Stimuli-Responsive Proteinosomes Based on Biohybrid Shell Cross-Linked Micelles.

A new method of stimuli-responsive proteinosome fabrication with the shell cross-linked micelle as a template is reported in this research. A thermoresponsive diblock copolymer poly[di(ethylene glycol) methyl ether methacrylate]-b-poly[poly(ethylene glycol) methyl ether methacrylate-co-pyridyl disulfide methacrylamide] [PDEGMA-b-P(PEGMA-co-PDSMA)] was synthesized and self-assembled into micelles with PDEGMA cores and P(PEGMA-co-PDSMA) shells at the temperature above its lower critical solution temperature (LCST). Reduced bovine serum albumin (BSA) molecules with six thiol groups were used to cross-link the shells of the micelles by reacting with the pendant pyridyl disulfide groups on the P(PEGMA-co-PDSMA) block. At a temperature below the LCST of the polymer, the PDEGMA cores were dissolved in water, affording proteinosomes with a size of about 50 nm and capsule-like structures. The proteinosome was also thermoresponsive with a phase transition temperature at 35 °C. The fabrication of the proteinosome had no obvious influence on the structure and activity of BSA, and BSA retained most of its secondary structure and esterase-like activity. Because the BSA molecules were connected to the polymer chains through disulfide bonds, they could be released upon addition of dithiothreitol. The in vitro cell viability evaluation and the cellular uptake assay demonstrated that the proteinosome showed low toxicity to NIH 3T3 and 4T1 cells and could be internalized into the 4T1 cells.

Antibacterial polyene-polyol macrolides and cyclic peptides from the marine-derived Streptomyces sp. MS110128.

Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10-12), were isolated from a culture of the marine Streptomyces sp. MS110128. In addition, four new polyene macrolides, pyranpolyenolides C-F (3-6), were identified as olefin geometric isomers that were most likely produced by photochemical conversion during the cultivation or isolation procedures. The pyranpolyenolides are 32-membered macrolides endowed with a conjugated tetraene and several pairs of 1,3-dihydroxyl groups. Pyranpolyenolides that contain a hydropyran group have not been previously reported. Four cyclic peptides (9-12) showed significant activities against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant S. aureus with supporting MIC values ranging from 0.025 to 1.25 µg/mL. These cyclic peptides containing piperazic moieties showed moderate activities with MIC values of 12.5 µg/mL against Bacille Calmette Guerin (BCG), an attenuated form of the bovine. Additionally, cyclic peptide 12 showed moderate antifungal activity against Candida albicans with an MIC value of 12.5 µg/mL. KEY POINTS: • Discovery of new polyenes and cyclic peptides from a marine-derived Actinomycete. • Cyclic peptides containing piperazic moieties exhibited good antibacterial activity.

Adsorption Properties of Comb-Shaped Polycarboxylate Dispersant onto Different Crystal Pyraclostrobin Particle Surfaces.

The stability of the suspension system of the two crystal forms of pyraclostrobin is evaluated using multiple light technology, and the adsorption performance of polycarboxylate dispersant on the surface of two different crystalline pyraclostrobin particles is compared in combination with XRD, FTIR, XPS, and SEM from the microscopic view. The adsorption kinetics and thermodynamics studies of 2700 on the surfaces of different crystalline forms of pyraclostrobin particles show that the adsorption process of 2700 on the surfaces of pyraclostrobin crystal forms II and IV conform to pseudo-second-order kinetic adsorption model. The Ea values for crystal forms II and IV are 12.93 and 14.39 kJ∙mol-1, respectively, which indicates that both adsorption processes are physical adsorption. The adsorption models of 2700 on the surfaces of pyraclostrobin crystal forms II and IV are in accordance with Langmuir adsorption isotherms. The ∆Gad values of crystal forms II and IV are negative and the ∆Sad values are positive at different temperatures. Therefore, the adsorption processes are spontaneous and accompanied by entropy increase. The results of this study provide an important theoretical basis for the selection of polycarboxylate dispersants in the suspension of pyraclostrobin. This study also provides a reference for the research of polycrystalline pesticide suspension concentrate.

Exogenous application of urea and a urease inhibitor improves drought stress tolerance in maize (Zea mays L.).

Drought is believed to cause many metabolic changes which affect plant growth and development. However, it might be mitigated by various inorganic substances, such as nitrogen. Thus, the study was carried out to investigate the effect of foliar-applied urea with or without urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on a maize cultivar under drought stress simulated by 15% (w/v) polyethylene glycol 6000. Foliar-applied urea resulted in a significant increase in plant dry weight, relative water content, and photosynthetic pigments under water stress condition. Furthermore, the activities of superoxide dismutase (SOD), peroxidase (POD), and hydrogen peroxidase (CAT), were enhanced with all spraying treatments under drought stress, which led to decreases in accumulation of hydrogen peroxide (H2O2), superoxide anion ([Formula: see text]) and malondialdehyde (MDA). The contents of soluble protein and soluble sugar accumulated remarkably with urea-applied under drought stress condition. Moreover, a further enhancement in above metabolites was observed by spraying a mixture of urea and urease inhibitor as compared to urea sprayed only. Taken together, our findings show that foliar application of urea and a urease inhibitor could significantly enhance drought tolerance of maize through protecting photosynthetic apparatus, activating antioxidant defense system and improving osmoregulation.

Preparation of Janus Graphene Oxide (GO) Nanosheets Based on Electrostatic Assembly of GO Nanosheets and Polystyrene Microspheres.

A facile and versatile method for the synthesis of Janus graphene oxide (GO) nanosheets with different structures is reported. Based on electrostatic assembly, Janus GO nanosheets can be easily functionalized with a template polymer or be defunctionalized by altering the ionic strength. By using this approach, Janus GO nanosheets are prepared successfully with hydrophobic polystyrene chains on one side and hydrophilic poly(2-(dimethylamino)ethyl methacrylate) chains on the other side.

Cytotoxic cardenolides from the latex of Calotropis procera.

Three new cardenolides (3, 9 and 10), along with eight known ones, were isolated from the latex of Calotropis procera. The structural determination was accomplished by the 1D- and 2D-NMR spectra as well as HRESIMS analysis. The growth inhibitory activity of the latex and its sub-fractions as well as isolated compounds was evaluated against human A549 and Hela cell lines. The results exhibited that latex had strong growth inhibitory activity with IC50s of (3.37 µM, A-549) and (6.45 µM, Hela). Among the four extracts (hexane, chloroform, ethyl acetate and aqueous), chloroform extract displayed the highest potential cytotoxic activity, with IC50s of (0.985 µM, A-549) and (1.471 µM, Hela). All the isolated compounds displayed various degrees of cytotoxic activity and the highest activity was observed by calactin (1) with IC50s values of (0.036 µM, A-549) and (0.083 µM, Hela). None of these isolated compounds exhibited good antimicrobial activity evaluated by determination of their MICs using the broth microdilution method against various infectious pathogens. The structure-activity relationships for cytotoxic activity were also discussed.

Enhanced reparatory effect of EI1 on dental pulp via extracellular matrix remodeling by miR-181b-2-3p inhibitor.

Background/purpose: Extracellular matrix (ECM) is crucial for dental pulp repair. The aim of this paper is to investigate the ECM remodeling effect of miR-181b-2-3p (a microRNA) and to verify the reparatory effect of EI1 (an epigenetic drug) and miR-181b-2-3p inhibitor on dental pulp. Materials and methods: Levels of ECM-related factors in EI1-treated human dental pulp cells (hDPCs) were measured by qRT-PCR and Western blot. The anti-inflammation effect of EI1 was examined in Lipopolysaccharide-stimulated hDPCs. miR-181b-2-3p mimics or inhibitors were transfected into hDPCs and then the cells' functions were detected. A dual luciferase reporter assay was used to identify the targets of miR-181b-2-3p. Pulpotomy using miR-181b-2-3p antagomirs and EI1 as pulp capping materials was performed in male six-week-old Sprague-Dawley rats. Results: EI1 upregulated ECM-related genes expression in hDPCs, but failed to upregulate the collagen1A1 (COL1A1) protein level. Pro-inflammatory factors were downregulated by EI1 in Lipopolysaccharide-stimulated hDPCs. Overexpression of miR-181b-2-3p downregulated the expression of transforming growth factor-ß2 (TGF-ß2) and fibronectin type III domain-containing protein 5 precursor (FNDC5), while the inhibition had the opposite effect. Dual luciferase reporter assays demonstrated that miR-181b-2-3p targets TGF-ß2, FNDC5 and integrin alpha 4 protein (ITGA4). Compared to EI1 was used alone, EI1 combined with the inhibitor upregulated the protein levels of COL1A1, fibronectin (FN1) and TGF-ß2 in hDPCs, promoted hDPCs migration, and exhibited reparatory effects on inflamed rat pulp tissue. Conclusion: miR-181b-2-3p inhibitor could enhance the reparatory effect of EI1 via ECM remodeling in dental pulp both in vitro and in vivo.

A stable delivery system for curcumin: Fabrication and characterization of self-assembling acylated kidney bean protein isolate nanogels.

The construction of protein-based nano-gels as curcumin delivery system effectively enhances the stability and bioavailability of curcumin. In this study, acylation modification and self-assembly techniques were jointly employed to construct acylated kidney bean protein isolate (AKBPI)-nanogels. Optimal conditions for AKBPI-nanogels were determined to be pH 7, concentration of 2 mg/mL, and temperature at 90℃ for 30 min. The optimized AKBPI-nanogels exhibited excellent uniformity as evidenced by decreasing average particle size (137.35 nm) and polydispersity index (0.38). Acylation enhanced the intermolecular interactions within the nanogel by reducing the polarity of tyrosine microenvironment and free sulfhydryl groups. AKBPI-nanogels demonstrated remarkable characteristics in terms of pH sensitivity, salt concentration, and storage tolerance. The curcumin-loaded AKBPI-nanogels exhibited an encapsulation efficiency of 92.30 % and maintained high antioxidant activity. In simulated gastrointestinal digestion, AKBPI-nanogels facilitated the controlled release and higher bioavailability of curcumin. Therefore, AKBPI-nanogels can be a stable tool for delivering curcumin.

The anti-hepatoma effect of nanosized Mn-Zn ferrite magnetic fluid hyperthermia associated with radiation in vitro and in vivo.

Joint therapy is a promising area of study in cancer treatment. In this paper, we prepared Mn-Zn ferrite (Mn0.5Zn0.5Fe2O4) magnetofluid using PEI as a surfactant, and investigated the anticancer effect of Mn0.5Zn0.5Fe2O4 magnetic fluid hyperthermia (MFH) combined with radiotherapy on hepatocellular carcinoma. Both in vitro and in vivo results suggest that this combined treatment with MFH and radiation has a better therapeutic effect than either of them alone. The apoptotic rate and necrotic rate of the combined treatment group was 38.80 and 25.20%, respectively. In contrast, it was only 7.49 and 3.62% in the radiation-alone group, 15.23 and 7.90% in the MFH-alone group, only 3.52 and 2.16% in the blank control group, and 23.56 and 27.56% in the adriamycin group. The cell proliferation inhibition rate of the combined treatment group (88.5%) was significantly higher than that of the radiation-alone group (37.5%), MFH-alone group (60.6%) and adriamycin group (70.6%). The tumor volume inhibition and mass inhibition rate of the combined treatment group was 87.62 and 88.62%, respectively, obviously higher than the 41.04 and 34.20% of the radiation-alone group, 79.87 and 77.92% of the MFH-alone group and 71.76 and 66.87% of the adriamycin group. It is therefore concluded that this combined application of MFH and radiation can give good synergistic and complementary effects, which offers a viable approach for treatment of cancer.

High nitrogen content bimolecular co-functionalized graphene nanoflakes for hypertoxic Cr(VI) removal: Insights into adsorption behavior and mechanisms.

The proven high carcinogenicity to humans and high destructive force to the environment determine the extreme urgency of eliminating hypertoxic Cr(VI) in water bodies. Herein, a route of room temperature synthesis and secondary grafting was proposed to fabricate graphene oxide-based nanoadsorbent co-functionalized with polydopamine and branched polyethyleneimine (GOPP) to remove Cr(VI). The flexible decoration of polydopamine and polyethyleneimine on GO flakes could gradually enhance the amount of N-containing functional groups and realize selective removal of Cr(VI) with the maximum experimental adsorption capacity of 564.7 mg/g, displaying a significantly high separation factor against alkali metal, alkaline earth metal, and other transition metal ions. Various combination mechanisms, such as electrostatic attraction, reduction, complexation, and hydrogen bonding, were demonstrated to be involved in the adsorption process of Cr(VI) by XPS, ESP, and DFT calculations. And the interaction energies of the five protonated configurations of primary amine, tertiary amine, secondary amine, imine, and secondary amine on the ring with HCrO4- were: -22.66, -12.08, -24.92, -24.26, -27.64 kcal/mol. In the actual industrial wastewater study, a Cr(VI) removal rate of 85.8% was realized. This work provided a viable idea for the elimination of Cr(VI) and was expected to be applied in the field of wastewater treatment.

Novel covalently coated diazoresin/polyvinyl alcohol capillary column for the analysis of proteins by capillary electrophoresis.

A novel method for the preparation of covalently linked capillary coatings of PVA was demonstrated using photosensitive diazoresin (DR) as coupling agents. Layer-by-layer self-assembly film of DR and PVA based on hydrogen bonding was first fabricated on the inner wall of capillary, then the hydrogen bonding was converted into covalent bonding after treatment with UV light through the unique photochemistry reaction of DR. The covalently bonded coatings suppressed basic protein adsorption on the inner surface of capillary, and thus a baseline separation of lysozyme, cytochrome c and BSA was achieved using CE. Compared with bare capillary or noncovalently bonded DR/PVA coatings, the covalently linked DR/PVA capillary coatings not only improved the CE separation performance for proteins, but also exhibited good stability and repeatability. Due to the replacement of highly toxic and moisture-sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide a green and easy way to make the covalently coated capillaries for CE.

Influences of different carbon substrates on the morphologies of carbon/g-C3N4 photocatalytic composites and the purification capacities of different composites in the weak UV underwater environment.

In order to explore the influence of various carbon introduction on the morphology and photodegradation performance of C/g-C3N4 composites, three kinds of different carbon materials: carbon nanotubes (CNT), graphene (GN) and carbon fibers (CF) were introduced to modify g-C3N4, and the morphologies, light absorption capacities and the underwater purifications of the composite photocatalysts were investigated. Results showed that the composites synthesized with different carbon substrates shows great differences in growth morphology. In addition, the introduction of various carbon sources also has a great impact on the physical and chemical properties of the composites. Compared with GN/g-C3N4 and CF/g-C3N4, CNT/g-C3N4 shows strong light absorption ability, especially in long-wavelength region (570-660 nm). To further study the difference of degradation ability of the composites in the underwater environment, the purification performance of modified g-C3N4 at different water depths were carried out. The results show that under 40 cm of water, where the light intensity and ultra violet spectral are seriously attenuated, the purification efficiency of CNT/g-C3N4 at 40 cm is 3.35 times than that of g-C3N4. This work provides insight in the design of highly efficient metal-free photocatalysts for the environmental remediation.

Regulation of Inflammatory Response and Osteogenesis to Citrate-Based Biomaterials through Incorporation of Alkaline Fragments.

A proper pH microenvironment is crucial to mobilizing regeneration function of biomaterials. Neutralizing the acidity in bone defects with alkaline substances is a promising strategy to create favorable environments for cell proliferation and bone repair. In this study, to neutralize the acidity and reduce the inflammation caused by the rapid release of citric acid, a novel citrate-based biodegradable elastomeric poly(citric acid-1,8-octanediol-1,4-bis(2-hydroxyethyl)piperazine (BHEp)) (POPC) is synthesized with the introduction of the alkaline fragment BHEp, and then POPC/ß-tricalcium phosphate (ß-TCP) porous scaffolds are fabricated by 3D printing technique. The results reveal that the alkaline fragment BHEp effectively corrects the acid environment and improves the biocompatibility, cells affinity and promoted cell adhesion, and proliferation of POPC. Furthermore, the improved pH of POPC15/ß-TCP (PTCP15) enhances the adhesion and the proliferation of rabbit bone marrow mesenchymal stem cells, and the expression of osteogenesis-related genes. Moreover, PTCP15 scaffolds relieve inflammatory response and switch RAW 264.7 toward a prohealing extreme. The rat femoral defect model further demonstrates good biocompatibility and enhanced bone regeneration of PTCP15. In conclusion, the results offer a promising approach for biodegradable polymers to address the degradation acidity issue. Meanwhile, a positive regulation strategy is provided for biopolymer to enhance cell proliferation, osteogenic differentiation, and bone repair.

Microbial Metabolite Inspired ß-Peptide Polymers Displaying Potent and Selective Antifungal Activity.

Potent and selective antifungal agents are urgently needed due to the quick increase of serious invasive fungal infections and the limited antifungal drugs available. Microbial metabolites have been a rich source of antimicrobial agents and have inspired the authors to design and obtain potent and selective antifungal agents, poly(DL-diaminopropionic acid) (PDAP) from the ring-opening polymerization of ß-amino acid N-thiocarboxyanhydrides, by mimicking ε-poly-lysine. PDAP kills fungal cells by penetrating the fungal cytoplasm, generating reactive oxygen, and inducing fungal apoptosis. The optimal PDAP displays potent antifungal activity with minimum inhibitory concentration as low as 0.4 µg mL-1 against Candida albicans, negligible hemolysis and cytotoxicity, and no susceptibility to antifungal resistance. In addition, PDAP effectively inhibits the formation of fungal biofilms and eradicates the mature biofilms. In vivo studies show that PDAP is safe and effective in treating fungal keratitis, which suggests PDAPs as promising new antifungal agents.

Face-Computer Interface (FCI): Intent Recognition Based on Facial Electromyography (fEMG) and Online Human-Computer Interface With Audiovisual Feedback.

Patients who have lost limb control ability, such as upper limb amputation and high paraplegia, are usually unable to take care of themselves. Establishing a natural, stable, and comfortable human-computer interface (HCI) for controlling rehabilitation assistance robots and other controllable equipments will solve a lot of their troubles. In this study, a complete limbs-free face-computer interface (FCI) framework based on facial electromyography (fEMG) including offline analysis and online control of mechanical equipments was proposed. Six facial movements related to eyebrows, eyes, and mouth were used in this FCI. In the offline stage, 12 models, eight types of features, and three different feature combination methods for model inputing were studied and compared in detail. In the online stage, four well-designed sessions were introduced to control a robotic arm to complete drinking water task in three ways (by touch screen, by fEMG with and without audio feedback) for verification and performance comparison of proposed FCI framework. Three features and one model with an average offline recognition accuracy of 95.3%, a maximum of 98.8%, and a minimum of 91.4% were selected for use in online scenarios. In contrast, the way with audio feedback performed better than that without audio feedback. All subjects completed the drinking task in a few minutes with FCI. The average and smallest time difference between touch screen and fEMG under audio feedback were only 1.24 and 0.37 min, respectively.

Candida albicans promotes tooth decay by inducing oral microbial dysbiosis.

Candida albicans has been detected in root carious lesions. The current study aimed to explore the action of this fungal species on the microbial ecology and the pathogenesis of root caries. Here, by analyzing C. albicans in supragingival dental plaque collected from root carious lesions and sound root surfaces of root-caries subjects as well as caries-free individuals, we observed significantly increased colonization of C. albicans in root carious lesions. Further in vitro and animal studies showed that C. albicans colonization increased the cariogenicity of oral biofilm by altering its microbial ecology, leading to a polymicrobial biofilm with enhanced acidogenicity, and consequently exacerbated tooth demineralization and carious lesion severity. More importantly, we demonstrated that the cariogenicity-promoting activity of C. albicans was dependent on PHR2. Deletion of PHR2 restored microbial equilibrium and led to a less cariogenic biofilm as demonstrated by in vitro artificial caries model or in vivo root-caries rat model. Our data indicate the critical role of C. albicans infection in the occurrence of root caries. PHR2 is the major factor that determines the ecological impact and caries-promoting activity of C. albicans in a mixed microbial consortium.

Application of Antibiotics/Antimicrobial Agents on Dental Caries.

Dental caries is the most common oral disease. The bacteriological aetiology of dental caries promotes the use of antibiotics or antimicrobial agents to prevent this type of oral infectious disease. Antibiotics have been developed for more than 80 years since Fleming discovered penicillin in 1928, and systemic antibiotics have been used to treat dental caries for a long time. However, new types of antimicrobial agents have been developed to fight against dental caries. The purpose of this review is to focus on the application of systemic antibiotics and other antimicrobial agents with respect to their clinical use to date, including the history of their development, and their side effects, uses, structure types, and molecular mechanisms to promote a better understanding of the importance of microbial interactions in dental plaque and combinational treatments.

Fabrication and photocatalytic performance evaluation of hydrodynamic erosion-resistant nano-TiO2-silicone resin composite films.

Herein, we present the preparation of nano-TiO2-silicone resin composite films by double liquid phase spray deposition. The films exhibit better adhesion stability and photocatalytic activity under a hydrodynamic erosion condition than conventional nano-TiO2 composite films. The TiO2 layer morphology and effective TiO2 coverage ratio (CR) were affected by the initial curing time (ICT) of the silicone resin, e.g., the increase in an ICT from 10 to 40 min resulted in a CR change from 79.1 to 98.7%. The surface morphology evolution of composite films was studied under a hydrodynamic erosion period of 4 weeks. Obtained results allowed the 4-week evolution to be divided into four stages (pitting, crack pregnant, banded stripping, and surface stripping periods), additionally revealed that the CR of all samples was remained above 65%. The photocatalytic activity of composite films before and after 4-week hydrodynamic erosion was evaluated by rhodamine B degradation experiments. The 4-week erosion only led to the decrease of the photodegradation efficiencies by less than 40% in all cases. Thus, the fabricated TiO2-silicone composite films demonstrated excellent durability and photocatalytic activity under the conditions of long-term hydrodynamic erosion, allowing one to conclude that this work paves the way to the fabrication of next-generation photocatalytic materials for industrial applications.

Efficient synthesis of amino acid polymers for protein stabilization.

Proteins are fragile such that even freezing, drying and dehydration may induce their denaturation, aggregation, and activity loss. To protect proteins from these kinds of damage, we prepared two types of amino acid polymers, poly-(l-glutamate)-r-poly-(l-lysine) (PLG-r-PLL) and poly-l-glutamate (PLG), from the efficient ring-opening polymerization of α-amino acid N-carboxyanhydride (NCA) using lithium hexamethyldisilazide (LiHMDS) as the initiator. ß-galactosidase (ß-Gal) was used in this study to examine the protein protecting effect of the synthesized amino acid polymers during lyophilization. The results indicate that both PLG-r-PLL and PLG exert significant protection on ß-Gal during lyophilization and improve the activity of the resulting protein from 40%, without using a protecting agent during lyophilization, to 80% of the original protein activity. Nevertheless, PLG generally performs better than PLG-r-PLL independent of the chain length. Our studies also show that PLG and PLG-r-PLL with a high content of PLG subunits display no observable cytotoxicity and hemolytic effect. Furthermore, dynamic light scattering (DLS) and transmission electron microscopy (TEM) characterization indicate that PLG protects ß-Gal upon lyophilization by preventing the aggregation of ß-Gal. Our studies demonstrate that amino acid polymers, such as PLG, can exert potent activity for protein stabilization. The easy operation of LiHMDS-initiated and efficient NCA polymerization implies the great potential of this strategy to prepare amino acid polymers quickly for the screening of protein stabilization and mechanism study.

Nitric oxide protects against polyethylene glycol-induced oxidative damage in two ecotypes of reed suspension cultures.

Dune reed (DR) is the more tolerant ecotype of reed to environmental stresses than swamp reed (SR). Under osmotic stress mediated by polyethylene glycol (PEG-6000), the suspension culture of SR showed higher ion leakage, and more oxidative damage to the membrane lipids and proteins was observed compared with the relatively tolerant DR suspension culture. Treatment with sodium nitroprusside (SNP) can significantly alleviated PEG-induced ion leakage, thiobarbituric acid reactive substances (TBARS) and carbonyl contents increase in SR suspension culture. The levels of H(2)O(2) and O(2)(-) were reduced, and the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were increased in both suspension cultures in the presence of SNP under osmotic stress, but lipoxygenase (LOX) activity was inhibited. 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific Nitric oxide (NO) scavenger, blocked the SNP-mediated protection. Depletion of endogenous NO with PTIO strongly enhanced oxidative damage in DR compared with that of PEG treatment alone, whereas had no effect on SR. Moreover, NO production increased significantly in DR while kept stable in SR under osmotic stress. Taken together, these results suggest that PEG induced NO release in DR but not SR can effectively protect against oxidative damage and confer an increased tolerance to osmotic stress in DR suspension culture.