Species and Organ Diversity in the Effects of Hydrogen Peroxide on Superoxide Dismutase Activity In Vitro

Superoxlde dlsmutase （SOD） is ubiquitous in aerobic organisms and constitutes the first link In the enzyme scavenging system of reactive oxygen species. In the present study, species and organ diversity of SOD activity In a solution and In an in-gel assay system, as well as the effects of hydrogen peroxide （H202） on SOD activity, were Investigated. In a solution assay system, SOD activity of jackfruIt root, shoot, leaves, axes, and cotyledons, of maize embryos and endosperms, of mung bean leaves and seeds, of sacred lotus axes and cotyledons, and of rice and wheat leaves was Increased by 1-15 mmol/L H2O2. However, SOD activity In rice root and seeds, maize roots and leaves, mung bean roots and shoots, and wheat seeds was decreased by 1-15 mmol/L H2O2. The SOD activity of wheat root and soybean roots, leaves, axes, and cotyledons was Increased by 1-4 mmol/L H2O2, but was decreased by concentrations of H2O2 〉4 mmol/L. The SOD activity of soybean shoots was not affected by 1-15 mmol/L H2O2. The SOD activity In crude mltochondrla of jackfruIt, maize, and upas seeds, as well as In purified mitochondria of jackfruIt, was also Increased by 1-15 mmol/L H2O2. In the In-gel assay system, the SOD In jackfruIt cotyledons was comprised of Mn-SOD, Cu/Zn-SOD, and Fe-SOD, the crude mltochondria of jackfruit seeds and maizes embryo was comprised of Mn-SOD and Cu/ Zn-SOD, and the crude mltochondria of maize seeds was comprised of Mn-SOD only. In the present study, H2O2 markedly Inhibited Cu/Zn-SOD and Fe-SOD activity.

EFFECTS OF CYPROHEPTADINE ON PLASMA SUPEROXIDE DISMUTASE ACTIVITY AND MALONDIALDEHYDE CONTENT IN RABBITS WITH HEMORRHAGIC SHOCK

Profound hemorrhagic shock was produced in thirty rabbits by exsanguination via the carotid artery until blood pressure (BP) reached 5.3 kPa (40 mmHg) and was sustained for a period of 90 minutes. The rabbits were equally divided into cyproheptadine (Cyp) treated group and control group. Blood samples 30 minutes after liquid and blood infusion and administration of Cyp (10 mg / kg) were collected from the carotid artery, and the plasma superoxide dismutase (SOD) activity and malondialdehyde (MDA) content measured. The results showed that Cyp remarkebly enhanced the plasma SOD activity (2462 338 vs 1955- 596, P<0.01) and reduced MDA content (2.68- 0.24 vs 3.20-0.49, P<0.01). We believe that the in crease of O2 production plays an important role in the develop-ment of shock, the single blood and liquid infusion can not significantly improve the shock conditions. Scavenging oxygen free radicals and alleviating cellular damage and multiple or gan failure are the possible mechanisms of cyproheptadine anti-shock effect.

Effect of N+ Beam Exposure on Superoxide Dismutase and Catalase Activities and Induction of Mn-SOD in Deinococcus Radiodurans

Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.

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.

Clinical Study on Zhuyu Tongfu (逐瘀通腑) Serial Recipe Combined with Acupuncture and Massotherapy in Treating Hypertensive Cerebral Hemorrhage

Objective. To observe the clinical efficacy and mechanism of Zhuyu Tongfu （逐瘀通腑, ZYTF） Serial Recipe combined with acupuncture and massotherapy in treating hypertensive cerebral hemorrhage （HCH）. Methods： One hundred and eighteen patients with hypertensive cerebral hemorrhage, on the basis of conventional Western medicine treatment, were randomly divided into ZYTF combined with acupuncture and massotherapy group （treated group） and simple Western medicine group （control group） ; the clinical efficacy, neurofunction deficit scoring （NDS） alterations and hematoma absorption rate of both groups were observed, and also the plasma superoxide dismutase （SOD） activity, plasma lipid peroxidase （LPO） content, erythrocyte glutathion peroxidase （GSH-Px） activity, hematocrit （Ht） and the whole blood viscosity （Va） change were also observed. Results： In the treated group, the clinical efficacy, NDS improvement and hematoma absorption rate were superior to that of the control group; comparison between the two groups after treatment showed that plasma SOD activity and GSH-Px activity got more elevated and plasma LPO content, Ht and Va more lowered in the the treated group than those in the control group. Cenclusien： ZYTF combined with acupuncture and massotherapy has better effect, its therapeutic mechanism was possibly correlated to the elevation of plasma SOD activity, GSH-Px activity and lowering of plasma LPO content, Ht and Va.

Relationship Between Changes in Leaf Endogenous Hormone Contents and Senescence During Grain Filling Stage of a Rice Hybrid and its Parents

A major problem in hybrid rice production is the occurrence of leaf senescence during the grain filling stage that can result in reduction of yield. Changes in contents of several endogenous hormones are related to leaf senescence. The relationship between endogenous hormones and leaf senescence in the rice hybrid Tiyou 418 and its parents Tijin and C418, was undertaken for investigation. Indicators of leaf senescence, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) accumulation and chlorophyll content, as well as the contents of abscisic acid (ABA), zeatin riboside (ZR), gibberellin (GA1/3) and auxin (IAA) in the leaves were determined. Different rates of leaf senescence were observed in the three materials. Senescence occurred earliest and fastest in Tijin, followed by Tiyou 418 and then C418. A similar trend was recorded in ABA, ZR, and IAA contents during the grain filling stage in the three materials. Changes in (GA1/3+ZR+IAA)/ABA ratios were also similar, being quite stable during the early stage of leaf senescence, and decreasing markedly during the late stage. The ratio declined more dramatically in Tijin, in accordance with its faster leaf senescence. The results suggest that the ratio of (GA1/3+ZR+IAA)/ABA regulates chlorophyll content, SOD activity, MDA content and membrane lipid peroxidation. It is postulated that endogenous hormones may play a role in the regulation of leaf senescence in a systematic way.

Study of Free-Radical Processes during Rotenone Modeling of Parkinson Disease

The study has shown free radical processes during modeling of Parkinson Disease (PD) with rotenone. We isolated striatum, brainstem, neocortex, cerebellum, spinal cord, thymus, heart, and liver of rats after rotenone injection in the right striatum. The samples were taken on the 5th, 10th and 15th days after the injection. According to chemiluminescence data, the injection of rotenone initiates the disturbance of intensity of free radical processes in striatum at 5th day in a bilateral mode. After this until the 10th day these changes had restoring character, but after 15 days according to chemiluminescence and thio-barbituric acid test disturbance of lipid peroxide oxidation processes occurred. While superoxide dismutase activity has been changed significantly in all studied tissues, especially in the striatum and neocortex. It should be noted that during rotenone model there are no observed clinical symptoms in rats during 1 to 20 days, and the symptoms of the disease are observed approximately 28 days after the injection. This research could help diagnose PD in the early stage of its onset.

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.

A study on some macrocyclic bicopper(Ⅱ) complexes as the model compounds of superoxide dismutase

24-Membered macrocyclic bicopper(Ⅱ) complexes wth bridging ligand imidzao-late,SCN-,N3-and H2O respectively were synthesized by condensation of diacetylpyridine with 3-oxapentane-1,5-diamine.As the model compounds of superoxide dismutase (SOD),the relationship between their SOD activities and properties of bridging ligands and redox potentials of copper(Ⅱ) were studied.

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.