Effects Of High Molecular Weight Research Articles

Matters of size: Roles of hyaluronan in CNS aging and disease

Involvement of extracellular matrix (ECM) components in aging and age-related neurodegeneration is not well understood. The role of hyaluronan (HA), a major extracellular matrix glycosaminoglycan, in malignancy and inflammation is gaining new understanding. In particular, the differential biological effects of high molecular weight (HMW-HA) and low molecular weight hyaluronan (LMW-HA), and the mechanism behind such differences are being uncovered. Tightly regulated in the brain, HA can have diverse effects on cellular development, growth and degeneration. In this review, we summarize the homeostasis and signaling of HA in healthy tissue, discuss its distribution and ontogeny in the central nervous system (CNS), summarize evidence for its involvement in age-related neurodegeneration and Alzheimer Disease (AD), and assess the potential of HA as a therapeutic target in the CNS.

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

In order to solve the problem of the poor oil displacement effect of high molecular weight alkali/surfactant/polymer (ASP) solution in low permeability reservoirs, Daqing Oilfield uses a partial quality tool to improve the oil displacement effect in low permeability reservoirs. In the formation, the partial quality tool degrades the polymer through active shearing action, reducing the molecular weight of the polymer, to improve the matching degree to the low permeability oil layer and the oil recovery. In order to study the ability of the partial quality tool to improve the oil displacement effect, the matching degree of high molecular weight ASP solution to low permeability cores is studied, and the ability of quality control tools to change the molecular weight is studied. Then, experimental research on the pressure and oil displacement effect of high molecular weight ASP solution before and after the actions of the partial quality tool is carried out. The results show that ASP solutions with molecular weights of 1900 × 104 and 2500 × 104 have a poor oil displacement effect in low permeability reservoirs. After the action of the partial quality tool, the injection pressure is reduced by 5.22 MPa, and the oil recovery is increased by 7.79%. The injection pressure of the ASP solution after shearing by the partial quality tool is lower than that of the ASP solution with the same molecular weight and concentration without shearing, but the oil recovery is lower. On the whole, the use of the partial quality tool can obviously improve the oil displacement effect in low permeability reservoirs.

Enhancing innate antiviral immune responses in rainbow trout by double stranded RNA delivered with cationic phytoglycogen nanoparticles

Innate immunity is induced when pathogen-associated molecular patterns (PAMPs) bind host pattern recognition receptors (PRRs). Polyinosinic:polycytidylic acid [poly(I:C)] is a synthetic analogue of viral dsRNA that acts as a PAMP, inducing type I interferons (IFNs) in vertebrates. In the present study, the immunostimulatory effects of high molecular weight (HMW) poly(I:C) in rainbow trout cells were measured when bound to a cationic phytoglycogen nanoparticle (Nano-HMW). The physical characteristics of the nanoparticle itself, when bound to different lengths of dsRNA and when cell associated was evaluated. Optimal concentration and timing for innate immune stimulation was measured using the RTG-P1 reporter cell line. The immunostimulatory effects of HMW poly (I:C) was compared to Nano-HMW in vitro using the RTgutGC cell line cultured in a conventional monolayer or a transwell culture system. The ability of an activated intestinal epithelium to transmit an antiviral signal to macrophages was evaluated using a co-culture of RTgutGC cells and RTSll (a monocyte/macrophage cell). In all culture conditions, Nano-HMW was a more effective inducer of IFN-related antiviral immune responses compared to HMW poly (I:C) alone. This study introduces the use of cationic phytoglycogen nanoparticles as a novel delivery system for immunomodulatory molecules to enhance immune responses in aquatic vertebrates.

Molecular docking and simulation analysis for elucidation of toxic effects of dicyclohexyl phthalate (DCHP) in glucocorticoid receptor-mediated adipogenesis

ABSTRACT‘Obesogens’ are chemical agents that improperly regulate the genes involved in glucose metabolism and adipocyte differentiation and promote lipid accumulation and adipogenesis. The human glucocorticoid receptor (hGR) is a steroid hormone triggered transcriptional factor and regulates target genes important in basal glucose homeostasis. Molecular docking analysis was performed in order to assess in-silico structure based toxic effects of high molecular weight phthalates dicyclohexyl phthalate (DCHP) and its monophthalate metabolite mono-cyclohexyl phthalate (MCHP). Molecular docking results show that the binding affinities of DCHP and MCHP lie in the comparable range (−7.87 kcal/mol and −6.24 kcal/mol) with Dexamethasone (−10.2 kcal/mol), a potent agonist for hGR. These two PAEs occupy the active site of hGR and interact with the key residues. Molecular simulation results infer that hGR-PAEs complexes were stable. Density functional theory (DFT) analysis indicates that HOMO and LUMO energy gap of DCHP (3.88 eV) and MCHP (3.39 eV) are comparable to DEX (4.69 eV). Binding free energy calculations of the DCHP-hGR and MCHP-hGR complexes were estimated by using Molecular Mechanic/Poisson-Boltzmann Surface Area (MMPBSA) method. Molecular Docking and simulation results emphasise that DCHP and MCHP can efficiently bind to hGR, which further leads to glucocorticoid-mediated adipogenesis in a synergistic manner.

Synthesis, spectroscopic characteristics, dyeing performance and TD-DFT study of quinolone based red emitting acid azo dyes

Eight novel fluorescent heterocyclic acid dyes were prepared by diazotizing various sulphonic acid based amines and coupling with 4-hyrdoxyl-1-methyl-2(1H)-quinolone. Structures of synthesized dyes were well supported by 1H NMR, 13C NMR, Mass spectroscopy, FTIR and elemental analysis. The effect of high molecular weight and heterocyclic moiety were observed to have significant influence on photophysical properties, color values and fastness performances of the dyes. Substitutions on ortho to azo linkage played an important role in enhancing light and wash fastness properties of the dyes. Dyeing characteristics of all the dyes were evaluated on wool, nylon and silk substrates. Evaluation of UV-protection factor (UPF) of the dyed fabrics suggested that these dyes can be used to make UV-protective fabric. DFT calculations were employed to calculate the stability of tautomeric forms of the dyes and find out electrophilicity index of prepared dyes. TD-DFT used to study structural effect on photophysical properties.

Anticancer properties of chitosan against osteosarcoma, breast cancer and cervical cancer cell lines.

Background:Cancer is still the most common cause of morbidity in the world. Chitosan, a commonly used natural polymer, is consisted of different molecular weight with different biological activities.The purpose of this study was to determine cytotoxicity effect of high molecular weight (HMWC) and low molecular weight of chitosan (LMWC) on three cancerous cell lines MCF-7, HeLa and Saos-2 with different histological origin.Methods:The anticancer property of two types of chitosan on three cancerous cell lines and human fibroblast as normal cell line, was evaluated by cytotoxic activity including their apoptosis induction properties. Chitosan solutions 2% (w/v) were prepared. The cells were treated by different concentration of chitosan and viability was determined by MTT assay after 24, 48 and 72 h .Also the mode of cell death-apoptosis vs necrosis ,was determined by Annexin V staining assay and analyzed by flow cytometry.Results:While both types of chitosan were effective in inhibiting cell proliferation of three cancerous cell lines, fibroblast cells showed somehow more compatibility with chitosan. Despite of a significant decrease in all 3 cell lines viability, up to 90%, but we didn't see a concentration dependent difference between both types of chitosan (HMWC and LMWC) in their cytotoxic effects. Flow cytometry analysis showed necrosis more observable with MCF7 while the apoptosis pattern of death was more in Saos-2 and HeLa. Also, higher viability with both types of chitosan was seen in fibroblast as normal cells.Conclusion:While chitosan is compatible with normal diploid fibroblast cells, it shows anticancerous effect against 3 cancerous cell lines. Furthermore, it seems that the molecular weight of chitosan does not affect its anticancerous property.

Effect of high molecular weight on pore formation and various properties of microporous membrane used for lithium-ion battery separator

In this article, iPP cast films with high molecular weight in middle layer were prepared to investigate the effect of high molecular weight component on pore formation and mechanical strength. The results of DSC, SEM and 2D-XRD indicated that higher molecular weight and die draw ratio (DDR) would not alter the thickness of lamellae but enhance the orientation and the content of extend-chain crystal. Then the tensile testing results show that higher DDR would improve the overall strength and the elastic recovery substantially but reduce the elongation at break dramatically. Additionally, the cast film containing higher molecular weight component has longer elongation and yield stress but shows a more gentle decrease of elastic recovery during the repeatedly stretching cycle. Moreover, further detailed characterization of the microporous structure after uniaxial stretching manifest that lower DDR is extremely unfavorable to pore formation, resulting in lowest porosity and poorer pore size distribution. While this inferior microporous structure would be improved by increasing DDR, accompanied by ascending porosity. Moreover, the membrane completely composed of high molecular weight also exhibits more coarse fibrils, which is stemmed from the undivided row-nucleated lamellae. Furthermore, the puncture and tensile strength were reinforced by boosting molecular weight and DDR significantly, which is more beneficial to battery assembly and safety.

Cationic polyacrylamide induced nanoparticles assembly in a cellulose nanofiber network

Polyacrylamides of different molecular weight, charges and dosages allow to control the retention and distribution of nanoparticles (NPs) in composites, and optimise composite properties and functionality. Our aim is to evaluate the effect of high molecular weight (13 MDa) cationic polyacrylamide (CPAM) charge and dosage on SiO2 (74 nm) NP’s assembly in cellulose nanofibers composites.Engineered cellulose/SiO2 composites were investigated by SEM, SAXS and DLS. SEM images show the local area retention of NPs into the cellulose matrix. SAXS provides an average NPs distribution and inter-NPs distance over complete volume of composite. DLS gives the hydrodynamic radius of CPAM adsorbed onto SiO2 NPs in a suspension.SAXS analysis reveals a structure conformation made of spherical SiO2 NPs core of diameter 74 nm surrounded by a CPAM polyelectrolyte shell 2.5 nm thick. Surprisingly, CPAM induced assembly of SiO2 NPs with constant inter-nanoparticle distance, which is irrelevant of polymer charge density. However, NPs retention in the cellulose fibre network increases with CPAM dosage. The assembly mechanism is governed by the balance of electrostatic and steric forces following CPAM coverage onto NPs and the inter-nanoparticle CPAM bridging conformation. This maintains the constant inter-nanoparticle distance and the assembly of NPs in the cellulose network.

Effects of high molecular weight poly-γ-glutamic acid on PIGS with porcine preproductive and respiratory syndrome virus (PRRSV) infection

Abstract Bacillus subtilis sups. chungkookjang produces a higher molecular mass poly-γ-glutamic acid (γ-PGA). Recently, previous studies have demonstrated immune stimulation and an antitumor effect of the high molecular mass γ-PGA using various mouse models although these effects have not been shown in other species of animals. Therefore, the current study was conducted to determine the effect of γ-PGA in pigs with and without PRRSV infection. PRRS-negative pigs were intramuscularly injected with 1, 3, or 5 ml of 20 mg/mll γ-PGA, and one group of pigs served as a non-treatment (NT) group. All groups treated with γ-PGA had significantly higher weight gains, and pigs treated with 5 ml of γ-PGA exhibited higher tumor necrosis factor (TNF)-α, interferon (IFN)-α and IFN-β expression levels compared with the NT group. According to the preliminary results, an animal challenge study was conducted with a highly virulent PRRSV strain, MN184, along with γ-PGA treatment at different time points. Pigs treated with γ-PGA had lower levels of viral loads in the sera and in lungs and gained significantly more weight (p<0.05) compared with the NT group after being challenged with MN184. Moreover, γ-PGA-treatment groups had higher levels of neutralizing antibodies and cytokines related to proinflammatory, humoral and cell-mediated responses than the control group after the PRRSV challenge. Therefore, it was concluded that γ-PGA induces higher levels of immune responses and increases resistance to PRRSV infection in pigs.

Neuroprotective effects of LMW and HMW FGF2 against amyloid beta toxicity in primary cultured hippocampal neurons

Basic Fibroblast growth factor (FGF2) is important in development and maintenance of central nervous system function. Studies have demonstrated that low molecular weight (LMW) FGF2 is a neuroprotective factor against various insults in vivo and in vitro. In the present study we investigated the neuroprotective effects of high molecular weight (HMW) and LMW FGF2 against amyloid beta-induced neurotoxicity. The results showed that both LMW and HMW FGF2 attenuated the amyloid beta toxicity in the primary cultured hippocampal neurons as measured by WST and LDH release assay. Moreover, the analysis suggested that HMW FGF2 had stronger neuroprotective effect than LMW FGF2. We then demonstrated that LMW and HMW FGF2 activated the ERK and AKT signaling pathways in a similar way. Furthermore, using the ERK inhibitor and AKT inhibitor, we found that the AKT signaling but not ERK signaling pathway was required for the neuroprotective effects of FGF2. Taken together, these results showed the neuroprotective effects of different forms of FGF2 in an AD model and the mechanism underlying the neuroprotection.

Quantifying Protein–Ligand Interactions by Direct Electrospray Ionization-MS Analysis: Evidence of Nonuniform Response Factors Induced by High Molecular Weight Molecules and Complexes

The deleterious effects of high molecular weight (MW) solute (polymers and noncovalent assemblies) on protein-ligand (PL) affinity measurements carried out using the direct electrospray ionization mass spectrometry (ESI-MS) assay are described. The presence of high MW solute, that do not interact with the protein (P) or ligand (L) of interest, is shown to result in a decrease in the abundance (Ab) ratio (R) of ligand-bound to free protein ions (i.e., Ab(PL)/Ab(P)) measured for protein-carbohydrate complexes. This effect, which can reduce the apparent association constant by more than 60%, is found to be more pronounced as the differences in the surface properties of P and PL become more significant. It is proposed that the decrease in R reflects a reduction in the number of available surface sites in the ESI droplets upon introduction of large solute and increased competition between P and the more hydrophilic PL for these sites. That a similar decrease in R is observed upon introduction of surfactants to solution provides qualitative support for this hypothesis.

Effect of high molecular weight carbohydrates on bud cell formation by Fusarium oxysporum in potato dextrose broth

Potato dextrose broth (PDB), one of the most popular culture media for fungi, can be made in the laboratory from potato extract and glucose (handmade PDB) and also bought as powder (commercial PDB). We compared growth of Fusarium oxysporum in handmade and commercial PDBs. For seven strains tested, bud cell formation and fungal biomass were higher in handmade PDB than in commercial PDB. Gel filtration analyses revealed that handmade PDB contained carbohydrates with molecular weights >20 MDa, while most carbohydrates in commercial PDB were 20 MDa and enhanced bud cell formation by five of seven strains when added to commercial PDB. The addition of glucose to commercial PDB promoted biomass production but not bud cell formation. Furthermore, in a semisynthetic medium containing raw potato starch, bud cell formation was enhanced for all strains tested. These results indicate that the high molecular carbohydrates present in raw potatoes enhanced bud cell formation by Fusarium oxysporum.

The effect of polymer structure type, pH and shear on the interfacial chemistry, rheology and dewaterability of model iron oxide dispersions

The effect of high molecular weight (7.5–9 × 10 6 Da) polyacrylamide flocculant structure type (anionic polyacrylamide, PAM A and non-ionic polyacrylamide, PAM N) on the interfacial chemistry, rheology and dewaterability of a colloidal iron oxide dispersion has been investigated at three pH values where the particles are at the isoelectric point (iep) and either side of the iep. PAM A was found to adsorb with a lower affinity than PAM N at all pH values tested, however, PAM A had a more significant effect on the particle zeta potential and the shear yield stress. Highest settling rates (100 m/h) were achieved with PAM A at pH values at and below the iep, with flocculant dosage below 100 g polymer/t solid. Settling rates with PAM N at similar concentrations, however, only produced settling rates between 5 and 10 m/h. Pulp pH and the addition of the flocculants (up to 500 g polymer/t solid) had no noticeable effect on the extent of the pulp consolidation. Significantly, shear of pre-sedimented dispersions was found to increase the consolidation by up to 15 wt%. Polymer structure type was found to have a significant effect on the rheology of the dispersion, with PAM A-flocculated dispersions leading to a higher yield stress than dewatering with PAM N.

Comparison of the inhibitory effects of two types (90 kDa and 190 kDa) of hyaluronic acid on the expression of fibrinolytic factors in human synovial fibroblasts

Hyaluronic acid (HA) has been shown to be clinically effective, and is currently used for the treatment of arthropathy. We previously reported that HA of molecular weight 90 kDa (90-HA) inhibits the fibrinolytic factors in human synovial fibroblasts. In the present study, we investigated the effect of high molecular weight (190 kDa) HA (190-HA) compared with 90-HA on the pericellular fibrinolytic system of human synovial fibroblasts in osteoarthritis (OA) and rheumatoid arthritis (RA). Human synovial fibroblasts were obtained from synovial tissues of OA and RA, and were cultured in the presence and absence of 90-HA and 190-HA. Antigens of urokinase-type plasminogen activator (u-PA) and PA inhibitor-1 (PAI-1) were measured by ELISA, and the u-PA activity of the cell surface fraction was evaluated by electrophoretic enzymography. The binding assay of u-PA and the immunocytochemical analysis of u-PA were performed to detect u-PA receptor (u-PAR). HA inhibited the secretion of both u-PA and PAI-1 antigens from the synovial fibroblasts of OA to their conditioned medium, and the degree of inhibition was more effective in OA than in RA. The u-RA binding assay to these cells showed that both 90-HA and 190-HA slightly decreased the maximal number of binding sites (Bmax) in OA. However, in RA, stimulation with 90-HA and 190-HA decreased Bmax by a half and a quarter, respectively. Immunohistochemical analysis showed that u-PAR was constitutively expressed in both synovial fibroblasts, but if these cells were treated with HA, the decrease in the staining of u-PAR was more pronounced in RA than in OA. Furthermore, the degree was more effective with 190-HA than with 90-HA. HA inhibited the pericellular fibrinolytic activity mediated by the u-PA/u-PAR system in synovial fibroblasts of OA and RA, and 190-HA inhibited it more effectively than 90-HA.

Comparison of the inhibitory effects of two types (90 kDa and 190 kDa) of hyaluronic acid on the expression of fibrinolytic factors in human synovial fibroblasts

Hyaluronic acid (HA) has been shown to be clinically effective, and is currently used for the treatment of arthropathy. We previously reported that HA of molecular weight 90 kDa (90-HA) inhibits the fibrinolytic factors in human synovial fibroblasts. In the present study, we investigated the effect of high molecular weight (190 kDa) HA (190-HA) compared with 90-HA on the pericellular fibrinolytic system of human synovial fibroblasts in osteoarthritis (OA) and rheumatoid arthritis (RA). Human synovial fibroblasts were obtained from synovial tissues of OA and RA, and were cultured in the presence and absence of 90-HA and 190-HA. Antigens of urokinase-type plasminogen activator (u-PA) and PA inhibitor-1 (PAI-1) were measured by ELISA, and the u-PA activity of the cell surface fraction was evaluated by electrophoretic enzymography. The binding assay of u-PA and the immunocytochemical analysis of u-PA were performed to detect u-PA receptor (u-PAR). HA inhibited the secretion of both u-PA and PAI-1 antigens from the synovial fibroblasts of OA to their conditioned medium, and the degree of inhibition was more effective in OA than in RA. The u-RA binding assay to these cells showed that both 90-HA and 190-HA slightly decreased the maximal number of binding sites (Bmax) in OA. However, in RA, stimulation with 90-HA and 190-HA decreased Bmax by a half and a quarter, respectively. Immunohistochemical analysis showed that u-PAR was constitutively expressed in both synovial fibroblasts, but if these cells were treated with HA, the decrease in the staining of u-PAR was more pronounced in RA than in OA. Furthermore, the degree was more effective with 190-HA than with 90-HA. HA inhibited the pericellular fibrinolytic activity mediated by the u-PA/u-PAR system in synovial fibroblasts of OA and RA, and 190-HA inhibited it more effectively than 90-HA.

In vivo binding of mannose specific lectin from garlic to intestinal epithelium

The present study was undertaken to determine the effect of high molecular weight (110 kDa) garlic ( Allium sativum) lectin (ASA 110) on body weight changes and its fate in the intestine of rats. Purified lectin or native/heat treated crude garlic extracts were administered to male swiss albino rats by intragastric intubation route for 7 days. The biological effects included arrest of gain in body weight, which was associated with decreased food intake. Results show that as lectin passed through the gut, it specifically bound to various cellular components of the intestinal mucosa. Although, jejunum showed the presence of mannose receptors located in the core of the lamina propria, duodenum showed lectin binding in the basal region and brush border membrane. Similar binding pattern between ASA 110 and normal intestinal mucosa was confirmed in vitro on tissue sections using fluorescent technique. Lectin activity was detected in the fecal extract of treated rats and was antigenically similar to the native lectin preparation. It suggests that the garlic lectin could withstand all enzymatic reactions while passing through the gut. However, its binding to the mucosal epithelium of gastrointestinal tract was indicative of deleterious effects.

The effects of high molecular weight- and low molecular weight-heparins on superoxide ion production and degranulation by human polymorphonuclear leukocytes

High molecular weight (HMW) and low molecular weight (LMW) heparins affected superoxide ion production and degranulation by polymorphonuclear leukocytes (PMNL) isolated from either chronic hemodialyzed patients or healthy controls. Low concentrations in HMW-heparin, below 1.76 aXa IU/ml for patients and 1.34 aXa IU/ml for controls, increased O 2 − production started by phorbol myristate acetate. High concentrations above these values decreased it. Increasing LMW-heparin concentrations constantly decreased O 2 − production using the same stimulus. Myeloperoxidase (MPO) released by PMNL was found to be significantly HMW- and LMW-heparins dose-dependent. The addition of calcium chloride significantly increased MPO release. Lactoferrin release was not dose-dependent of HMW- or LMW-heparins. However, an increase of the percentage of positive responses for lactoferrin release was observed in the simultaneous presence of HMW-heparin and CaCl 2, compared to HMW-heparin alone. Lysozyme release was also not dose-dependent of HMW- or LMW-heparins. An increase of the percentage of positive responses for lysozyme release was observed in the presence of CaCl 2 alone compared to HMW-heparin.

High Molecular Weight Glutenin Genes: Effects on Quality in Wheat

To utilize electrophoretic variants of wheat (Triticum aestivum L.) storage proteins as rapid screening criteria in selection of parents or progeny for end‐use quality, breeders should know the relative effects of the alternate alleles at the storage‐protein loci on which selection will act. The objective of this study was to determine the direct effects of high molecular weight (HMW) glutenin genes on quality in wheat, without the confounding effects of linkage disequilibrium. Genetic analyses of the direct effects of loci coding for glutenin subunits on mixing time, mixing tolerance, absorption, and protein concentration were conducted with 135 random wheat selections from a randomly mated population. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS‐PAGE) was used to screen for HMW glutenin subunits. Significant differences were observed among alleles within loci for some of the quality traits measured. Some of the epistatic interactions also were significant, indicating that the effects of some subunits depend partly on which of the snbunits coded by other genomes are present. The Subunit 5 + 10 combination at the Glu‐Dl locus had the largest positive effects on dough mixing traits, and the 6 + 8 combination at Glu‐Bl had large negative effects on most traits. Alleles at Glu‐Al had no significant effects on any traits. Glutenin‐based selection for increased mixing time and tolerance gave lower predicted gains than phenotypic selection.

Inhibitory effects of high molecular weight dissolved organic matter upon metabolic processes in biofilms from contrasting rivers and streams

SUMMARY. 1. The effect of removal of organic manor >1000 apparent molecular weight (AMW) upon biofilm processes was determined in three contrasting streams in West Germany and three contrasting rivers in the U.K. This process removed 66–85% of the dissolved organic matter supply.2. Elevations in extra cellular enzyme activity (β‐glucosidase, phosphatase and esterase), metabolic heat‐output, bacterial density and poly‐beta‐hydroxy alkanoate (PHA) content (a prokaryote storage product) were noted throughout the study in response to the removal of organic matter. This suggests that there are inhibitory substances present in the dissolved organic matter pool >1000 AMW. Evidence is presented to suggest that phenolics play a role in this inhibition.3. Decreases in metabolic heat output, β‐glucosidase activity and PHA content were noted at four sites in response to the removal of >1000 AMW material.4. The divergent responses of the six river/stream biofilms are indicative of radically differing metabolic/catabolic processes, on a spatial and/or temporal basis, to a major organic supply perturbation.