Total Sulfhydryl Research Articles

The effects of sodium chloride on proteins aggregation, conformation and gel properties of pork myofibrillar protein Running Head: Relationship aggregation, conformation and gel properties.

The objective of this study was to evaluate relationship with aggregation, secondary structures and gel properties of pork myofibrillar protein with different sodium chloride (1%, 2% and 3%). When the sodium chloride increased from 1 to 3%, the active sulfhydryl, surface hydrophobicity, hardness and cooking yield of myofibrillar protein were increased significantly (p < 0.05), the particle size, total sulfhydryl and Zeta potential were decreased significantly (p < 0.05), these meant the aggregations of pork myofibrillar protein were decreased. The changes of proteins aggregation induced the strongest intensity band of Amide I shifted up from 1660cm-1 to 1661cm-1, meanwhile, the β-sheet structure content was increased significantly (p < 0.05) with the sodium chloride increased. From the above, the lower proteins aggregation and higher β-sheet structure content could improve the water holding capacity and texture of pork myofibrillar protein gel.

The Protective Effects of Perindopril Against Acute Kidney Damage Caused by Septic Shock.

Acute kidney injury (AKI) resulting from septic shock caused by sepsis is an important health problem encountered at rates of 55-73%. Increasing oxidative stress and inflammation following sepsis is a widely observed condition with rising mortality rates. The purpose of this study was to determine whether perindopril (PER) can prevent sepsis-associated AKI with its antioxidant, anti-inflammatory, and anti-apoptotic effects. The control group received an oral saline solution only for 4 days. Cecal ligation and puncture (CLP)-induced sepsis only was applied to the CLP group, while the CLP + PER (2 mg/kg) received CLP-induced sepsis together with 2 mg/kg PER via the oral route for 4 days before induction of sepsis. Finally, all rats were euthanized by anesthesia and sacrificed. TBARS, total SH levels and NF-κβ, TNF-α, and Caspase-3 expression were then calculated for statistical analysis. TBARS, total SH, NF-kβ/p65, TNF-a, and Caspase-3 levels increased in the CLP group. In contrast, oral administration of PER (2 mg/kg) to septic rats reduced TBARS levels and NF-kβ/p65, TNF-α, and Caspase-3 immunopositivity at biochemical analysis. PER treatment appears to be a promising method for preventing sepsis-induced acute kidney injury through its antioxidant anti-inflammation and anti-apoptotic activities.

Effects of oxidative modification on the functional, conformational and gelling properties of myofibrillar proteins from Culter alburnus

Protein oxidation is a critical process in the deterioration and spoilage of fish and related commodities during processing and storage. In this study, the hydroxyl radical generation system (HRGS) was used to simulate the effect of oxidation on the functional, conformational and gelling properties of topmouth culter (Culter alburnus) myofibrillar proteins (MP). Additionally, the effects of oxidation on the gel-forming abilities of MP were also systematically analyzed from the perspective of intermolecular interaction forces. Oxidation was shown to decrease the total sulfhydryl content, increase the surface hydrophobicity, and induce conformational changes in MP. Rheological analysis showed that oxidation reduced the gel strength. Water holding capacity (WHC) and low-field nuclear magnetic resonance (LF-NMR) analyses showed that low oxidation could enhance water binding of protein matrix, while high-degree oxidation could substantially reduce the gelling properties of MP. The selective solubility of MP gel proved that oxidation could reduce the content of ionic and hydrogen bonds and increase hydrophobic interactions. All the results indicate that oxidation could alter the intermolecular interactions between protein-protein and protein-water molecules, due to irregular unfolding and inhibition of the cross-linking of amino acid side chains, leading to reduction in the quality and function of fish and related products.

Effects of direct current magnetic field treatment time on the properties of pork myofibrillar protein

SummaryThis study investigated the effects of direct current magnetic field (DC‐MF) treatment time (1, 3, 5, 8 h) on properties of porcine myofibrillar protein (MP). Gel water‐holding capacity increased from 83.40% to 87.20% when DC‐MF‐treatment time changed from 1‐h to 8‐h. The 3‐h treatment time of DC‐MF was found to promote MP unfolding, rearrangement and aggregation, leading to the loss of total sulfhydryl, the increase of reactive sulfhydryl, surface hydrophobicity, turbidity as well as the formation of MP clusters and the greater degree of crosslinking as compared with 0‐h treatment, thus a firmer and more ordered MP gel network for trapping more water. However, excessive DC‐MF treatment (8‐h) weakened DC‐MF effect on MP aggregation as well as gel network and texture. This study has shed light on the effects of DC‐MF treatment time on MP properties and provides useful information for the application of DC‐MF in the food industry.

Oxidative Stress in Endometrial Flushing Fluid of Patients with Polycystic Ovary Syndrome, Endometrioma and Uterine Leiomyoma: Comparison with Healthy Controls

OBJECTIVE: Polycystic ovary syndrome, myoma uteri and endometrioma are frequently seen gynecologic problems and all three diseases may cause infertility. Aim of this cross-sectional study was to compare total antioxidant status, ceruloplasmin, total sulfhydryl , total oxidant status, lipid hydroperoxide and oxidative stress index levels in endometrial flushing fluid of patients with Polycystic ovary syndrome (n=20), uterine leiomyoma (n=20), endometrioma (n=19), and healthy women (n=20).STUDY DESIGN: We compare endometrial flushing fluid of patients with polycystic ovary syndrome (n=20), uterine leiomyoma (n=20), endometrioma (n=19) and healthy women (n=20). Endometrial flushing fluid samples were collected during the implantation window of all women.RESULTS: Mean age of groups was 28.90±5.45, 37.25±2.73, 32.84±6.62 and 32.15±5.18 in Polycystic ovary syndrome, myoma uteri, endometrioma and control groups, respectively (p&lt;0.05). Mean total antioxidant status, ceruloplasmin and total sulfhydryl levels indicating antioxidant state were comparable between Polycystic ovary syndrome, myoma uteri, endometrioma and control groups (p=0.806, p=0.156, p=0.328 respectively for markers). Similarly, oxidant state-related markers didn’t differ significantly between 4 groups (p=0.090 for total oxidant status, p=0.087 for lipid hydroperoxide, p=0.312 for oxidative stress index).CONCLUSION: Endometrial flushing fluid total antioxidant status, total oxidant status, lipid hydroperoxide, ceruloplasmin, and total sulfhydryl levels during implantation window didn’t differ between women with Polycystic ovary syndrome, uterine leiomyoma, endometrioma, and healthy controls.

Effects of constant power microwave on the adsorption behaviour of myofibril protein to aldehyde flavour compounds

This study explored the influence of constant power microwave on the adsorption ability of myofibril protein from beef to typical aldehyde flavour compounds. Results showed that there was a significant increasing trend in surface hydrophobicity and reactive sulfhydryls content of myofibril protein with an increase in microwave power and treatment time. The adsorption ability of myofibril protein to aldehyde flavour compounds increased with increasing microwave power and time. The percentage of free aldehyde flavour compounds was related to the content of surface hydrophobicity, and reactive and total sulfhydryls of myofibril protein under microwave conditions, which could be fitted according to the multilevel relational (MLR) model. Furthermore, the reduced interface energy was probably the driving force for myofibril protein-flavour compounds adsorption behaviour at the gas–liquid interface.

Ameliorative role of curcumin on copper oxide nanoparticles-mediated renal toxicity in rats: An investigation of molecular mechanisms.

The increasing role of copper oxide nanoparticles (CuO NPs) in many industries and their broad range of applications increase its potential toxic effects. Curcumin possesses a wide range of health benefits. This study aimed to evaluate the role of curcumin in attenuating CuO NPs toxicity in rat kidney. Thirty six animals were divided into five groups; control groups (I, II), curcumin group orally received curcumin 200 mg/kg bw, CuO NPs group orally gavaged 250 mg/kg bw CuO NPs and combined group orally gavaged curcumin and CuO NPs. Treatment was given for 3 months. Administration of CuO NPs revealed elevation in serum creatinine and blood urea nitrogen levels, elevated kidney and urine levels of kidney injury molecule-1, decreased catalase, superoxide dismutase activities, total sulfhydryl, reduced glutathione content, increased serum reactive oxygen species, tissue total oxidant status, lipid hydroperoxides, protein carbonyl, malondialdehyde, nitric oxide levels, increased interleukin-1β, tumor necrosis factor-α, nuclear factor (NF-κB), and decreased heme oxygenase-1 (HO-1) and γ-glutamylcysteine synthetase (γ-GCS) genes expression. Moreover, histopathological alteration in kidney structure was detected. Immunohistochemical-stained sections by caspase-3 reaction revealed apoptosis. Pretreatment with curcumin improved most of the adverse effects in rats treated with CuO NPs regarding oxidative stress and inflammatory indices in kidney, and kept histopathological- and immunohistochemical-stained sections near to normal. This study shows that curcumin administration attenuates the toxicity in the kidney of CuO NPs-treated rats through its antioxidant, anti-inflammatory, and antiapoptotic effects.

EFFECT OF N-ACETYLCYSTEINE ON APOPTOSIS OF P19 CANCER CELLS DURING HYPOXIA

Introduction. Hypoxia in tumor growth contributes to mitochondrial dysfunction and exacerbates oxidative stress in the immortalized cell. The objective of the study was to investigate the molecular mechanisms of the effects of N-acetylcysteine on redox regulation of tumor cell apoptosis under hypoxia.Material and Methods. P19 cells (mouse teratocarcinoma) cultured under hypoxia served as the material for the study. The redox status was modulated with N-acetylcysteine in the final concentration of 5 mM. The level of reactive oxygen species, concentration of calcium ions, transmembrane potential and the number of CD95-, CD120- and Annexin V-positive cells were determined by flow cytometry. The concentration of glutathione system components as well as the levels of protein SH groups and protein carbonyl derivatives were measured by spectrophotometry.Results. The use of N-acetylcysteine under hypoxic conditions was accompanied by the increased total glutathione concentration and protein SH groups levels, decreased levels of Са2+ ions, proteinbound glutathione and protein carbonyl derivatives, as well as the production of reactive oxygen species and more appropriate functioning of P19 cells mitochondria. N-acetylcysteine contributed to the development of additional resistance of P19 cells to apoptosis under hypoxia.Conclusion. The alteration in the state of the glutathione system under hypoxia influences the changes in tumor cell metabolism on the whole and promotes formation of additional mechanisms to escape apoptosis.

Influence of timolol, benzalkonium-preserved timolol, and benzalkonium-preserved brimonidine on oxidative stress biomarkers in the tear film

Purpose The objective of this study was to investigate the influence of topical preservative-free timolol, benzalkonium chloride(BAC)-preserved timolol, BAC-preserved timolol, and BAC-preserved brimonidine on total protein concentration, advanced oxidation protein products (AOPP) content, total sulfhydryl groups content, the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as Total Oxidant Status (TOS), Total Antioxidant Response, and Oxidative Stress Index (OSI) in the tear film. Methods The patients were divided into four groups: group C (n = 25)—control group—subjects who did not use topical antiglaucoma medications, group T (n = 17)—patients using topical preservative-free timolol, group T + BAC (n = 24)—patients using topical BAC-preserved timolol, and group BR + BAC (n = 19)—patients using topical BAC-preserved brimonidine. Results The SOD, CAT, and GPx activities as well as AOPP, TOS, and OSI were found to be higher in the tear film of patients treated with BAC-preserved topical timolol or brimonidine in comparison with patients treated with preservative-free timolol or patients who did not use antiglaucoma topical medications. Conclusions This indicates that using BAC-preserved topical medications increases oxidative stress in the tear film and may, in the long-term, contribute to the clinical presentation of dry eye disease.

The dual effects of riboflavin and kelp polyphenol extracts on the gel properties of myofibrillar protein from Scomberomorus Niphonius under UVA irradiation.

In the present study, effects of riboflavin (RF) and kelp polyphenol extracts (KPE) on mackerel (Scomberomorus Niphonius) myofibrillar protein (MP) gel were studied with or without ultraviolet A (UVA) irradiation treatment. The gel strength was increased with the addition of RF and KPE under UVA irradiation. Analysis of the proteins in the gel indicated that the carbonyl content increased, while the contents of total sulfhydryl and amino groups decreased. The proteins appeared to have no α-helix structures, and the endogenous tryptophan content appeared to decrease. The results of SDS-PAGE indicated that the RF and KPE treated samples under UVA irradiation showed massive MP cross-linking by covalent bonds. Electron spin resonance (ESR) results indicated that UVA irradiation generated free radicals in RF and KPE, which ultimately led to an improvement in MP gel properties. It also indicated that KPE could prevent the occurrence of peroxidation to improve the gel properties.

Thiol/disulfide homeostasis in patients with chronic hepatitis B

Aim: The purpose of this study was to evaluate the relation between chronic hepatitis B (CHB) and the thiol/disulfide balance, used as a marker of oxidative stress. Materials and Methods: This study was conducted between May 2016 and July 2016 at the Erzurum Regional Training and Research Hospital Infectious Diseases Polyclinic. 63 subjects with CHB and 60 healthy volunteers without any known diseases were included in the study. In term of measuring dynamic thiol/disulfide homeostasis, we used the novel automated assay method developed by Erel and Neselioglu. Results: Native thiol (SH), total thiol (total SH) and disulfide (SS) levels were determined; measures such as SS/SH, SS/total SH, and SH/total SH were calculated. It is determined that CHB group’s SH levels (P=0.041), total SH levels (P=0.043) were lower than the control group’s. There is negative correlation between Anti-HBc total IgG and total SH, SH, SH/total SH, there is positive correlation between Anti-HBc total IgG and SS/SH, SS/total SH ratio. There is negative correlation between BMX index and total SH, SH, SH/total SH and positive correlation between SS/total SH, SS/SH. Positive correlation is determined between total protein, albumin and total SH, SH. Conclusions: In our study thiol levels as an antioxidant were found to be low in CHB patients. Thiol levels were again emphasized as a new marker in hepatitis B. Thiol levels in CHB are thought to shed light to slowing of disease course and improving new treatment efforts with more wide studies.

Endocan and advanced oxidation protein products in adult population with hypertension.

Hypertension is closely related to oxidative stress and inflammation. Endocan is a new inflammation marker whose role is not completely elucidated in hypertension. The aim of this study was to explore the association between endocan and several oxidative stress markers [i.e., advanced oxidation protein products (AOPP), total protein sulfhydryl (SH-) groups and prooxidant-antioxidant balance (PAB)] in adult population with hypertension. A total of 90 patients with hypertension were compared with 44 controls. Blood pressure, anthropometric and biochemical parameters were measured. Associations of clinical data with hypertension were tested with univariable and multivariable logistic ordinal regression analysis. Endocan and AOPP were significantly higher in hypertensive patients than in the controls (p=0.006 and p=0.046, respectively). In the multivariable logistic regression analysis, AOPP and endocan kept their independent positive associations with hypertension. As AOPP rose by 1 μmol/L and endocan rose by 1 pg/mL, the probability for hypertension presence rose by 4.2% and 32.2%, respectively and 39.9% of variation in hypertension could be explained with the Model. The area under the Receiver Operating Characteristic curve [(AUC) for AOPP=0.638 (0.550-0.719), p=0.01 and for endocan=0.679 (0.593-0.757), p<0.001] demonstrated sufficient clinical accuracy towards hypertension. On the contrary, the Model showed very good clinical accuracy [AUC= 0.825 (0.749-0.900), p<0.001]. Endocan and AOPP are independently correlated with hypertension in adult population and these tested markers together could be reliable parameters to discriminate patients with hypertension from normotensive ones.

Factors associated with oxidative stress status in pediatric patients with type 1 diabetes mellitus

Background Oxidative stress is implicated in both, the onset and the progression of type 1 diabetes mellitus (T1DM). There is accumulated evidence of increased biomarkers of oxidative stress in newly diagnosed, T1DM patients without complications, and in those with advanced disease. In this cross-sectional study, we investigated factors affecting oxidative stress status in pediatric patients with T1DM. Methods Advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), total sulfhydryl (SH) groups, and superoxide dismutase (SOD) activity were determined in 170 children and adolescents with T1DM. Principal component analysis was used to investigate clustering of clinical and laboratory variables associated with elevated oxidative stress and reduced antioxidative defense biomarkers. Results Factor analysis extracted five factors, interpreted as (1) "weight status factor" including age, BMI, waist and hip circumferences; (2) "proatherogenic factor" that included LDL-cholesterol, non-HDL-cholesterol, and triglycerides; (3) "metabolic control factor" including glucose and HbA1c; (4) "renal marker factor" with positive loading of urinary albumin excretion rate and negative loading of GFR; and (5) "antiatherogenic factor" that included HDL-cholesterol. High AOPP levels were independently predicted by "proatherogenic" (OR: 2.32; 95% CI: 1.44-3.71; p < 0.001), "metabolic control" (OR: 2.24; 95% CI: 1.35-3.73; p < 0.01), and "renal marker" (OR: 1.65; 95% CI: 1.03-2.65; p < 0.05) factors. "Renal marker factor" was a significant predictor of PAB (OR: 0.52; 95% CI: 0.34-0.81; p < 0.01). Regarding antioxidative defense markers, reduced SH groups were predicted by "proatherogenic factor" (OR: 0.56; 95% CI: 0.34-0.94; p < 0.05), while "weight status factor" predicted lower SOD activity (OR: 1.66; 95% CI: 1.03-2.67; p < 0.05). Conclusions Cardiometabolic risk factors and renal function are associated with oxidative stress in pediatric T1DM patients.

Influence of two different feeding strategies in the dry period on dry matter intake and plasma protein peroxidative and antioxidative profile during dry period and early lactation

BackgroundDairy cows undergo dramatic changes in endocrine and metabolic status around parturition and in early lactation. Meeting the nutritional requirements of transition dairy cows is important for animal health, production and animal wellbeing. Dry cow feeding and managing play an essential role in this. The changes in metabolism of periparturient cows also lead to a rise in the production of oxidising agents, leading to oxidative stress. The relationship between dry cow diet composition and oxidative stress has received little research attention so far. In the present study, the influence of two different dry cow feedings (single diet with medium energy content over the whole dry period versus traditional two-phase diet with a low-energy “far-off” ration and a high energy “close-up” ration) on dry matter intake, energy intake and plasma protein peroxidative and antioxidative profile was investigated.ResultsThe examined parameters revealed a dynamic profile within the experimental period. Dry matter intake (DMI) did not differ between groups. However, there was a time and a group x time interaction effect: Group 1 (“one-phase”) had a very constant DMI with a slow and even decrease until calving. In Group 2 (“two-phase”), an initial increase in DMI two weeks antepartum (a.p.) was followed by a sharp drop at week 1 a.p.. The highest total antioxidant capacity and sulfhydryl residue concentration was noted at partus. In contrast, concentration of formylokinurenine and bityrosine bridges as representatives of protein peroxidation were lowest at parturition. The time course of formylokinurenine and bityrosine bridges showed parallels to the DMI. The contents of sulfhydryl groups, formylokinurenine and total antixoxidant capacity did not differ between groups. In contrast, concentration of bityrosine bridges was always higher in Group 2 compared with Group 1 and these differences were statistically significant at week 3 a.p., week 2 a.p., week 1 a.p. and at parturition.ConclusionThe results of our study suggest time-related changes of pro- and antioxidative plasma parameters. Different dry cow feeding affected antepartal DMI. Furthermore, DMI and diet compositions seemed to have an influence on plasma protein peroxidative profile and activity of antioxidative defence.

Açaí (Euterpe oleracea Martius) Promotes Jejunal Tissue Regeneration by Enhancing Antioxidant Response in 5-Fluorouracil-Induced Mucositis

Intestinal mucositis (IM) caused by antineoplastic chemotherapy is characterized by an important inflammatory process, which may compromise ongoing treatment. Our study aimed to investigate the effect of Açaí (Euterpe oleracea Martius) on the antioxidant response in BALB/c mice pretreated with Açaí pulp (200 g/kg) for 14 day. A group of animals receiving a single intraperitoneal injection of 5-FU (200 mg/kg) were euthanized on day three (D3) or seven (D7) after administration, the distal jejunum was isolated for the analyses of histology, superoxide dismutase (SOD) and catalase (CAT) enzyme activities, and concentration of total sulfhydryl groups (GSH). Seven days after induction, the intake of Açaí by the IM group almost completely regenerated tissue histology. Notably, SOD activity decreased in the MUC + Açaí group (D3). CAT activity reduced on D3 and D7 in the IM groups and Açaí treatment groups, respectively. No change was observed in the total GSH concentration at the tissue level. Our results demonstrated the protective effect of Açaí pulp components on intestinal damage induced by 5-FU, as well as the ability to control the response to oxidative stress, in order to mobilize defense pathways and promote tissue repair.

Evaluation of Noah-MP Land-Model Uncertainties over Sparsely Vegetated Sites on the Tibet Plateau

The water budget and energy exchange over the Tibetan Plateau (TP) region play an important role on the Asian monsoon. However, it is not well presented in the current land surface models (LSMs). In this study, uncertainties in the Noah with multiparameterization (Noah-MP) LSM are assessed through physics ensemble simulations in three sparsely vegetated sites located in the central TP. The impact of soil organic matter on energy flux and water cycles, along with the influence of uncertainties in precipitation are explored using observations at those sites during the third Tibetan Plateau Experiment from 1August2014 to31July2015. The greatest uncertainties are in the subprocesses of the canopy resistance, soil moisture limiting factors for evaporation, runoff (RNF) and ground water, and surface-layer parameterization. These uncertain subprocesses do not change across the different precipitation datasets. More precipitation can increase the annual total net radiation (Rn), latent heat flux (LH) and RNF, but decrease sensible heat flux (SH). Soil organic matter enlarges the annual total LH by ~26% but lessens the annual total Rn, SH, and RNF by ~7%, 7%, and 39%, respectively. Its effect on the LH and RNF at the Nagqu site, which has a sand soil texture type, is greater than that at the other two sites with sandy loam. This study highlights the importance of precipitation uncertainties and the effect of soil organic matter on the Noah-MP land-model simulations. It provides a guidance to improve the Noah-MP LSM further and hence the land-atmosphere interactions simulated by weather and climate models over the TP region.

Effect of Atmospheric Pressure Cold Plasma on Biophysical Properties and Aggregation of Natural Actomyosin from Threadfin Bream (Nemipterus bleekeri)

Biophysical properties and aggregation of natural actomyosin (NAM) from threadfin bream (Nemipterus bleekeri) subjected to atmospheric pressure cold plasma (APCP) treatment with different contact times were determined. Protein solubility, turbidity, Ca2+-ATPase activity, total sulfhydryl (SH) group content, protein carbonyl content, and SDS-PAGE were monitored. With increasing APCP contact times (from 0 to 30 min), total SH group content (5.74–3.77 mol/105 g protein), Ca2+-ATPase activity (0.32–0.23 μmol Pi/mg protein/min), and solubility (100–92%) of NAM decreased, while protein carbonyl content (1.43–36.47 μmol/g protein) increased to a higher extent. During APCP treatment, cross-linking via disulfide bond as visualized by SDS-PAGE along with increased turbidity of NAM was observed. Therefore, APCP treatment markedly induced biophysical changes and aggregation of NAM which can be used as a possible approach to strengthen the gel formation of threadfin bream surimi.

D‐glucose and D‐galactose affect Band 3 protein function and oxidative stress in human erythrocytes

Metabolic dysfunctions continuously expose human erythrocytes to sugars present in plasma during their circulatory life span of 120 days. Hyperglycemia in diabetes mellitus causes glycation of proteins along with oxidative stress in erythrocytes. Moreover, acute systemic administration of D‐galactose was used to artificially induce blood senescence in human models as well to mimic galactosemia. The purpose of this study is to understand the effect of D‐glucose and D‐galactose in human erythrocytes and in particular on the function of Band 3 protein, which is an excellent tool for studying the oxidative events on the erythrocyte membrane. Human erythrocytes in vitro were exposed to increasing concentrations of D‐glucose (5‐15‐35 mM) for 3h or D‐galactose (0.1‐3‐5‐10 mM) for 1h. The rate constant for SO4= uptake, accounting for the efficiency of anion exchange through Band 3 protein along with levels of TBARS levels and membrane –SH groups have been measured. When erythrocytes were exposed to high D‐glucose (15–35 mM) for 3 h, TBARS levels and membrane –SH groups were unchanged while the rate constant for SO4= uptake was significantly accelerated with respect to control (5 mM). After exposure to high D‐galactose (5–10 mM) for 1 h, TBARS levels were higher and membrane –SH levels were lower than control, while the rate constant for SO4= uptake was significantly slower with respect to control (0.1 mM). The present findings show that the measurement of the rate constant for SO4= uptake is a suitable tool to monitor the effect of sugars on erythrocytes; hyperglycemia due to high glucose applied for 3 h affects anion exchange capability without producing lipid peroxidation and oxidative protein damage. High concentrations of D‐galactose (&gt; 5 mM) decreased the rate constant for SO4= uptake, induced lipid peroxidation and reduced total sulfhydryl content. Based on this evidence, future studies will evaluate if the acceleration of Band 3 protein in presence of high D‐glucose depends on altered Bp3 conformation, affecting crosslink with Hb, or on altered glycosylation or phosphorylation signaling underlying Band 3 protein function. In addition, alterations of parameters of oxidative stress caused by D‐galactose on the erythrocytes membrane open the view to consider a potential therapeutic strategy ameliorating the damage caused by D‐galactose.

Teratozoospermia: Its association with sperm DNA defects, apoptotic alterations, and oxidative stress.

This study was carried out to evaluate the level of nuclear sperm DNA damage in men with isolated polymorphic teratozoospermiaand examining its relationship with apoptosis and oxidative stress. A total of 89 subjects were divided into two groups: men with isolated teratozoospermia (n=69) and men with normal semen parameters (n=20) as controls. Sperm DNA breaks were determined by using acridine orange staining. The proportion of viable spermatozoa with mitochondrial transmembrane depolarization was detected by fluorescence microscopy through the use of MitoPTJC-1 staining method. Bivariate Annexin V/6-CFDA analysis was then set out in order to measure the percentage of both viable and dead spermatozoa with phosphatidylserine (PS) externalization. Seminal antioxidant profile (reduced glutathione (GSHr); oxidized glutathione (GSSG); glutathione S-transferase (GST)) and total protein sulfhydryl (P-SH) concentrations were measured spectrophotometrically. Men with isolated teratozoospermia, when compared to controls, showed significantly increased level of single sperm DNA breaks and higher proportions of spermatozoa with phosphatidylserine externalization and mitochondrial depolarization. Among the differently studied oxidative stress seminal parameters, the rates of seminal GSHr, GST, and P-SH were significantly decreased in the teratozoospermic group. However, the seminal rates of GSSG and GST have decreased, but only GST did not show a significant difference. Interestingly, significant correlations were found between the studied apoptotic markers and the rate of atypical sperm forms with the incidences of head abnormalities. Furthermore, positive inter-correlations were found between sperm DNA defects, impaired seminal antioxidant status, and the apoptotic sperm markers. Such data provide clear evidence that the apoptotic alterations are closely correlated to abnormal sperm morphology and DNA damage. Moreover, decreased seminal antioxidant profile may be a crucial factor involved in the mechanism of sperm cell death-mediated DNA breaks in teratozoospermic semen.

Cadmium and proton adsorption onto a halophilic archaeal species: The role of cell envelope sulfhydryl sites

The adsorption of metal onto archaea could affect metal behavior and bioavailability in hypersaline environments where archaea represent the dominant life form. However, the mechanism and thermodynamics of metal adsorption onto halophilic archaea are not well understood. In this study, Cd adsorption experiments and potentiometric titrations were conducted to model metal adsorption by the halophilic archaeon Halobacterium sp.. Cd adsorption onto the archaeal cells exhibits slow adsorption kinetics, taking 8 h to reach steady-state. The extent of Cd adsorption depends strongly on pCH+ and Cd loading. Desorption of Cd is even slower than adsorption, but exposure of the Cd-adsorbed biomass to high concentrations of cysteine promotes desorption and demonstrates that the distribution of Cd is controlled by reversible adsorption reactions, likely involving sulfhydryl binding of Cd on the cell surface. We conducted potentiometric titration experiments with and without sulfhydryl site blocking to yield a total sulfhydryl site concentration of 91 ± 28 μmol/g within the archaeal cell envelope. Using a combination of the X-ray absorption fine structure analysis results from Showalter et al. (2016) and the Cd adsorption measurements and titration data from this study, we construct a surface complexation model of the Cd adsorption behavior. Because the Cd adsorption behavior is likely similar to that of a range of chalcophilic micronutrients, the importance of Cd-sulfhydryl binding suggests that the production of high affinity sulfhydryl binding sites by the archaea may represent an adaptive strategy for halophiles to obtain metal nutrients in environments in which aqueous metal-chloride complexation dominates the speciation for many metals.