scholarly journals Production of In Vitro Lytic Characteristics of Paroxysmal Nocturnal Hemoglobinuria Erythrocytes in Normal Erythrocytes

Blood ◽  
1968 ◽  
Vol 32 (1) ◽  
pp. 49-58 ◽  
Author(s):  
HERBERT E. KANN ◽  
CHARLES E. MENGEL ◽  
WILHELM D. MERIWETHER ◽  
LARRY EBBERT
Keyword(s):  
Disulfide Bonds ◽  
Reduced Glutathione ◽  
Lipid Peroxide ◽  
Acetylcholinesterase Activity ◽  
Membrane Lipid ◽  
Alkaline Solutions ◽  
Magnesium Ion ◽  
Ph Optimum ◽  
Protein Disulfide Bonds

Abstract The concept that production of a "perfect" PNH RBC, artificially, might supply information as to the nature of the defect(s) in PNH RBCs was the basis for a study in which normal RBCs were studied after preincubation in concentrated, alkaline solutions of reduced glutathione. These RBCs exhibited the following features of PNH RBCs. 1. Sensitivity to lysis by acidified serum a. pH optimum identical to that of PNH RBCs b. complete prevention by prior heating of serum to 56° C for 30 minutes c. complete prevention by addition of dextran to serum d. complete prevention by removal of magnesium ion from serum, reversed by re-addition of magnesium ion to serum 2. Positive thrombin lysis test. 3. Positive sucrose lysis test. 4. No agglutination in type-compatible serum. 5. No greater than normal agglutination in serum containing isoantibodies or elevated titers of cold agglutinins, but marked enhancement of lytic sensitivity to these antibodies, identical to that achieved with "natural" PNH cells. 6. Positive Hegglin-Maier test. 7. Decreased acetylcholinesterase activity. 8. Increased lysis and lipid peroxide formation during incubation with hydrogen peroxide. The broad scope of these similarities permits cautious speculation that some biochemical feature(s) of PNH RBCs may have been produced in normal RBCs, artificially. The mechanism by which reduced glutathione produces the change is uncertain, but may involve either oxidation of membrane lipid or splitting of membrane protein disulfide bonds, or both.

scholarly journals A Novel Group of Glutaredoxins in the cis-Golgi Critical for Oxidative Stress Resistance

2008 ◽  
Vol 19 (6) ◽  
pp. 2673-2680 ◽  
Author(s):  
Nikola Mesecke ◽  
Anne Spang ◽  
Marcel Deponte ◽  
Johannes M. Herrmann
Keyword(s):  
Disulfide Bonds ◽  
Secretory Pathway ◽  
Reduced Glutathione ◽  
General Role ◽  
Growth Defects ◽  
Early Secretory Pathway ◽  
Full Complement ◽  
Increased Sensitivity ◽  
Substrate Proteins

Glutaredoxins represent a ubiquitous family of proteins that catalyze the reduction of disulfide bonds in their substrate proteins by use of reduced glutathione. In an attempt to identify the full complement of glutaredoxins in baker's yeast, we found three so-far uncharacterized glutaredoxin-like proteins that we named Grx6, Grx7, and Grx8. Grx6 and Grx7 represent closely related monothiol glutaredoxins that are synthesized with N-terminal signal sequences. Both proteins are located in the cis-Golgi, thereby representing the first glutaredoxins found in a compartment of the secretory pathway. In contrast to formerly described monothiol glutaredoxins, Grx6 and Grx7, showed a high glutaredoxin activity in vitro. Grx6 and Grx7 overlap in their activity and deletion mutants lacking both proteins show growth defects and a strongly increased sensitivity toward oxidizing agents such as hydrogen peroxide or diamide. Our observations suggest that Grx6 and Grx7 do not play a general role in the oxidative folding of proteins in the early secretory pathway but rather counteract the oxidation of specific thiol groups in substrate proteins.

Prophylactic Effect Of Aqueous Propolis Extract Against Acute Experimental Hepatotoxicity In Vivo

2002 ◽  
Vol 57 (3-4) ◽  
pp. 379-385 ◽  
Author(s):  
Aiman S. El-Khatib ◽  
Azza M. Agha ◽  
Laila G. Mahran ◽  
Mohamed T. Khayyal
Keyword(s):  
Reduced Glutathione ◽  
Wide Spectrum ◽  
Folk Medicine ◽  
Lipid Peroxide ◽  
Isolated Hepatocytes ◽  
Propolis Extract ◽  
Single Intraperitoneal Injection ◽  
Liver Homogenates

Propolis has been extensively used in folk medicine for the management of a wide spectrum of disorders. In a previous study, we demonstrated the protective effect of the aqueous propolis extract (APE) against the injurious effects of carbon tetrachloride (CCl4) on hepatocytes in vitro. The present investigation was carried out to show whether the hepatoprotective effect of the extract could also be manifested in vivo. Rats were given APE orally for 14 consecutive days, before being subjected to a single intraperitoneal injection of CCl4. One day after the CCl4 injection, the animals were sacrificed, hepatocytes were isolated and liver homogenates were prepared for the assessment of liver injury. In isolated hepatocytes, APE afforded protection against CCl4-induced injury as manifested by a decrease in the leakage of the cytosolic enzyme lactate dehydrogenase (LDH), decreased generation of lipid peroxide and maintenance of cellular reduced glutathione (GSH) content. In principle, similar findings were observed in liver homogenates. The present findings show that APE has in vivo hepatoprotective potential which could be attributed at least in part to the maintenance of cellular GSH content. The latter effect seems to play an important role in conserving the integrity of biomembranes as it was associated with a decrease in lipid peroxidation and reduced leakage of cytosolic LDH

scholarly journals Effect of Exogenous Glutathione, Glutathione Reductase, Chlorine Dioxide, and Chlorite on Osmotic Fragility of Rat Blood In Vitro

1984 ◽  
Vol 3 (4) ◽  
pp. 269-275 ◽  
Author(s):  
M. S. Abdel-Rahman ◽  
D. Couri ◽  
R. J. Bull
Keyword(s):  
Glutathione Reductase ◽  
Chlorine Dioxide ◽  
Disulfide Bonds ◽  
Reduced Glutathione ◽  
Osmotic Fragility ◽  
Rat Blood ◽  
Before And After ◽  
The Difference

Chlorine dioxide (CIO2), chlorite (CIO-2), and chlorate (CIO-3) in drinking water decreased blood glutathione and RBC osmotic fragility in vivo. The osmotic fragility and glutathione content were also studied in rat blood treated with CIO2, CIO-2, CIO-3 in vitro. RBC hemolysis was decreased in rat blood after 30, 60, and 120 minutes by all treatments. The glutathione content expressed as percentage of controls was decreased with incubation time. When CIO2 was added with reduced glutathione (GSH) to the blood, no effect on hemolysis was observed compared to control or to GSH alone at 2 hours, but decreased hemolysis was observed with CIO2 treatment alone. Addition of NADPH alone prevented CIO2 and CIO-2 and CIO-3 from exhibiting hemolysis resistance, while glutathione reductase (GR) and its cofactor (NADPH) increased hemolysis about 1.5–2 fold. Removing GR only resulted in increased resistance to hemolysis with CIO2 or CIO-2. The formation of disulfide bonds between sulfhydryl groups in erythrocytic membranes and hemoglobin, causing precipitation of hemoglobin (yielding apparent resistance to hemolysis) can account for the difference between the hemolysis before and after the addition of GR.

THE ROLE OF REDUCED GLUTATHIONE IN THYROGLOBULIN PROTEOLYSIS IN VITRO

1975 ◽  
Vol 79 (1) ◽  
pp. 76-85 ◽  
Author(s):  
M. A. Pisarev ◽  
J. E. Dumont
Keyword(s):  
Tissue Concentration ◽  
Reduced Glutathione ◽  
Hormone Secretion ◽  
Low Ph ◽  
Acid Protease ◽  
Ph Optimum ◽  
Distribution Studies ◽  
Enzyme Source

ABSTRACT During the process of secretion of the thyroid hormones, stored thyroglobulin (Tg) is digested within the lysosomes. An acid protease has been found, but this enzyme hydrolyses Tg at a relatively slow rate and has a low pH optimum (3.6). Since previous work has shown a stimulatory effect of reduced glutathione (GSH) on Tg digestion the following studies have been performed. Homogenates were obtained from dog thyroid and total homogenate or different subcellular fractions were used as enzyme source. Labelled thyroglobulin (125I) was purified from prelabelled dog thyroid and its hydrolysis, judged from the increase in butanol soluble radioactivity, was studied. The greatest stimulatory effect of GSH on Tg hydrolysis was found around pH 5.6. When butanol soluble radioactivity was considered as a function of incubation time and tissue concentration a linear relationship was found. GSH effect was evident at 2 mm. Subcellular distribution studies showed that the GSH-stimulated proteolytic activity was mainly found in the 15 000 × g pellet. Labelled Tg hydrolysis was progressively decreased with increasing amounts of non-labelled purified Tg. GSH also stimulated labelled insulin hydrolysis, but failed to alter haemoglobin or casein degradation. GSH could also be replaced by other reducing agents, like cysteine or dithiothreitol. The significance of these findings is discussed in relation to the process of thyroid hormone secretion.

scholarly journals Decreased enzymic protection and increased sensitivity to oxidative damage in erythrocytes as a function of cell and donor aging

1984 ◽  
Vol 218 (2) ◽  
pp. 531-537 ◽  
Author(s):  
G A Glass ◽  
D Gershon
Keyword(s):  
Gradient Centrifugation ◽  
Lipid Peroxide ◽  
Lipid Peroxides ◽  
Thiobarbituric Acid ◽  
Membrane Lipid ◽  
Cell Aging ◽  
Young Rats ◽  
Old Rats ◽  
Specific Activities

Erythrocytes from young and old rats were separated into four age fractions by density-gradient centrifugation. The specific activities per cell were determined for glucose-6-phosphate dehydrogenase (EC 1.1.1.49), glutathione peroxidase (EC 1.11.1.9), glutathione reductase (EC 1.6.4.2) and catalase (EC 1.11.1.6). Decreased specific activities were observed with increasing cell age for all four enzymes in both young and old animals. In addition, significant differences in the activities of these enzymes were observed between cells of the same age fraction from young and old donors. Susceptibility of fractionated erythrocytes to oxidative attack in vitro generated by incubation with xanthine/xanthine oxidase increased with both cell and animal age. The amount of membrane-lipid peroxidation also increased with cell and animal aging, as measured by both thiobarbituric acid and fluorescent chromolipid assays. Increases of 2-3-fold in the contents of lipid peroxides were observed between the youngest and oldest age fractions of young rats. Lipid peroxide contents in young cells of old animals were equal to those in old erythrocytes from young rats and increased by 30% with cell aging in the old donors. These results suggest that the extent of enzymic protection against oxidative and peroxidative damage decreases with erythrocyte aging. More importantly, enzymic protection in cells of old rats is considerably decreased already in the early stages of their lifespan.

scholarly journals The Combination of Bromelain and Acetylcysteine (BromAc) Synergistically Inactivates SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 425 ◽  
Author(s):  
Javed Akhter ◽  
Grégory Quéromès ◽  
Krishna Pillai ◽  
Vahan Kepenekian ◽  
Samina Badar ◽  
...  
Keyword(s):  
Envelope Protein ◽  
Disulfide Bonds ◽  
Host Cells ◽  
Nasal Administration ◽  
Disulfide Bridges ◽  
Dependent Inactivation ◽  
Virus Culture ◽  
Protein Disulfide Bonds ◽  
Protein Disulfide

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection is the cause of a worldwide pandemic, currently with limited therapeutic options. The spike glycoprotein and envelope protein of SARS-CoV-2, containing disulfide bridges for stabilization, represent an attractive target as they are essential for binding to the ACE2 receptor in host cells present in the nasal mucosa. Bromelain and Acetylcysteine (BromAc) has synergistic action against glycoproteins by breakage of glycosidic linkages and disulfide bonds. We sought to determine the effect of BromAc on the spike and envelope proteins and its potential to reduce infectivity in host cells. Recombinant spike and envelope SARS-CoV-2 proteins were disrupted by BromAc. Spike and envelope protein disulfide bonds were reduced by Acetylcysteine. In in vitro whole virus culture of both wild-type and spike mutants, SARS-CoV-2 demonstrated a concentration-dependent inactivation from BromAc treatment but not from single agents. Clinical testing through nasal administration in patients with early SARS-CoV-2 infection is imminent.

Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition

1982 ◽  
Vol 48 (01) ◽  
pp. 049-053 ◽  
Author(s):  
C G Fenn ◽  
J M Littleton
Keyword(s):  
Platelet Aggregation ◽  
Lipid Composition ◽  
Saturated Fatty Acids ◽  
Calcium Ionophore ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Increased Sensitivity

SummaryEthanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.

Acetylcholinesterase Inhibitory Potential and Antioxidant Activities of Five Cultivars of Rosa Damascena Mill. From Isparta, Turkey

2020 ◽  
Vol 18 (4) ◽  
pp. 354-359
Author(s):  
Shirin Tarbiat ◽  
Azize Simay Türütoğlu ◽  
Merve Ekingen
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Free Radical ◽  
Neurodegenerative Disorder ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Acetylcholinesterase Activity ◽  
Rosa Damascena ◽  
Free Radical Damage

Alzheimer's disease is a neurodegenerative disorder characterized by memory loss and impairment of language. Alzheimer's disease is strongly associated with oxidative stress and impairment in the cholinergic pathway, which results in decreased levels of acetylcholine in certain areas of the brain. Hence, inhibition of acetylcholinesterase activity has been recognized as an acceptable treatment against Alzheimer's disease. Nature provides an array of bioactive compounds, which may protect against free radical damage and inhibit acetylcholinesterase activity. This study compares the in vitro antioxidant and anticholinesterase activities of hydroalcoholic extracts of five cultivars of Rosa Damascena Mill. petals (R. damascena 'Bulgarica', R. damascena 'Faik', R. damascena 'Iranica', R. damascena 'Complex-635' and R. damascena 'Complex-637') from Isparta, Turkey. The antioxidant activities of the hydroalcoholic extracts were tested for ferric ion reduction and DPPH radical scavenging activities. The anti-acetylcholinesterase activity was also evaluated. All rose cultivars showed a high potency for scavenging free radical and inhibiting acetylcholinesterase activity. There was a significant correlation between antioxidant and acetylcholinesterase inhibitory activity. Among cultivars, Complex-635 showed the highest inhibitory effect with an IC50 value of 3.92 µg/mL. Our results suggest that all these extracts may have the potential to treat Alzheimer's disease with Complex-635 showing more promise.

Spirocyclohexadienones as an Uncommon Scaffold for Acetylcholinesterase Inhibitory Activity

2019 ◽  
Vol 15 (4) ◽  
pp. 373-382 ◽  
Author(s):  
Ralph C. Gomes ◽  
Renata P. Sakata ◽  
Wanda P. Almeida ◽  
Fernando Coelho
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Population Aging ◽  
Acetylcholinesterase Inhibitors ◽  
Acetylcholinesterase Activity ◽  
Docking Study ◽  
Biological Properties ◽  
Ache Inhibitor ◽  
Molecular Docking Study

Background: The most important cause of dementia affecting elderly people is the Alzheimer’s disease (AD). Patients affected by this progressive and neurodegenerative disease have severe memory and cognitive function impairments. Some medicines used for treating this disease in the early stages are based on inhibition of acetylcholinesterase. Population aging should contribute to increase the cases of patients suffering from Alzheimer's disease, thus requiring the development of new therapeutic entities for the treatment of this disease. Methods: The objective of this work is to identify new substances that have spatial structural similarity with donepezil, an efficient commercial drug used for the treatment of Alzheimer's disease, and to evaluate the capacity of inhibition of these new substances against the enzyme acetylcholinesterase. Results: Based on a previous results of our group, we prepared a set of 11 spirocyclohexadienones with different substitutions patterns in three steps and overall yield of up to 59%. These compounds were evaluated in vitro against acetylcholinesterase. We found that eight of them are able to inhibit the acetylcholinesterase activity, with IC50 values ranging from 0.12 to 12.67 µM. Molecular docking study indicated that the spirocyclohexadienone, 9e (IC50 = 0.12 µM), a mixedtype AChE inhibitor, showed a good interaction at active site of the enzyme, including the cationic (CAS) and the peripheral site (PAS). Conclusion: We described the first study aimed at investigating the biological properties of spirocyclohexadienones as acetylcholinesterase inhibitors. Thus, we have identified an inhibitor, which provided valuable insights for further studies aimed at the discovery of more potent acetylcholinesterase inhibitors.

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