Cell Membrane Lipid Peroxidation Research Articles

Effect of Superoxide Dismutase (SOD) Supplementation on Plasma Levels of Malondialdehyde (MDA), Total Cholesterol and LDL Cholesterol in the Elderly

Background: Several various physiological functions in elderly people are diminished due to cell or tissue damage. One of the probable causes are oxidative stress yielded by free radicals.Oxidative stress (ROS) induce lipid peroxidation in endothelial cell membrane, which generates atherosclerotic plaque. In a state of oxidative stress, MDA level will increased. The purpose of this study is to determine the effect of SOD supplementation on MDA, total cholesterol and LDL cholesterol plasma levels in the elderly.Methods: This study was open label, a randomized control trial. Subjects were elderly people aged > 60 years (median 75, 60-82 ys, male 10 (24,4%)) institutionalized at Social Rehabilitation Unit Pucang Gading Semarang, Indonesia. The treatment group consisted of 16 people, received SOD (GlisodinR) 1 capsule (250 IU) 1 hour before meals, plus exercise scheduled for 8 weeks. The control group consisted of 15 people, received placebo, and exercise. Plasma MDA levels were examined using TBARS method, while total cholesterol and LDL cholesterol were examined using CHOD-PAP method.Results: This study show a reduction of plasma MDA levels in the treatment group compare to control group ( p = 0.062 ). A significant reduction of total cholesterol and LDL cholesterol levels in the treatment group were found (before 190.00 and 131.47 g/dl, after 182.27 and 121.93 g/dl, p = 0.005 and 0.001).Conclusion: The SOD supplementation significantly reduce Total Cholesterol and LDL level, but not MDA level in the elderly.

THE RESULTS OF THE USE OF SELENIUM IN THE COMPLEX TREATMENT OF PATIENTS WITH CHRONIC GENERALIZED PERIODONTITIS

Treatment of chronic generalized periodontitis remains a rather complicated medical problem. The attention of scientists has been recently given to the microelement of selenium, which is a component of selenium-dependent glutathione peroxidase. An important advantage of using of this element is that the regulation of cell membrane lipid peroxidation can be realized by selenium without the involvement of glutathione peroxidase mechanism of peroxide utilization. Selenium-containing drugs have a positive effect on the clinical course of the disease, the process of blood supply to periodontal tissues and the state of antioxidant protection.
 Therefore, it is relevant to study the effect of selenium in the complex treatment of periodontal diseases.
 The goal of the study is to increase the effectiveness of treatment of patients with chronic generalized periodontitis by selenium preparations.
 Research materials and methods. 90 patients with chronic generalized periodontitis between the ages from 27 to 43 years old were examined to solve these problems. Among the examined patients were 47 (52.2%) patients with chronic generalized periodontitis of I grade and there were 43 (47.8%) patients with chronic generalized periodontitis of II grade. The patients were divided into three groups of 30 people.
 All patients were examined according to the standard scheme including complaints, life anamnesis information, objective data, and special indices: oral hygiene was performed by the Silness-Loe indices, Stellard, gingivitis severity by the PMA index, blood index clear for H.R. Muhlemann, A.S. Mazor (1958), periodontal index (Russell, 1956), index of need for treatment of periodontal diseases was CPITN.
 Results and Discussion. The patients of the first group with chronic generalized periodontitis were treated according to the traditional scheme. Patients of the second group with chronic generalized periodontitis were treated according to a similar algorithm with an additional usage of an oily solution of retinol acetate, topically applied α-tocopherol acetate, ascorbic acid by ultrafonophoresis. Additional mineral complex "Selenium active" was used for the treatment of patients of the third group.
 In the first group had a decrease in the Silness-Loe index to 0.74 ± 0.06 (by 63.9%; p <0.001), in the second group had index to 0.61 ± 0.07 (by 69.8%; p <0.001), the most significant changes occurred in patients in the third group, index was to 0.21 ± 0.01 (89.6%; p <0.001).The Stellard index also dropped significantly (p <0.001) in the first group from 2.14 ± 0.09 to 0.79 ± 0.07, in the second group it was from 2.11 ± 0.09 to 0.81 ± 0.04, the third group had index from 2.10 ± 0.09 to 0.60 ± 0.03.
 Scale index decreased in patients of the first group to 0.26 ± 0.01 (p <0.001), the second group had 0.24 ± 0.01 (p <0.001), the third group had 0.21 ± 0.01 (p <0.001)).
 H.R. Muhleman bleeding index was 1.01 ± 0.06 in the first group, 0.61 ± 1.58 was in the second group and 0.21 ± 0.02 was in the third group after treatment.
 The periodontal index showed an improvement in the clinical picture among patients of the first group - 0.99 ± 2.28, the second group had 0.67 ± 0.04, and the most significant changes occurred among patients of the third group - 0.24 ± 0.02.
 The index of need for treatment of periodontal diseases was CPITN in the first group; it decreased from 2.45 ± 0.10 to 1.01 ± 0.02, in the second group index was from 2.41 ± 0.10 to 0.75 ± 0.04, in the third group index was from 2.38 ± 0.10 to 0.45 ± 0.04.
 The PMA index after treatment in third group of patients decreased from 61.43 ± 1.98 to 18.35 ± 0.49.
 Although periodontal tissue improvement occurred in all patients, changes in the third group were more significant, indicating that the proposed regimen was effective.
 Conclusions. The inclusion of selenium in the scheme of complex treatment of chronic generalized periodontitis significantly increases the effectiveness of it, which is determined by the improvement of the clinical course of the disease.

Not merely noxious? Time-dependent hormesis and differential toxic effects systematically induced by rare earth elements in Escherichia coli.

Progressive rare earth element (REE) enrichment in aquatic environments worldwide and their resulting anthropogenic anomalies have highlighted the need for a better understanding of their biological effects, with a special emphasis on microbial cells since they play a crucial role in good ecosystem functioning. Therefore, the primary aim of this work was to achieve simultaneous characterization of the 16 REE toxicity effects on the growth kinetics of the commonly found Gram-negative bacterium E. coli (BW25113 strain). Bacterial growth curve modelling showed hormetic effects in the presence of REEs, while EC50 determination (in the mid-log phase) indicated that the four HREEs from Er to Lu in addition to Y were the most toxic metals (EC50 in the range of 8.3 to 3μM), just after Sc (EC50 of 1.1μM). Additional subcellular parameter assessment revealed cell membrane lipid peroxidation as well as enhanced membrane depolarization and permeability in the presence of La, Gd, or Yb as representatives of LREEs and HREEs. These subcellular effects appeared to be more intense with Gd and Yb compared with La-exposed cells, in relation to the overall higher toxicity potential reported for HREEs on bacterial growth. Also, the cellular ATP production decreased after REE exposure at their EC50.Finally, these results emphasize the importance of growth kinetic consideration as well as the complexity of REE biological effect mechanisms towards bacteria.

Synergistic inhibition effect of citral and eugenol against Aspergillus niger and their application in bread preservation

Consumers’ preferences for cleaner label products require the food industry to replace synthetic preservatives with natural substitutes. Therefore, the synergistic inhibitory effect of eugenol and citral (SEC) on Aspergillus niger was explored. On this basis, the antimicrobial sachet containing SEC was developed and its application potential in bread preservation was evaluated. The content of reactive oxygen species (ROS) and malondialdehyde (MDA) showed that SEC could significantly induce lipid peroxidation in cell membranes, in which citral played a leading role. The permeation experiments of SEM, TEM, propyl iodide and fluorescein diacetate showed that SEC could destroy the integrity of the cell membrane. Eugenol contributed more than citral. The OD260 and the relative conductivity of the SEC group increased by 5.2 and 4.1 times, respectively, after 8 h. Finally, the shelf life experiment of bread showed that the antimicrobial sachets containing SEC could significantly prolong the shelf life of bread without producing unpleasant odour.

Impact of copper in Xenopus laevis liver: Histological damages and atp7b downregulation.

Copper is an essential micronutrient but its excess in the dietary can be toxic. Both copper deficiency and abundance can occur in natural conditions and can lead to pathological dysfunctions. Many of the toxic effects of copper, such as increased lipid peroxidation in cell membranes and DNA damage, are due to its role in the generation of oxygen free radicals. Copper is released into the environment by both natural sources and human activities and it can damage organisms and ecosystems. In the present work the effects of copper has been studied on Xenopus laevis, an interesting model organism, after three weeks of exposure at 1 mg/L of CuCl, concentration allowed in the water for human use. The effects of this metal were analysed on the liver at light microscope by Hematoxylin-Eosin, Mallory, Pas and Perls stainings to evaluate the general histology, the glycogen metabolism and presence of hemosiderin. Moreover the number and area of melanomoacrophages, known as inflammation parameters, were assessment. Finally, we investigated the expression of atp7b gene and localization of respective ATP7B protein, the membrane protein involved in Cu detoxication. The achieved results showed that copper, even at a low concentration, causes serious histological alterations of liver. It induces an increase in the size and number of melanomacrophages and higher amount of hemosiderin in the treated than controls. Moreover, it alters the gene expression and localization of ATP7B protein. The data are indicative that an exposition at low and chronic concentration of copper in Xenopus laevis damages seriously the liver. For this reason it's important to consider this metal one of the pollutants involved in the decline of the amphibians and for its possible effects in other vertebrates including humans.

Alleviating effect of silicon on melon seed germination under autotoxicity stress

Melon (Cucumis melo L.) is an important horticultural crop worldwide. Continuous cropping obstacle occurs in many melon cultivation area, resulting in poor plant growth and fruit quality, autotoxicity is the main reason for the obstacle. Silicon (Si) plays an important role in improving the resistance of plants to biotic and abiotic stresses. In this study, melon plant water extracts (MPWE) were used to simulate the autotoxicity stress. Different concentrations of Na2SiO3 (0, 1, 2, 4, 8, 16, 32 mM) were added into MPWE for preliminary concentration screening and alleviating effect determination of Si on melon seed autotoxicity. The results showed that autotoxicity reduced the seed germination index, inhibited the growth of germinated seeds. 2 mM Si significantly increased seed germination index and improved subsequent growth under autotoxicity. The effect of Si showed a concentration-dependent manner, which can be counteracted or even reversed at high concentration. Three treatment combinations, double distilled water, 0.02 g/mL MPWE and 2 mM Na2SiO3 + 0.02 g/mL MPWE were used for subsequent physiology, biochemistry and gene analysis. During the germination of melon seed under autotoxicity, starch degradation ability decreased, amylase activity and amylase gene expression were inhibited, cell membrane lipid peroxidation increased, and antioxidant enzyme activity was abnormal. In Si-addition group, the radicle growth, lateral roots number, starch degradation ability, amylase activity and amylase gene expression level increased. The addition of Si also maintained the activities of superoxide dismutase, catalase and peroxidase and the content of malondialdehyde in a relatively normal state. The change trend of amylase gene and antioxidant enzyme activity was complex, but the acute change coincided with the key stage of seed germination, which occurred when the seed was about to break through or just broken through the seed coat. Appropriate concentration of Si is an effective strategy to alleviate the autotoxicity on melon seed.

Protective Effect of Cassava Leaf Extract on Gentamicin-Induced Hepatotoxity In Mice

Abstract
 Gentamicin usage can cause the damage of liver structure and function. The basic mechanism inducing liver damage from gentamicin is lipid peroxidation in cell membrane and the suppresion of antioxidant defence system in liver. Antioxidant in cassava leaf such as vitamin C, carotene, flavonoid, dan mineral can protect liver from drug toxicity effect. This research aimed to determine hepatoprotective effect of cassava leaf through microscopic observation of liver histopathology slide of mice induced by gentamicin. The research design was post test only control group design. Mice were divided into five groups, normal group, positive control (gentamicin 80 mg/kg b.w.); P1, P2, and P3 (gentamicin 80 mg/kg b.w. and cassava leaf extract 150 mg/kg b.w., 300 mg/kg b.w., 450 mg/kg b.w. respectively, for 14 days). The average score of liver cell damage was determined by microscopic observation of 200 liver cells undergoing parenchymal degeneration, hidrophic degeneration, and necrosis. One Way Anova analysis showed significant difference among the groups (p<0,05) and Post Hoc Tukey HSD test showed that cassava leaf extract at the dose level of 450 mg/kg b.w. resulted significant liver cell characteristic improvement in liver histophatology slide (p<0,05) compared to positive control group. It could be concluded that cassava leaf extract had protective effect on gentamicin-induced hepatotoxicity in mice. 
 Keywords: cassava leaf extract, hepatotoxicity, gentamicin, liver histopathology

Potential of PM-selected components to induce oxidative stress and root system alteration in a plant model organism

Over the last years, various acellular assays have been used for the evaluation of the oxidative potential (OP) of particular matter (PM) to predict PM capacity to generate reactive oxygen (ROS) and nitrogen (RNS) species in biological systems. However, relationships among OP and PM toxicological effects on living organisms are still largely unknown. This study aims to assess the effects of atmospheric PM-selected components (brake dust - BD, pellet ash - PA, road dust - RD, certified urban dust NIST1648a - NIST, soil dust - S, coke dust - C and Saharan dust - SD) on the model plant A. thaliana development, with emphasis on their capacity to induce oxidative stress and root morphology alteration. Before growing A. thaliana in the presence of the PM-selected components, each atmospheric dust has been chemically characterized and tested for the OP through dithiothreitol (DTT), ascorbic acid (AA) and 2′,7′-dichlorofluorescin (DCFH) assays. After the exposure, element bioaccumulation in the A. thaliana seedlings, i.e., in roots and shoots, was determined and both morphological and oxidative stress analyses were performed in roots. The results indicated that, except for SD and S, all the tested dusts affected A. thaliana root system morphology, with the strongest effects in the presence of the highest OPs dusts (BD, PA and NIST). Principal component analysis (PCA) revealed correlations among OPs of the dusts, element bioaccumulation and root morphology alteration, identifying the most responsible dust-associated elements affecting the plant. Lastly, histochemical analyses of NO and O2− content and distribution confirmed that BD, PA and NIST induce oxidative stress in A. thaliana, reflecting the high OPs of these dusts and ultimately leading to cell membrane lipid peroxidation.

Foliar application of gamma radiation processed chitosan triggered distinctive biological responses in sugarcane under water deficit stress conditions

Chitosan, being one of the most promising biological macromolecules, has an immense scope in agriculture to boost crop growth and defense responses. In this study, chitosan was exposed to gamma rays in order to obtain a low molecular weight derivative. Viscometric characterization showed a sharp decrease in molecular weight and FTIR based analysis confirmed retention of structural integrity of the polymer upon gamma irradiation. Assessments of various physiological and biochemical attributes were carried out on sugarcane plantlets that were subjected to progressive water deficit stress. The irradiated chitosan was found to differentially ameliorate water deficit stress tolerance against that of normal chitosan through positive modulation of various gas exchange parameters alongside significant improvement in relative tissue water content, SOD activity, soluble sugars and adenine energetics. Furthermore, application of irradiated chitosan significantly reduced cell membrane damage, lipid peroxidation, H2O2 and free-proline accumulations. This is the first report on the use of gamma irradiated chitosan to alleviate water deficit stress tolerance in sugarcane. Overall comparative assessments showed that differential plant responses were triggered upon foliar application of normal and gamma irradiated chitosan in sugarcane plants grown under water deficit stress conditions.

Lipid peroxidation increases hydrogen peroxide permeability leading to cell death in cancer cell lines that lack mtDNA.

4‐Hydroxynonenal (HNE) is an important product of plasma membrane lipid peroxidation, which is a cause of cell and tissue injury. Mitochondrial DNA (mtDNA)‐depleted ρ0 cells were established using human cervical cancer and oral squamous cell carcinoma cell lines. We investigated the effect of reactive oxygen species in ρ0 cells, especially the mechanism of hydrogen peroxide (H2O2)‐mediated cell death. These cell were subjected to high oxidative stress and, compared with their parental cells, showed greater sensitivity to H2O2 and high lipid peroxidation. Upregulation of HNE in the plasma membrane was observed prior to the increase in intracellular H2O2. The amount of oxidized lipid present changed H2O2 permeability and administration of oxidized lipid led to further cell death after treatment with H2O2. Expression levels of lipoxygenase ALOX genes (ie ALOX5, ALOX12, and ALOX15) were upregulated in ρ0 cells, as were expression levels of ALOX12 and ALOX15 proteins. ALOX5 protein was mainly distributed in the nucleus, while ALOX12 and ALOX15 proteins were distributed in the nucleus and the cytoplasm. Although expression of COX2 gene was upregulated, its protein expression did not increase. ALOX (especially ALOX15) may be involved in the sensitivity of cancer cells to treatment. These data offer promise for the development of novel anticancer agents by altering the oxidation state of the plasma membrane. Our results showed that lipid peroxidation status is important for H2O2 sensitivity and that ALOX15 is involved in lipid peroxidation status.

Nitric Oxide Increases the Physiological and Biochemical Stability of Soybean Plants under High Temperature

Thermal stress reduces plant growth and development, resulting in considerable economic losses in crops such as soybeans. Nitric oxide (NO) in plants is associated with tolerance to various abiotic stresses. Nevertheless, there are few studies of the range of observed effects of NO in modulating physiological and metabolic functions in soybean plants under high temperature. In the present study, we investigated the effects of sodium nitroprusside (SNP, NO donor), on anatomical, physiological, biochemical, and metabolic processes of soybean plants exposed to high temperature. Soybean plants were grown in soil: sand (2:1) substrate in acclimatized growth chambers. At developmental V3 stage, plants were exposed to two temperatures (25 °C and 40 °C) and SNP (0 and 100 μM), in a randomized block experimental design, with five replicates. After six days, we quantified NO concentration, leaf anatomy, gas exchange, chlorophyll a fluorescence, photosynthetic pigments, lipid peroxidation, antioxidant enzyme activity, and metabolite profiles. Higher NO concentration in soybean plants exposed to high temperature and SNP showed increased effective quantum yields of photosystem II (PSII) and photochemical dissipation, thereby maintaining the photosynthetic rate. Under high temperature, NO also promoted greater activity of ascorbate peroxidase and peroxidase activity, avoiding lipid peroxidation of cell membranes, in addition to regulating amino acid and organic compound levels. These results suggest that NO prevented damage caused by high temperature in soybean plants, illustrating the potential to mitigate thermal stress in cultivated plants.

THE IMPACT OF OXIDATIVE STRESS UPON MEMBRANE AND CYTOPLASMIC LIPIDS PEROXIDATION IN ERYTHROCYTES FROM HYPERTENSIVE PATIENTS WITH STROKE

Objective: The aim of our study was to evaluate the effects of oxidative stress generated by stroke upon erythrocytes‘ membrane and plasma and upon antioxidant enzymes in hypertensive patients associated with stroke. Design and method: This study has been done on 80 patients:40 male and 40 female aged between 35–87 years old with arterial hypertension (AHT) associated with stroke from Emergency Universitary Hospital, Cardiology Clinic. Blood was collected by vein puncture from hypertensive and normotensive patients and processed by centrifugation at 3000 g at 4C. Lipid peroxidation in plasma and red blood cell membrane as well as thiol groups and GGT, GST, catalase and superoxid dismutase antioxidant enzymes have been evaluated using standard biochemical techniques. Results: Our data have pointed out that there is less lipid peroxidation in female patients with stroke (p < 0.05) where membrane fluidity is decreased due to activation of plasma and erythrocyte superoxid dismutase and catalase. The diminished catalase activity can be accounted for as a mechanism of glutathion peroxidase regulation. In male with stroke the low Catalase activity has been associated with an increased level of lipid peroxidation (p < 0.05) both in membrane and plasma, while concentration of cytoplasm thiols was low(p < 0.01)Concentration of free thiols in membrane is significantly increased(p < 0.01)in stroke patients despite the age or gender. Conclusions: Following stroke, there is a modification of antioxidant and detoxification potential of erythrocytes by decreasing their capacity to uptake GSH from plasma but also elimination of GSH conjugates.

The Pseudomonas aeruginosa biofilm matrix and cells are drastically impacted by gas discharge plasma treatment: A comprehensive model explaining plasma-mediated biofilm eradication.

Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P. aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P. aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.

The Rice Bran as Therapy Agent to Decrease the SGOT/SGPT activities and Improve the Histopathology of Liver in White Rat (Rattus norvegicus) Induced by High Cholesterol Diet

Hypercholesterolemia is a metabolic disorder on increase of total cholesterol levels in blood exceeding normal values. The high cholesterol levels in the blood will be balance by converting to bile acids. The synthesis of bile acids will produce the excessive free radicals leading to oxidative stress. The oxidative stress cause lipid peroxidation of hepatic cell membranes that will increase SGOT and SGPT activities in the blood and changes in the histology of the liver. The content of crude fiber and antioxidants in rice bran are able to overcome the hypercholesterolemia. This study aimed to determine the effect of rice bran as a therapy in white rats (Rattusnorvegicus) high-cholesterol diet model on SGOT and SGPT activities and histopathologic images of liver. Rats were divided into 5 groups, namely: negative control group, positive control group, rice bran therapy group with dose 16%/rat/day, 38%/rat/day and 57%/rat/day. Rice bran therapy performed for 21 days. SGOT and SGPT activities were determined by spectrophotometry and hepatic histopathologic images were observed with HE (Hematoxylin-Eosin) staining. The levels of SGOT and SGPT were analyzed by one-wayANOVA with α = 5% and histopathology of liver was analyzed descriptively. The results showed that rice bran with dose of 57%/rat/day significantly (p <0.05) can decrease SGOT and SGPT activities. Histopathologic observations showed that antioxidants in rice bran could reduce fatty acids on hepatic histopathology. The dosage of 57%/rat/day showed to decrease SGOT, SGPT activities and can reduce fatty acids on hepatic. It can be concluded that the administration of rice bran can reduce the activities of SGOT, SGPT and improve the histopathology of liver rat induced by high cholesterol diet.

Pyridoxine Decreases Oxidative Stress on Human Erythrocyte Membrane Protein in vitro

Background: Pyridoxine has reduction and prevention against the levels of reactive oxygen species in in vitro studies. However, the biochemical mechanism that explains this behavior has not yet been fully clarified. Objective: To evaluate the effect of pyridoxine against oxidative damage on the membrane of human erythrocytes. Methods: Cumene hydroperoxide was used to induce oxidative stress in protein and lipid. Human erythrocytes were incubated with pyridoxine and cumene hydroperoxide, either alone or together for 8 h. Oxidative damage was determined by measuring lipid peroxidation and membrane protein carbonylation. Results: The results indicate that the malondialdehyde concentration decreased with increasing concentration of pyridoxine. The membrane protein content also decreased with increasing concentration of vitamin B6, which was confirmed by the decreased signal intensity in the western blot when compared to control without pyridoxine. Results demonstrate that pyridoxine can significantly decrease lipid peroxidation and protein carbonylation in red cell membrane exposed to high concentrations of oxidant agent. Conclusion: Pyridoxine showed a protective effect against the oxidative stress in human erythrocytes in vitro, inhibiting the carbonylation and the oxidative damage of erythrocyte membrane proteins. To date, such an effect has not yet been reported in terms of protein oxidation.

The RAGE expression in glomerulus and the Malondialdehyde level in the kidney of Diabetes Mellitus rat model after exercise

Background: The main cause of complications in diabetes mellitus is a condition of oxidative stress due to increased reactive oxygen species (ROS). The increase in ROS can be triggered by the increase in advanced glycation end-products (AGE), which binds to its receptor (RAGE). The result of increased ROS will lead to lipid peroxidation in cell membranes and induce particular increase in malondialdehyde (MDA).&#x0D; Objectives: The objective of this study was to evaluate the benefits of physical exercise in preventing complications of the kidneys caused by hyperglycemia.&#x0D; Method: This study was a pure experimental research with post-test only group design. Subjects were 10 male Sprague Dawley rats induced with 35 mg/kgdose of streptozotocin (STZ). The subjects were divided into two groups, i.e. the STZ group and STZ group with physical exercise. Physical exercise was given in 9 weeks using a treadmill, in 5 times/week frequency, moderate intensity, 0 degree of tilt, gradually increased speed and duration.&#x0D; Result: Regular and measurable physical exercise can decrease the blood glucose level(0,048) and reduce the RAGE expression in glomerulus(0,003) but increase MDA level in kidney (0,767).&#x0D; Conclusion: Regular and measurable physical exercise can decrease the blood glucose level and reduce the RAGE expression in glomerulus.&#x0D; Bangladesh Journal of Medical Science Vol.18(3) 2019 p.484-490

Physiological responses of Broussonetia papyrifera to manganese stress, a candidate plant for phytoremediation

Effective phytoremediation of Mn contaminated soil requires the selection of a species with good manganese tolerance. Broussonetia papyrifera is an important economic plant and pioneer species, it could be well adapted to drought and saline-alkali environment. In order to understand the effect of Mn stress on B. papyrifera, the effects of different concentrations of Mn (0–50 mmol/L) stress on the growth, morphology, Mn tolerance and physiological indexes of the plant were explored. The results showed that the biomass, surface area, length, root volume, tips, forks, and crossings of B. papyrifera reached the maximum at the Mn concentration of 1 mmol/L. Mn content in the tissue and TF in plants increased with the increase of concentration, while the BCF increased first and then decreased, and the maximum BCF was 0.154 at 10 mmol/L. The accumulation of Mn lead to cell membrane lipid peroxidation, which increased toxic substances in plants, resulting in the increase of MDA and PRO, and affected the synthesis of chlorophyll. However, B. papyrifera could effectively alleviate oxidative stress by increasing the activities of antioxidant enzymes (SOD, POD, CAT), protein and soluble sugar. The results suggested that B. papyrifera had a good oxidative stress mechanism to Mn stress and could be used as candidates for remediation of pollution in mining areas.

Sodium pheophorbide a has photoactivated fungicidal activity against Pestalotiopsis neglecta

Sodium pheophorbide a (SPA) is a natural photosensitizer. To explore its antifungal activity and mechanism, we studied its inhibitory effects on spore germination and mycelial growth of Pestalotiopsis neglecta. We used sorbitol, 2-thiobarbituric acid (TBA) and electron microscopy to determine its effects on cell wall integrity, cell membrane lipid peroxidation and mycelial morphology. Finally, the effects of SPA on enzyme activity in mycelia were determined. The results showed that SPA effectively inhibited spore germination and mycelial growth of P. neglecta under light conditions (4000 lx, 24 h). Scanning electron microscopy (SEM) revealed that SPA treatment resulted in a roughened, twisted and knotted mycelial surface and abnormal mycelial growth. SPA influenced cell wall integrity, and the content of MDA, a cell membrane lipid peroxidation product was significantly increased (P < 0.05). SPA also significantly inhibited SOD, POD and PG activity, but enhanced PPO activity (P < 0.05). In conclusion, SPA may have potential to become a biological pesticide.

Solar-excited graphene quantum dots for bacterial inactivation via generation of reactive oxygen species

Nanoscale photocatalysts have attracted abundant research attention in the solar-activated disinfection. In this work, we find that solar irradiation significantly improves the antimicrobial activity of graphene quantum dots (GQDs), accompanied by severe oxidative stress and membrane damage. By using electron spin resonance (ESR) technique, we confirm that different reactive oxygen species (ROS), including singlet oxygen (1O2), hydroxyl radical (•OH), and superoxide anion (O2•−) were generated by GQDs upon irradiation with simulated sunlight. Additionally, these generated ROS will further facilitate lipid peroxidation of cell membrane and suppress bacterial antioxidant systems, enhancing the phototoxicity of GQDs. These findings will bring major advancements of GQDs in applications of solar-driven bacterial disinfection.

Heat-induced tolerance to browning of fresh-cut lily bulbs (Lilium lancifolium Thunb.) under cold storage.

Fresh-cut lily bulbs were submerged in hot water at 50°C for 3min as a condition of heat treatment (HT), and then stored at 4°C for 15days to investigate the effects of HT on browning. Results showed that heat-treated samples exhibited lower browning degree and had reduced cell death rate and cell membrane permeability when compared to control samples during storage. HT resulted in a significant inhibition in total phenol content and the activities of phenylalanine ammonialyase, polyphenol oxidase, and peroxidase. HT also stimulated the activities of superoxide dismutase and catalase, however, inhibited lipoxygenase activity and malondialdehyde accumulation. Correlation analysis showed that lipid peroxidation of cell membrane was significantly correlated with browning of fresh-cut lily bulbs. The results indicated that HT could serve as an effective approach to retard browning of fresh-cut lily bulbs. PRACTICAL APPLICATIONS: The effect of heat treatment (HT) on fresh-cut lily bulbs by treating in hot water (50°C) for 3min was investigated. It provided experimental basis for further studies of HT in extending the shelf life of fresh-cut lily bulbs. Furthermore, it is a foundation for the application of HT in the processing of fresh-cut lily bulbs. The results suggested that HT could be a promising method to inhibit browning and sustain the quality of fresh-cut lily bulbs.