Total Sulfhydryl Research Articles

Effects of Different Lipase Inactivation Treatments on Physicochemical Properties of Naked Oat Globulins

Lipase inactivation is an essential treatment for oat processing, because of the negative effects of lipase on nutrient preservation and storage extension. The effects of different lipase inactivation treatments including hot air roasting, infrared roasting, normal‐pressure steaming, and high‐pressure steaming on the physicochemical properties of oat globulins were investigated. Results showed that normal‐pressure steaming had little effect on solubility of oat globulins; hot air roasting increased foaming capacity of oat globulins but did not change their foaming stability; and all the inactivation treatments increased the surface hydrophobicity and content of total sulfhydryls of oat globulin but decreased exposed sulfhydryl groups. In addition, oat globulin granules from the hot air roasting treatment were distributed more evenly in oat globulin powder compared with the control group. All treatments except normal‐pressure steaming changed the molecular weight of oat globulin subunits, which made the bands of 66,000 and 45,000 disappear from SDS‐PAGE. These results indicated that normal‐pressure steaming was ideal to maintain good solubility of oat globulins, and hot air roasting was ideal to maintain relatively good foaming properties. The treatments changed physicochemical properties of oat globulins by influencing protein aggregation and subunit composition that resulted in different content of sulfhydryl groups and surface hydrophobicity.

Ultrastructural investigation of the protective effects of propolis on bleomycin induced pulmonary fibrosis

We investigated the antioxidant and anti-inflammatory effects of propolis on bleomycin induced lung fibrosis and compared these effects to prednisolone treatment. Forty rats were divided into four groups of ten: group 1 was treated with intratracheal infusion of 0.2 ml physiological saline followed by daily treatment with 0.5 ml physiological saline for 20 days. In the remaining groups (groups 2 − 4), 5 mg/kg bleomycin was given via the trachea. Rats in group 2 were given 0.5 ml physiological saline. Rats in group 3 were treated with 100 mg/kg propolis, and 10 mg/kg prednisolone was given to rats in group 4. The treatments for all groups were continued for 20 days. On postoperative day 21, blood and lung samples were taken for biochemistry, histopathology and electron microscopy evaluation. We compared oxidative stress parameters and found lower malondialdehyde and myeloperoxidase levels, and higher total sulfhydryl levels and catalase activities for the bleomycin + propolis group than for the bleomycin and bleomycin + prednisolone groups. The highest mean fibrosis score was detected in the bleomycin group. Although the mean fibrosis scores of the bleomycin + propolis and bleomycin + prednisolone groups were not significantly different, electron microscopy revealed that propolis diminished bleomycin induced lung fibrosis more effectively than prednisolone. The effects of propolis might be due to its potent antioxidant and anti-inflammatory properties.

Protein Oxidation Levels After Different Corneal Collagen Cross-Linking Methods.

To evaluate advanced oxidation protein products (AOPP) levels, superoxide dismutase (SOD) enzyme activity, and total sulfhydryl (TSH) levels in rabbit corneas after different corneal collagen cross-linking (CXL) methods. Eighteen eyes of 9 adult New Zealand rabbits were divided into 3 groups of 6 eyes. The standard CXL group was continuously exposed to UV-A at a power setting of 3 mW/cm for 30 minutes. The accelerated CXL (A-CXL) group was continuously exposed to UV-A at a power setting of 30 mW/cm for 3 minutes. The pulse light-accelerated CXL (PLA-CXL) group received UV-A at a power setting of 30 mW/cm for 6 minutes of pulsed exposure (1 second on, 1 second off). Corneas were obtained after 1 hour of UV-A exposure, and 360-degree keratotomy was performed. SOD enzyme activity, AOPP, and TSH levels were measured in the corneal tissues. Compared with the standard CXL and A-CXL groups (133.2 ± 8.5 and 140.2 ± 6.2 μmol/mg, respectively), AOPP levels were found to be significantly increased in the PLA-CXL group (230.7 ± 30.2 μmol/mg) (P = 0.005 and 0.009, respectively). SOD enzyme activities and TSH levels did not differ between the groups (P = 0.167 and 0.187, respectively). CXL creates covalent bonds between collagen fibers because of reactive oxygen species. This means that more oxygen concentration during the CXL method will produce more reactive oxygen species and, thereby, AOPP. This means that in which CXL method occurs in more oxygen concentration that will produce more reactive oxygen species and thereby AOPP. This study demonstrated that PLA-CXL results in more AOPP formation than did standard CXL and A-CXL.

Antioxidative responses of the tissues of two wild populations of Pelophylax kl. esculentus frogs to heavy metal pollution

Heavy metal pollution of the aquatic environment is of great concern worldwide. Heavy metals are capable of inducing oxidative stress by increasing the formation of reactive oxygen species (ROS), and directly affecting the antioxidant defense system (AOS) in living organisms. The frog Pelophylax kl. esculentus is a semiaquatic species with semipermeable skin and a complex lifecycle, and represents a potentially useful bioindicator organism. The aim of this study was to investigate the accumulation of several heavy metals (Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb and Zn), and their effects on selected parameters of the AOS, including the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), phase II biotransformation enzyme glutathione-S-transferase (GST), the total glutathione (GSH) contents and sulfhydryl (SH) group concentrations, as well as cholinesterases (ChEs) activities in the liver, skin and muscle of P. kl. esculentus. Frog samples were collected at two sites (the Danube–Tisza–Danube canal (DTDC) and the river Ponjavica) in Serbia, which are characterized by different levels of metal pollution. Differences between the metal contents in different tissues showed that the skin of frogs from the DTDC accumulated statistically higher concentrations of Cd, Cu, Pb and Zn, while only the Fe concentration was lower. No significant differences between metal concentrations in muscle tissues of frogs from the DTDC and Ponjavica were observed. Examination of the parameters of the AOS revealed that frogs from the DTDC had higher concentrations of GSH in the liver and of SH groups in the skin and muscle, whereas the activities of the antioxidative enzymes SOD, GHS-Px and GR in the liver and of GR in the skin were lower than in frogs from the Ponjavica. The relationship between metal concentrations and AOS parameters showed the highest number of correlations with GSH, GR and CAT, and with Ni, Zn, Hg, Cr and Cd. Based on the results in this study, we concluded that increased concentrations of heavy metals in frog tissues can alter the AOS, which leads to higher concentrations of GSH and SH groups and lower activities of antioxidative enzymes. The response of the AOS to metal pollutants allowed us to make a distinction between different frog tissues, and to conclude that the liver and skin are more suitable for assessing metal-induced oxidative stress in frogs than muscle.

Changes of microstructure characteristics and intermolecular interactions of preserved egg white gel during pickling

Changes in gel microstructure characteristics and in intermolecular interactions of preserved egg whites during pickling were investigated. Spin–spin relaxation times of preserved egg whites significantly decreased in the first 8days and remained unchanged after the 16th day. SEM images revealed a three-dimensional gel network, interwoven with a loose linear fibrous mesh structure. The protein gel mesh structure became more regular, smaller, and compacted with pickling time. Free sulfhydryl contents in the egg whites increased significantly, while total sulfhydryl contents dramatically decreased during pickling. The primary intermolecular forces in the preserved egg white gels were ionic and disulfide bonds. Secondary forces included hydrophobic interaction and relatively few hydrogen bonds. During the first 8days, the proportion of ionic bonds sharply decreased, and that of disulfide bonds increased over the first 24days.

Effects of ozone on the removal of geosmin and the physicochemical properties of fish meat from bighead carp ( Hypophthalmichthys nobilis )

Two manners of ozone treatment (washing with ozonized water and ozone-flotation) were selected to remove the geosmin in the fish muscle from bighead carp. A total of 42.09%–54.28% and 42.78%–69.19% geosmin in fish muscle could be eliminated by ozone water and ozone-flotation washing for 5–20 min, respectively. Treatment with ozone of an appropriate condition significantly increased the salt-extractable protein, Ca2 +-ATPase activity, total sulfhydryl and active sulfhydryl contents, carbonyl content of the myofibrillar protein, and gel strength without improving PV and TBA values too much. No apparent changes in the protein distribution and no new patterns appeared in SDS-PAGE after the ozone water treatment. The results indicate that ozone water treatment is a prospectively mild oxidation protocol than ozone flotation to enhance the physicochemical properties of fish protein from bighead carp as well as to eliminate muddy flavours. Ozonation has been used for years to disinfect water for drinking purposes in Europe. A number of other commercial uses have been found for ozone including disinfection of bottled water, swimming pools, prevention of fouling of cooling towers, and wastewater treatment. Ozone use may have many advantages in the food industry. There are suggested applications of ozone in the food industry such as food surface hygiene, sanitation of food plant equipment, reuse of waste water, and lowering of the biological oxygen demand (BOD) and chemical oxygen demand (COD) of food plant waste. Ozone is a strong oxidant that also has decolorizing and deodorizing effects, and thus offers many advantages in the food industry, and has been traditionally used in freshwater aquaculture systems in the treatment of fish, disinfection of eggs, sterilization of water to improve the water quality, and decomposition of odorous compounds in natural water in addition to its applications for improving the sensory quality and shelf life of fish. Since 1920, scientists have attempted to exploit the wide-range disinfection characteristics of ozone to slow the decomposition for improving the safety of fishing products. A number of commercial uses have been found for ozone, including the disinfection and preservation of aquatic products. In the United States, ozone received Generally Recognized as Safe (GRAS) classification in 1997, and in 2001, the FDA officially approved ozone for use in the food industry and for direct contact with food products, including fish, meat, and poultry. Ozone has continued to gain momentum in the food processing industry as the safest, most cost-effective, and a chemical-free way of dealing with food safety management.

Quality changes and predictive models of radial basis function neural networks for brined common carp (Cyprinus carpio) fillets during frozen storage

To investigate and predict quality of 2% brined common carp (Cyprinus carpio) fillets during frozen storage, free fatty acids (FFA), salt extractable protein (SEP), total sulfhydryl (SH) content, and Ca2+-ATPase activity were determined at 261K, 253K, and 245K, respectively. There was a dramatic increase (P<0.05) in FFA and a sharp decrease (P<0.05) in SH at 261K during the first 3weeks. SEP decreased to 67.31% after 17weeks at 245K, whereas it took about 7weeks and 13weeks to decrease to the same extent at 261K and 253K, respectively. Ca2+-ATPase activity kept decreasing to 18.28% after 7weeks at 261K. Furthermore, radial basis function neural networks (RBFNNs) were developed to predict quality (FFA, SEP, SH, and Ca2+-ATPase activity) of brined carp fillets during frozen storage with relative errors all within ±5%. Thus, RBFNN is a promising method to predict quality of carp fillets during storage at 245–261K.

Paraoxonase and arylesterase levels in autoimmune thyroid diseases

Objective: The aim of this study was to evaluate serum paraoxonase-1 (PON1) activity and its association with oxidative stress in autoimmune thyroid disease (AITD).Methods: A total of 50 patients with AITD, including 25 with Hashimoto's thyroiditis and 25 with Graves’ disease were enrolled. The control group comprised 27 healthy subjects. Blood samples were obtained in the euthyroid period and 3 months after initiation of medical treatment. Serum samples from patients with AITD and the healthy control group were analyzed for basal PON1, salt-stimulated PON1, and arylesterase (ARE) activities, along with lipid hydroperoxide (LOOH) and total free sulfhydryl (–SH) levels.Results: Serum PON1 activities and –SH levels were significantly lower (P < 0.001, for each), whereas LOOH levels were significantly higher (P < 0.001, for each) in patients with AITD, compared to the control group. We observed no significant differences in ARE levels between the patient and healthy control groups (P > 0.05). PON1 activity was positively correlated with –SH (r = 0.522, P < 0.001) and negatively correlated with LOOH (r = −0.487, P < 0.001). PON1 phenotype distribution of the subjects was not significantly different among the three groups (P = 0.961).Conclusions: Serum PON1 activity is decreased in patients with AITD, and correlated positively with –SH, a well-known antioxidant, and negatively with LOOH, an index of lipid oxidation.

Gel properties of SPI modified by enzymatic cross-linking during frozen storage

The functional properties (elasticity and water holding capacity) of soy protein isolate (SPI) are degraded by denaturalization during frozen storage. To solve this problem, a modified SPI was prepared by cross-linking SPI and gelatin with transglutanminase (TGase). The gel properties of the modified SPI were analyzed during frozen storage. After 20 days of frozen storage, the water holding capacity (WHC) of the SPI gels decreased from 89% to 65%, whereas that of the modified soybean protein isolate (MSPI) gels remained above 85%, which was 29.6% higher than that of the SPI gels. In addition, the hardness increment of the MSPI gels only accounted for 47.1% that of the SPI gels. The moisture distribution of the MSPI gels showed no significant change during frozen storage, and the content of unfreezing water in the MSPI gels was higher than that in the SPI gels. Confocal laser scanning microscopy revealed that the microstructure of the MSPI gels suffered minimal damage after frozen storage, whereas that of the SPI gels presented a honeycomb pattern after frozen storage. Analysis of soluble protein, total SH groups, and gel chemical interaction showed that the improvement of MSPI gel properties during frozen storage was due to the slight decrease in the amount of gel soluble proteins and total SH groups and to the chemical interaction among different gels.

Properties and oxidative stability of emulsions prepared with myofibrillar protein and lard diacylglycerols

The objective of this study was to investigate the emulsifying properties and oxidative stability of emulsions prepared with porcine myofibrillar proteins (MPs) and different lipids, including lard, glycerolized lard (GL) and purified glycerolized lard (PGL). The GL and PGL emulsions had significantly higher emulsifying activity indices and emulsion stability indices than the lard emulsion (P<0.05). The PGL emulsion presented smaller droplet sizes, thus decreasing particle aggregation and improving emulsion stability. The static and dynamic rheological observations of the emulsions showed that the emulsions had pseudo-plastic behavior, and the PGL emulsion presented a larger viscosity and a higher storage modulus (G′) and loss modulus (G′′) compared with the other two emulsions (P<0.05). The formation of thiobarbituric acid-reactive substances, carbonyl contents and total sulfhydryl contents was not significantly different between the emulsions with PGL, GL and lard (P<0.05). In general, lard diacylglycerols enhanced emulsifying abilities and had no adverse effects on the oxidation stability of the emulsions prepared with MPs.

On the Anticataractogenic Effects of L-Carnosine: Is It Best Described as an Antioxidant, Metal-Chelating Agent or Glycation Inhibitor?

Purpose. L-Carnosine is a naturally occurring dipeptide which recently gained popularity as an anticataractogenic agent due to its purported antioxidant activities. There is a paucity of research and conclusive evidence to support such claims. This work offers compelling data that help clarify the mechanism(s) behind the anticataract properties of L-carnosine. Methods. Direct in vitro antioxidant free radical scavenging properties were assayed using three different antioxidant (TEAC, CUPRAC, and DPPH) assays. Indirect in vitro and ex vivo antioxidant assays were studied by measuring glutathione bleaching capacity and total sulfhydryl (SH) capacity of bovine lens homogenates as well as hydrogen-peroxide-stress assay using human lens epithelial cells. Whole porcine lenses were incubated in high galactose media to study the anticataract effects of L-carnosine. MTT cytotoxicity assays were conducted on human lens epithelial cells. Results. The results showed that L-carnosine is a highly potent antiglycating agent but with weak metal chelating and antioxidant properties. There were no significant decreases in lens epithelial cell viability compared to negative controls. Whole porcine lenses incubated in high galactose media and treated with 20 mM L-carnosine showed a dramatic inhibition of advanced glycation end product formation as evidenced by NBT and boronate affinity chromatography assays. Conclusion. L-Carnosine offers prospects for investigating new methods of treatment for diabetic cataract and any diseases that are caused by glycation.

Enhancement of the Gelling Properties of Sardine Surimi with Transglutaminase and Optimization of its Activity Using Response Surface Methodology

In order to improve the gelling properties of sardine surimi gel and to determine the maximum activity range of microbial transglutaminase (MTGase), we investigated the characteristics of surimi gel as a function of MTGase concentration, as well as temperature and reaction time, using the response surface methodology. Specifically, we assessed the following mechanical and physicochemical characteristics of the gel: rheological properties, disulphide bond and total sulfhydryl group content, and waterholding capacity. Our results demonstrated that temperature and enzyme concentration had more influence than reaction time on all dependent variables, incorporation of MTGase markedly ameliorated all the responses. The optimal properties were predicted to be obtained by employing the optimised setting conditions as follows: a concentration of MTGase of 10 g/kg of surimi at 45°C for 1 h. All the mathematical models derived for the various responses were found to be a good fit to predict the data.

Açai (Euterpe oleracea Mart.) pulp dietary intake improves cellular antioxidant enzymes and biomarkers of serum in healthy women

ObjectivesThe aim of the present study was to evaluate the effect of açai pulp (Euterpe oleracea Martius) intake on the prevention of oxidative damage by measuring the activity of antioxidant enzymes and biomarkers of protein oxidation in women. MethodsA nutritional intervention study was conducted with thirty-five healthy women who were asked to consume 200 g/d of açai pulp for 4 wk. Blood samples were collected, and blood pressure and anthropometric parameters were measured before and after the experimental period. Antioxidant enzymes, superoxide dismutase, catalase, glutathione, production of reactive oxygen species, and total antioxidant capacity were evaluated in polymorphonuclear cells. Serum concentration of protein carbonyl and sulfhydryl groups were also determined. ResultsThe açai intake increased catalase activity, total antioxidant capacity, and reduced the production of reactive oxygen species. Furthermore, it reduced serum concentration of protein carbonyl and increased total serum sulfhydryl groups. ConclusionsThese results show the antioxidant benefit of dietary açai for the healthy women included in the present study, and may increase understanding of the beneficial health properties of this fruit.

Alteration in systemic markers of oxidative and antioxidative status in Tunisian patients with asthma: relationships with clinical severity and airflow limitation

Objective: This study aims to determine the systemic oxidant-antioxidant status in Tunisian patients with asthma. Methods: We evaluated the levels of malondialdehyde (MDA) as thiobarbituric acid complexes, total protein carbonyls (PCs) and advanced oxidation protein products (AOPP). The levels of total thiols, protein sulfhydryls, glutathione (GSH), together with hydrogen peroxide, ascorbic acid, iron and total antioxidant status (TAS) were colorimetrically estimated. Glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) activities were assessed in plasma and erythrocytes by spectrophotometry. We also determined the levels of nitric oxide (NO) and peroxynitrite in plasma from asthmatic patients and healthy controls. The volume of fractionated exhaled NO (FeNO) was evaluated by the Medisoft HypAir method. Estimation of DNA damage was determined using the comet assay. Results: Asthmatic patients showed increased levels of MDA in comparison to healthy controls (p < 0.001), while no significant difference was found in protein carbonyls (p = 0.79) and AOPP (p = 0.98). Patients with asthma also had significantly lower levels of total thiols (355.9 ± 15.72 versus 667.9 ± 22.65, p < 0.001), protein sulfhydryls (333.99 ± 16.41 versus 591.95 ± 24.28, p < 0.001) and glutathione (p < 0.001). They also showed decreased GSH-Px activity (p < 0.001), whereas no significant differences in measurements of catalase and SOD enzyme activities were observed between the two groups (respectively, p = 0.06 and p = 0.55). In addition, ascorbic acid and nitric oxide levels were decreased in asthmatics in comparison to controls (p < 0.01). Conclusions: Our findings highlight that oxidative stress and defective anti-oxidative status are major alterations in Tunisian patients with asthma.

Conformational Changes and Kinetic Study of Actomyosin from Silver Carp Surimi with Modified Starch–Sucrose Mixtures during Frozen Storage

AbstractThe cryoprotective effects of modified starch–sucrose mixtures on silver carp surimi were compared with commercial cryoprotectant using the changes in gel strength and actomyosin conformation during frozen storage. Acetic acid esterification starch (AAES)‐sucrose maintained the maximum gel strength and Ca2+–ATPase activity throughout the frozen storage (P &lt; 0.05). Hydroxypropylated starch (HS)‐sucrose showed a similar retention of Ca2+–ATPase activity (39.34%) and salt‐soluble protein (SSP) content (60.20%) to that of AAES–sucrose (40.14%, 63.89%, respectively) after 91 days of storage (P &gt; 0.05). AAES–sucrose and HS–sucrose separately showed the best effect on depressing loss of total sulfhydryl content in the early 28 days and later 63 days. Therefore, they protected actomyosin structure more effectively than commercial cryoprotectant. The relationship of Ca2+–ATPase activity and SSP content with respect to storage time could be fitted with a first‐order model to predict the changes in fish protein structure during frozen storage (R2 &gt; 0.99).Practical ApplicationsModified starch–sucrose mixtures tended to improve gel strength of frozen surimi, as well as effectively prevent conformational changes of actomyosin during long period of frozen storage at −20C. The effectiveness of acetic acid esterification starch (AAES)‐sucrose and hydroxypropylated starch (HS)‐sucrose seemed to be slightly evident than commercial cryoprotectant. Therefore, the application of AAES‐sucrose or HS‐sucrose in frozen surimi products could be popularized at reduced cost and more healthy quality.

Oxidative stress, biochemical alterations, and hyperlipidemia in female rats induced by lead chronic toxicity during puberty and post puberty periods.

Lead (Pb) is a toxic metal inducing many destructive effects leading to a broad range of physiological, biochemical, and neurological dysfunctions in humans and laboratory animals. Here, we investigated the effect of chronic exposure to Pb (50 mg/l) on oxidative stress, hepatotoxicity, nephrotoxicity, and lipid profile of two different age groups of female rats treated with Pb from delivery until puberty period (40 days, Pb40) and post puberty period (65 days, Pb65). Our results clearly show that the administration of Pb produces oxidative damage in liver and kidney, as strongly suggested by the significant increase in TBARS, decrease in total SH, and the alteration of SOD activity. Elevation in liver function biomarkers, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and reduction in total protein (liver and plasma) and albumin are evidence of perturbations of liver synthetic function. In young Pb-treated group, Pb-induced nephropathy was more pronounced by the increase in the levels of creatinine, urea, and uric acid. However, hyperlipidemia was evident for both Pb-exposed groups leading to a potential risk for cardiovascular diseases and atherosclerosis. It is concluded that Pb induces metabolic and oxidative disturbances depending on the age of the animals, which are not negligible.

Physicochemical and rheological parameters changes for determining the quality of surimi and kamaboko produced by conventional, acid and alkaline solubilization process methods from common kilka (Clupeonella cultriventris caspia)

Physicochemical properties of surimi and kamaboko obtained of solubility in acid, alkaline and conventional methods were compared. The results indicated that the highest protein recovery was related to solubility in acid, alkaline and conventional methods, respectively. The highest removal of lipid and myoglobin was observed by solubility in alkali. Excretion of total pigment and sulfhydryl groups was not significantly different between solubility in alkali and acid methods. Whiteness of surimi prepared by acid method was more than the other two methods. Electrophoresis pattern in surimi produced by conventional method indicated loss of myofibril and sarcoplasmic proteins through the washing process. Solubility in acid and alkali methods showed myofibril proteins recovery along a part of the sarcoplasmic proteins and disintegration of myosin heavy chain. Physically, study of kamaboko showed that solubility in alkali generated features such as gel strength, expressible moisture, hardness, gumminess and elasticity was superior to the other two methods. About folding test and cohesiveness factor, there was no significant difference between solubility in alkali and conventional methods. In general, solubility in alkali method was better.

Protective effect of pomegranate seed oil against cisplatin-induced nephrotoxicity in rat

Purpose: Clinical use of cisplatin is limited by its nephrotoxicity. Cisplatin-induced nephrotoxicity is associated with an increase in oxidative stress, leading ultimately to kidney dysfunction. The aim of this study was to investigate the effect of pomegranate seed oil against nephrotoxicity induced by cisplatin in adult rats. Methods: Animals were divided into four groups. Group I received corn oil (1 mL/kg). Group II received cisplatin (8 mg/kg). Group III and IV received pomegranate seed oil (PSO) 0.4 mL/kg and 0.8 mL/kg one hour before cisplatin injection for 3 days, respectively. Blood samples were collected by cardiac puncture and used for measuring urea and creatinine concentration. Twenty-hour urine samples were collected to measure protein and glucose concentration. The right kidney fixed in formalin for histological examination and the left kidney was homogenized for measurement of malondialdehyde and total sulfhydryl groups. Results: A significant elevation of serum creatinine, urea, urinary glucose, protein concentrations, and non-significant decrease in total thiol content and increase in MDA level in kidney homogenates were observed in cisplatin-treated rats. Also cisplatin reduced animal’s body weight. Mild-to-moderate tubular cell necrosis, hyaline casts, and vascular congestion were observed in group II. PSO pre-treatment significantly decreased urinary protein, glucose, and serum creatinine concentration. PSO also caused a decrease in serum urea, renal MDA, and increase in thiol content, but the level of these parameters were not significant. Conclusion: The present results suggest that PSO is an effective agent for the prevention of cisplatin-induced renal dysfunction and oxidative damage in rat.

Sodium nitrite-induced oxidative stress causes membrane damage, protein oxidation, lipid peroxidation and alters major metabolic pathways in human erythrocytes

Nitrite salts are present as contaminants in drinking water and in the food and feed chain. In this work, the effect of sodium nitrite (NaNO2) on human erythrocytes was studied under in vitro conditions. Incubation of erythrocytes with 0.1–10.0mM NaNO2 at 37°C for 30min resulted in dose dependent decrease in the levels of reduced glutathione, total sulfhydryl and amino groups. It was accompanied by increase in hemoglobin oxidation and aggregation, lipid peroxidation, protein oxidation and hydrogen peroxide levels suggesting the induction of oxidative stress. Activities of all major erythrocyte antioxidant defense enzymes were decreased in NaNO2-treated erythrocytes. The activities of enzymes of glycolytic and pentose phosphate pathways were also compromised. However, there was a significant increase in acid phosphatase and also AMP deaminase, a marker of erythrocyte oxidative stress. Thus, the major metabolic pathways of cell were altered. Erythrocyte membrane damage was suggested by lowered activities of membrane bound enzymes and confirmed by electron microscopic images. These results show that NaNO2-induced oxidative stress causes hemoglobin denaturation and aggregation, weakens the cellular antioxidant defense mechanism, damages the cell membrane and also perturbs normal energy metabolism in erythrocytes. This nitrite-induced damage can reduce erythrocyte life span in the blood.

Involvement of sulfhydryl compounds and antioxidant enzymes in H2S-induced heat tolerance in tobacco (Nicotiana tabacum L.) suspension-cultured cells

Hydrogen sulfide (H2S) is a multifunctional second messenger involved in plant growth, development, and acquisition of stress tolerance, including heat tolerance, but the mechanism of H2S-induced heat tolerance in tobacco suspension-cultured cells is not completely clear. This study investigated the effects of pretreatment with the H2S donor sodium hydrosulfide (NaHS) and its precursors cysteine and potassium bisulfite (KHSO3) on the heat tolerance of tobacco suspension-cultured cells and the involvement of sulfhydryl compounds and antioxidant enzymes in conferring heat tolerance. Pretreatment with NaHS, cysteine, and KHSO3 significantly increased the survival percentage of tobacco suspension-cultured cells under heat stress, while treatment with the H2S scavenger hypotaurine in combination with NaHS eliminated heat tolerance induced by treatment with NaHS alone. In addition, NaHS treatment increased the levels of water-soluble sulfhydryl compounds such as H2S, total sulfhydryl compounds, total sulfhydryl proteins, cysteine, and glutathione (GSH) as well as the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), and glutathione reductase (GR) under normal culture conditions (26°C). Under heat stress at 43°C, the levels of water-soluble sulfhydryl compounds and the activities of antioxidant enzymes all dropped, but the cells treated with NaHS sustained significantly higher levels of water-soluble sulfhydryl compounds and activities of antioxidant enzymes than the control. These results suggest that the pretreatment with NaHS could improve the heat tolerance of tobacco suspension-cultured cells and that the acquisition of this heat tolerance is caused by the elevated levels of water-soluble sulfhydryl compounds and elevated activities of antioxidant enzymes induced by NaHS.