Molecular Mass Components Research Articles

Stability constants of mixed-ligand cobalt(II) complexes with pyridinedicarboxylic acids and small bioligands studied by potentiometric measurements

In this work, we have studied the stability constants of ternary cobalt(II) complexes with the primary ligands: pyridine-2,3-dicarboxylic acid (H22,3-Dipic, H2L) and pyridine-3,4-dicarboxylic acid (H23,4-Dipic, H2L) and secondary ligands representing low molecular mass components of blood serum: lactic acid (HLac), oxalic acid (H2Ox), citric acid (H3Cit), and phosphoric acid (H3PO4). Potentiometric data were analyzed using the least squares computational program LETAGROP. Ionic strength and temperature were both kept constant using 1.0 mol dm−3 NaNO3 as ionic medium at 25 °C. Species distribution diagrams were generated to determine the speciation variations with respect to pH.

Enzymatic hydrolysis of whey proteins by the combination of Alcalase and Neutrase: Kinetic model and hydrolysis control

A combination of Alcalase and Neutrase was used to hydrolyse whey proteins and the hydrolysis kinetics mechanism was studied to achieve accurate control of the hydrolysis process. By measuring the degree of hydrolysis (DH) at different enzyme concentrations and different substrate concentrations, the hydrolysis kinetic model was established as: DH=6.536Ln[1+(4.687E0S0–0.0007)t]. The results showed that the theoretical and actual values of the model were in good agreement. Subsequently, the molecular mass distribution of the whey proteins hydrolysates at different DH was determined; it was found that the molecular mass components of 5–20 and >20 kDa gradually decreased with the increase of DH, while the percentage of <1 kDa gradually increased. Extensive hydrolysis of whey proteins was achieved when the DH reached 21–25%. The establishment of kinetic model has theoretical guidance for the accurate control of the whey proteins hydrolysis by the combination of Alcalase and Neutrase.

Water-extractable polysaccharide fraction PNE-P1 from Pinus koraiensis pine nut: Structural features and immunostimulatory activity

The polysaccharide fraction PNE-P1 was isolated from hot water extract (PNE) of the defatted meal of pine nuts (Pinus koraiensis) using DEAE-cellulose column chromatography. This fraction had three components of molecular masses 1251, 616, and 303 g/mol consisting mainly of arabinose, xylose, and galacturonic acid at a molar ratio of 2:1.6:1. Structural analysis with FTIR/Raman, methylation and GC-MS, and NMR revealed that PNE-P1 is a cell wall polysaccharide complex including arabinan, heteroxylan, homogalacturonan (HM) and rhamnogalacturonan I (RG-I) parts. Being nontoxic to RAW 264.7 macrophages in the concentration range of 10–200 μg/mL, PNE-P1 promoted proliferation of these cells, significantly induced the secretion of proinflammatory cytokines (TNF-α and IL-6) and chemokines (RANTES and MIP-1α) and enhanced the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and nitric oxide (NO). PNE-P1 also markedly induced macrophage-mediated phagocytosis of apoptotic Jurkat T cells. These results demonstrate that pine nuts Pinus koraiensis contain a complex of water-soluble plant cell wall polysaccharides, which can stimulate innate immunity by potentiating macrophage function.

Understanding the Immunomodulatory Effects of Bovine Colostrum: Insights into IL-6/IL-10 Axis-Mediated Inflammatory Control.

Bovine colostrum (COL), the first milk secreted by lactating cows postpartum, is a rich source of bioactive compounds that exert a significant role in the survival, growth, and immune development of neonatal calves. This study investigated the immunomodulatory effects of COL on cytokine production in vitro using a Caco-2/THP-1 macrophage co-culture model stimulated with Phorbol 12-myristate 13-acetate (PMA). COL pretreatment significantly reduced IL-6 (241.3 pg/mL) production induced by PMA (p < 0.05), while increasing IL-10 production (45.3 pg/mL), in comparison to PMA control (441.1 and 12.5 pg/mL, respectively). Further investigations revealed that the IL-6 suppressive effect of colostrum was heat-sensitive and associated with components of higher molecular mass (100 kDa). Moreover, colostrum primarily influenced THP-1 macrophages rather than Caco-2 epithelial cells. The effects of colostrum on IL-6 production were associated with reduced NF-κB activation in THP-1 macrophages. In calf-FMT transplanted C57BL/6 murine model, colostrum decreased intestinal permeability, reduced immune cell infiltration and intestinal score, and suppressed IL-6 (142.0 pg/mL) production during S. typhimurium infection, in comparison to control animals (215.2 pg/mL). These results suggest the immunomodulatory activity of bovine colostrum and its potential applications in inflammatory disorders. Further studies are needed to elucidate the underlying mechanisms and validate the findings in bovine models.

Polysaccharides Obtained from Vegetables: an effective source of alternative excipient.

Polymers are the major constructive material of pharmaceutical formulations that play a prime role in designing effective drug-delivery systems and releasing drugs at their sites of application. Polymers are composed of multiple repeating units of high molecular mass components with attendant properties. Most synthetic polymers are non-biocompatible, expensive, and extremely inclined to deliver adverse impacts. Meanwhile, edible polymers obtained from natural sources have gained remarkable recognition for their promising use in modern medicine. Moreover, polymers derived from natural sources are generally preferred due to certain of their unique features such as abundant availability, biocompatibility, nontoxicity, economical, safe, and effective functions that fit the purpose. Polysaccharides including starch, cellulose, hemicellulose, pectin, and mucilage are identified as a major class of naturally obtained molecules that have a substantial role as functional polymers. This review summarizes the potential role of polysaccharides derived from vegetable sources such as adhesives, anticaking agents, binders, disintegrants, emulsifiers, film-framing agents, and thickeners. This is simply an opportunity to abandon synthetic excipients that hurt our bodies and think back to nature from where we originate.

Protein Hydrolysates from Flaxseed Oil Cake as a Media Supplement in CHO Cell Culture

This is the first report about flaxseed protein hydrolysates applied as media supplements in CHO cell culture. The hydrolysates were produced by three separate enzymatic digestions of proteins isolated from flaxseed oil cake. The enzymes used were Alcalase, Neutrase, and Protamex, and the most efficient hydrolysis was achieved with Alcalase. The three hydrolysates were first tested as a partial substitute for serum in basal media in order to evaluate their effects on the adherent IgG-producing CHO cell line. The cells that grew in such media reached higher density than the cells in media supplemented with serum only. Consequently, the increased cell number improved the final IgG titer. In the next experiment, the impact of hydrolysates was evaluated in suspension CHO culture adapted to chemically defined media. In this preliminary investigation, the cells showed no response to the hydrolysate addition concerning the growth rate and productivity. Despite this outcome, we speculate that low molecular mass components in the hydrolysates, besides nutritive, may have a cell-protective function.

Pharmacologically Active Vanadium Species: Distribution in Biological Media and Interaction with Molecular Targets.

Biospeciation of some of the most studied vanadium (symbol V) complexes with biological or medicinal activity is discussed in this review in order to emphasize the importance of the distribution of V species in biological media. The exact knowledge of the chemical species present in blood or cells may provide essential information regarding the biological effect of V potential drugs. In blood serum, vanadium species can interact with low (citrate, lactate, oxalate, amino acids, etc., indicated with bL) and high molecular mass (proteins like transferrin, albumin, immunoglobulins, etc.) components, while the interaction with red blood cells can interfere with the transport of these drugs towards the target cells. The interaction of bLs and proteins is discussed through the analysis of instrumental and computational data. The fate of the active V species, when these are in the real serum samples and when they reach and cross cell membranes, is also discussed. The differences in the V complexes selected in this review (donor atoms, stability, coordination geometry, electric charge, hydrolipophilicity balance, substituents and redox properties) cover all the possible modes of interaction with bLs and proteins, allowing for the biodistribution of the studied compounds to be predicted. This approach could be applied to newly synthesized potential V drugs.

Enzymatic Modification of Porphyra dioica-Derived Proteins to Improve their Antioxidant Potential.

Enzymatic hydrolysis has been employed to modify protein functional properties and discover new sources of antioxidants. In this study, the effect of different enzymatic treatments on antioxidant activity of Porphyra dioica (blades and protein isolate (PI)) was investigated. Protein nitrogen content of P. dioica blades and PI were 23 and 50% (dry weight), respectively. Blades and PI were hydrolyzed with Prolyve® and Prolyve® plus Flavourzyme®. Peptide profiles and molecular mass distribution of the hydrolysates were investigated. The hydrolysis promoted generation of peptides and low molecular mass components <1 kDa. Antioxidant activity was assessed using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) scavenging, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS·+) inhibition, and reactive oxygen species scavenging ability, i.e., oxygen radical absorbance capacity (ORAC) and hypochlorous acid (HOCl) scavenging assays. In general, enzymatic hydrolysis of P. dioica blades and PI enhanced the in vitro antioxidant activity. Direct hydrolysis of blades improved ORAC values up to 5-fold (from 610 to 3054 μmol Trolox eq./g freeze dried sample (FDS). The simultaneous release of phenolic compounds suggested a potential synergistic activity (ORAC and ABTS·+ assays). Such hydrolysates may be of value as functional food ingredients.

Elucidation of the Structure and Synthesis of Neuroprotective Low Molecular Mass Components of the Parawixia bistriata Spider Venom.

The South American social spider Parawixia bistriata produces a venom containing complex organic compounds with intriguing biological activities. The crude venom leads to paralysis in termites and stimulates l-glutamate uptake and inhibits GABA uptake in rat brain synaptosomes. Glutamate is the major neurotransmitter at the insect neuromuscular junction and at the mammalian central nervous system, suggesting a modulation of the glutamatergic system by the venom. Parawixin1, 2, and 10 (Pwx1, 2 and 10) are HPLC fractions that demonstrate this bioactivity. Pwx1 stimulates l-glutamate uptake through the main transporter in the brain, EAAT2, and is neuroprotective in in vivo glaucoma models. Pxw2 inhibits GABA and glycine uptake in synaptosomes and inhibits seizures and neurodegeneration, and Pwx10 increases l-glutamate uptake in synaptosomes and is neuroprotective and anticonvulsant, shown in in vivo epilepsy models. Herein, we investigated the low molecular mass compounds in this venom and have found over 20 small compounds and 36 unique acylpolyamines with and without amino acid linkers. The active substances in fractions Pwx1 and Pwx2 require further investigation. We elucidated and confirmed the structure of the active acylpolyamine in Pwx10. Both fraction Pwx10 and the synthesized component enhance the activity of transporters EAAT1 and EAAT2, and, importantly, offer in vitro neuroprotection against excitotoxicity in primary cultures. These data suggest that compounds with this mechanism could be developed into therapies for disorders in which l-glutamate excitotoxicity is involved.

Enzymolysis kinetics and structural-functional properties of high-intensity ultrasound-assisted alkali pretreatment ovalbumin

ABSTRACT This research investigated the enzymolysis kinetics of high-intensity ultrasound (HIU)-assisted alkali pretreatment Ovalbumin (OVA) through using Alcalase, and its structural and functional properties. The structural characteristics of OVA were performed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), surface hydrophobicity, Fourier Transform Infrared, and differential scanning calorimetry. SDS-PAGE analysis indicated that the pretreatment sample showed proportion of lower molecular mass components (14.3–20.1 kDa). There was an increase in the intensity of fluorescence spectrum and changes in functional groups after the pretreatment on OVA compared with the control (without treatment), which might be the reason for the significantly enhancing efficiency of the enzymatic hydrolysis. The thermal denaturation temperature of enzymatic hydrolysis of OVA after pretreatment was 95.1°C, which was 17.5°C higher than that of control. As compared to OVA (control), the enzymatic hydrolysis with HIU-assisted alkali pretreatment was found to significantly improve protein solubility, emulsifying properties, foaming ability (FA) and foam stability, oil, and water absorption capacity (WAC). Especially emulsifying activity index, FA, WAC, and oil absorption capacity were increased by 228.7%, 88.5%, 102.6%, and 67.4%, respectively (P< 0.05). A simplified kinetic equation for the enzymolysis model was deduced to successfully describe the enzymatic hydrolysis of pretreated OVA. The results proved the effects of the pretreatment on the substrate enhanced the enzymolysis process and this influence had relation to the structure changes. Furthermore, the enzymatic hydrolysis process for other proteins demonstrated the applicability of the model.

Phase diagram of the low-density polyethylene – dimethyl terephthalate system: A new topology

A new type of phase diagram semicrystalline polymer – low molecular mass substance is found for the low-density polyethylene – dimethyl terephthalate mixture. Exploiting an original optical method and differential scanning calorimetry, we demonstrate that the studied system combines the features of polymer – poor solvent and polymer – high-melting substance mixtures. Its diagram also contains a curve describing the solubility of the low molecular mass component in the polymer, which is often missing in the literature. An experimental phase diagram enables us to perform a detailed analysis of the differential scanning calorimetry, optical and scanning electron microscopy data on the cooling of homogenized mixtures of different compositions, which leads to the formation of capillary-porous polyethylene bodies via thermally induced phase separation and following removal of dimethyl terephthalate crystals.

Isotactic polypropylene–1,2,4,5-tetrachlorobenzene: porous bodies via thermally induced phase separation

Using recently constructed experimental phase diagram isotactic polypropylene–1,2,4,5-tetrachlorobenzene (TeCB), we formulate a physically consistent scenario of the mixture evolution under thermally induced phase separation and predict the morphology of capillary-porous bodies that are formed after cooling down the binary system and removal of the low molecular mass component. This approach allows us to interpret the experimental data obtained by optical microscopy, scanning electron microscopy, and differential scanning calorimetry on the system with two crystallizable components. At any composition, TeCB forms needle-like crystals of nearly square section. Increasing polymer content affects crystal growth by limiting their length and by generating another population of small TeCB crystals of irregular shape and close to log-normal size distribution, located in the amorphous polymer regions. Finite rate of cooling the system leads to a hysteresis, when the values of characteristic temperatures and compositions in the phase diagram appear to be considerably shifted to lower temperatures and higher polymer contents. Combination of structural and calorimetric data provides an opportunity to characterize polymer–solvent systems from both thermodynamic and technological standpoints.

A holistic study to understand the detoxification of mycotoxins in maize and impact on its molecular integrity using cold atmospheric plasma treatment

The need for safe and quality food, free from the presence of hazardous contaminants such as mycotoxins is an on-going and complex challenge. Cold atmospheric pressure plasma (CAPP) has the potential to contribute to achieving this goal. Decontamination efficacy of CAPP against six of the most common mycotoxins found in foods and feedstuffs was assessed herein. Concentration reduction of up to 66% was achieved in maize for both aflatoxin B1 and fumonisin B1. Degradation products were detected only in the case of aflatoxin B1 and zearalenone and were tested on human hepatocarcinoma cells with no increase in cytotoxicity observed. Analysis of treated maize revealed substantial changes to small molecular mass components of the matrix. While CAPP shows promise in terms of mycotoxin detoxification important questions concerning potential changes to the nutritional and safety status of the food matrix require further investigations.

Effects of heating or ultrasound treatment on the enzymolysis and the structure characterization of hempseed protein isolates.

The effects of heating (90°C/30min) or ultrasound (200/400/600W) treatment on antioxidant and angiotensin-converting enzyme inhibitory (ACEI) activity of hydrolysates from hempseed protein isolates (HPI) were studied. The secondary structure, surface hydrophobicity, intrinsic fluorescence, scanning electron microscopy (SEM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of HPI treated by heating or ultrasound were measured. The results showed that hydrolysate from HPI treated with ultrasound at 200W showed higher hydrolysis degree, proportion of lower molecular mass components (1.0-3.0kDa), antioxidant and ACEI activity than those from heating or high-power treated. The changes in secondary structure, surface hydrophobicity and intrinsic fluorescence indicated the unfolding of HPI after ultrasound. The SEM results showed that HPI treated with ultrasound at 200W exhibited decrease in particle size and deformation and further increased in power caused the aggregates of HPI. In conclusion, the ultrasound treatment at low-power was superior to 90°C/30min treatment in facilitating enzymatic release of antioxidant and ACEI peptides from HPI.

Comparative analysis of Naja kaouthia venom from North-East India and Bangladesh and its cross reactivity with Indian polyvalent antivenoms

Naja kaouthia is one of the most prevalent medically important snakes of North East India and Bangladesh responsible for most of the bite cases. In this study, an attempt was made to decipher venom variation of Naja kaouthia venom from North East India and Bangladesh. Using multidimensional methods including reverse phase HPLC, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D-PAGE) and two-dimensional gel electrophoresis (2D-PAGE), the quantitative differences in venom composition have been revealed. Moreover, tested in-vitro biochemical and biological activities also exhibited differences which could be due to venom variability. Furthermore, neutralization efficacy of commercially available Indian polyvalent antivenoms (Vins, Bharat Serum, Haffkine) was evaluated and the results displayed significant differences in neutralizing efficacy between the antivenoms. Immunoblotting experiments showed antivenom molecules cross reacted with high molecular mass components while poorly reacted towards low molecular mass proteins. Immuno-depletion study demonstrated that Vins polyvalent antivenom was poor in immunocapturing the venom proteins of both North East Indian and Bangladesh origin Naja kaouthia at the ratio of 1:16 (venom: antivenom).

Mass Spectrometry Analysis and Biological Characterization of the Predatory Ant Odontomachus monticola Venom and Venom Sac Components.

We previously identified 92 toxin-like peptides and proteins, including pilosulin-like peptides 1–6 from the predatory ant Odontomachus monticola, by transcriptome analysis. Here, to further characterize venom components, we analyzed the venom and venom sac extract by ESI-MS/MS with or without trypsin digestion and reducing agent. As the low-molecular-mass components, we found amino acids (leucine/isoleucine, phenylalanine, and tryptophan) and biogenic amines (histamine and tyramine) in the venom and venom sac extract. As the higher molecular mass components, we found peptides and proteins such as pilosulin-like peptides, phospholipase A2s, hyaluronidase, venom dipeptidyl peptidases, conotoxin-like peptide, and icarapin-like peptide. In addition to pilosulin-like peptides 1–6, we found three novel pilosulin-like peptides that were overlooked by transcriptome analysis. Moreover, pilosulin-like peptides 1–6 were chemically synthesized, and some of them displayed antimicrobial, hemolytic, and histamine-releasing activities.

Venom characterization of the Amazonian scorpion Tityus metuendus

The soluble venom from the scorpion Tityus metuendus was characterized by various methods. In vivo experiments with mice showed that it is lethal. Extended electrophysiological recordings using seven sub-types of human voltage gated sodium channels (hNav1.1 to 1.7) showed that it contains both α- and β-scorpion toxin types. Fingerprint analysis by mass spectrometry identified over 200 distinct molecular mass components. At least 60 sub-fractions were recovered from HPLC separation. Five purified peptides were sequenced by Edman degradation, and their complete primary structures were determined. Additionally, three other peptides have had their N-terminal amino acid sequences determined by Edman degradation and reported. Mass spectrometry analysis of tryptic digestion of the soluble venom permitted the identification of the amino acid sequence of 111 different peptides. Search for similarities of the sequences found indicated that they probably are: sodium and potassium channel toxins, metalloproteinases, hyaluronidases, endothelin and angiotensin-converting enzymes, bradykinin-potentiating peptide, hypothetical proteins, allergens, other enzymes, other proteins and peptides.

Fast protocol for the production of Histoplasma capsulatum antigens for antibody detection in the immunodiagnosis of histoplasmosis

BackgroundCurrent methods for the production of Histoplasma capsulatum antigens are problematic in terms of standardization, specificity, stability, repeatability and reproducibility. AimsIn this study, we sought to optimize the methodology for producing H. capsulatum antigens, and to evaluate its applicability. MethodsAntigenic preparations obtained from 12 H. capsulatum isolates were evaluated by double immunodiffusion and immunoblotting assays against homologous and heterologous sera. ResultsThe evaluated and optimized protocol allowed a more stable production, as well as repeatable, reproducible, with shorter culture time and less costly. By double immunodiffusion and immunoblotting assays, the best pattern of reactivity was observed for antigens obtained with 33 days of culture from the isolates 200 and 406 against the M antigen and for the isolate 200 with 15 days against H antigen. The SDS-PAGE presented antigenic components of molecular masses between 17 and 119kDa. The immunoblotting sensitivity was 95.5% and 100% with histoplasmosis sera from ill patients and sera from H. capsulatum infected but otherwise healthy patients, respectively, to the antigen derived from isolates 200 and 406. ConclusionsWe suggest the employment of the antigen from isolate 200, with 15 or 30 days of culture, in the double immunodiffusion and immunoblotting assays due to its good ability to discriminate both sera from patients with histoplasmosis illness and histoplasmosis infection, in addition to its high specificity against heterologous sera.

Insights into head-column field-amplified sample stacking: Part II. Study of the behavior of the electrophoretic system after electrokinetic injection of cationic compounds across a short water plug

Part I on head-column field-amplified sample stacking comprised a detailed study of the electrokinetic injection of a weak base across a short water plug into a phosphate buffer at low pH. The water plug is converted into a low conductive acidic zone and cationic analytes become stacked at the interface between this and a newly formed phosphoric acid zone. The fundamentals of electrokinetic processes occurring thereafter were studied experimentally and with computer simulation and are presented as part II. The configuration analyzed represents a discontinuous buffer system. Computer simulation revealed that the phosphoric acid zone at the plug-buffer interface becomes converted into a migrating phosphate buffer plug which corresponds to the cationically migrating system zone of the phosphate buffer system. Its mobility is higher than that of the analytes such that they migrate behind the system zone in a phosphate buffer comparable to the applied background electrolyte. The temporal behaviour of the current and the conductivity across the water plug were monitored and found to reflect the changes in the low conductivity plug. Determination of the buffer flow in the capillary revealed increased pumping caused by the mismatch of electroosmosis within the low conductivity plug and the buffer. This effect becomes elevated with increasing water plug length. For plug lengths up to 1% of the total column length the flow quickly drops to the electroosmotic flow of the buffer and simulations with experimentally determined current and flow values predict negligible band dispersion and no loss of resolution for both low and large molecular mass components.

Thermo-rheological properties of coal-tar pitch modified with phenol-formaldehyde resin

Test results of changing the thermo-rheological properties of coal-tar pitch under influence of phenol-formaldehyde resin are presented in this research work. Influence of modifying agent amount and crosslinking conditions (time) of resin in bitumen was evaluated. Tests were carried out using the rheometer in oscillation mode. They enabled the evaluation of changes in bitumen viscous and elastic properties and draw the conclusions about changes in bitumen structure on that basis. Compositions of the coal-tar pitch with phenol-formaldehyde resin show increased thermal and mechanical resistance. Furthermore, phenol-formaldehyde resin has an effect on increase in the coal-tar pitch viscosity. It probably results from the increased content of components of higher average molecular mass in the pitch and lower solubility in organic solvents.