 mutant was significantly lower than that of the WT strain, indicating that AOL_s00083g511 might play a role in oxidative stress resistance. These findings provide a basis for further analysis of the related functions of the JRL gene in A. oligospora and their potential roles in the biological control of nematodes in the future.

Synbiotic supplementation containing Bifidobacterium infantis and xylooligosaccharides alleviates dextran sulfate sodium-induced ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease whose prevalence is increasing globally. A synbiotic has probiotic and prebiotic components and is regarded as a promising candidate for alleviating UC-associated inflammation. The purpose of this study is to determine whether there is an additive efficacy between the probiotic Bifidobacterium infantis (B. infantis) and the prebiotic xylooligosaccharide (XOS) against UC. C57BL/6 mice were treated with B. infantis, XOS, or synbiotic (combination of B. infantis and XOS) for 21 d. During the final 7 d of treatment, the mice were administered dextran sulfate sodium (DSS) dissolved in drinking water to induce colitis. All treatments decreased the disease activity index (DAI) and pathological scores, and synbiotic treatment was more efficacious than either the probiotic or prebiotic alone. Compared with the DSS-induced colitis group, all treatment groups significantly downregulated the proinflammatory cytokines TNF-α and IL-1ß, and synbiotic treatment significantly upregulated the anti-inflammatory cytokine IL-10 in the colon tissues. Furthermore, all treatments significantly reduced the NLR family pyrin domain containing 3 (NLRP3) inflammasome mRNA level in the colon tissues. All treatments significantly inhibited oxidative stress and increased zonula occludens-1 (ZO-1), occludin, and claudin-1 tight junction (TJ) molecule mRNA levels in the colon tissues. Therefore, the observed efficacy of synbiotics against colitis may be explained by the additive combination of the direct anti-inflammatory effects of the probiotic and prebiotic components and their ability to fortify colonic epithelial barrier integrity. Our findings suggest that a synbiotic is a promising dietary supplement or functional food for the effective management of UC.

Grape seed proanthocyanidin extract ameliorates dextran sulfate sodium-induced colitis through intestinal barrier improvement, oxidative stress reduction, and inflammatory cytokines and gut microbiota modulation.

It is widely believed that grape seed proanthocyanidin extract (GSPE) exerts antioxidant and anti-inflammatory effects. Dietary supplementation with GSPE has been reported to alleviate colitis signs in mice, but the mechanisms involved require further exploration. The present study investigated how the oral administration of GSPE ameliorates colitis signs and reduces colitis-associated inflammation. C57BL/6 mice were treated with GSPE for 21 days. During the final 7 days of treatment, the mice were administered dextran sulfate sodium (DSS) dissolved in drinking water to induce experimental colitis. We found that GSPE treatment improved DSS-induced colitis, which was evidenced by decreases in disease activity index (DAI) scores, pathological scores, and oxidative stress and increases in zonula occludens-1 (ZO-1), occludin, and claudin-1 mRNA levels of colon tissue. Notably, the proinflammatory cytokines TNF-α and IL-1ß were significantly downregulated as a result of GSPE treatment in colon tissues. GSPE treatment also reduced NLR family pyrin domain-containing 3 (NLRP3) inflammasome mRNA levels of colon tissue. Furthermore, an analysis of 16S rRNA sequences showed that GSPE rebalanced the DSS-damaged gut microbiota, including reducing Bacteroidetes, Dubosiella, and Veillonella, increasing Verrucomicrobia and Akkermansia, and elevating the Firmicutes to Bacteroidetes ratio. In conclusion, GSPE supplementation alleviates DSS-induced colitis by modulating inflammatory cytokines and oxidation stress, maintaining the intestinal barrier, and improving the microbial community. These results indicate that GSPE might be a new dietary strategy for the treatment of ulcerative colitis.

Heterologous expression and molecular binding properties of AofleA, a fucose-specific lectin from nematophagous fungus Arthrobotrys oligospora.

Lectins are the primary recognition macromolecules for various types of fucosylation, a common eukaryotic post-translational modification. In this study, we report the heterologous expression and molecular binding properties of a fucose-specific lectin, AofleA, isolated from Arthrobotrys oligospora. This is the first reported fucose-specific lectin found in nematophagous fungi. The recombinant AofleA (r-AofleA) was expressed in Escherichia coli with high efficiency, yielding at least 500 mg of soluble and functional r-AofleA per liter of broth. Using hemagglutination inhibition assay and glycan microarray analysis, r-AofleA was found to be broadly specific for fucosylated glycans or oligosaccharides including Fucα(1-2), Fucα(1-3), Fucα(1-4) and Fucα(1-6) linkages, similar to Aleuria aurantia lectin (AAL). Frontal affinity chromatography showed that r-AofleA has high affinity towards PA-L-fucose with an average Kd value of 15 nM. These findings provide a basis for improved understanding of the structure and functions of AofleA during recognition and capture of prey nematodes by nematophagous fungus A. oligospora.

Application of nanodiagnostics in point-of-care tests for infectious diseases.

Although tremendous efforts have been put into the treatment of infectious diseases to prevent epidemics and mortality, it is still one of the major health care issues that have a profound impact on humankind. Therefore, the development of specific, sensitive, accurate, rapid, low-cost, and easy-to-use diagnostic tools is still in urgent demand. Nanodiagnostics, defined as the application of nanotechnology to medical diagnostics, can offer many unique opportunities for more successful and efficient diagnosis and treatment for infectious diseases. In this review, we provide an overview of the nanodiagnostics for infectious diseases from nanoparticle-based, nanodevice-based, and point-of-care test (POCT) platforms. Most importantly, emphasis focused on the recent trends in the nanotechnology-based POCT system. The current state-of-the-art and most promising point-of-care nanodiagnostic technologies, including miniaturized diagnostic magnetic resonance platform, magnetic barcode assay system, cell phone-based polarized light microscopy platform, cell phone-based dongle platform, and paper-based POCT platform, for infectious diseases were fully examined. The limitations, challenges, and future trends of the nanodiagnostics in POCTs for infectious diseases are also discussed.

Nanobody-derived nanobiotechnology tool kits for diverse biomedical and biotechnology applications.

Owing to peculiar properties of nanobody, including nanoscale size, robust structure, stable and soluble behaviors in aqueous solution, reversible refolding, high affinity and specificity for only one cognate target, superior cryptic cleft accessibility, and deep tissue penetration, as well as a sustainable source, it has been an ideal research tool for the development of sophisticated nanobiotechnologies. Currently, the nanobody has been evolved into versatile research and application tool kits for diverse biomedical and biotechnology applications. Various nanobody-derived formats, including the nanobody itself, the radionuclide or fluorescent-labeled nanobodies, nanobody homo- or heteromultimers, nanobody-coated nanoparticles, and nanobody-displayed bacteriophages, have been successfully demonstrated as powerful nanobiotechnological tool kits for basic biomedical research, targeting drug delivery and therapy, disease diagnosis, bioimaging, and agricultural and plant protection. These applications indicate a special advantage of these nanobody-derived technologies, already surpassing the "me-too" products of other equivalent binders, such as the full-length antibodies, single-chain variable fragments, antigen-binding fragments, targeting peptides, and DNA-based aptamers. In this review, we summarize the current state of the art in nanobody research, focusing on the nanobody structural features, nanobody production approach, nanobody-derived nanobiotechnology tool kits, and the potentially diverse applications in biomedicine and biotechnology. The future trends, challenges, and limitations of the nanobody-derived nanobiotechnology tool kits are also discussed.

Characterization and in vitro antioxidant activities of polysaccharides from Pleurotus ostreatus.

Two polysaccharide fractions (PSPO-1a and PSPO-4a) were isolated from the fruiting bodies of Pleurotus ostreatus using ethanol precipitation, anion-exchange chromatography and gel permeation chromatography. Both fractions were heteropolysaccharide containing protein and uronic acid. PSPO-1a was composed of mannose, glucose, galactose, xylose and rhamnose with a molar ratio of 2.47:0.91:1.00:1.66:3.87. PSPO-4a was composed of only three monosaccharides: rhamnose, mannose and galactose with a molar ratio of 0.92:2.69:1.00. The average molecular weight of PSPO-1a and PSPO-4a determined by HPLC were estimated to be 1.8 × 10(4)Da and 1.1 × 10(6)Da respectively. The in vitro tests revealed that two polysaccharides were natural potential antioxidant. Both polysaccharides presented stronger DPPH radical and superoxide anion radical scavenging activity with increasing concentrations, but less effective on scavenging hydroxyl radical. Compared with PSPO-4a, PSPO-1a was the more effective free-radical scavenger. In conclusion, the two polysaccharides may be useful as a naturally potential antioxidant agent for application in food and medicinal fields.