scholarly journals Analysis of Bioavailability and Induction of Glutathione Peroxidase by Dietary Nanoelemental, Organic and Inorganic Selenium

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1073
Author(s):  
Mitchell T. Ringuet ◽  
Billie Hunne ◽  
Markus Lenz ◽  
David M. Bravo ◽  
John B. Furness
Keyword(s):  
Glutathione Peroxidase ◽  
Similar Efficacy ◽  
Enzymatic Assays ◽  
Germ Free ◽  
Organic Selenium ◽  
Protein Levels ◽  
Antioxidant Protein ◽  
Inorganic Selenium ◽  
Fresh Frozen ◽  
Gpx Activity

Dietary organic selenium (Se) is commonly utilized to increase formation of selenoproteins, including the major antioxidant protein, glutathione peroxidase (GPx). Inorganic Se salts, such as sodium selenite, are also incorporated into selenoproteins, and there is evidence that nanoelemental Se added to the diet may also be effective. We conducted two trials, the first investigated inorganic Se (selenite), organic Se (L-selenomethionine) and nanoelemental Se, in conventional mice. Their bioavailability and effectiveness to increase GPx activity were examined. The second trial focused on determining the mechanism by which dietary Se is incorporated into tissue, utilising both conventional and germ-free (GF) mice. Mice were fed a diet with minimal Se, 0.018 parts per million (ppm), and diets with Se supplementation, to achieve 0.07, 0.15, 0.3 and 1.7 ppm Se, for 5 weeks (first trial). Mass spectrometry, Western blotting and enzymatic assays were used to investigate bioavailability, protein levels and GPx activity in fresh frozen tissue (liver, ileum, plasma, muscle and feces) from the Se fed animals. Inorganic, organic and nanoelemental Se were all effectively incorporated into tissues. The high Se diet (1.7 ppm) resulted in the highest Se levels in all tissues and plasma, independent of the Se source. Interestingly, despite being ~11 to ~25 times less concentrated than the high Se, the lower Se diets (0.07; 0.15) resulted in comparably high Se levels in liver, ileum and plasma for all Se sources. GPx protein levels and enzyme activity were significantly increased by each diet, relative to control. We hypothesised that bacteria may be a vector for the conversion of nanoelemental Se, perhaps in exchange for S in sulphate metabolising bacteria. We therefore investigated Se incorporation from low sulphate diets and in GF mice. All forms of selenium were bioavailable and similarly significantly increased the antioxidant capability of GPx in the intestine and liver of GF mice and mice with sulphate free diets. Se from nanoelemental Se resulted in similar tissue levels to inorganic and organic sources in germ free mice. Thus, endogenous mechanisms, not dependent on bacteria, reduce nanoelemental Se to the metabolite selenide that is then converted to selenophosphate, synthesised to selenocysteine, and incorporated into selenoproteins. In particular, the similar efficacy of nanoelemental Se in comparison to organic Se in both trials is important in the view of the currently limited cheap sources of Se.

Glutathione peroxidase activity and expression levels are significantly increased in acute coronary syndromes

2017 ◽  
Vol 65 (5) ◽  
pp. 919-925 ◽  
Author(s):  
Ana Holley ◽  
Janet Pitman ◽  
John Miller ◽  
Scott Harding ◽  
Peter Larsen
Keyword(s):  
Glutathione Peroxidase ◽  
Acute Coronary Syndromes ◽  
Stable Coronary Artery Disease ◽  
Density Lipoprotein ◽  
Mrna Levels ◽  
Healthy Controls ◽  
Protein Levels ◽  
Coronary Syndromes ◽  
Stable Cad ◽  
Gpx Activity

High levels of the antioxidant enzyme, glutathione peroxidase (GPx), have been associated with improved outcomes following acute coronary syndromes (ACS), suggesting a protective role. How GPx levels are altered with coronary disease is not clearly established. This study examined GPx activity, protein, and mRNA levels in healthy controls, patients with stable coronary artery disease (CAD), and patients with ACS. We studied 20 individuals from each of the healthy control, stable CAD, and ACS groups. GPx activity and protein levels, along with oxidized low-density lipoprotein (oxLDL) were assayed in plasma. GPx mRNA levels from whole blood were quantified using real-time PCR. Levels of GPx activity in the plasma were higher in ACS (109±7.7 U/mL) compared with patients with stable CAD (95.2±16.4 U/mL, p<0.01) and healthy controls (87.6±8.3 U/mL, p<0.001). Plasma GPx protein levels were also elevated in ACS (21.6±9.5 µg/mL) compared with patients with stable CAD (16.5±2.8 µg/mL, p<0.05) and healthy controls (16.3±5.3 µg/mL, p<0.05). Levels ofGPX1,GPX3, andGPX4mRNA were significantly higher in the patients with ACS. Levels of oxLDL were also significantly higher in patients with ACS (61.9±22.2 U/L) than in patients with stable CAD (47.8±10.4 U/L, p<0.05) and healthy controls (48.9±11.9 U/L, p<0.05). Levels of oxLDL, GPx activity, protein, and mRNA are all significantly higher in patients with ACS compared with patients with stable CAD and healthy controls. These findings suggest that GPx may be upregulated in response to a change in oxidative stress during an ACS.

scholarly journals Post-transcriptional regulation of glutathione peroxidase gene expression by selenium in the HL-60 human myeloid cell line

Blood ◽  
1989 ◽  
Vol 74 (7) ◽  
pp. 2535-2541 ◽  
Author(s):  
S Chada ◽  
C Whitney ◽  
PE Newburger
Keyword(s):  
Glutathione Peroxidase ◽  
Enzymatic Activity ◽  
Cell Line ◽  
Myeloid Cell ◽  
Mrna Levels ◽  
Protein Levels ◽  
Myeloid Cell Line ◽  
Cloned Cdna ◽  
Post Transcriptional Regulation ◽  
Gpx Activity

We have used a cloned cDNA for the major human selenoprotein, glutathione peroxidase (GPx), to assess the mode of regulation of human GPx gene (GPX-1) expression by selenium. When the HL-60 human myeloid cell line is grown in a selenium-deficient medium, GPx enzymatic activity decreases 30-fold compared with selenium-replete cells. Upon return to a medium containing selenium in the form of selenite, GPx activity in the cells starts to increase within 48 hours and reaches maximal (selenium-replete) levels at 7 days. Steady-state immunoreactive protein levels correlate with enzymatic activity. Cycloheximide inhibits the rise in GPx activity that accompanies selenium replenishment, indicating that protein synthesis is required for the increase. However, GPx mRNA levels and the rate of transcription of the human GPx gene change very little and thus appear to be independent of the selenium supply. Thus the human GPx gene appears to be regulated post-transcriptionally, probably cotranslationally, in response to selenium availability.

scholarly journals Post-transcriptional regulation of glutathione peroxidase gene expression by selenium in the HL-60 human myeloid cell line

Blood ◽  
1989 ◽  
Vol 74 (7) ◽  
pp. 2535-2541 ◽  
Author(s):  
S Chada ◽  
C Whitney ◽  
PE Newburger
Keyword(s):  
Glutathione Peroxidase ◽  
Enzymatic Activity ◽  
Cell Line ◽  
Myeloid Cell ◽  
Mrna Levels ◽  
Protein Levels ◽  
Myeloid Cell Line ◽  
Cloned Cdna ◽  
Post Transcriptional Regulation ◽  
Gpx Activity

Abstract We have used a cloned cDNA for the major human selenoprotein, glutathione peroxidase (GPx), to assess the mode of regulation of human GPx gene (GPX-1) expression by selenium. When the HL-60 human myeloid cell line is grown in a selenium-deficient medium, GPx enzymatic activity decreases 30-fold compared with selenium-replete cells. Upon return to a medium containing selenium in the form of selenite, GPx activity in the cells starts to increase within 48 hours and reaches maximal (selenium-replete) levels at 7 days. Steady-state immunoreactive protein levels correlate with enzymatic activity. Cycloheximide inhibits the rise in GPx activity that accompanies selenium replenishment, indicating that protein synthesis is required for the increase. However, GPx mRNA levels and the rate of transcription of the human GPx gene change very little and thus appear to be independent of the selenium supply. Thus the human GPx gene appears to be regulated post-transcriptionally, probably cotranslationally, in response to selenium availability.

scholarly journals Relative hypoxia and oxidative stress in spleen lymphocytes of immunized Balb/c mice as indicated by HIF-1α, HIF-2α, Nrf2 expression, and glutathione peroxidase activity

2018 ◽  
Vol 27 (4) ◽  
pp. 223-8 ◽  
Author(s):  
Citra Praditi ◽  
Ani R. Prijanti ◽  
Sri W.A. Jusman ◽  
Mohamad Sadikin
Keyword(s):  
Oxidative Stress ◽  
Glutathione Peroxidase ◽  
Buffy Coat ◽  
Mrna Levels ◽  
Post Immunization ◽  
Protein Levels ◽  
Spleen Lymphocytes ◽  
And Oxidative Stress ◽  
Gpx Activity ◽  
Nrf2 Protein

Background: Lymphocytes activated by immunization must increase their metabolism to meet the energy requirements for mitosis, differentiation, and protein synthesis, which may subject the cell to conditions of relative hypoxia and oxidative stress. This study was conducted to investigate the increase in the levels of transcription factors involved in both conditions.Methods: Male Balb/c mice were divided into the following four groups, each consisting of six animals: the control and three experimental groups. The experimental groups were immunized by injection of 0.2 ml of 2% sheep red blood cells (SRBC) suspended in phosphate-buffered saline (PBS). Lymphocytes were harvested from the spleens of each group at time intervals of 24-, 48-, and 72-h post-immunization. The buffy coat from splenocytes was separated using Ficoll Histopaque as the medium. The lymphocytes were separated from adherent cells by incubating the purified splenocytes in microtubes for 2-h. Cells were lysed by three freeze–thaw cycles (−80°C and 37°C) and used to analyze the levels of HIF-1α and HIF-2α (mRNA and protein), Nrf2 (protein), and glutathione peroxidase (GPx) activity.Results: The treatment caused an increase in GPx activity and HIF-1α protein concentration 24-h post-immunization, whereas the HIF-1α mRNA levels remained static. Elevated Nrf2 protein levels were detected within 48-h after treatment. Meanwhile, the HIF-2α mRNA and protein levels increased within72-h after immunization.Conclusion: Immunization with SRBC suspension induced relative hypoxia, elevated reactive oxygen species (ROS), and oxidative stress in the lymphocytes as indicated by the increase in both HIF-1α and HIF-2α protein and mRNA levels, GPx activity, and Nrf2 protein levels.

scholarly journals Creating a ‘Molecular Band-Aid’; Blocking an Exposed Protease Target Site in Desmoplakin

2021 ◽  
Vol 11 (5) ◽  
pp. 401
Author(s):  
Catherine A. Hoover ◽  
Kendahl L. Ott ◽  
Heather R. Manring ◽  
Trevor Dew ◽  
Maegen A. Borzok ◽  
...  
Keyword(s):  
Hot Spot ◽  
Single Point ◽  
Md Simulations ◽  
Amino Acid Position ◽  
Target Site ◽  
Molecular Band ◽  
Single Point Mutation ◽  
Enzymatic Assays ◽  
Protein Levels ◽  
Clinical Variants

Desmoplakin (DSP) is a large (~260 kDa) protein found in the desmosome, a subcellular complex that links the cytoskeleton of one cell to its neighbor. A mutation ‘hot-spot’ within the NH2-terminal third of the DSP protein (specifically, residues 299–515) is associated with both cardiomyopathies and skin defects. In select DSP variants, disease is linked specifically to the uncovering of a previously-occluded calpain target site (residues 447–451). Here, we partially stabilize these calpain-sensitive DSP clinical variants through the addition of a secondary single point mutation—tyrosine for leucine at amino acid position 518 (L518Y). Molecular dynamic (MD) simulations and enzymatic assays reveal that this stabilizing mutation partially blocks access to the calpain target site, resulting in restored DSP protein levels. This ‘molecular band-aid’ provides a novel way to maintain DSP protein levels, which may lead to new strategies for treating this subset of DSP-related disorders.

scholarly journals Glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities in riboflavin-deficient rats infected with Plasmodium berghei malaria

1998 ◽  
Vol 79 (3) ◽  
pp. 305-309 ◽  
Author(s):  
D. A. Adelekan ◽  
D. I. Thurnham
Keyword(s):  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Plasmodium Berghei ◽  
Control Group ◽  
Riboflavin Deficiency ◽  
Sod Activity ◽  
Parasite Protein ◽  
Riboflavin Deficient ◽  
Gpx Activity ◽  
Deficient Group

Riboflavin deficiency interferes with the growth and multiplication of malaria parasites as well as the host response to malaria. The objective of the present work was to determine the effects of riboflavin deficiency on erythrocyte glutathione peroxidase (EC1.11.1.9; GPx) and superoxide dismutase (EC1.15.1.1; SOD) in rats infected withPlasmodium bergheimalaria. Riboflavin in its co-enzyme form, FAD, is required by glutathione reductase (EC1.6.4.1) to regenerate GSH and GSH is an important cellular antioxidant both in its own right and also as a substrate for the enzyme GPx. Weanling rats were deprived of riboflavin for 8 weeks before intraperitoneal injection of 1 × 106P. bergheiparasites. Control animals were weight-matched to the respective riboflavin-deficient group. At 10d post-infection, parasite counts were higher in the weight-matched control group than the riboflavin-deficient group (P= 0.004). GPx activity was higher in erythrocytes of rats parasitized withP. bergheithan comparable non-infected rats regardless of riboflavin status (P< 0.05). As mature erythrocytes do not synthesize new protein, the higher GPx activities were probably due to the presence of the parasite protein. In erythrocytes from riboflavin-deficient rats, GPx activity tended to be lower than in those rats fed on diets adequate in riboflavin (weight-matched controls) whether parasitized or not, but the difference was not significant. Neither riboflavin deficiency nor malaria had any effect on erythrocyte SOD activity. It was concluded that riboflavin deficiency has no marked effect on erythrocyte GPx or SOD activity in the rat.

scholarly journals Dietary supplementation of organic selenium to improve growth performance and protein utilization in African catfish fed with different protein level diets

2021 ◽  
Vol 20 (2) ◽  
pp. 130-138
Author(s):  
Giri Maruto Darmawangsa ◽  
Muhammad Agus Suprayudi ◽  
Nurbambang Priyo Utomo ◽  
Julie Ekasari
Keyword(s):  
Growth Performance ◽  
Dietary Protein ◽  
Protein Level ◽  
Dietary Supplementation ◽  
High Protein ◽  
Utilization Efficiency ◽  
African Catfish ◽  
Protein Utilization ◽  
Organic Selenium ◽  
Protein Levels

This study aimed to evaluate the effect of organic selenium supplementation on diet with different protein levels on the growth performance and protein utilization of African catfish juvenile. A randomized 2×3 factorial design with two dietary protein levels (27% and 32%) and three dietary selenium (Se) supplementation levels (0 mg/kg, 3 mg/kg, and 6 mg/kg diet) in triplicates were applied in the study. African catfish juvenile with an initial average body weight and body length of 27.00 ± 0.14 g and 15.0 ± 0.5 cm, respectively, was reared in 18 units of aquarium (141 L) at a density of 142 fish/m3 for a rearing period of 40 days. Increasing organic Se supplementation level up to 6 mg/kg at high protein feed resulted in higher fish growth and final biomass, lower FCR, and higher protein utilization efficiency than those of other treatments.  Furthermore, supplementation of organic Se also resulted in lower lipid and higher Se concentrations in the fish body as well as higher blood protein level compared to those of the control. In conclusion, the result of this study suggested that dietary supplementation of organic Se up to 6 mg/kg could enhance the growth and protein utilization in African catfish fed with both low and high protein diet.   Keywords: African catfish, growth, dietary protein, protein utilization, organic selenium.   ABSTRAK   Penelitian ini bertujuan mengevaluasi pengaruh suplementasi selenium organik pada pakan dengan kadar protein yang berbeda terhadap kinerja pertumbuhan dan pemanfaatan protein pakan ikan lele Clarias gariepenus. Penelitian didesain menggunakan rancangan acak lengkap faktorial 2×3 dengan dua tingkat protein pakan (27% dan 32%) dan tiga tingkat suplementasi selenium (Se) pakan (0 mg/kg, 3 mg/kg, dan 6 mg/kg diet) sebanyak tiga ulangan. Ikan lele yang digunakan memiliki bobot awal rata-rata dan panjang tubuh 27 ± 0.14 g dan 15.0 ± 0.5 cm, dipelihara dalam 18 unit akuarium (141 L) dengan kepadatan 142 ekor/m3 selama 40 hari pemeliharaan. Peningkatan suplementasi Se organik hingga 6 mg/kg pada ikan yang diberi pakan protein tinggi menghasilkan kinerja pertumbuhan ikan dan biomassa akhir yang lebih tinggi, FCR yang lebih rendah, dan efisiensi pemanfaatan protein pakan yang lebih tinggi daripada perlakuan lain. Selain itu, suplementasi Se organik juga menghasilkan kadar lemak yang lebih rendah dan konsentrasi Se tubuh yang lebih tinggi serta kadar protein darah yang lebih tinggi. Kesimpulan dari penelitian ini yaitu suplementasi Se organik pada pakan hingga 6 mg/kg dapat meningkatkan kinerja pertumbuhan dan pemanfaatan protein pakan pada ikan lele yang diberi pakan dengan kadar protein rendah dan tinggi.   Kata kunci: ikan lele, pertumbuhan, protein pakan, pemanfaatan protein, selenium organik.

scholarly journals Effects of Moderate Intensity Exercise on Glutathione Peroxidase Activity and VO2max in Elderly Women

2020 ◽  
Vol 8 (A) ◽  
pp. 230-233
Author(s):  
Gusbakti Rusip ◽  
Sri Mukti Suhartini
Keyword(s):  
Glutathione Peroxidase ◽  
Aerobic Exercise ◽  
Elderly Women ◽  
The Elderly ◽  
Walking Distance ◽  
Moderate Intensity ◽  
Optimum Level ◽  
Moderate Intensity Exercise ◽  
Spearman Test ◽  
Gpx Activity

BACKGROUND: Sedentary lifestyle in the elderly decreases the function of cardiovascular system may lead reduction performance. Many previous studies reported that moderate intensity aerobic exercise was recommended for older persons because it may increases reactive oxygen species (ROS) at optimum level. The increasing of ROS can activate antioxidant mechanism against oxidatif stress due to exercise. AIM: The aim of this study was to investigate the change of glutathione peroxidase (GPx) activity and VO2max on moderate intensity aerobic exercise and its correlation. METHODS: The study design was quasi-experimental. Subjects were sedentary elderly women age 65 ± 5.06 years old. Total subject was 73 persons selected by consecutive sampling. Subjects did moderate intensity aerobic exercise for 12 weeks by walking for 30 min a day, 3 times a week at 50–85% of maximum heart rate. The parameters were measured on the baseline and 12 weeks after exercise. GPx activity from the plasma was examined by ELISA and the VO2max was measured by 6-min walking distance. The data were analyzed by unpaired t-test and Spearman test. RESULTS: GPx activity and VO2max were significantly increased about 41.75% and 24.11% (p < 0.05) on the experimental group, respectively. There was a correlation between GPx activity and VO2max (r = 0.223, p = 0.041). CONCLUSION: Regular moderate intensity aerobic exercise significantly increased GPx activity and VO2max. This kind of exercise is advised for the elderly because it can elevate antioxidant level as a defense against oxidative stress due to aging; therefore, it can improve aerobic capacity in the elderly.

Response of growing cattle to supplementation with organically bound or inorganic sources of selenium or yeast cultures

1991 ◽  
Vol 71 (3) ◽  
pp. 803-811 ◽  
Author(s):  
J. W. G. Nicholson ◽  
R. E. McQueen ◽  
R. S. Bush
Keyword(s):  
Glutathione Peroxidase ◽  
Whole Blood ◽  
Yeast Culture ◽  
Feed Conversion ◽  
Or Efficiency ◽  
Linear Rate ◽  
Beef Calves ◽  
Organic Selenium ◽  
Yeast Cultures ◽  
Holstein Calves

Bioavailability of organically bound and inorganic Se sources differ, the organic form being absorbed more efficiently. Dairy and beef calves (250 kg initial weight) were given a low Se diet alone or supplemented with sodium selenite (1 mg Se d−1; inorganic Se), a Se-enriched yeast (1.5 g yeast d−1 providing 1 mg of Se; organic Se), a live yeast culture (1.5 g d−1) or autoclaved yeast culture (1.5 g d−1). The latter treatments were included to determine the response to yeast per se. There were no treatment effects on rate of weight gain or efficiency of feed conversion by the calves. The Se souces had no effect on digestibility of the diet by sheep. The inorganic Se supplement increased the level of whole blood Se and glutathione peroxidase (GSH-Px) activity at a linear rate with time up to 3 mo from the start of supplementation. The effect of organic Se was sustained for 4 mo and both indices of Se status in blood were higher (P < 0.01) for calves fed the organic Se than for those fed inorganic Se after 4 mo (124 vs. 96 units of GSH-Px activity g−1 haemoglobin and 141 vs. 102 μg Se L−1 of whole blood). The values near the beginning of the trial were higher (P < 0.01) for Holstein calves than for beef calves but both groups showed the same response to source of Se. Subsequently, levels declined for Holstein and increased for beef calves given diets without supplemental Se. The results showed that Se supplementation for 4 mo had no effect on animal performance; that more than 4 mo are required to fully deplete or replete blood Se and GSH-Px; and, that supplemental organic Se gives higher (P < 0.01) blood Se and GSH-Px activity than does inorganic Se. Key words: Organic selenium, calves, glutathione peroxidase

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