Effects of Several Pesticides on Superoxide Dismutase (SOD) Activities of Different Rice Varieties

Effects of several pesticides on superoxide dismutase (SOD) activities of different rice varieties were studied. The results showed that SOD activities of almost all the herbicide treatments on different rice varieties increased during 15 days after treatment (DAT). SOD activity of rice plants reached a maximum at 10 DAT, began to decline at 15 DAT and then recovered to the control level at 21 DAT. The SOD activity of rice plants at 2 days after the second application of pesticides (spraying with insecticide-bisultap or fungicide-jing-ganmycin at 22 days after herbicide treatments) (2 DAST) increased and declined at 6 DAST in comparison with that of the control, indicating that two applications of pesticides had a more serious impact on rice plants compared with one application. SOD activity of rice plants may be an index of rice plant resistance.

Changes of SOD Activity in Corn Leaves Infected by Setosphaeria turcica with Different Pathogenicity

[ Objective] The paper was to explore the relationship between SOD activity and resistance of corn against Setosphaeria turcica. [ Method] Strain YC and 01-23T of S. turcica with different pathogenicity were inoculated into corn leaves by fungal disc inoculation method, and the dynamic changes of SOD activity in infected corn leaves was measured. [Result] After inoculation of higly virulent strain YC and weakly virulent strain 01-23T of S. turcica, SOD activity in corn leaves within 1 -5 d showed obvious stages, which gradually decreased within 1 -3 d, then gradually increased within 3 -4 d, and decreased again within 4 -5 d. The SOD activity of corn leaves in inoculation treatment was higher than that in the treatment without inoculation within 1 - 4 d, which significantly decreased at fifth day. The pathogen with different pathogenicity would lead to different changes in SOD activity of corn leaves. SOD activity of corn leaves infected by weakly virulent strain 01-23T for the first day was extremely higher than that infected by strong virulent strain YC, but had no significant difference with highly virulent strain YC at 2 -3 d. [ Conclusion] SOD activity played an important role in initial resistant ability of corn against pathogen infection, and had no significant effect on resistance against pathogen extension after incidence.

SOD-like Activity of Copper Salicylate Complex in Tween Micel-lar Systems

opper salicylate complex has been synthesized and its composition was analyzed. The four surfactants(Tween 20, 40, 60, 80) were purified and their critical micelle concentrations(CMC) in phosphate buffer (pH=7.4) were measured. The SOD like activity of copper salicylate complex was assayed using the cytochrome c reduction method in different media. The cooperative effect of the complex with micelles was studied in detail. SOD like activity of the complex was enhanced in the presence of surfactants. The four surfactants themselves display SOD like activities to a certain extent. Similar results were obtained in the experiment for the antilipid peroxidation of red cell membrane. These results might be explained by the fact of micellar catalysis. It was suggested that the copper salicylate Tween system used as a potential antiinflammatory drug might be worthwhile to be further studied.

Physiological characteristics changes of Aesculus chinensis seeds during natural dehydration

A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.

Response of Rice Varieties to Bound Residues of Metsulfuron-Methyl in a Paddy Soil

Metsulfuron-methyl is one of the widely used sulfonylurea herbicides. However, approximately half of the applied metsulfuron-methyl may remain as bound residues in soil. To characterize the response of rice plants to residual metsulfuron-methyl in soil, the activities of acetolactate synthase （ALS）, superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） were investigated in two rice varieties that differed in susceptibility to the herbicide. Changes in the activity of these enzymes in leaves and roots of Xiushui 63, a sensitive rice variety, were greater than those in a resistant variety Zhenong 952. Irrespective of variety, changes in the enzyme activity were greater in the roots than in the leaves. The activities of ALS and CAT decreased, while the SOD activity increased with the increase in the amounts of bound residues of metsulfuron-methyl （BRM） in soil. The POD activity increased at the BRM level of 0.025 mg kg^-1, but decreased at the BRM level of 0.05 mg kg^-1. The results showed that the bound residues of sulfonylurea herbicides may affect metabolism of rice plants.

Impact of dietary oils and fats on lipid peroxidation in liver and blood of albino rats

Objective:To investigate the effects of different dietary fat and oils(differing in their degree of saturation and unsaturation)on lipid peroxidation in liver and blood of rats.Methods:The study was conducted on SO albino rats that were randomly divided into 5 groups of 10 animals.The groups were fed on dietary butter(Group I),margarine(Croup II),olive oil(Group III),sunflower oil(Group IV)and com oil(Group V)for 7 weeks.After 12 h of diet removal,livers were excised and blood was collected to measure malondialdehyde(MDA)levels in the supernatant of liver homogenate and in blood.Blood superoxide dismutase activity(SOD),glutathione peroxidase activity(GPx),serum vitamin E and total antioxidant capacity(TAC)levels were also measured to determine the effects of fats and oils on lipid peroxidation.Results:The results indicated that no significant differences were observed in SOD activity,vitamin E and TAC levels between the five groups.However,there was significant decrease of GPx activity in groups IV and V when compared with otlier groups.The results indicated that feeding corn oil caused significant increases in liver and blood MDA levels as compared with other oils and fats.There were positive correlations between SOD and GPx,vitamin E and TAC as well as between GPx and TAC(r:0.743;P<0.001)and between blood MDA and liver MDA(r:0.897;P<0.00l).The results showed also negative correlations between blood MDA on one hand and SOD,GPx,vitamin E and TAC on the other hand.Conclusions:The results demonstrated that feeding oils rich in polyunsaturated fatly acids(PUFA)increases lipid peroxidation significantly and may raise the susceptibility of tissues to free radical oxidative damage.

Effects of heat on the biological activity of wild Cordyceps sinensis

Background:Current methods of extending the storage time of wild Cordyceps sinensis adversely affect the nutritive and medicinal value of the product.Thus,this study was designed to investigate the effects of heat treatment,a relatively safe storage extension method,on the biological activity of wild C.sinensis.Methods:Samples were heated to 60,80,or 100℃ for 15,30,or 60 minutes.SOD activity in wild C.sinensis before and after heating was assayed using a standard colorimetric assay.Deoxyribonuclease (DNase) activity was measured using the plasmid-nicking assay.Cordycepin content was analyzed using HPLC.Polysaccharide content was measured using the phenol sulfuric method.The Student's t-test was used for comparison.Results:After heating at 60,80,100℃ for 15,30,60 minutes,respectively,no significant reduction in DNase activity or polysaccharide dissolution was noted (P >.05).Interestingly,heating at 80℃ for 30 minutes led to a significant increase in the SOD activity of C.sinensis (P <.05).In addition,heating at 60℃ for 60 minutes or at 80℃ for 15 minutes significantly increased cordycepin dissolution (P <.05).Other heat treatments had no significant effects on SOD activity or cordycepin dissolution (P >.05).Conclusions:These results suggested that heat treatment does not adversely affect SOD or DNase activity,polysaccharide content,or cordycepin dissolution.Thus,heat treatment might be a safe processing method to extend the storage time of wild C.sinensis without compromising biological activity.

Study on Volatile Oil Components and Total Anti-oxidation Capacity and Simulated SOD Activity of Leaves from Michelia chapensis and M. fovelata

The volatile oils from leaves of Michelia chapensis Dandy and M. foveolata Merr.ex Dandy were isolated by organic solvent extraction and their components were analyzed and quantified by GC/MS. Then, the total anti-oxidation capacity and simulated SOD activity were tested. Forty-four compounds in M. chapensis were identified and the main constituents are aromatic (11.057%), ester (5.041%) and terpenoid compounds (19.772%). Fifty-two compounds in M. foveolata were identified, and their main constituents are aromatic (21.293%), alcohol (17.403%), alkene (6.909%), ester (5.657%) and alkane compounds (5.134%). The results showed that the two oils have strong anti-oxidation capacity and simulated SOD activity. The total anti-oxidation capacities were the highest when the volatile oil from M. foveolata was diluted by 50 times and that from M.chapensis by 100 times. The simulated SOD activity of volatile oil from M. chapensis was higher than that from M. foveolata, and CuZn-SODs in the two oils held 73%-74% of the total SOD. These results will provide scientific foundation for the exploration of the bioactivity of M. chapensis and M. foveolata.

Multiscale structural design of MnO_(2)@GO superoxide dismutase nanozyme for protection against antioxidant damage

Rational design of metallic active sites and its microenvironment is critical for constructing superoxide dismutase(SOD)nanozymes.Here,we reported a novel SOD nanozyme design,with employing graphene oxide(GO)as the framework,andδ-MnO_(2)as the active sites,to mimic the natural Mn-SOD.This MnO_(2)@GO nanozyme exhibited multiscale laminated structures with honeycomb-like morphology,providing highly specific surface area for·O_(2)−adsorption and confined spaces for subsequent catalytic reactions.Thus,the nanozyme achieved superlative SOD-like catalytic performance with inhibition rate of 95.5%,which is 222.6%and 1605.4%amplification over GO and MnO_(2)nanoparticles,respectively.Additionally,such unique hierarchical structural design endows MnO_(2)@GO with catalytic specificity,which was not present in the individual component(GO or MnO_(2)).This multiscale structural design provides new strategies for developing highly active and specific SOD nanozymes.

Physiological and transcriptional responses to heat stress in a typical phenotype of Pinellia ternata

Pinellia ternata is an important medicinal plant,and its growth and development are easily threatened by high temperature.In this study,comprehensive research on physiological,cytological and transcriptional responses to different levels of heat stress were conducted on a typical phenotype of P.ternata.First,P.ternata exhibited tolerance to the increased temperature,which was supported by normal growing leaves,as well as decreased and sustained photosynthetic parameters.Severe stress aggravated the damages,and P.ternata displayed an obvious leaf senescence phenotype,with significantly increased SOD and POD activities(46%and 213%).In addition,mesophyll cells were seriously damaged,chloroplast thylakoid was fuzzy,grana lamellae and stroma lamellae were obviously broken,and grana thylakoids were stacked,resulting in a dramatically declined photosynthetic rate(74.6%).Moreover,a total of 16808 genes were significantly differential expressed during this process,most of which were involved in photosynthesis,transmembrane transporter activity and plastid metabolism.The number of differentially expressed transcription factors in MYB and bHLH families was the largest,indicating that these genes might participate in heat stress response in P.ternata.These findings provide insight into the response to high temperature and facilitate the standardized cultivation of P.ternata.

Water-soluble copper-based simulated enzyme:Biomimetic synthesis and activities in vitro

Two copper(Ⅱ)complexes were obtained by solvothermal reaction induced by isonicotinic acid ligand through the study of natural simulated enzymes.The activity of superoxide dismutase(SOD)1 and 2 is higher than that of most Cu-SOD mimics,and they have the activity of catechol analogues.It is found that SOD activity and cat-echolase activity are directly affected by the coordination configuration of the central metal atom and the ability of the complex to accept electrons.It is also responsible for the excellent enzyme activity of these two Cu-based complexes.The results of MTT assay show that complexes 1 and 2 have no significant inhibitory effect on cell proliferation.It has good application potential in the clinical biomedical field in the future.

Polyoxometalate-based nanozyme： Design of a multifunctional enzyme for multi-faceted treatment of Alzheimer＇s disease

Proteolytic degradation of amyloid-β （Aβ） aggregates and clearance of Aβ- induced reactive oxygen species （ROS） have received significant attention for the treatment of Alzheimer＇s disease （AD）. However, it is difficult, and often unfeasible, to directly upregulate or transport intraceUular native enzymes. More importantly, penetration of the blood-brain barrier （BBB） has presented a major impediment. Herein, we report on the rational design of a polyoxometalate- based nanozyme with both protease-like activity for depleting A~ aggregates, and superoxide dismutase （SOD）-like activity for scavenging A[3-mediated ROS. Furthermore, this nanozyme acts as a metal chelator to remove Cu from Cu-induced Aβ oligomers. More intriguingly, the nanozyme can cross the BBB and exhibits low toxicity. This work provides new insights into the design and synthesis of inorganic nanozymes as multifunctional therapeutic agents in the treatment of AD.

Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings

The root growth,changes in superoxide dismutase(SOD,EC 1.15.1.1)activity,malonyldialdehyde(MDA)and total soluble protein level of broadbean(Vicia faba)seedlings were researched at different soil concentrations of chlorobenzene(CB),1,2,4-trichlorobenzene(TCB)and hexachlorobenzene(HCB).The results showed that root growth of seedlings was interrupted after 5d of 50-200μg·g^(-1)TCB treatment.During a 3 d of recovery period,root growth was,however,restored to some extent although there was a delay in returning to the control level.The total soluble protein content in seedlings increased with TCB concentration and duration of exposure.Effect of TCB stress on SOD activity in seedlings displayed a significant dose-effect relationship for 1-5 d of 50-200μg·g^(-1)treatment.When broadbean seedlings were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water for 3 d,SOD activity at 50μg·g^(-1)TCB recovered towards control level(P>0.05)while a significant increase in SOD activity was observed at 100 and 200μg·g^(-1)TCB compared to control(P<0.05).The experiments also revealed that a significant increase of MDA level in seedlings occurred after 3 and 5 d of 100 and 200μg·g^(-1)TCB treatment(P<0.05 and P<0.01),and there was a positive correlation between TCB concentration and MDA level.All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil.Compared to TCB,the toxicity of 50-1000μg·g^(-1)CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

Superoxide-like Cu/GO single-atom catalysts nanozyme with high specificity and activity for removing superoxide free radicals

Although nanozyme has become an emerging area of research attracting extensive attention recently,the activity and specificity of currently reported nanozymes are generally lower than those of natural enzymes.Developing highly active and specific nanozymes is therefore extremely necessary and also remains a great challenge.Superoxide dismutase(SOD)catalyzes the disproportionation of cytotoxic O_(2)·^(−)into hydrogen peroxide and oxygen,and plays an important role in reducing human oxidative stress.In this work,we prepare Cu single-atom catalysts(Cu/GO SACs,GO=graphene oxide)through a simple and low-cost strategy at room temperature using Cu foam and graphene oxide.Cu/GO SACs can maintain excellent catalytic activity under harsh environment.Compared with the natural enzyme,SOD-like Cu/GO SAC nanozyme has higher catalytic activity and meanwhile,it does not possess the common properties of other mimic enzymes often existing in nanomaterials.Based on the excellent SOD-like enzyme activity of Cu/GO SACs,it successfully eliminates the active oxygen in cigarette smoke.This work not only provides a new idea for the design and synthesis of nanozymes with excellent SOD mimetic properties,but also is promising in the treatment of lung injury and inflammatory diseases related to free radical production.

Shape design of cerium oxide nanoparticles for enhancement of enzyme mimetic activity in therapeutic applications

Cerium oxide nanoparticles （CONPs）, widely used in catalytic applications owing to their robust redox reaction, are now being considered in therapeutic applications based on their enzyme mimetic properties such as catalase and super oxide dismutase （SOD） mimetic activities. In therapeutic applications, the emerging demand for CONPs with low cytotoxicity, high cost efficiency, and high enzyme mimetic capability necessitates the exploration of alternative synthesis and effective material design. This study presents a room temperature aqueous synthesis for low-cost production of shape-selective CONPs without potentially harmful organic substances, and additionally, investigates cell viability and catalase and SOD mimetic activities. This synthesis, at room temperature, produced CONPs with particular planes： {111}/{100} nanopolyhedra, {100} nano/submicron cubes, and {111}/{100} nanorods that grew in [110] longitudinal direction. Enzymatic activity assays indicated that nanopolyhedra with a high concentration of Ce4＋ ions promoted catalase mimetic activity, while nanocubes and nanorods with high Ce3＋ ion concentrations enhanced SOD mimetic activity. This is the first study indicating that shape and facet configuration design of CONPs, coupled with the retention of dominant, specific Ce valence states, potentiates enzyme mimetic activities. These findings may be utilized for CONP design aimed at enhancing enzyme mimetic activities in therapeutic applications.