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Journal of Artificial Organs : the... Jun 2024Excessive albumin losses during HC (haemocatharsis) are considered a potential cause of hypoalbuminemia-a key risk factor for mortality. This review on total albumin... (Review)
Review
Excessive albumin losses during HC (haemocatharsis) are considered a potential cause of hypoalbuminemia-a key risk factor for mortality. This review on total albumin losses considers albumin "leaking" into the dialysate and losses due to protein/membrane interactions (i.e. adsorption, "secondary membrane formation" and denaturation). The former are fairly easy to determine, usually varying at the level of ~ 2 g to ~ 7 g albumin loss per session. Such values, commonly accepted as representative of the total albumin losses, are often quoted as limits/standards of permissible albumin loss per session. On albumin mass lost due to adsorption/deposition, which is the result of complicated interactions and rather difficult to determine, scant in vivo data exist and there is great uncertainty and confusion regarding their magnitude; this is possibly responsible for neglecting their contribution to the total losses at present. Yet, many relevant in vitro studies suggest that losses of albumin due to protein/membrane interactions are likely comparable to (or even greater than) those due to leaking, particularly in the currently favoured high-convection HDF (haemodiafiltration) treatment. Therefore, it is emphasised that top research priority should be given to resolve these issues, primarily by developing appropriate/facile in vivo test-methods and related analytical techniques.
Topics: Humans; Dialysis Solutions; Hemodiafiltration; Hypoalbuminemia; Renal Dialysis; Serum Albumin
PubMed: 38238597
DOI: 10.1007/s10047-023-01430-y -
Food Research International (Ottawa,... Aug 2023Proteins are excellent polymeric materials for encapsulating essential oils (EOs) by electrospinning and electrospraying to protect these compounds and form... (Review)
Review
Proteins are excellent polymeric materials for encapsulating essential oils (EOs) by electrospinning and electrospraying to protect these compounds and form nanomaterials with active properties. Proteins can encapsulate bioactive molecules by several mechanisms, including surface activity, absorption and stabilization mechanisms, amphiphilic nature, film-forming capacity, foaming, emulsification, and gelation, due to interactions among their functional groups. However, proteins have some limitations in encapsulating EOs by the electrohydrodynamic process. Their properties can be improved by using auxiliary polymers, increasing their charges by adding ionic salts or polyelectrolytes, denaturing their structure by heat, and exposure to specific pH conditions and ionic strength. This review addresses the main proteins used in electrospinning/electrospraying techniques, production methods, their interactions with EOs, bioactive properties, and applications in food matrices. Multivariate analysis associated with bibliometrics of metadata extracted from studies in Web of Science using the keywords electrospinning and essential oil (EO) were used as the search strategy.
Topics: Bibliometrics; Food; Hot Temperature; Multivariate Analysis; Oils, Volatile; Polymers
PubMed: 37316009
DOI: 10.1016/j.foodres.2023.112970 -
Journal of Enzyme Inhibition and... Dec 2023Prions are infectious protein particles known to cause prion diseases. The biochemical entity of the pathogen is the misfolded prion protein (PrP) that forms insoluble...
Prions are infectious protein particles known to cause prion diseases. The biochemical entity of the pathogen is the misfolded prion protein (PrP) that forms insoluble amyloids to impair brain function. PrP interacts with the non-pathogenic, cellular prion protein (PrP) and facilitates conversion into a nascent misfolded isoform. Several small molecules have been reported to inhibit the aggregation of PrP but no pharmacological intervention was well established thus far. We, here, report that acylthiosemicarbazides inhibit the prion aggregation. Compounds and showed almost perfect inhibition (EC = 5 µM) in prion aggregation formation assay. The activity was further confirmed by atomic force microscopy, semi-denaturing detergent agarose gel electrophoresis and real-time quaking induced conversion assay (EC = 0.9 and 2.8 µM, respectively). These compounds also disaggregated pre-existing aggregates and one of them decreased the level of PrP in cultured cells with permanent prion infection, suggesting their potential as a treatment platform. In conclusion, hydroxy-2-naphthoylthiosemicarbazides can be an excellent scaffold for the discovery of anti-prion therapeutics.
Topics: Humans; Prions; Prion Proteins; Brain; Prion Diseases; Cells, Cultured
PubMed: 36950944
DOI: 10.1080/14756366.2023.2191164 -
ACS Chemical Biology Jul 2023Disulfide bonds form covalent bonds between distal regions of peptides and proteins to dramatically impact their folding, stability, and oligomerization. Given the...
Disulfide bonds form covalent bonds between distal regions of peptides and proteins to dramatically impact their folding, stability, and oligomerization. Given the prevalence of disulfide bonds in many natural products, considerable effort has been invested in site-selective disulfide bond formation approaches to control the folding of chemically synthesized peptides and proteins. Here, we show that the careful choice of thiol oxidation conditions can lead to monomeric or dimeric species from fully deprotected linear bisthiol peptides. Starting from a p53-derived peptide, we found that oxidation under aqueous (nondenaturing) conditions produces antiparallel dimers with enhanced α-helical character, while oxidation under denaturing conditions promotes formation of a nonhelical intramolecular disulfide species. Examination across peptide variants suggests that intramolecular disulfide formation is robust across diverse peptide sequences, while dimerization is sensitive to both the α-helical folding of the linear peptide and aromatic residues at the dimerization interface. All disulfide species are more resistant to protease degradation than the linear peptide but are easily reduced to restore the initial bisthiol peptide. Both disulfide formation approaches are compatible with α-helix-stabilizing cross-linkers. These results provide an approach for using disulfide bonds to control peptide folding and oligomerization to better understand how folding influences interactions with diverse molecular targets.
Topics: Disulfides; Protein Folding; Dimerization; Proteins; Peptides; Oxidation-Reduction
PubMed: 37390465
DOI: 10.1021/acschembio.3c00268 -
Foods (Basel, Switzerland) Dec 2023Tea () has grown for over 300 years and is recognized worldwide as among other well-renowned crops. The quality of black tea depends on plucking (method, standard,... (Review)
Review
Tea () has grown for over 300 years and is recognized worldwide as among other well-renowned crops. The quality of black tea depends on plucking (method, standard, season, and intervals), withering and rolling (time and temperature), fermentation (time, temperature, and RH), drying (temperature and method), and storage conditions, which have a high influence on the final quality of black tea. At the rolling stage, the oxidation process is initiated and ends at the early drying stage until the enzymes that transform tea polyphenols into thearubigins (TRs) and theaflavins (TFs) are denatured by heat. By increasing fermentation time, TRs increased, and TF decreased. Each is liable for black tea's brightness, taste, and color. The amino acids and essential oils also grant a distinctive taste and aroma to black tea. Throughout withering, rolling, and fermentation, increases were found in essential oil content, but during drying, a decrease was observed. However, the Maillard reaction, which occurs when amino acids react with sugar during drying, reimburses for this decrease and enhances the flavor and color of black tea. As compared to normal conditions, accelerated storage showed a slight decrease in the total color, TF, and TRs. It is concluded that including plucking, each processing step (adopted technique) and storage system has a remarkable impact on black tea's final quality. To maintain the quality, an advanced mechanism is needed to optimize such factors to produce high-quality black tea, and an objective setting technique should be devised to attain the desirable quality characteristics.
PubMed: 38137271
DOI: 10.3390/foods12244467 -
Journal of Ayurveda and Integrative... 2023Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to...
BACKGROUND
Rheumatoid arthritis (RA) is an inflammation of joints with increased cellularity of synovial tissue. Allopathic drugs possess several adverse effects, which have led to increase in the utilization of herbal medicines. Polyherbal emulgel resolves the bioavailability issue associated with hydrophobic drugs and can be used effectively in the treatment of RA.
OBJECTIVES
The present study aimed at the formulation of polyherbal emulgel, and evaluation of in vitro anti-inflammatory activity and in vivo antiarthritic activity.
METHODS
Seven emulgels F-1 to F-7 were optimally formulated. In vitro anti-inflammatory activity was determined using protein denaturation method employing Diclofenac sodium as the standard. In antiarthritic study Complete Freund's Adjuvant (CFA) model was used. The various parameters were assessed, like paw volume, body weight, hematological parameters, antioxidant parameters, Rheumatic factor (RF), and histopathological study of ankle joint.
RESULTS
F-4 and F-7 were found to be optimized formulations as compared to other formulations. The in vitro anti-inflammatory activity was found to be highest in F-4 with IC 7.74 and F-7 with IC 8.87 in comparison with Diclofenac sodium having IC 57.0. Both formulations F-7 and F-4 showed a significant reduction in paw volume and normalization of body weights. The formulation F-7 even showed more potent antiarthritic activity than F-4 by decreasing white blood cells (WBC), lymphocytes, increasing packed cell volume (PCV), neutrophils, superoxide dismutase (SOD), catalase and decreasing malondialdehyde (MDA) levels in serum. This was further confirmed by histopathological study.
CONCLUSION
As an anti-inflammatory agent, this newly developed emulgel was found to possess more therapeutic efficacy than commercially available diclofenac sodium.
PubMed: 38016365
DOI: 10.1016/j.jaim.2023.100828 -
Cureus Feb 2024Thermal, electrical, chemical, or electromagnetic radiation can cause painful wounds or burns. Spilling hot liquids onto the skin can also cause these kinds of... (Review)
Review
Thermal, electrical, chemical, or electromagnetic radiation can cause painful wounds or burns. Spilling hot liquids onto the skin can also cause these kinds of injuries. The two biggest factors contributing to burn injuries in the elderly are smoking and exposure to open flames, while scalding is the primary cause of burn damage in children. Newborns and the elderly make up the majority of burn casualties. In India, there are estimated to be 6-7 million burn cases per year. The high incidence is attributed to the population's illiteracy, poverty, and lack of awareness of safety. The problem is made much worse by the fact that basic and secondary healthcare levels do not provide systematic burn care. Coagulation necrosis is caused by denaturing proteins due to heat from burns. Platelets clump together, arteries narrow, and partly perfused tissue (called the stasis zone) may spread out around the wound. In the stasis zone, tissue is hyperemic and inflammatory. When the skin's natural barrier is breached, microorganisms can enter the body and cause poor temperature regulation, fluid loss, and invasion. Intravascular volume loss is typically worsened by injured or edematous tissues. Significant heat loss may occur from the wounded dermis' lack of thermoregulation, particularly in exposed wounds. The severity determines the different treatments. Serious burns require considerable care, while lesser burns just require cleaning and painkillers. Just-partially thickened burns must be cleansed with soap and water before being clothed. For full-thickness burns, surgery, including skin grafting, is frequently required. Extensive intravenous fluid doses are often required to treat serious burns resulting from tissue edema and capillary fluid leakage.
PubMed: 38544618
DOI: 10.7759/cureus.54915 -
Methods in Molecular Biology (Clifton,... 2024Label-retention expansion microscopy (LR-ExM) is a sample preparation technique, which embeds the cells or tissues in a swellable hydrogel and expands the sample so that...
Label-retention expansion microscopy (LR-ExM) is a sample preparation technique, which embeds the cells or tissues in a swellable hydrogel and expands the sample so that one can achieve a high resolution with any conventional fluorescence microscopes. Fluorescence loss during polymerization and protein denaturation have been a major limitation of standard expansion microscopy. To minimize fluorescence loss, LR-ExM uses trifunctional anchors, which can survive from polymerization and denaturation, and then introduce fluorophores after expansion. By using LR-ExM, one can study the structure of primary cilia at molecular-scale resolution with a much higher signal-to-noise ratio, compared with previously introduced expansion microscopy methods. In this chapter, we describe a detailed procedure showing how LR-ExM is used to study ciliary proteins.
Topics: Microscopy, Fluorescence; Proteins; Hydrogels
PubMed: 37856018
DOI: 10.1007/978-1-0716-3507-0_4 -
Cell Reports Sep 2023Inorganic polyphosphate (polyP) is a linear polymer of orthophosphate that is present in nearly all organisms studied to date. A remarkable function of polyP involves...
Inorganic polyphosphate (polyP) is a linear polymer of orthophosphate that is present in nearly all organisms studied to date. A remarkable function of polyP involves its attachment to lysine residues via non-enzymatic post-translational modification (PTM), which is presumed to be covalent. Here, we show that proteins containing tracts of consecutive histidine residues exhibit a similar modification by polyP, which confers an electrophoretic mobility shift on NuPAGE gels. Our screen uncovers 30 human and yeast histidine repeat proteins that undergo histidine polyphosphate modification (HPM). This polyP modification is histidine dependent and non-covalent in nature, although remarkably it withstands harsh denaturing conditions-a hallmark of covalent PTMs. Importantly, we show that HPM disrupts phase separation and the phosphorylation activity of the human protein kinase DYRK1A, and inhibits the activity of the transcription factor MafB, highlighting HPM as a potential protein regulatory mechanism.
PubMed: 37660293
DOI: 10.1016/j.celrep.2023.113082 -
Nature Protocols Jan 2024The isolation of proteins in high yield and purity is a major bottleneck for the analysis of their three-dimensional structure, function and interactome. Here, we... (Review)
Review
The isolation of proteins in high yield and purity is a major bottleneck for the analysis of their three-dimensional structure, function and interactome. Here, we present a streamlined workflow for the rapid production of proteins or protein complexes using lentiviral transduction of human suspension cells, combined with highly specific nanobody-mediated purification and proteolytic elution. Application of the method requires prior generation of a plasmid coding for a protein of interest (POI) fused to an N- or C-terminal GFP or ALFA peptide tag using a lentiviral plasmid toolkit we have designed. The plasmid is then used to generate human suspension cell lines stably expressing the tagged fusion protein by lentiviral transduction. By leveraging the picomolar affinity of the GFP and ALFA nanobodies for their respective tags, the POI can be specifically captured from the resulting cell lysate even when expressed at low levels and under a variety of conditions, including detergents and mild denaturants. Finally, rapid and specific elution of the POI (in its tagged or untagged form) under native conditions is achieved within minutes at 4 °C, using the engineered SUMO protease SENP. We demonstrate the wide applicability of the method by purifying multiple challenging soluble and membrane protein complexes to high purity from human cells. Our strategy is also directly compatible with many widely used GFP-expression plasmids, cell lines and transgenic model organisms. Finally, our method is faster than alternative approaches, requiring only 8 d from plasmid to purified protein, and results in substantially improved yields and purity.
Topics: Humans; Proteins; Peptides; Proteolysis; Recombinant Fusion Proteins; Chromatography, Affinity
PubMed: 37974029
DOI: 10.1038/s41596-023-00904-w