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Several proteins and peptides tend to form an amyloid fibril, causing a range of unrelated diseases, from neurodegenerative to certain types of cancer. In the native state, these proteins are folded and soluble. However, these proteins acquired ß-sheet amyloid fibril due to unfolding and aggregation. The conversion mechanism from well-folded soluble into amorphous or amyloid fibril is not well understood yet. Here, we induced unfolding and aggregation of hen egg-white lysozyme (HEWL) by reducing agent dithiothreitol and applied mechanical sheering force by constant shaking (1000 rpm) on the thermostat for 7 days. Our turbidity results showed that reduced HEWL rapidly formed aggregates, and a plateau was attained in nearly 5 h of incubation in both shaking and non-shaking conditions. The turbidity was lower in the shaking condition than in the non-shaking condition. The thioflavin T binding and transmission electron micrographs showed that reduced HEWL formed amorphous aggregates in both conditions. Far-UV circular dichroism results showed that reduced HEWL lost nearly all alpha-helical structure, and ß-sheet secondary structure was not formed in both conditions. All the spectroscopic and microscopic results showed that reduced HEWL formed amorphous aggregates under both conditions.
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Amiloide , Muramidasa , Animales , Temperatura , Muramidasa/química , Amiloide/química , Dicroismo Circular , Concentración de Iones de Hidrógeno , Pollos/metabolismoRESUMEN
Background and Objectives: Glycation and oxidative stress are the major contributing factors responsible for diabetes and its secondary complications. Aminoguanidine, a hydrazine derivative, is the only approved drug that reduces glycation with its known side effects. As a result, research into medicinal plants with antioxidant and antiglycation properties is beneficial in treating diabetes and its consequences. This investigation aimed to examine the efficacy of the aqueous extract of Nigella sativa seeds against the D-ribose-induced glycation system. Materials and Methods: The suppression of α-amylase and α-glucosidase enzymes were used to assess the antidiabetic capacity. UV-Visible, fluorescence, and FTIR spectroscopy were used to characterize the Nigella sativa seed extract and its efficacy in preventing glycation. The inhibition of albumin glycation, fluorescent advanced glycation end products (AGEs) formation, thiol oxidation, and amyloid formation were used to evaluate the extracts' antiglycation activity. In addition, the extent of glycoxidative DNA damage was analyzed using agarose gel electrophoresis. Results: The IC50 for the extract in the α-amylase and α-glucosidase enzyme inhibition assays were approximately 1.39 ± 0.016 and 1.01 ± 0.022 mg/mL, respectively. Throughout the investigation, it was found that the aqueous extract of Nigella sativa seeds (NSAE) inhibited the level of ketoamine, exerted a considerable drop in fluorescence intensity, and reduced carbonyl production and thiol modification when added to the D-ribose-induced glycation system. In addition, a reduction in the BSA-cross amyloid formation was seen in the Congo red, thioflavin T assay, and electrophoretic techniques. NSAE also exhibited a strong capability for DNA damage protection. Conclusion: It can be concluded that Nigella sativa could be used as a natural antidiabetic, antiglycation treatment and a cost-effective and environmentally friendly source of powerful bioactive chemicals.
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Nigella sativa , Extractos Vegetales , alfa-Amilasas , alfa-Glucosidasas , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Reacción de Maillard , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Extractos Vegetales/química , Ribosa , Semillas , Compuestos de SulfhidriloRESUMEN
BACKGROUND: Diabetes mellitus is one of the major global health disorders increasing at an alarming rate in both developed and developing countries. The objective of this study was to assess the effect of aqueous extract of Momordica charantia (AEMC) on fasting blood glucose (FBG), tissue glycogen, glycosylated haemoglobin, plasma concentrations of insulin and GLP-1 hormone (glucagon-like peptide 1) in healthy and diabetic wistar rats. METHODS: Male Wistar rats (both normal and diabetic) were treated with AEMC by gavaging (300 mg/kg body wt/day for 28 days). RESULTS: AEMC was found to increase tissue glycogen, serum insulin and GLP-1 non-significantly (P > 0.05) in normal, significantly (P < 0.01) in diabetic Wistar rats, whereas decrease in FBG and Glycosylated haemoglobin non-significantly (P > 0.05) in normal, significantly (P < 0.01) in diabetic Wistar rats. The elevation of GLP-1 level in normal and diabetic treated groups may be due to the L-cell regeneration and proliferation by binding with L-cell receptors and makes a conformational change, resulting in the activation of a series of signal transducers. The polar molecules of M. charantia also depolarize the L-cell through elevation of intracellular Ca2+ concentration and which in turn releases GLP-1. GLP-1 in turn elevates beta-cell proliferation and insulin secretion. CONCLUSION: The findings tend to provide a possible explanation for the hypoglycemic action of M. charantia fruit extracts as alternative nutritional therapy in the management and treatment of diabetes.
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Diabetes Mellitus Experimental/metabolismo , Péptido 1 Similar al Glucagón/sangre , Hipoglucemiantes , Momordica charantia , Extractos Vegetales , Animales , Diabetes Mellitus Experimental/sangre , Péptido 1 Similar al Glucagón/metabolismo , Glucógeno/análisis , Glucógeno/metabolismo , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/farmacología , Insulina/sangre , Insulina/metabolismo , Masculino , Extractos Vegetales/administración & dosificación , Extractos Vegetales/farmacología , Ratas , Ratas WistarRESUMEN
Following publication of the original article [1], the authors reported that there was an error in the acknowledgements.
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Following publication of the original article [1], the authors reported that there was an error in the acknowledgements. In this Correction, the incorrect and correct acknowledgements are shown.
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Diabetes-induced damages in brain are known as diabetic encephalopathy, which is well characterized by cellular, molecular and functional changes in the brain of diabetic subjects and rodents. However, little is known about the mechanism of damages and the therapeutic strategies in ameliorating those damages in the diabetic brain. In this study, we utilized a flavonoid, morin which is emerging as a potent drug against a wide range of free radical-mediated as well as neurodegenerative diseases. Morin (15 and 30 mg/kg body weight/day) was orally administered to two different groups of rats after 1 week of diabetes induction, and continued for five consecutive weeks. Two other untreated groups of diabetic and non-diabetic rats were used to compare with drug-treated groups. After drug treatments, cerebral cortex of the brain harvested and analyzed for different factors. Morin supplementation especially at high dose increased the levels of insulin, reduced glutathione, superoxide dismutase and catalase activities, and decreased fasting glucose and thiobarbituric acid reactive substances in the diabetic brain compared to untreated diabetic rats (P < 0.05). Morin also significantly decreased the level of inflammatory markers (TNFα, IL1ß, IL-6) in the diabetic brain compared to untreated diabetic rats. Furthermore, the drug influenced an increase in the level of neurotrophic factors (BDNF, NGF and IGF-1) in the diabetic brain compared to untreated diabetic rats (P < 0.05). Thus, our results indicate a beneficial effect of morin by decreasing oxidative stress, inflammation and increasing the neurotrophic support in the diabetic brain, which may ameliorate diabetic encephalopathy.
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Antioxidantes/uso terapéutico , Diabetes Mellitus Experimental , Flavonoides/uso terapéutico , Inflamación , Factores de Crecimiento Nervioso/metabolismo , Estrés Oxidativo/efectos de los fármacos , Animales , Antioxidantes/farmacología , Glucemia/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/fisiopatología , Catalasa/metabolismo , Citocinas/metabolismo , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/patología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Flavonoides/farmacología , Glutatión/metabolismo , Inflamación/tratamiento farmacológico , Inflamación/etiología , Inflamación/metabolismo , Masculino , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismo , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
Diabetic retinopathy (DR) is one of the major complications of diabetes causing vision loss and blindness worldwide. DR is widely recognized as a neurodegenerative disease as evidenced from early changes at cellular and molecular levels in the neuronal component of the diabetic retina, which is further supported by various retinal functional tests indicating functional deficits in the retina soon after diabetes progression. Diabetes alters the level of a number of neurodegenerative metabolites, which increases influx through several metabolic pathways which in turn induce an increase in oxidative stress and a decrease in neurotrophic factors, thereby damage retinal neurons. Loss of neurons may implicate in vascular pathology, a clinical signs of DR observed at later stages of the disease. Here, we discuss diabetes-induced potential metabolites known to be detrimental to neuronal damage and their mechanism of action. In addition, we highlight important neurotrophic factors, whose level have been found to be dysregulated in diabetic retina and may damage neurons. Furthermore, we discuss potential drugs and strategies based on targeting diabetes-induced metabolites, metabolic pathways, oxidative stress, and neurotrophins to protect retinal neurons, which may ameliorate vision loss and vascular damage in DR.
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Diabetic retinopathy (DR) is widely recognized as a neurovascular disease. Retina, being a neuronal tissue of the eye, produces neurotrophic factors for its maintenance. However, diabetes dysregulates their levels and thereby may damage the retina. Among neurotrophins, brain derived neurotrophic factor (BDNF) is the most abundant in the retina. In this study, we investigated the level of BDNF in the serum of patients with DR and also in the serum and retina of streptozotocin-induced diabetic rats. The level of BDNF was significantly decreased in the serum of proliferative diabetic retinopathy patients as compared to that of non-diabetic healthy controls (25.5 ± 8.5-10.0 ± 8.1 ng/ml, p < 0.001) as well as compared to that of diabetic patients with no retinopathy (21.8 ± 4.7-10.0 ± 8.1 ng/ml, p < 0.001), as measured by ELISA techniques. The levels of BDNF in the serum and retina of diabetic rats were also significantly reduced compared to that of non-diabetic controls (p < 0.05). In addition, the expression level of tropomyosin-related kinase B (TrkB) was significantly decreased in diabetic rat retina compared to that of non-diabetic controls as determined by Western blotting technique. Caspase-3 activity was increased in diabetic rat retina after 3 weeks of diabetes and remained elevated until 10 weeks, which negatively correlated with the level of BDNF (r = -0.544, p = 0.013). Our results indicate that reduced levels of BDNF in diabetes may cause apoptosis and neurodegeneration early in diabetic retina, which may lead to neuro-vascular damage later in DR.
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Factor Neurotrófico Derivado del Encéfalo/sangre , Diabetes Mellitus Experimental/metabolismo , Retinopatía Diabética/sangre , Retina/metabolismo , Animales , Western Blotting , Estudios de Casos y Controles , Caspasa 3/metabolismo , Demografía , Diabetes Mellitus Experimental/sangre , Retinopatía Diabética/enzimología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ratas , Receptor trkB/metabolismo , Retina/enzimología , Retina/patologíaRESUMEN
Neurodegeneration is an early event in the diabetic retina which may lead to diabetic retinopathy. One of the potential pathways in damaging retinal neurons is the activation of renin angiotensin system including angiotensin II type 1 receptor (AT1R) in the diabetic retina. The purpose of this study was to determine the effect of telmisartan, an AT1R blocker on retinal level of brain derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and tyrosine hydroxylase (TH), glutathione (GSH) and caspase activity in the diabetic rats. The dysregulated levels of these factors are known to cause neurodegeneration in diabetic retina. Three weeks streptozotocin induced diabetic rats were orally treated or untreated with telmisartan (10 mg/kg/day). After 4 weeks of treatments, the levels of BDNF and GSH were found to be increased systemically in the sera as well as in the retina of diabetic rats compared to untreated rats as measured by enzyme-linked immunosorbent assay and biochemical techniques (p < 0.05). The caspase-3 activity in the telmisartan treated diabetic retina was decreased compared to untreated diabetic rats (p < 0.05). Western blotting experiments showed the expression levels of BDNF, CNTF and TH were increased compared to untreated diabetic rats (p < 0.05). Thus, our findings show a beneficial effect of AT1R blocker telmisartan in efficiently increasing neurotrophic support, endogenous antioxidant GSH content, and decreasing signs of apoptosis in diabetic retina.
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Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bencimidazoles/farmacología , Benzoatos/farmacología , Diabetes Mellitus Experimental/metabolismo , Estrés Oxidativo/efectos de los fármacos , Animales , Glucemia/análisis , Western Blotting , Factor Neurotrófico Derivado del Encéfalo/sangre , Ensayo de Inmunoadsorción Enzimática , Glutatión/sangre , Glutatión/metabolismo , Masculino , Ratas , Ratas Wistar , Estreptozocina , TelmisartánRESUMEN
Diabetic retinopathy (DR) is the most common complication of diabetes. It causes vision loss, and the incidence is increasing with the growth of the diabetes epidemic worldwide. Over the past few decades a number of clinical trials have confirmed that careful control of glycemia and blood pressure can reduce the risk of developing DR and control its progression. In recent years, many treatment options have been developed for clinical management of the complications of DR (e.g., proliferative DR and macular edema) using laser-based therapies, intravitreal corticosteroids and anti-vascular endothelial growth factors, and vitrectomy to remove scarring and hemorrhage, but all these have limited benefits. In this review, we highlight and discuss potential molecular targets and new approaches that have shown great promise for the treatment of DR. New drugs and strategies are based on targeting a number of hyperglycemia-induced metabolic stress pathways, oxidative stress and inflammatory pathways, the renin-angiotensin system, and neurodegeneration, in addition to the use of stem cells and ribonucleic acid interference (RNAi) technologies. At present, clinical trials of some of these newer drugs in humans are yet to begin or are in early stages. Together, the new therapeutic drugs and approaches discussed may control the incidence and progression of DR with greater efficacy and safety.
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Antiinflamatorios/uso terapéutico , Retinopatía Diabética/tratamiento farmacológico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Antioxidantes/uso terapéutico , Humanos , Hiperglucemia/tratamiento farmacológico , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Poli(ADP-Ribosa) Polimerasas/metabolismoRESUMEN
Diabetic retinopathy is widely considered to be a neurovascular disease. This is in contrast to its previous identity as solely a vascular disease. Early in the disease progression of diabetes, the major cells in the neuronal component of the retina consist of retinal ganglion cells and glial cells, both of which have been found to be compromised. A number of retinal function tests also indicated a functional deficit in diabetic retina, which further supports dysfunction of neuronal cells. As an endocrinological disorder, diabetes alters metabolism both systemically and locally in several body organs, including the retina. A growing body of evidences indicates increased levels of excitotoxic metabolites, including glutamate, branched chain amino acids and homocysteine in cases of diabetic retinopathy. Also present, early in the disease, are decreased levels of folic acid and vitamin-B12, which are potential metabolites capable of damaging neurons. These altered levels of metabolites are found to activate several metabolic pathways, leading to increases in oxidative stress and decreases in the level of neurotrophic factors. As a consequence, they may damage retinal neurons in diabetic patients. In this review, we have discussed those potential excitotoxic metabolites and their implications in neuronal damage. Possible therapeutic targets to protect neurons are also discussed. However, further research is needed to understand the exact molecular mechanism of neurodegeneration so that effective neuroprotection strategies can be developed. By protecting retinal neurons early in diabetic retinopathy cases, damage of retinal vessels can be protected, thereby helping to ameliorate the progression of diabetic retinopathy, a leading cause of blindness worldwide.
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This study aimed to investigate the chemical composition and antidiabetic properties of cultivated Hyoscyamus albus L. The ethanol extract was analyzed using LC-MS/MS, and 18 distinct phenolic compounds were identified. Among these, p-coumaric acid (6656.8 ± 3.4 µg/g), gallic acid (6516 ± 1.7 µg/g), luteolin (6251.9 ± 1.3 µg/g), apigenin (6209.9 ± 1.1 µg/g), and rutin (5213.9 ± 1.3 µg/g) were identified as the most abundant polyphenolic molecules. In the in vitro antidiabetic experiment, the ability of the plant extract to inhibit α-glucosidase and α-amylase activities was examined. The results indicated that the extract from H. albus L. exhibited a higher inhibitory effect on α-amylase compared to α-glucosidase, with an IC50 of 146.63 ± 1.1 µg/mL and 270.43 ± 1.1 µg/mL, respectively. Docking simulations revealed that luteolin, fisetin, and rutin exhibited the most promising inhibitory activity against both enzymes, as indicated by their high contrasting inhibition scores. To further investigate the in vivo antidiabetic effects of H. albus L., an experiment was conducted using STZ-induced diabetic mice. The results demonstrated that the plant extract effectively reduced the levels of cholesterol and triglycerides. These findings suggest that H. albus L. may have therapeutic potential for managing hyperlipidemia, a common complication associated with diabetes. This highlights its potential as a natural remedy for diabetes and related conditions.
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BACKGROUND: Gold nanoparticles (AuNPs) are finding increased use in therapeutics and imaging. However, their toxic effects still remain to be elucidated. Therefore this study was undertaken to study the biochemical effects of AuNPs on rat brain and identify potential biomarkers of AuNP toxicity. METHODS: Male Wister rats weighing 150-200 g were injected with 20 µg/kg body weight of 20-nm gold nanoparticles for 3 days through the intraperitoneal route. The rats were killed by carbon dioxide asphyxiation 24 h after the last dose of gold nanoparticle injection. The parameters studied included lipid peroxidation, glutathione peroxidase, 8- hydroxydeoxyguanosine, caspase-3, heat shock protein70, serotonin, dopamine, gamma amino-butyric acid and interferon-γ. RESULTS: In this study AuNPs caused generation of oxidative stress and a decrease of antioxidant enzyme, viz., glutathione peroxidase activity in rat brain. This was accompanied by an increase in 8-hydroxydeoxyguanosine, caspase-3 and heat shock protein70, which might lead to DNA damage and cell death. Gold nanoparticles also caused a significant decrease in the levels of neurotransmitters like dopamine and serotonin, indicating a possible change in the behavior of the treated animals. There was a significant increase in the cerebral levels of IFN-γ in treated animals. CONCLUSION: This study concludes that AuNPs cause generation of oxidative stress and an impairment of the antioxidant enzyme glutathione peroxidase in rat brain. AuNPs also cause generation of 8-hydroxydeoxyguanosine (8OHdG), caspase-3 and heat shock protein70 (Hsp70), and IFN-γ, which may lead to inflammation and DNA damage/cell death.
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Química Encefálica/efectos de los fármacos , Oro/toxicidad , Nanopartículas del Metal/toxicidad , Animales , Antioxidantes/química , Antioxidantes/fisiología , Biomarcadores/química , Química Encefálica/fisiología , Contraindicaciones , Glutatión Peroxidasa/antagonistas & inhibidores , Glutatión Peroxidasa/biosíntesis , Glutatión Peroxidasa/deficiencia , Oro/química , Peroxidación de Lípido/efectos de los fármacos , Peroxidación de Lípido/fisiología , Masculino , Nanopartículas del Metal/química , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Ratas , Ratas WistarRESUMEN
CONTEXT: Increased use of engineered nanoparticles may result in exposure of workers and consumers, making them a health concern. OBJECTIVE: To identify potential blood miRNA biomarkers after intravenous gold nanoparticle (AuNP) exposure. MATERIALS AND METHODS: miRNA microarray analysis was carried out on blood of rats at 1 week and 2 months after injection. RESULTS: Many up- and downregulated miRNAs were detected. Of these, rno-miR-298 was confirmed to be increased at 1 week postinjection by reverse transcription-PCR (RT-PCR). DISCUSSION AND CONCLUSION: Blood miRNAs could be useful as biomarkers for exposure to nanoparticles. miR-298 regulates ß-amyloid (Aß) precursor protein-converting enzyme-1 (BACE1) in Alzheimer's disease.
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Biomarcadores/sangre , Oro/química , Nanopartículas del Metal/administración & dosificación , MicroARNs/sangre , Animales , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Inyecciones Intravenosas , Nanopartículas del Metal/química , MicroARNs/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de TiempoRESUMEN
Diabetic retinopathy (DR) is one of the major complications of diabetic eye diseases, causing vision loss and blindness worldwide. The concept of diabetic retinopathy has evolved from microvascular disease into more complex neurovascular disorders. Early in the disease progression of diabetes, the neuronal and glial cells are compromised before any microvascular abnormalities clinically detected by the ophthalmoscopic examination. This implies understanding the pathophysiological mechanisms at the early stage of disease progression especially due to diabetes-induced metabolic alterations to damage the neural retina so that early intervention and treatments options can be identified to prevent and inhibit the progression of DR. Hyperglycemia has been widely considered the major contributor to the progression of the retinal damage, even though tight control of glucose does not seem to have a bigger effect on the incidence or progression of retinal damage that leads to DR. Emerging evidence suggests that besides diabetes-induced hyperglycemia, dyslipidemia and amino acid defects might be a major contributor to the progression of early neurovascular retinal damage. In this review, we have discussed recent advances in the alterations of key metabolites of carbohydrate, lipid, and amino acids and their implications for neurovascular damage in DR.
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Proflavine is a well-known antiseptic and bacteriostatic drug, however, it has the potential to be hazardous and mutagenic. Proflavine enters cells and intercalates between DNA base pairs, resulting in mutation and replication inhibition. Previously several investigators demonstrated that photo-activated proflavine generated double-stranded DNA breakage and protein structural alterations. The present study investigated the role of hydroxyl radical (·OH) due to activation of proflavine in the breakdown of protein and enzyme by photo-activated proflavine. The results show that the formation of hydroxyl radicals increased as the photo-illumination period increased, as did the concentrations of proflavine and Cu (II). As demonstrated by SDS-PAGE, the excess of free radicals due to proflavine resulted in oxidative modifications and degradation of BSA protein and trypsin enzyme. Additionally, with an increase in Cu (II) concentration, photo-illuminated proflavine induced a considerable loss of enzyme activity and also accelerated the degradation of the enzyme. Bathocuproine, a particular Cu (I)-sequestering agent, prevented protein degradation and enzyme inactivation. Hydroxyl radical scavengers inhibited the protein-damaging process, indicating that hydroxyl radicals play a substantial role in protein damage. The tryptophan moiety was quenched by proflavine, demonstrating that it binds to proteins and enzymes, changing their structure and activity. As a result, this study helps to better understand proflavine's deleterious influence on protein and enzyme degradation by oxygen-free radicals.
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Alpha-crystallin protein performs structural and chaperone functions in the lens and comprises alphaA and alphaB subunits at a molar ratio of 3:1. The highly complex alpha-crystallin structure challenges structural biologists because of its large dynamic quaternary structure (300−1000 kDa). Camel lens alpha-crystallin is a poorly characterized molecular chaperone, and the alphaB subunit possesses a novel extension at the N-terminal domain. We purified camel lens alpha-crystallin using size exclusion chromatography, and the purity was analyzed by gradient (4−12%) sodium dodecyl sulfate−polyacrylamide gel electrophoresis. Alpha-crystallin was equilibrated in the pH range of 1.0 to 7.5. Subsequently, thermal stress (20−94 °C) was applied to the alpha-crystallin samples, and changes in the conformation and stability were recorded by dynamic multimode spectroscopy and intrinsic and extrinsic fluorescence spectroscopic methods. Camel lens alpha-crystallin formed a random coil-like structure without losing its native-like beta-sheeted structure under two conditions: >50 °C at pH 7.5 and all temperatures at pH 2.0. The calculated enthalpy of denaturation, as determined by dynamic multimode spectroscopy at pH 7.5, 4.0, 2.0, and 1.0 revealed that alpha-crystallin never completely denatures under acidic conditions or thermal denaturation. Alpha-crystallin undergoes a single, reversible thermal transition at pH 7.5. The thermodynamic data (unfolding enthalpy and heat capacity change) and chaperone activities indicated that alpha-crystallin does not completely unfold above the thermal transition. Camels adapted to live in hot desert climates naturally exhibit the abovementioned unique features.
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Protein aggregation is of two types: (i) amorphous and (ii) amyloid fibril. Several extrinsic factors (temperature, pH, and small ligands) stimulate protein aggregation in vitro. In this study, we have examined the role of sunset yellow (SY) on the ß-lactoglobulin (BLG) aggregation at pH 2.0. We have used spectroscopic (turbidity, Rayleigh light scattering (RLS), far-UV CD) and microscopic (transmission electron microscopy [TEM]) techniques to describe the effects of SY on BLG aggregation. Our results showed that BLG aggregation is dependent on SY concentrations. Very low concentrations (0.0-0.07 mM) of SY were unable to induce aggregation, while SY in the concentrations range of 0.1-5.0 mM induces aggregation in BLG. The kinetics of SY-stimulated aggregation is very fast and monomeric form of BLG directly converted into polymeric aggregates. The kinetics results also showed SY-induced BLG aggregation disappeared in the presence of NaCl. The far-UV CD and TEM results indicated the amorphous nature of SY-induced BLG aggregates. We believe that our results clearly suggest that SY dye effectively stimulates BLG aggregation.
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MERS-CoV main protease (Mpro) is essential for the maturation of the coronavirus; therefore, considered a potential drug target. Detailed conformational information is essential to developing antiviral therapeutics. However, the conformation of MERS-CoV Mpro under different conditions is poorly characterized. In this study, MERS-CoV Mpro was recombinantly produced in E.coli and characterized its structural stability with respect to changes in pH and temperatures. The intrinsic and extrinsic fluorescence measurements revealed that MERS-CoV Mpro tertiary structure was exposed to the polar environment due to the unfolding of the tertiary structure. However, the secondary structure of MERS-CoV Mpro was gained at low pH because of charge-charge repulsion. Furthermore, differential scanning fluorometry studies of Mpro showed a single thermal transition at all pHs except at pH 2.0; no transitions were observed. The data from the spectroscopic studies suggest that the MERS-CoV Mpro forms a molten globule-like state at pH 2.0. Insilico studies showed that the covid-19 Mpro shows 96.08% and 50.65% similarity to that of SARS-CoV Mpro and MERS-CoV Mpro, respectively. This study provides a basic understanding of the thermodynamic and structural properties of MERS-CoV Mpro.
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Proteasas 3C de Coronavirus , Coronavirus del Síndrome Respiratorio de Oriente Medio , Proteasas 3C de Coronavirus/genética , Proteasas 3C de Coronavirus/metabolismo , Coronavirus del Síndrome Respiratorio de Oriente Medio/enzimología , Coronavirus del Síndrome Respiratorio de Oriente Medio/genética , Conformación Proteica , Proteínas RecombinantesRESUMEN
INTRODUCTION: Natural phytochemicals are considered safe to use as therapeutic agents. There is a growing trend toward exploring anticancer effects of crude algal extracts or their active ingredients. Euglena tuba, a microalga, contains excellent antioxidant potential. However, the anticancer property of E. tuba has not been explored. This study investigates the chemical profiling as well as antitumor property of methanolic extract of E. tuba (ETME) against Dalton's lymphoma (DL) cells. MATERIALS AND METHODS: E. tuba, procured from northern part of India, was extracted in 70% methanol, dried at room temperature, and stored at -20 ∘C for future use. A freshly prepared aqueous solution of ETME of different concentrations was employed into each experiment. The ETME mediated anti-tumor response in Dalton's lymphoma was evaluated in the inbred populations of BALB/c (H2d) strain of mice of either sex at 8-12 weeks of age. The cytotoxicity of ETME in cancer cells, effects on morphology of cell and nucleus, alteration in the mitochondrial membrane potential, and level of expression of proapoptotic proteins (Bcl-2, cyt C, Bax and p53) were done using known procedures. RESULTS: The ETME contained high content of total alkaloids (96.02 ± 3.30 mg/100 mg), flavonoids (15.77 ± 2.38 mg/100 mg), carbohydrate (12.71 ± 0.59 mg/100 mg), ascorbic acid (12.48 ± 2.59 mg/100 mg), and phenolics (0.94 ± 0.05 mg/100 mg). Gas chromatography-mass spectrometry (GC-MS) analysis indicated the presence of 23 phytochemicals with known anticancer properties. DL cells treated with ETME exhibited significant and concentration dependent cytotoxicity. Florescent microscopy and flow cytometry of ETME treated DL cells indicated significant repair in cellular morphology and decreased mitochondrial potential, respectively. Western blot analysis displayed up-regulation of proapoptotic proteins (Bax, Cyt-c, p53) and down regulation of anti-apoptotic protein (Bcl2) in DL cells treated with ETME. CONCLUSIONS: The findings of this study clearly indicated that the anticancer property of ETME was mediated via reduction in mitochondrial potential and induction of apoptotic mechanism. Further studies are warranted to explore the anticancer activities of active ingredients present in this microalga of pharmaceutical importance.