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1.
J Mol Recognit ; 37(4): e3086, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38686702

RESUMEN

Organophosphorus are typically hazardous chemicals used in the pharmaceutical, agricultural, and other industries. They pose a serious risk to human life and can be fatal upon direct exposure. Hence, studying the interaction between such compounds with proteins is crucial for environmental, health, and food safety. In this study, we investigated the interaction mechanism between azinphos-methyl (AZM) and ß-lactoglobulin (BLG) at pH 7.4 using a combination of biophysical techniques. Intrinsic fluorescence investigations revealed that BLG fluorescence was quenched in the presence of increasing AZM concentrations. The quenching mechanism was identified as static, as evidenced by a decrease in the fluorescence quenching constant (1.25 × 104, 1.18 × 104, and 0.86 × 104 M-1) with an increase in temperatures. Thermodynamic calculations (ΔH > 0; ΔS > 0) affirmed the formation of a complex between AZM and BLG through hydrophobic interactions. The BLG's secondary structure was found to be increased due to AZM interaction. Ultraviolet -visible spectroscopy data showed alterations in BLG conformation in the presence of AZM. Molecular docking highlighted the significant role of hydrophobic interactions involving residues such as Val43, Ile56, Ile71, Val92, Phe105, and Met107 in the binding between BLG and AZM. A docking energy of -6.9 kcal mol-1, and binding affinity of 1.15 × 105 M-1 suggest spontaneous interaction between AZM and BLG with moderate to high affinity. These findings underscore the potential health risks associated with the entry of AZM into the food chain, emphasizing the need for further consideration of its impact on human health.


Asunto(s)
Azinfosmetilo , Lactoglobulinas , Simulación del Acoplamiento Molecular , Plaguicidas , Termodinámica , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Bovinos , Animales , Azinfosmetilo/química , Plaguicidas/química , Plaguicidas/metabolismo , Espectrometría de Fluorescencia , Interacciones Hidrofóbicas e Hidrofílicas , Unión Proteica , Estructura Secundaria de Proteína
2.
J Mol Recognit ; 36(6): e3009, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36841950

RESUMEN

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.


Asunto(s)
Amiloide , Muramidasa , Animales , Temperatura , Muramidasa/química , Amiloide/química , Dicroismo Circular , Concentración de Iones de Hidrógeno , Pollos/metabolismo
3.
Sensors (Basel) ; 22(4)2022 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-35214282

RESUMEN

Recent technological developments, such as the Internet of Things (IoT), artificial intelligence, edge, and cloud computing, have paved the way in transforming traditional healthcare systems into smart healthcare (SHC) systems. SHC escalates healthcare management with increased efficiency, convenience, and personalization, via use of wearable devices and connectivity, to access information with rapid responses. Wearable devices are equipped with multiple sensors to identify a person's movements. The unlabeled data acquired from these sensors are directly trained in the cloud servers, which require vast memory and high computational costs. To overcome this limitation in SHC, we propose a federated learning-based person movement identification (FL-PMI). The deep reinforcement learning (DRL) framework is leveraged in FL-PMI for auto-labeling the unlabeled data. The data are then trained using federated learning (FL), in which the edge servers allow the parameters alone to pass on the cloud, rather than passing vast amounts of sensor data. Finally, the bidirectional long short-term memory (BiLSTM) in FL-PMI classifies the data for various processes associated with the SHC. The simulation results proved the efficiency of FL-PMI, with 99.67% accuracy scores, minimized memory usage and computational costs, and reduced transmission data by 36.73%.


Asunto(s)
Internet de las Cosas , Dispositivos Electrónicos Vestibles , Inteligencia Artificial , Nube Computacional , Atención a la Salud , Humanos
4.
J Dairy Sci ; 104(5): 5141-5151, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33685710

RESUMEN

Amyloid fibril formation of proteins is associated with a number of neurodegenerative diseases. Several small molecules can accelerate the amyloid fibril formation in vitro and in vivo. However, the molecular mechanism of amyloid fibrillation is still unclear. In this study, we investigated how the food dye quinoline yellow (QY) induces amyloid fibrillation in α-lactalbumin (α-LA), a major whey protein, at pH 2.0. We used several spectroscopy techniques and a microscopy technique to explore how QY provokes amyloid fibrillation in α-LA. From turbidity and Rayleigh light scattering experiments, we found that QY promotes α-LA aggregation in a concentration-dependent manner; the optimal concentration for α-LA aggregation was 0.15 to 10.00 mM. Below 0.1 mM, no aggregation occurred. Quinoline yellow-induced aggregation was a rapid process that escaped the lag phase, but it depended on the concentrations of both α-LA and QY. We also demonstrated that aggregation switched the secondary structure of α-LA from α-helices to cross-ß-sheets. We then confirmed the amyloid-like structure of aggregated α-LA by transmission electron microscopy measurements. Molecular docking and simulation confirmed the stability of the α-LA-QY complex due to the formation of 1 hydrogen bond with Lys99 and 2 electrostatic interactions with Arg70 and Lys99, along with hydrophobic interactions with Leu59 and Tyr103. This study will aid in our understanding of how small molecules induce aggregation of proteins inside the stomach (low pH) and affect the digestive process.


Asunto(s)
Amiloide , Agregado de Proteínas , Animales , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Simulación del Acoplamiento Molecular , Quinolinas , Electricidad Estática , Proteína de Suero de Leche
5.
Molecules ; 26(24)2021 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-34946628

RESUMEN

Janerin is a cytotoxic sesquiterpene lactone that has been isolated and characterized from different species of the Centaurea genus. In this study, janerin was isolated form Centaurothamnus maximus, and its cytotoxic molecular mechanism was studied in THP-1 human leukemic cells. Janerin inhibited the proliferation of THP-1 cells in a dose-dependent manner. Janerin caused the cell cycle arrest at the G2/M phase by decreasing the CDK1/Cyclin-B complex. Subsequently, we found that janerin promoted THP-1 cell death through apoptosis as indicated by flow cytometry. Moreover, apoptosis induction was confirmed by the upregulation of Bax, cleaved PARP-1, and cleaved caspase 3 and the downregulation of an anti-apoptotic Bcl-2 biomarker. In addition, immunoblotting indicated a dose dependent upregulation of P38-MAPK and ERK1/2 phosphorylation during janerin treatment. In conclusion, we have demonstrated for the first time that janerin may be capable of inducing cell cycle arrest and apoptosis through the MAPK pathway, which would be one of the mechanisms underlying its anticancer activity. As a result, janerin has the potential to be used as a therapeutic agent for leukemia.


Asunto(s)
Antineoplásicos Fitogénicos , Apoptosis/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Leucemia , Puntos de Control de la Fase M del Ciclo Celular/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sesquiterpenos , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Humanos , Leucemia/tratamiento farmacológico , Leucemia/metabolismo , Sesquiterpenos/química , Sesquiterpenos/farmacología , Células THP-1
6.
Saudi Pharm J ; 28(3): 238-245, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32194324

RESUMEN

Polyphenols has attained pronounced attention due to their beneficial values of health and found to prevent several chronic diseases. Here, we elucidated binding mechanism between frequently consumed polyphenol "tea catechin" and milk protein bovine beta-lactoglobulin (ß-Lg). We investigated the conformational changes of ß-Lg due to interaction with catechin using spectroscopic and in silico studies. Fluorescence quenching data (Stern-Volmer quenching constant) revealed that ß-Lg interacted with catechin via dynamic quenching. Thermodynamic data revealed that the interaction between ß-Lg and catechin is endothermic and spontaneously interacted mainly through hydrophobic interactions. The UV-Vis absorption and far-UV circular dichroism (CD) spectroscopy exhibited that the tertiary as well as secondary structure of ß-Lg distorted after interaction with catechin. Molecular docking and simulation studies also confirm that catechin binds at the central cavity of ß-Lg with high affinity (~105 M-1) and hydrophobic interactions play significant role in the formation of a stable ß-Lg-catechin complex.

7.
Food Chem ; 455: 139937, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38850973

RESUMEN

Debittering of pomelo juice was conducted using 3.7 g of activated resin, resulting in a 36.8% reduction in bitterness without affecting the bioactive properties of juice. The debittered juice was then encapsulated with Moringa oleifera exudate at various ratios (1-5%), yielding a powder with a slightly rough surface. Total phenol content (TPC) increased by 46-56% compared to the debittered juice. Functional yoghurt containing encapsulates at concentrations of 1% and 2% demonstrated that the 2% concentration led to longer storage duration, resulting in increased acidity and syneresis compared to the control. TPC of the yoghurt (161.89-198.22 µg Gallic acid equivalent (GAE)/g) remained significantly higher (p < 0.05) than that of the control (47.15 µg GAE/g) and acacia gum-based yoghurt (141.89-171.37 µg GAE/g), decreasing with storage duration. Addition of encapsulates significantly altered the yoghurt's texture, resulting in lower firmness (0.57 to 0.64 N) compared to the control, while adhesiveness values remained comparable (6.33 to 6.25 g.s). The highest values of G' and G" were observed in samples containing 2% encapsulates with moringa compared to those with acacia gum. This study suggests potential avenues for further exploration in functional foods with enhanced health benefits.

8.
Int J Biol Macromol ; 266(Pt 2): 131282, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38565369

RESUMEN

IRF9 is a crucial component in the JAK-STAT pathway. IRF9 interacts with STAT1 and STAT2 to form IFN-I-stimulated gene factor 3 (ISGF3) in response to type I IFN stimulation, which promotes ISG transcription. However, the mechanism by which IFN signaling regulates Malabar grouper (Epinephelus malabaricus) IRF9 is still elusive. Here, we explored the nd tissue-specific mRNA distribution of the MgIRF9 gene, as well as its antiviral function in E. malabaricus. MgIRF9 encodes a protein of 438 amino acids with an open reading frame of 1317 base pairs. MgIRF9 mRNA was detected in all tissues of a healthy M. grouper, with the highest concentrations in the muscle, gills, and brain. It was significantly up-regulated by nervous necrosis virus infection and poly (I:C) stimulation. The gel mobility shift test demonstrated a high-affinity association between MgIRF9 and the promoter of zfIFN in vitro. In GK cells, grouper recombinant IFN-treated samples showed a significant response in ISGs and exhibited antiviral function. Subsequently, overexpression of MgIRF9 resulted in a considerable increase in IFN and ISGs mRNA expression (ADAR1, ADAR1-Like, and ADAR2). Co-immunoprecipitation studies demonstrated that MgIRF9 and STAT2 can interact in vivo. According to the findings, M. grouper IRF9 may play a role in how IFN signaling induces ISG gene expression in grouper species.


Asunto(s)
Lubina , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón , Animales , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/genética , Lubina/genética , Lubina/inmunología , Lubina/metabolismo , Nodaviridae , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Enfermedades de los Peces/virología , Enfermedades de los Peces/inmunología , Secuencia de Aminoácidos , Poli I-C/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Antivirales/farmacología , Regiones Promotoras Genéticas , Filogenia , ARN Mensajero/genética , ARN Mensajero/metabolismo
9.
Int J Biol Macromol ; 269(Pt 2): 132184, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38723814

RESUMEN

Phase separation and aggregation behaviour of triton X-100 (TX-100) and bovine serum albumin (BSA) mixture were investigated using cloud point and UV-visible spectroscopic techniques. The effects of various hydrotropes (HYTs) - namely, sodium salicylate (SS), sodium benzoate (SB), glycerol (Glyc), and 4-aminobenzoic acid (4-ABA) - on the cloud point (CP) of TX-100 + BSA were determined. The obtained CP values for the mixed system in the presence of HYTs followed the order: The measured critical micellization concentration (CMC) values of the TX-100 + BSA mixture were found to be significantly altered with varying amounts of BSA. The calculated free energy of clouding and micellization indicated the non-spontaneous nature of the phase transition and the spontaneous association of the TX-100 + BSA mixture. The non-spontaneity of phase separation decreased with increasing concentrations of HYTs. The enumerated values of ∆Hco and ∆Sco were consistently recorded as negative and positive magnitudes, respectively, in all aqueous HYTs media. The clouding process occurred due to a combination of hydrophobic and electrostatic interactions. The binding constant of the mixed system was determined employing the UV-vis spectroscopic method using the Benesi-Hildebrand equation.


Asunto(s)
Octoxinol , Albúmina Sérica Bovina , Espectrofotometría Ultravioleta , Albúmina Sérica Bovina/química , Octoxinol/química , Animales , Bovinos , Interacciones Hidrofóbicas e Hidrofílicas , Agregado de Proteínas , Micelas , Transición de Fase , Tensoactivos/química , Separación de Fases
10.
Int J Biol Macromol ; 267(Pt 2): 131677, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38641280

RESUMEN

The research investigates the virulence factors of Pseudomonas aeruginosa (P. aeruginosa), a pathogen known for its ability to cause human infections by releasing various exoenzymes and virulence factors. Particularly relevant in ocular infections, where tissue degeneration can occur, even after bacterial growth has ceased due to the potential role of secreted proteins/enzymes. Clinical isolates of P. aeruginosa, both ocular (146) and non-ocular (54), were examined to determine the frequency and mechanism of virulence factors. Phenotypic characterization revealed the production of alginate, biofilm, phospholipase C, and alkaline protease, while genotypic testing using internal uniplex PCR identified the presence of Exo U, S, T, Y, and LasB genes. Results showed a significant prevalence of Exo U and Y genes in ocular isolates, a finding unique to Indian studies. Additionally, the study noted that ocular isolates often contained all four secretomes, suggesting a potential link between these factors and ocular infections. These findings contribute to understanding the pathogenesis of P. aeruginosa infections, particularly in ocular contexts, and highlights the importance of comprehensive virulence factor analysis in clinical settings.


Asunto(s)
Biopelículas , Pseudomonas aeruginosa , Factores de Virulencia , Pseudomonas aeruginosa/patogenicidad , Pseudomonas aeruginosa/genética , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Humanos , Biopelículas/crecimiento & desarrollo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Infecciones por Pseudomonas/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Fosfolipasas de Tipo C/genética , Fosfolipasas de Tipo C/metabolismo , Endopeptidasas
11.
Int J Biol Macromol ; 265(Pt 1): 130442, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38417745

RESUMEN

Protein aggregation poses a significant concern in the field of food sciences, and various factors, such as synthetic food dyes, can contribute to protein aggregation. One such dye, Sunset Yellow (SY), is commonly employed in the food industry. Trypsin was used as a model protein to assess the impact of SY. We employed several biophysical techniques to examine the binding and aggregation mechanisms between SY and trypsin at different pHs. Results from intrinsic fluorescence measurements indicate a stronger interaction between SY and trypsin at pH 2.0 compared to pH 6.0. Turbidity data reveal trypsin aggregation in the presence of 0.05-3.0 mM SY at pH 2.0, while no aggregation was observed at pH 6.0. Kinetic data demonstrate a rapid, lag-phase-free SY-induced aggregation of trypsin. Circular dichroism analysis reveals that trypsin adopts a secondary structure in the presence of SY at pH 6.0, whereas at pH 2.0, the secondary structure was nearly lost with increasing SY concentrations. Furthermore, turbidity and kinetics data suggest that trypsin aggregation depends on trypsin concentrations and pH. Our study highlights potential health risks associated with the consumption of SY, providing insights into its impact on human health and emphasizing the necessity for further research in this field.


Asunto(s)
Colorantes , Agregado de Proteínas , Humanos , Colorantes/química , Tripsina , Compuestos Azo/química
12.
Heliyon ; 10(9): e30595, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38726166

RESUMEN

Malnutrition, defined as both undernutrition and overnutrition, is a major global health concern affecting millions of people. One possible way to address nutrient deficiency and combat malnutrition is through biofortification. A comprehensive review of the literature was conducted to explore the current state of biofortification research, including techniques, applications, effectiveness and challenges. Biofortification is a promising strategy for enhancing the nutritional condition of at-risk populations. Biofortified varieties of basic crops, including rice, wheat, maize and beans, with elevated amounts of vital micronutrients, such as iron, zinc, vitamin A and vitamin C, have been successfully developed using conventional and advanced technologies. Additionally, the ability to specifically modify crop genomes to improve their nutritional profiles has been made possible by recent developments in genetic engineering, such as CRISPR-Cas9 technology. The health conditions of people have been shown to improve and nutrient deficiencies were reduced when biofortified crops were grown. Particularly in environments with limited resources, biofortification showed considerable promise as a long-term and economical solution to nutrient shortages and malnutrition. To fully exploit the potential of biofortified crops to enhance public health and global nutrition, issues such as consumer acceptance, regulatory permitting and production and distribution scaling up need to be resolved. Collaboration among governments, researchers, non-governmental organizations and the private sector is essential to overcome these challenges and promote the widespread adoption of biofortification as a key part of global food security and nutrition strategies.

13.
Biochem Biophys Res Commun ; 441(3): 681-8, 2013 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-24394939

RESUMEN

The effect of sodium dodecyl sulfate (SDS) on human, bovine, porcine, rabbit and sheep serum albumins were investigated at pH 3.5 by using various spectroscopic techniques like circular dichroism (CD), intrinsic fluorescence and dynamic light scattering (DLS). In the presence of 4.0mM SDS the secondary structure of all the albumins were not affected as measured by CD but fluorescence spectra revealed 8.0 nm blue shift in emission maxima. We further checked the stability of albumins in the absence and presence of 4.0mM SDS by urea and temperature at pH 3.5. In the absence of SDS, urea starts unfolding both secondary as well as tertiary structural elements of the all the albumins at approximately 2.0M urea but in the presence of 4.0mM SDS, urea was unable to unfold even up to 9.0M. The albumins were thermally less stable at pH 3.5 with decrease in Tm but in the presence of 4.0mM SDS, the Tm was increased. From this study, it was concluded that SDS is showing a protective effect against urea as well as thermal denaturation of albumins. This behavior may be due to electrostatic as well as the hydrophobic interaction of SDS with albumins. Further, we have proposed the mechanism of action of urea. It was found that urea interacted with proteins directly when proteins are in charged form. Indirect interaction may be taking place when the environment is more hydrophobic.


Asunto(s)
Desnaturalización Proteica , Albúmina Sérica/química , Dodecil Sulfato de Sodio/química , Urea/química , Animales , Bovinos , Dicroismo Circular , Calor , Humanos , Concentración de Iones de Hidrógeno , Luz , Estabilidad Proteica , Estructura Secundaria de Proteína , Conejos , Dispersión de Radiación , Ovinos , Espectrometría de Fluorescencia , Porcinos
14.
Arch Biochem Biophys ; 540(1-2): 101-16, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24184422

RESUMEN

Sodium dodecyl sulfate, a biological membrane mimetic, can be used to study the conversion of globular proteins into amyloid fibrils in vitro. Using multiple approaches, the effect of SDS was examined on stem bromelain (SB), a widely recognized therapeutic protein. SB is known to exist as a partially folded intermediate at pH 2.0, situation also encountered in the gastrointestinal tract (its site of absorption). In the presence of sub-micellar SDS concentration (500-1000 µM), this intermediate was found to exhibit great propensity to form large-sized ß-sheeted aggregates with fibrillar morphology, the hall marks of amyloid structure. We also observed inhibition of fibrillation by two naphthalene-based compounds, ANS and bis-ANS. While bis-ANS significantly inhibited fibril formation at 50 µM, ANS did so at relatively higher concentration (400 µM). Alcohols, but not salts, were found to weaken the inhibitory action of these compounds suggesting the possible involvement of hydrophobic interactions in their binding to protein. Besides, isothermal titration calorimetry and molecular docking studies suggested that inhibition of fibrillation by these naphthalene derivatives is mediated not just through hydrophobic forces, but also by disruption of π-π interactions between the aromatic residues together with the inter-polypeptide chain repulsion among negatively charged ANS/bis-ANS bound SB.


Asunto(s)
Bromelaínas/química , Naftalenos/química , Naftalenos/farmacología , Multimerización de Proteína/efectos de los fármacos , Dodecil Sulfato de Sodio/análogos & derivados , Dodecil Sulfato de Sodio/farmacología , Alcoholes/farmacología , Bromelaínas/metabolismo , Tampones (Química) , Relación Dosis-Respuesta a Droga , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Micelas , Simulación del Acoplamiento Molecular , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína
15.
Int J Biol Macromol ; 247: 125790, 2023 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-37451378

RESUMEN

Amyloid fibrillation is a process by which proteins aggregate and form insoluble fibrils that are implicated in several neurodegenerative diseases. In n this study, we aimed to investigate the impact of the negatively charged detergent sodium dodecyl sulfate (SDS) on insulin amyloid fibrillation at pH 7.4 and 2.0, as SDS has been linked to the acceleration of amyloid fibrillation in vitro, but the underlying molecular mechanism is not fully understood. Our findings show that insulin forms amyloid-like aggregates in the presence of SDS at concentrations ranging from 0.05 to 1.8 mM at pH 2.0, while no aggregates were observed at SDS concentrations greater than 1.8 mM, and insulin remained soluble. However, at pH 7.4, insulin remained soluble regardless of the concentration of SDS. Interestingly, the aggregated insulin had a cross-ß sheet secondary structure, and when incubated with higher SDS concentrations, it gained more alpha-helix. The electrostatics and hydrophobic interaction of SDS and insulin may contribute to amyloid induction. Moreover, the SDS-induced aggregation was not affected by the presence of salts. Furthermore, as the concentration of SDS increased, the preformed insulin amyloid induced by SDS began to disintegrate. Overall, our study sheds light on the mechanism of surfactant-induced amyloid fibrillation in insulin protein.


Asunto(s)
Insulina , Tensoactivos , Tensoactivos/farmacología , Tensoactivos/química , Dodecil Sulfato de Sodio/química , Amiloide/química , Proteínas Amiloidogénicas
16.
Int J Biol Macromol ; 230: 123370, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36693606

RESUMEN

Protein aggregation and amyloid fibrillation are connected with neurodegenerative disorders. Insulin, a small molecular weight protein related to type II diabetes, has been shown to self-assemble to form protein aggregates. In this work, we investigated the effects of cetyltrimethylammonium bromide (CTAB) of insulin on the in vitro aggregation process at pH 7.4 and 2.0. The aggregation tendency of insulin was measured using a variety of biophysical approaches, including turbidity measurements, light scattering, far UV-CD, ThT dye binding, and transmission electron microscopy. The turbidity results demonstrated that at pH 7.4, a low concentration of CTAB (30-180 µM) causes insulin aggregation but at higer concentration (>180 µM) aggregation was not seen. However, at pH 2.0, both low as well as high concentrations of CTAB were unable to promote insulin aggregation. The ThT dye binding and far-UV CD data suggest that aggregation induced by CTAB is not having an ordered structure. Insulin treated with higher concentrations (>180 µM) of CTAB, the insulin gained a secondary structure. The possible cause of inducing aggregation in insulin is electrostatic and hydrophobic interaction because insulin contains a net negative charge at pH 7.4 and no aggregation at pH 2.0 due to electrostatic repulsion.


Asunto(s)
Diabetes Mellitus Tipo 2 , Insulina , Humanos , Cetrimonio , Tensoactivos/química
17.
Int J Biol Macromol ; 253(Pt 8): 127606, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37871717

RESUMEN

Amyloid fibrils have been linked to several incurable diseases. They are long and thin fibrous proteins that self-assemble into fibrils. Small molecules can stimulate amyloid fibrillation, but the mechanism by which this happens is not well understood. This study examined how a negatively charged benzene ring containing surfactant, sodium dodecylbenzene sulphonate (SDBS), affects the fibrillation of bovine liver catalase (BLC). After SDBS treatment, BLC conformational changes were examined in vitro using turbidity, RLS kinetics, intrinsic fluorescence, ThT fluorescence, far-UV CD, and TEM. BLC in the native state was alpha-helical at pH 7.4, while it was converted to a random coil structure at pH 2.0. Far-UV CD and intrinsic fluorescence data showed that at concentrations <0.1 mM of SDBS, randomly coiled BLC assumed a native-like alpha-helical structure. However, between 0.1 and 1.0 mM SDBS, BLC was aggregated. ThT fluorescence and far-UV CD measurements showed the amyloid-like structures in the aggregated BLC. At higher SDBS concentrations (>1.0 mM) at pH 2.0, BLC again attains a native-like alpha-helical structure. It is essential for therapeutic purposes to clearly understand the process underlying surfactant- or lipid-induced fibrillation.


Asunto(s)
Amiloide , Tensoactivos , Bovinos , Animales , Dicroismo Circular , Catalasa/química , Tensoactivos/farmacología , Tensoactivos/química , Conformación Molecular , Amiloide/química
18.
Colloids Surf B Biointerfaces ; 229: 113481, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37536170

RESUMEN

The mechanism by which anionic surfactants promote amyloid fibril is not well understood. Here, we investigated how sodium dodecyl sulfate (SDS), a negatively charged surfactant, affects the fibrillation of the partially unfolded random-coiled bovine liver catalase (BLC) at a pH of 2.0. We used several methods, including turbidity, RLS kinetics, intrinsic fluorescence, ThT fluorescence, far-UV CD, and TEM imaging, to evaluate the conformational changes of BLC in vitro in response to SDS treatment. BLC is a multimeric protein and well folded at physiological pH but forms a random coil structure at pH 2.0. Intrinsic fluorescence and far-UV CD data showed that below 0.1 mM SDS, random coiled BLC turned into a native-like structure. BLC incubated with an SDS concentration ranging from 0.1 to 2.0 mM led to the formation of aggregates. The ThT fluorescence intensity was enhanced in the aggregated BLC samples (0.1-2.0 mM SDS), and cross beta-sheeted structure was detected by the far UV CD measurements. BLC adopts a complete alpha-helical structure upon interacting with SDS at a more than 2.0 mM concentration at pH 2.0. Understanding the mechanism of surfactant- or lipid-induced fibrillation is important for therapeutic purposes.


Asunto(s)
Hígado , Tensoactivos , Animales , Bovinos , Catalasa/química , Tensoactivos/química , Dodecil Sulfato de Sodio/química , Estructura Secundaria de Proteína
19.
Int J Biol Macromol ; 231: 123237, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36639087

RESUMEN

Amyloid fibrils have been linked to a number of diseases. Surfactants imitate plasma membrane lipids and induce amyloid fibrils. This study examined the effects of the anionic surfactant sodium dodecyl sulfate (SDS) at pH 4.5 on equine skeletal muscle myoglobin (E-Mb). To analyze the effect of SDS on aggregation and amyloid-fibril formation to E-Mb, we used various spectroscopic techniques (turbidity, light scattering, intrinsic fluorescence, ThT fluorescence, and circular dichroism (CD)), electrophoretic, and microscopic techniques. Turbidity, SDS-PAGE, and light scattering all indicated the formation of E-Mb aggregates at SDS concentrations ranging from 0.2 mM to 1.0 mM. In the presence of 0.4 mM SDS, far-UV CD and TEM data indicate that E-MB forms amorphous aggregates. ThT binding, Far-UV CD, and TEM findings indicate that E-Mb forms amyloid-like structures in the presence of 0.6-1.0 mM SDS. However, no aggregation was seen at SDS concentrations above 1 mM. In the presence of high SDS concentrations (> 1 mM), the E-Mb exhibited native-like α-helical structure. As a result, SDS exhibited three distinct behaviors: amorphous aggregates, amyloid-fibrils, and helix-inducer. These findings also shed light on how amyloid fibrils are formed when anionic surfactants are introduced, which is a significant takeaway.


Asunto(s)
Mioglobina , Tensoactivos , Animales , Caballos , Mioglobina/metabolismo , Conformación Proteica en Hélice alfa , Tensoactivos/química , Dodecil Sulfato de Sodio/química , Dicroismo Circular , Amiloide/química , Concentración de Iones de Hidrógeno
20.
3 Biotech ; 13(8): 284, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37520341

RESUMEN

This research was designed to evaluate the pharmaceutical potentials of various proportions of nanoemulsions, Cardiospermum halicacabum Nanoemulsion A and Cardiospermum halicacabum Nanoemulsion B (CHE-NE-A & CHE-NE-B) prepared from the hydroalcoholic extract of Cardiospermum halicacabum through in vitro approach, and their physicochemical properties were characterized using standard scientific analytical techniques. The physicochemical and morphological properties of CHE-NE-A and CHE-NE-B were characterized by FTIR, SEM, TEM, zeta potential, and scattering light intensity analyses. The results revealed that the size, shape, and exterior conditions of nano-droplets of the CHE-NE-A nanoemulsion were suitable as a drug carrier. The reports obtained from in vitro drug releasing potential analysis support this as well. CHE-NE-A nanoemulsion constantly removes the drug from the dialysis bag than CHE-NE-B. Moreover, the CHE-NE-A showed considerable dose-dependent antioxidant activity on DPPH, ABTS, and FRAP free radicals. CHE-NE-A and CHE-NE-B were tested for their antibacterial activity with various bacterial strains. The results demonstrated that the CHE-NE-A nanoemulsion showed remarkable antibacterial activity (zone of inhibition) against test bacterial pathogens than CHE-NE-B. The antibacterial activity of CHE-NE-A at a concentration of 200 µg mL-1was in the following order, P. aeruginosa > S. aureus > S. typhimurium > S. pneumoniae > E. coli. Furthermore, CHE-NE-A has the lowest MIC values against these test bacterial pathogens than CHE-NE-B. Moreover, the CHE-NE-A also demonstrated good antifungal activity against the test fungal pathogens such as Cryptococcus neoformans, Aspergillus niger, Candida pneumonia, and Penicillium expansum than CHE-NE-B. These results strongly suggest that the CHE-NE-A nanoemulsion possesses considerable pharmaceutical potential. Interestingly, the physicochemical properties also rope that the CHE-NE-A nanoemulsion may be considered a drug carrier and useful for drug formulation.

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