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1.
Environ Res ; : 119487, 2024 Jun 23.
Article in English | MEDLINE | ID: mdl-38917932

ABSTRACT

The nutraceutical value, and physicochemical profile as well as anti-inflammatory activity potential of Odonthalia floccose and Odonthalia dentata (red macroalgae) dry biomass were investigated in this study. Proximate composition study results revealed that the dry biomass of O. floccose and O. dentae were found to be as ash: 9.11 & 8.7 g 100 g-1, moisture: 8.24 & 8.1 g 100 g-1, total fat: 6.9 & 7.2 g 100 g-1, protein: 24.52 & 25.6 g 100 g-1, and total carbohydrate/polysaccharides: 53.84 & 48.85 g 100 g-1 of dry weight biomass respectively. Both algae biomass contain considerable quantity of minerals (Fe, Cu, Mg, and Zn). Furthermore, the major saturated fatty acids (6.24 & 5.82 g FAME 100 g-1 of total fat of O. floccose and O. dentate) (ΣFAs) present in the test algae were stearic acid, palmitic acid, and margaric acids. O. floccose and O. dentata also contain remarkable protein composition profile that compiled with considerable quantity of essential and non-essential amino acids. The vitamins such as vitamin A, B1, B2, B3, B6, B9, C, and E of O. floccose and O. dentate biomass were also identified at sufficient quantity level. The swelling capacity (SWC), water holding capacity (WHC), and oil holding capacity (OHC) properties of O. floccose and O. dentate at various temperature conditions (25 and 37 ᵒC) were found to be 8.11 & 7.02 mL g-1 and 8.95 & 7.55 mL g-1, 5.1 & 4.87 and 4.8 & 4.1 mL g-1, as well as 2.11 & 1.81 and 1.96 & 1.89 mL g-1 respectively. Among these two marine red macroalgae samples, the O. dentate showed better anti-inflammatory activity than O. floccose at 150 µg mL-1 dosage. Thus, this O. floccose and O. dentate biomass can be considerable as nutritional supplement and pharmaceutical product development related research.

3.
Environ Res ; 252(Pt 1): 118705, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38548251

ABSTRACT

The dyeing industry effluent causes severe environmental pollution and threatens the native flora and fauna. The current study aimed to analyze the physicochemical parameters of dyeing industry wastewater collected in different sites (K1, E2, S3, T4, and V5), as well as the metal tolerance and decolourisation ability of Aspergillus flavus. Furthermore, the optimal biomass quantity and temperatures required for efficient bioremediation were investigated. Approximately five dyeing industry wastewater samples (K1, E2, S3, T4, and V5) were collected from various sampling stations, and the majority of the physical and chemical characteristics were discovered to be above the permissible limits. A. flavus demonstrated outstanding metal resistance to As, Cu, Cr, Zn, Hg, Pb, Ni, and Cd on Potato Dextrose Agar (PDA) plates at concentrations of up to 500 g mL-1. At 4 g L-1 concentrations, A. flavus biomass decolorized up to 11.2-46.5%. Furthermore, 35°C was found to be the optimal temperature for efficient decolourisation of A. flavus biomass. The toxicity of 35°C-treated wastewater on V. mungo and prawn larvae was significantly reduced. These findings indicate that the biomass of A. flavus can be used to decolorize dyeing industry wastewater.


Subject(s)
Aspergillus flavus , Biodegradation, Environmental , Biomass , Coloring Agents , Industrial Waste , Wastewater , Water Pollutants, Chemical , Aspergillus flavus/metabolism , Wastewater/chemistry , Wastewater/microbiology , Coloring Agents/chemistry , Industrial Waste/analysis , Water Pollutants, Chemical/analysis , Animals , Waste Disposal, Fluid/methods , Metals, Heavy/analysis , Metals, Heavy/toxicity , Larva
4.
Waste Manag ; 177: 34-45, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38290346

ABSTRACT

Mobile phones have turned into a highly essential device for numerous individuals. Swift innovation and decrease in in-use lifespan have increased the generation of end-of-life mobile phones (EOL-MPs). Lesser formal recycling of EOL-MPs has detrimental outcomes on the environment, human health, and circular economy. Therefore, this research was undertaken to investigate factors impacting mobile phone users' behavioural intention to give their EOL-MPs for formal recycling. The conceptual model was developed by integrating the theory of planned behaviour, norm activation model, and value-belief-norm theory. Responses were collected from mobile phone users aged 18 and above residing in Bengaluru, Mangaluru, and Huballi-Dharvad cities of Karnataka state, India. 1135 responses were analysed by applying partial least squares structural equation modelling. Incentives was figured out to be the most positively impacting construct on behavioural intention. Followed by awareness of consequences, social media, past recycling experience, and recycling attitude. Whereas risk perception regarding information security and convenience of recycling negatively impacts behavioural intention. Personal norms get activated by awareness of consequences and ascription of responsibility. As a result, personal norms positively impact behavioural intention. In addition, biospheric values also positively impact personal norms. The outcomes of PLSpredict signify that the conceptual model has high out-of-sample predictive power. The outcomes of this research can be utilized by various stakeholders like e-waste collection organisations, e-waste recycling organisations, mobile phone manufacturing companies, city corporations, educational institutions, etc for improving sustainable end-of-life management of EOL-MPs.


Subject(s)
Cell Phone , Intention , Humans , India , Cities , Commerce
5.
Waste Manag Res ; 41(1): 18-36, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35722875

ABSTRACT

Usage/consumption of mobile phones has increased rapidly around the world. As of April 2021, there were 5.27 billion mobile phone users. Meanwhile, the generation of obsolete mobile phones/mobile phone wastes is also increased mainly due to the replacement of mobile phones. The in-use lifespan of mobile phones is correspondingly getting decreased. The inappropriate disposal of obsolete mobile phones leads to adverse consequences on the environment, human health and on metal recovery. This review article provides an insight on findings from various articles on disposal of obsolete mobile phones by users/consumers. The various aspects, such as reasons for replacement, disposal methods adopted by users/consumers, impact due to the adoption of improper disposal methods such as handing them over to the informal recycling sector and storage/hibernation after its in-use lifespan, were covered. Along with this, the study even focuses on reduce, reuse and recycle (3Rs) of sustainability. Reduce means reduction of mobile phone replacement frequency. Storage of mobile phones post-in-use lifespan is the most opted disposal method, and it is one of the significant barriers to reuse, recycling and metal recovery. When it comes to recycling, the research undertaken on the recycling of obsolete mobile phones is not as in-depth when compared to the research done on recycling of e-waste in general. This article identifies future directions for sustainable end-of-life management of obsolete mobile phones.


Subject(s)
Cell Phone , Electronic Waste , Humans , Longevity , Recycling/methods
6.
J Endocrinol Invest ; 46(6): 1205-1218, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36528847

ABSTRACT

PURPOSE: Metformin is widely used to treat type 2 diabetes mellitus (T2DM) individuals. Clinically, inter-individual variability of metformin response is of significant concern and is under interrogation. In this study, a targeted exome and whole transcriptome analysis were performed to identify predictive biomarkers of metformin response in drug-naïve T2DM individuals. METHODS: The study followed a prospective study design. Drug-naïve T2DM individuals (n = 192) and controls (n = 223) were enrolled. T2DM individuals were administered with metformin monotherapy and defined as responders and non-responders based on their glycated haemoglobin change over three months. 146 T2DM individuals were used for the final analysis and remaining samples were lost during the follow-up. Target exome sequencing and RNA-seq was performed to analyze genetic and transcriptome profile. The selected SNPs were validated by genotyping and allele specific gene expression using the TaqMan assay. The gene prioritization, enrichment analysis, drug-gene interactions, disease-gene association, and correlation analysis were performed using various tools and databases. RESULTS: rs1050152 and rs272893 in SLC22A4 were associated with improved response to metformin. The copy number loss was observed in PPARGC1A in the non-responders. The expression analysis highlighted potential differentially expressed targets for predicting metformin response (n = 35) and T2DM (n = 14). The expression of GDF15, TWISTNB, and RPL36A genes showed a maximum correlation with the change in HbA1c levels. The disease-gene association analysis highlighted MAGI2 rs113805659 to be linked with T2DM. CONCLUSION: The results provide evidence for the genetic variations, perturbed transcriptome, allele-specific gene expression, and pathways associated with metformin drug response in T2DM.


Subject(s)
Diabetes Mellitus, Type 2 , Metformin , Humans , Metformin/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/metabolism , Hypoglycemic Agents/therapeutic use , Alleles , Prospective Studies , Polymorphism, Single Nucleotide , Gene Expression
7.
Neurochem Int ; 162: 105461, 2023 01.
Article in English | MEDLINE | ID: mdl-36460239

ABSTRACT

Parkinson's disease (PD) is characterized by an abnormal post-translational modifications (PTM) in amino acid sequence and aggregation of alpha-synuclein (α-Syn) protein. It is generally believed that dopamine (DA) metabolite in dopaminergic (DAergic) neurons promotes the aggregation of toxic α-Syn oligomers and protofibrils, whereas DA inhibits the formation of toxic fibers and even degrades the toxic fibers. Therefore, the study on interaction between DA metabolites and α-Syn oligomers is one of the current hot topics in neuroscience, because this effect may have direct relevance to the selective DAergic neuron loss in PD. Several mechanisms have been reported for DA metabolites induced α-Syn oligomers viz. i) The reactive oxygen species (ROS) released during the auto-oxidation or enzymatic oxidation of DA changes the structure of α-Syn by the oxidation of amino acid residue leading to misfolding, ii) The oxidized DA metabolites directly interact with α-Syn through covalent or non-covalent bonding leading to the formation of oligomers, iii) DA interacts with lipid or autophagy related proteins to decreases the degradation efficiency of α-Syn aggregates. However, there is no clear-cut mechanism proposed for the interaction between DA and α-Syn. However, it is believed that the lysine (Lys) side chain of α-Syn sequence is the initial trigger site for the oligomer formation. Herein, we review different chemical mechanism involved during the interaction of Lys side chain of α-Syn with DA metabolites such as dopamine-o-quinone (DAQ), dopamine-chrome (DAC), dopamine-aldehyde (DOPAL) and neuromelanin. This review also provides the promotive effect of divalent Cu2+ ions on DA metabolites induced α-Syn oligomers and its inhibition effect by antioxidant glutathione (GSH).


Subject(s)
Parkinson Disease , alpha-Synuclein , Humans , alpha-Synuclein/metabolism , Parkinson Disease/metabolism , Dopamine/metabolism , Antioxidants
8.
Int J Biol Macromol ; 223(Pt A): 1024-1041, 2022 Dec 31.
Article in English | MEDLINE | ID: mdl-36379279

ABSTRACT

Fibril formation of α-synuclein is linked with Parkinson's disease. The intrinsically disordered nature of α-syn provides extensive conformational plasticity and becomes difficult to characterize its transition pathway from native monomeric to disease-associated fibril form. We implemented different simulation methods such as steered dynamics-umbrella sampling, and replica-exchange and conventional MD simulations to access various conformational states of α-syn. Nineteen distinct intermediate structures were identified by free energy landscape and cluster analysis. They were then sorted based on secondary structure and solvent exposure of fibril-core residues to illustrate the fibril dissociation pathway. The analysis showed that following the initial dissociation of the polypeptide chain from the fibril, α-syn might form either compact-conformations by long-range interactions or extended-conformations stabilized by local interactions. This leads α-syn to adapt two different pathways. The secondary structure, solvation, contact distance, interaction energies and backbone dihedrals of thirty-two selected residues were analyzed for all the 19 intermediates. The results suggested that formation of ß-turns, reorganization of salt bridges, and dihedral changes in the hydrophobic regions are the major driving forces for helix-fibril transition. Structural features of the intermediates also correlated with the earlier experimental and computational studies. The study provides critical information on the fibrillation pathway of α-syn.


Subject(s)
Parkinson Disease , alpha-Synuclein , Humans , alpha-Synuclein/chemistry , Protein Structure, Secondary , Parkinson Disease/metabolism , Hydrophobic and Hydrophilic Interactions , Entropy
9.
Clin Radiol ; 77(8): e613-e619, 2022 08.
Article in English | MEDLINE | ID: mdl-35589430

ABSTRACT

AIM: To analyse the computed tomography (CT) findings of paraduodenal pancreatitis (PP) in patients treated at Amrita Institute of Medical Sciences. MATERIALS AND METHODS: Clinical, laboratory, and CT findings of 30 patients with PP treated from July 2007 to December 2020 were reviewed retrospectively. RESULTS: The average age of the patients was 45.9 years (19-60 years), which included 29 (96.7%) men, and 90% had a history of alcohol abuse. The majority [22 (73.3%)] presented with recurrent abdominal pain. Serum amylase was elevated in 21 (70%) patients and serum lipase was elevated in 25 (83.3%) patients. Carbohydrate antigen (CA 19-9) was elevated in three (10%) patients. The cystic pattern was seen in three (10%), solid pattern in 13 (43.3%), and solid-cystic pattern in 14 (46.7%) patients. The pure form of the disease was seen in seven (23.3%) patients, whereas the segmental form was seen in 23 (76.7%) patients. Descending duodenal wall thickening and enhancement was seen in 25 (83.3%) and 18 (60%) patients, respectively. The gastroduodenal artery was displaced medially in 12 (40%) patients and encased in five (16.7%) patients; however, it was not occluded in any of the patients. Calcifications were seen in the groove lesion in nine (30%) patients. The pancreas showed atrophic changes in 14 (46.6%) patients and calcifications in 12 (40%) patients. Distal common bile duct strictures were seen in three (10%) patients. CONCLUSIONS: The presence of sheet-like soft-tissue thickening in the groove with diffuse duodenal thickening and intramural/paraduodenal cysts are highly suggestive of PP. Identifying characteristic imaging findings of PP may help in prospective diagnosis and lead to conservative management of most of these patients avoiding unnecessary invasive procedures.


Subject(s)
Choristoma , Pancreatitis , Female , Humans , Male , Middle Aged , Pancreas/diagnostic imaging , Pancreas/pathology , Pancreatitis/diagnosis , Prospective Studies , Retrospective Studies , Tomography, X-Ray Computed
10.
Mol Microbiol ; 117(6): 1324-1339, 2022 06.
Article in English | MEDLINE | ID: mdl-35301756

ABSTRACT

Plasmodium sporozoites are extracellular forms introduced during mosquito bite that selectively invade mammalian hepatocytes. Sporozoites are delimited by a cell membrane that is linked to the underlying acto-myosin molecular motor. While membrane proteins with roles in motility and invasion have been well studied, very little is known about proteins that maintain the sporozoite shape. We demonstrate that in Plasmodium berghei (Pb) a conserved hypothetical gene, PBANKA_1422900 specifies sporozoite structural integrity maintenance protein (SIMP) required for maintaining the sporozoite shape and motility. Sporozoites lacking SIMP exhibited loss of regular shape, extensive membrane blebbing at multiple foci, and membrane detachment. The mutant sporozoites failed to infect hepatocytes, though the altered shape did not affect the organization of cytoskeleton or inner membrane complex (IMC). Interestingly, the components of IMC failed to extend under the membrane blebs likely suggesting that SIMP may assist in anchoring the membrane to IMC. Endogenous C-terminal HA tagging localized SIMP to membrane and revealed the C-terminus of the protein to be extracellular. Since SIMP is highly conserved among Plasmodium species, these findings have important implications for utilizing it as a novel sporozoite-specific vaccine candidate.


Subject(s)
Protozoan Proteins , Sporozoites , Animals , Dipeptides , Hepatocytes/metabolism , Mammals/metabolism , Plasmodium berghei/genetics , Plasmodium berghei/metabolism , Protozoan Proteins/metabolism , Sporozoites/metabolism
11.
J Biomol Struct Dyn ; 40(2): 820-832, 2022 02.
Article in English | MEDLINE | ID: mdl-32954952

ABSTRACT

Osmolytes are known to stabilize proteins against denaturing conditions. Ethylene glycol (EG), however, shows a distinctive effect on α-lactalbumin (α-LA) that it stabilizes the protein against cold-induced denaturation, whereas it destabilizes during heat denaturation. The replica exchange molecular dynamics (REMD) simulation of α-LA in the presence of EG shows that EG denatures the protein at higher temperatures whereas it retards the denaturation at sub-zero temperature. Representative structures of α-LA were selected from REMD trajectories at three different temperature conditions (240, 300 and 340 K) with and without EG, and classical molecular dynamics (MD) simulations were performed. The results suggest that the presence of water around α-LA is more at lower temperatures; however, water around the hydrophobic residues is reduced with the addition of EG at sub-zero temperature. The partition coefficient of EG showed that the binding of EG with hydrophobic residues was higher at lower temperatures. Preferential interaction parameters at different temperatures were calculated based on the mean distribution (Γ23) and Kirkwood-Buff integral (G23) methods. Γ23 shows a larger positive value at 240 K compared to higher temperatures. G23 shows positive values at lower temperatures, whereas it becomes negative at above 280 K. These results indicate that the preferential binding of EG with α-LA is more at sub-zero temperature compared to higher temperature conditions. Thus, the study suggests that the preferential binding of EG reduces the hydrophobic hydration of α-LA at lower temperatures, and stabilizes the protein against cold denaturation. However, the preferential binding of EG at higher temperature drives the folding equilibrium towards the denatured state.Communicated by Ramaswamy H. Sarma.


Subject(s)
Ethylene Glycol , Lactalbumin , Ethylene Glycol/chemistry , Lactalbumin/chemistry , Molecular Dynamics Simulation , Protein Denaturation , Protein Folding , Protein Stability , Temperature , Thermodynamics
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120307, 2022 Jan 05.
Article in English | MEDLINE | ID: mdl-34461523

ABSTRACT

Fibril formation of globular proteins is driven by attaining an appropriate partially-unfolded conformation. Excluded volume effect exerted by the presence of other macromolecules in the solution, as found in the cellular interior, might affect the conformational state of proteins and alter their fibril formation process. The change in structure, stability and rate of fibril formation of aggregation-prone partially-unfolded states of lysozyme (Lyz) and α-lactalbumin (ALA) in the presence of different sizes of polyethylene glycol (PEG) is examined using spectroscopic methods. Thermal denaturation and far-UV CD studies suggest that Lyz is stabilized by PEGs and the stability increases with increasing concentration of PEGs. However, the stability of ALA depends on the size and concentration of PEG. The change in enthalpy of unfolding indicates the existence of soft-interactions between the proteins and PEG along with excluded volume effect. Fibrillation rate of Lyz is not significantly altered in the presence of lower concentrations of PEGs suggesting that the crowding effect dominates the viscosity-induced retardation of protein association whereas at higher concentrations the rates are reduced. In case of ALA, the rate of fibrillation is drastically reduced; however, there is a marginal increase with the increasing concentration of PEG. The results suggest that the fibril formation is influenced by change in initial conformation of the partially-unfolded states of the proteins and their stability in the presence of the crowding agent. Further, the size and concentration of the crowding agent, and the soft-interaction between the proteins and PEG also affects the fibrillation.


Subject(s)
Polyethylene Glycols , Protein Folding , Circular Dichroism , Lactalbumin , Molecular Conformation
13.
J Biomol Struct Dyn ; 40(21): 11216-11228, 2022.
Article in English | MEDLINE | ID: mdl-34308796

ABSTRACT

Studies on the intermediate states of proteins provide essential information on folding pathway and energy landscape of proteins. Osmolytes, known to alter the stability of proteins, might also affect the structure and energy states of folding intermediates. This was examined using cytochrome c (Cyt) as a model protein which forms a spectroscopically detectable intermediate during thermal denaturation transition. Most of the secondary structure and the native heme-ligation were intact in the intermediate state of the protein. Denaturants, urea and guanidinium hydrochloride, and ionic salt destabilizes the intermediate and drive the protein to follow two-state transition. The effect of polyol class of osmolytes, glycol, glycerol, erythritol, xylitol and sorbitol (with OH-groups two to six), on the intermediate was studied using Soret absorbance and far-UV circular dichroism. With the increasing concentration of any of the polyols, the transition-midpoint temperature (Tm) and the enthalpy change (ΔH) for native to intermediate transition were decreased. This indicated that the intermediate was destabilized by the polyols. However, the polyols increased the overall stability of the protein by increasing Tm and ΔH for intermediate to unfolded transition, except for glycol which destabilized the protein. These results show that the polyols could alter the energy state of the intermediate, and the effect of lower and higher polyols might be different on the stability and folding pathway of the protein.Communicated by Ramaswamy H. Sarma.


Subject(s)
Cytochromes c , Polymers , Protein Denaturation , Polymers/chemistry , Thermodynamics , Circular Dichroism , Glycols , Protein Folding
14.
J Phys Chem B ; 124(45): 10077-10088, 2020 11 12.
Article in English | MEDLINE | ID: mdl-33143422

ABSTRACT

Osmolytes are known to stabilize proteins under stress conditions. Thermal denaturation studies on globular proteins (ß-lactoglobulin, cytochrome c, myoglobin, α-chymotrypsin) in the presence of ethylene glycol (EG), a polyol class of osmolyte, demonstrate a unique property of EG. EG stabilizes proteins against cold denaturation and destabilizes them during heat-induced denaturation. Further, chemical denaturation experiments performed at room temperature and at a sub-zero temperature (-10 °C) show that EG stabilizes the proteins at subzero temperature but destabilizes them at room temperature. The experiments carried out in the presence of glycerol, however, showed that glycerol stabilizes proteins against all of the denaturing conditions. This differential effect has not been reported for any other polyol class of osmolyte and might be specific to EG. Moreover, molecular dynamics simulations of all of the four proteins were carried out at three different temperatures, 240, 300, and 340 K, in the absence and presence of EG (20 and 40%). The results suggest that EG preferably accumulates around the hydrophobic residues and reduces the hydrophobic hydration of the proteins at a low temperature leading to stabilization of the proteins. At 340 K, the preferential hydration of the proteins is significantly reduced and the preferential binding of EG destabilizes the proteins like common denaturants.


Subject(s)
Ethylene Glycol , Glycerol , Molecular Dynamics Simulation , Protein Denaturation , Temperature , Thermodynamics
15.
Transfus Apher Sci ; 59(6): 102905, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32807651

ABSTRACT

Blood and its components are stored to meet the demands of blood transfusion. Erythrocytes undergo progressive modifications during storage known as storage lesions. Storage solutions were developed to improve shelf life and extend red cell viability. Therefore, the objective of this study is to analyze the effects of AS-7 on young and old erythrocytes during storage. Blood was collected from the blood bank at Kempegowda Institute of Medical Sciences (KIMS) hospital, Bengaluru. Erythrocytes were isolated from whole blood and separated based on its age using Percoll density gradient. The young and old erythrocytes were stored in AS-7 for 35 days and every 5th day, oxidative stress markers - Hemoglobin (Hb), Oxidative Hemolysis, Mechanical Fragility, Sialic Acid, Superoxides, Glucose, Lactate Dehydrogenase (LDH), Glutathione, antioxidant capacity (TACCUPRAC), Plasma Membrane Redox System (PMRS), antioxidant enzymes, lipid peroxidation, and protein oxidation products were assessed. Hb, glucose, TACCUPRAC, and superoxide dismutase reduced, while oxidative hemolysis, mechanical fragility, protein oxidation, and lipid peroxidation products increased in young and old cells over storage. LDH, PMRS, catalase, advanced oxidation protein products, and conjugate dienes were significant in old cells from day 5 itself, whereas in young cells towards the end of storage (from day 25). Oxidative insult was higher in old cells compared to young cells. AS-7 was beneficial to young erythrocytes during storage and thus laying the foundation for the possibilities of utilizing young cells as models for storage studies.


Subject(s)
Blood Preservation/methods , Erythrocytes/metabolism , N-Acetylneuraminic Acid/metabolism , Oxidative Stress/drug effects , Erythrocytes/cytology , Humans
16.
J Mol Graph Model ; 98: 107602, 2020 07.
Article in English | MEDLINE | ID: mdl-32251994

ABSTRACT

In the present study, we investigate the interaction of amino acid osmolytes, Arg, Lys, Asp and Glu, and a denaturant, guanidinium chloride (Gdm) with proteins. To achieve this, molecular dynamics (MD) simulation of RNase A and α-lactalbumin was performed in the presence of three charged amino acids Arg, Lys, and Asp and the molecular mechanism of amino acid-induced (de)stabilization of the proteins was examined by combining with our earlier report on Glu. As Arg has the side chain similar to that of Gdm and destabilizes the proteins, MD simulation was carried out in the presence of Gdm as well. Radial distribution function and hydration fraction around the protein surface reveals that preferential hydration increases upon the addition of any of the cosolvent; however, the extent of increase is more in the presence of stabilizing cosolvents (stAAs: Lys, Asp and Glu) compared to destabilizing cosolvents (Arg and Gdm). Moreover, the preferential interaction of Arg and Gdm with the proteins is higher than that of stAAs. Residue-level interaction analysis suggests that stAAs preferably interacts with charged amino acids of the proteins whereas Arg and Gdm interactions could be found on almost all the surface exposed residues which might provide higher preferential interaction for these residues. From the results, we propose that the net outcome of preferential hydration versus preferential interaction of the amino acids might determine their effect on the stability of proteins.


Subject(s)
Amino Acids , Molecular Dynamics Simulation , Protein Stability , Protein Structure, Secondary , Thermodynamics
17.
Transfus Med Hemother ; 46(4): 257-266, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31700508

ABSTRACT

BACKGROUND: During storage of erythrocytes, storage lesions are formed that reduce the safety and efficacy of the stored blood. Thus, there is a need to understand the changes that occur during storage. Most studies have focused on storage of a mixed population of erythrocytes. The aim of this study is to analyze the changes in young and old erythrocytes over the course if storage. MATERIALS AND METHODS: Blood was collected from the blood bank at the Kempegowda Institute of Medical Sciences (KIMS) Hospital (Bengaluru, India) and stored for 35 days in CPDA-1 at 4°C. Every 5 days, erythrocytes were separated based on the blood's age using a Percoll-BSA gradient. Young and old erythrocytes obtained were used for analysis of the following oxidative stress (OS) markers: hemoglobin (Hb), hemolysis, mechanical fragility, antioxidant enzymes (superoxide dismutase and catalase [CAT]), superoxides, sialic acid, glutamic oxaloacetate transaminase (GOT), glucose, plasma membrane redox system (PMRS), total antioxidant capacity-cupric ion reducing antioxidant capacity assay (TACCUPRAC), lactate dehydrogenase (LDH), lipid peroxidation products (malondialdehyde [MDA] and conjugate dienes), and protein oxidation products (advanced oxidation protein products and protein sulfhydryls). RESULT: Young cells had higher amounts of Hb, sialic acid, GOT, LDH, TACCUPRAC, CAT, and superoxides compared to old cells. Old cells, however, had higher PMRS and MDA levels with respect to young cells. DISCUSSION: Young cells could endure OS during storage more efficiently than old cells. In conclusion, the efficacy of stored blood depends on the ratio of young cells in the population. This study highlights the prospects of storing young erythrocytes for a prolonged shelf life of blood.

18.
Appl Biochem Biotechnol ; 189(2): 541-555, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31056736

ABSTRACT

Studies on osmolyte-induced effects on proteins help in enhancing protein stability under stressed conditions for various applications. Using mixtures of osmolytes could indeed widen their applications. The combinatorial effects of osmolytes with methylamines are majorly found in the literature; however, such studies are limited on the amino acid class of osmolytes. The present study examines the effect of charged amino acids Arg, Asp, and Lys on the stability of RNase A and α-LA. The thermal stabilities of the proteins in the presence of osmolytes are monitored by absorption changes, and the structural changes are analyzed using fluorescence quenching and near-UV circular dichroism (CD). These results are compared with our previous report on the effect of Glu. Arg destabilizes both the proteins whereas Asp, Lys, and Glu stabilize the proteins. The extent of stability provided by Asp and Glu is almost same and higher than Lys in RNase A. However, the stability acquired in the presence of Asp and Lys is comparable for α-LA and Glu provides higher stability. Further, the quenching and CD results suggest that the addition of amino acids do not alter the structure of the proteins significantly. The counteracting abilities of the stabilizing amino acids (stAAs) against Arg are then investigated. The results show that Glu could counteract Arg at the lowest fraction in the mixture. Lys requires nearly equimolar concentration whereas Asp needs almost double the concentration to counteract Arg induced destabilization of the proteins. At higher concentrations, the counteracting ability of Asp and Lys is similar for both the proteins. The counteracting ratio might slightly vary among the proteins, and it is not necessary that the amino acid providing higher stability to the protein could more effectively counteract Arg. This could be due to the change in the extent of preferential hydration of the proteins by stAAs in the presence of Arg. The results suggest that the addition of stAAs could be an effective strategy to increase the protein stability in biotechnology and biopharma applications.


Subject(s)
Arginine/chemistry , Ribonuclease, Pancreatic/chemistry , Circular Dichroism , Enzyme Stability , Protein Structure, Secondary
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