Role of Disulfide Bonds and Sulfhydryl Blocked by N-Ethylmaleimide on the Properties of Different Protein-Stabilized Emulsions

To investigate the role of sulfhydryl groups and disulfide bonds in different protein-stabilized emulsions, N-ethylmaleimide (NEM) was used as a sulfhydryl-blocking agent added in the emulsion. The addition of NEM to block the sulfhydryl groups resulted in a reduction in disulfide bond formation, which enabled the internal structure of the protein molecule to be destroyed, and then decreased the restriction of protein membrane on the oil droplets. Furthermore, with the NEM content increasing in the emulsion, a reduction in the protein emulsifying activity and emulsion stability also occurred. At the same time, the intermolecular interaction of the protein on the oil droplet interface membrane was destroyed, and the emulsion droplet size increased with the NEM content in the emulsion. Although NEM blocking sulfhydryl groups from forming disulfide bonds has similar effects on three types of protein emulsion, the degree of myofibrillar protein (MP), egg-white protein isolate (EPI), and soybean protein isolate (SPI) used as emulsifiers had a subtle difference.

Role of Disulfide Bonds and Sulfhydryl Blocked by N-Ethylmaleimide on the Properties of Different Protein-Stabilized Emulsions

To investigate the role of sulfhydryl groups and disulfide bonds in different protein-stabilized emulsions, N-ethylmaleimide (NEM) was used as sulfhydryl-blocking agent to be added in the emulsion. The addition of NEM to block the sulfhydryl groups resulted in a reduction of the content of disulfide bonds formation, which enabled destruction of the internal structure of the protein molecule, and then decreased the restriction of protein membrane on the oil droplets. Furthermore, with NEM content increasing in the emulsion, a reduction of protein emulsifying activity and emulsion stability also occurred. At the same time, the intermolecular interaction of the protein on the oil droplet interface membrane was destroyed, and the emulsion droplet size increased with the NEM content in the emulsion. Although NEM blocking sulfhydryl groups not to form disulfide bonds has similar effects on three types of protein emulsion, the degree of myofibrillar protein (MP), egg-white protein isolate (EPI), and soybean protein isolate (SPI) as emulsifier had a subtle difference.

Quantification of nonprotein sulfhydryl groups (NPSH) optimized for zebrafish brain tissue v2

Zebrafish are incresingly used as a model animal in neuroscience research. Here we describe a protocol to quantify nonprotein sulfhydryl groups (NPSH), an indirect evaluation of the levels of reduced glutathione (GSH), a major oxidative stress defense in the central nervous system.

State of antioxidant system in urogenital trichomoniasis and membranotropic effect of metronidazole

The objective of this work was to study the activity of glutathione peroxidase, glutathione reductase and the level of sulfhydryl groups in erythrocytes of patients with urogenital trichomoniasis and the effect of metronidazole on the degree of osmotic and peroxide resistance of erythrocytes from healthy donors. We examined 15 patients with urogenital trichomoniasis and 20 healthy volunteers. We studied native preparations, and also carried out a culture method using the Johnson-Trussel nutrient medium (CPLM) to identify Trichomona vaginalis. The activity of glutathione reductase, glutathione peroxidase and the level of total sulfhydryl groups were determined in erythrocytes of peripheral blood. The membrane effect of metronidazole was evaluated in in vitro experiment by the degree of osmotic and peroxide resistance of erythrocytes from healthy people. It has been established that a significant decrease in glutathione reductase and glutathione peroxidase activities in erythrocytes is observed, which indicates a violation of the antioxidant system in this pathology. It was shown in vitro experiment, that metronidazole in low concentration (80 μmol /l) has the ability to inhibit erythrocyte hypotonic hemolysis, and high concentration (250 μmol/l) leads to a decrease in osmotic and peroxide resistance of erythrocytes. Thus, inhibition of the activity of the enzymatic link of the antioxidant defense is observed in urogenital trichomoniasis, which is one of the mechanisms for the development of pathology at the cellular level in this disease. It has been shown that the isolated membranotropic action of metronidazole depends on its concentration – the drug at low concentration is able to inhibit hypotonic hemolysis of erythrocytes, and high concentration makes them more sensitive to the osmotic and peroxide hemolysis. The obtained results should be taken into account in the development of complex methods of therapy for urogenital trichomoniasis.

Plant-Based Antioxidant-Rich Snacks Elevate Circulating Antioxidant Capacity and Alter Gut Microbiome Profile in Older Adults

Objectives Oxidative stress and gut dysbiosis are considered as the contributors in aging. Diets rich in plant foods may against aging-associated syndrome. The present study aimed to explore the effects of plant-based antioxidant-rich smoothies and sesame snacks (PBASS) on antioxidant capacity and gut microbiome profile in older adults. Methods Healthy and sub-healthy older adults (79.7 ± 8.6 years old, F/M = 30/12) from 2 elderly care institutions were administered with PBASS for 4 months. Blood and fecal samples were collected before and after 2 and 4 months of PBASS consumption. Results PBASS consumption significantly increased plasma glutathione and total antioxidant capacity and erythrocyte protein-bound sulfhydryl groups (PBSH) and decreased hematocrit, serum albumin and erythrocyte glutathione and activities of superoxide dismutase and glutathione peroxidase in a time-dependent manner (generalized estimating equations with repeated measure analysis, P < 0.05). In females, 4 months of PBASS resulted in significant decreases in red blood cells and serum blood urea nitrogen and increases in plasma PBSH and erythrocyte total sulfhydryl groups. In the fecal microbiome profile of older adults, observed species and richness of gut microbiome were decreased after 2 months of PBASS, whereas beta-diversity and the ratio of Firmicutes to Bacteroidetes were not significantly altered by PBASS consumption. PBASS consumption significantly increased Bacteroidetes and decreased Actinobacteria and Patescibacteria in the feces. Conclusions The results of this study suggest that older adults consumed with plant-based antioxidant-rich snacks may have elevated antioxidant capacity and altered fecal microbiome profile; however, their protein nutritional status need to be monitored, especially in old females. Funding Sources MOST 106-2321-B-030-001,107-2321-B-030-001 and 108-2321-B-030-001.

Serum Sulfhydryl Groups, Malondialdehyde, Uric Acid, and Bilirubin as Predictors of Adverse Outcome in Heart Failure Patients due to Ischemic or Nonischemic Cardiomyopathy

Oxidative stress plays a significant role in the pathogenesis of heart failure (HF). The aim of the study was to investigate the prognostic value of oxidation-reduction (redox) markers in patients with HF due to ischemic and nonischemic cardiomyopathy. The study included 707 patients of HF allocated into two groups depending on ethology: ischemic cardiomyopathy (ICM) ( n = 435 ) and nonischemic cardiomyopathy (nICM) ( n = 272 ), who were followed up for one year. The endpoint occurrence (mortality or heart transplantation) in a 1-year follow-up was similar in the ICM and nICM group. The predictive value of endpoint occurrence of oxidative stress biomarkers such as the serum protein sulfhydryl groups (PSH), malondialdehyde (MDA), uric acid (UA), bilirubin, and MDA/PSH ratio and other clinical and laboratory data were assessed in both groups (ICM and nICM) separately using univariate and multivariate Cox regression analyses. In multivariate analysis, the higher concentrations of UA ( p = 0.015 , HR = 1.024 , 95% CI (1.005-1.044)) and MDA ( p = 0.004 , HR = 2.202 , 95% CI (1.296-3.741)) were significantly associated with adverse prognosis in patients with ICM. Contrastingly, in patients with nICM, we observed that higher bilirubin concentration ( p = 0.026 , HR = 1.034 , 95% CI (1.004-1.064)) and MDA/PSH ratio ( p = 0.034 , HR = 3.360 , 95% CI (1.096-10.302)) were significantly associated with increased risk of death or HT. The results showed the association of different oxidative biomarkers on the unfavorable course of heart failure depending on etiology.