Presence Of PEG4000 Research Articles

The Effects of Osmosis and Thermo-Priming on Salinity Stress Tolerance in Vigna radiata L.

A plant’s response to osmotic stress is a complex phenomenon that causes many abnormal symptoms due to limitations in growth and development or even the loss of yield. The current research aimed to analyze the agronomical, physiological, and biochemical mechanisms accompanying the acquisition of salt resistance in the Vigna radiata L. variety ‘Ramzan’ using seed osmo- and thermopriming in the presence of PEG-4000 and 4 °C under induced salinity stresses of 100 and 150 mM NaCl. Seeds were collected from CCRI, Nowshera, and sowing was undertaken in triplicate at the Department of Botany, Peshawar University, during the 2018–2019 growing season. Rhizospheric soil pH (6.0), E.C (2.41 ds/m), field capacity, and moisture content level were estimated in the present study. We observed from the estimated results that the agronomic characteristics, i.e., shoot fresh weight and shoot dry weight in T9 (4oC + 150 mM NaCl), root fresh weight and root dry weight in T4 (PEG + 100 mM NaCl), shoot moisture content in T5 (PEG + 100 mM NaCl), and root moisture content in T6 (PEG + 150 mM NaCl) were the highest, followed by the lowest in T1 (both shoot and root fresh weights) and T2 (shoot and root dry weights). Similarly, the shoot moisture content was the maximum in T5 and the minimum in T6, and root moisture was the highest in T6. We observed from the estimated results that agronomical parameters including dry masses (T4, T6, T4), leaf area index, germination index, leaf area, total biomass, seed vigor index under treatment T9, and relative water content and water use efficiency during T5 and T6 were the highest. Plant physiological traits such as proline, SOD enhanced by T1, carotenoids in treatment T2, and chlorophyll and protein levels were the highest under treatment T4, whereas sugar and POD were highest under treatments T7 and T8. The principal component analysis enclosed 63.75% of the total variation among all biological components. These estimated results confirmed the positive resistance by Vigna radiata during osmopriming (PEG) and thermopriming (4 °C) on most of the features with great tolerance under a low-saline treatment such as T4 (PEG), T5 (PEG + 100 mM NaCl), T7 (4 °C), and T8 (4 °C + 100 mM NaCl), while it was susceptible in the case of T6 (PEG + 150 mM NaCl) and T9 (4 °C + 150 mM NaCl) to high salt application. We found that the constraining impact of several priming techniques improved low salinity, which was regarded as economically inexpensive and initiated numerous metabolic processes in plants, hence decreasing germination time. The current study will have major applications for combatting the salinity problem induced by climate change in Pakistan.

Enhancing enzyme-aided production of fermentable sugars from poplar pulp in the presence of non-ionic surfactants.

Addition of surfactants to enzymatic hydrolysis has been reported to enhance the hydrolytic potential of enzymes in the bioconversion of lignocellulosic biomass to fermentable sugars. The objective of this investigation was to evaluate the effects of four non-ionic surfactants (PEG4000, PEG8000, TitronX-100, and Tween80) on the efficiency of enzymatic hydrolysis of steam-pretreated poplar using a commercial cellulase preparation (Cellic® CTec2). Statistical discriminant analysis at four variable factors (surfactant type, surfactant concentration, hydrolysis time, and substrate consistency) revealed that enzymatic hydrolysis was significantly enhanced in the presence of PEG4000, with 19.2% increase in glucose yield over control without surfactant, whereas ANOVA test indicated substrate consistency and hydrolysis time as the most significant factors (P < 0.05). Hydrolysis of poplar pulp at 5% w/w pulp consistency with CTec2 in presence of 1% w/w PEG4000 produced the highest glucose yield of 58.5% after 96h reaction time.

Surface-modified mucoadhesive microgels as a controlled release system for miconazole nitrate to improve localized treatment of vulvovaginal candidiasis

The use of conventional vaginal formulations of miconazole nitrate (MN) in the treatment of deep-seated VVC (vulvovaginal candidiasis) is limited by poor penetration capacity and low solubility of MN, short residence time and irritation at the application site. Surface-modified mucoadhesive microgels were developed to minimize local irritation, enhance penetration capacity and solubility and prolong localized vaginal delivery of MN for effective treatment of deep-seated VVC. Solid lipid microparticles (SLMs) were prepared from matrices consisting of hydrogenated palm oil (Softisan® 154, SF) and super-refined sunseed oil (SO) with or without polyethylene glycol (PEG)-4000, characterized for physicochemical performance and used to prepare mucoadhesive microgels (MMs) encapsulating MN, employing Polycarbophil as bioadhesive polymer. The MMs were evaluated for physicochemical performance and in vitro drug release in simulated vaginal fluid (pH=4.2), whereas mucoadhesive, rheological and stability tests, anticandidal efficacy in immunosuppressed estrogen-dependent female rats and vaginal tolerance test in rabbits were performed with optimized formulation. The amorphicity of 1:9 phytolipid blend (SO:SF) was increased in the presence of PEG-4000. The physicochemical properties of the SLMs and MMs indicated their suitability for vaginal drug delivery. Overall, MN-loaded PEGylated MMs exhibited significantly (p<0.05) more prolonged drug release than non-PEGylated MMs. Additionally, optimized PEGylated MMs was stable at 40±2°C over a period of 6months, viscoelastic, mucoadhesive, non-sensitizing, histopathologically safe and gave remarkably (p<0.05) higher reduction in Candida albicans load (86.06%) than Daktarin® (75.0%) and MN-loaded polymeric-hydrogel (47.74%) in treated rats in 12days. Thus, PEGylated MMs is promising for effective and convenient treatment of VVC.

Synthesis and characterization of FeSe2 nanoparticles and FeSe2/FeO(OH) nanocomposites by hydrothermal method

FeSe2 nanoparticles and FeSe2/FeO(OH) nanocomposites have been synthesized through a novel controllable hydrothermal method with FeSO4⋅7H2O and SeCl4 as precursors. In this procedure, H2SeO3 (obtained from aqueous solution of SeCl4) is gradually reduced to Se and Se2− by reductant. The reduced Se and Se2− ions are combined with Fe2+ ion to give FeSe2. By varying the surfactant, reaction time, temperature, reductant and amount of hydrazine hydrate (N2H4⋅H2O), the method permits us to synthesize different products. The FeSe2 nanoparticles are synthesized in the presence of PEG4000 at 140°C for 13h. Using PEG600 (at 140°C or 110°C for 13h) and sodium dodecyl sulfate (at 140°C for 7h), FeSe2/FeO(OH) nanocomposites are synthesized. SEM and TEM images show the morphology and size of the as-synthesized samples. Chemical composition of the samples is characterized by XRD, XPS and EDS. Ultraviolet–visible and photoluminescence spectra exhibit optical properties of nanostructures. Magnetization measurement shows a twofold behavior, ferromagnetic and paramagnetic behaviors, for FeSe2 nanoparticles.

Preparation of cobalt ferrite nanoparticles via a novel solvothermal approach using divalent iron salt as precursors

Cobalt ferrite (CoFe2O4) nanoparticles are synthesized by a facile novel solvothermal method. The reactions are firstly performed in water–glycol system and Fe2+ salt is used as iron source without oxidant help. Some factors influenced the reactions, including temperature, reaction time, additives, are investigated. The samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), respectively. The magnetic properties of some samples are detected by vibrating sample magnetometry techniques (VSM). It is firstly found that the magnetism of cobalt ferrites nanomaterials can be modified by some additives. The coercivity of CoFe2O4 nanoparticles evidently decreases from 600 to 50Oe in the presence of PEG-4000 in the system.

An investigation into silk fibroin conformation in composite materials intended for drug delivery

Regenerated silk fibroin (SF) is a promising biomaterial to design drug delivery systems. To guarantee satisfactory prolonged release of loaded drugs, the native β-sheet conformation of SF is generally induced by a final curing which can determine instability of the loaded drug. This work aimed to investigate the influence on SF conformation of the addition of hydrophilic polymers, namely poloxamer 188 (PEO), a range of poly(ethylenglycol) (PEG)and poly(vinyl pyrrolidone) (PVP) and drying conditions, namely spray-drying or evaporation at 60 °C. DSC data on spray-dried products indicated that SF in composite materials was in the random coil conformation. ATR-FTIR spectroscopy with Fourier self-deconvolution of the amide I band revealed that SF in spray dried products was partially organized in the β-sheet structure only in presence of PEG4000. Both DSC and ATR-FTIR spectra registered on composite materials obtained by the slowest evaporation method indicated that all hydrophilic polymers favoured the β-sheet conformation. This feature was attributed to the formation of H-bonds with the tyrosine residues of the semicrystalline region in SF. In conclusion, this approach to prepare of SF/hydrophilic polymer composites at slow evaporation rate leads to water insoluble materials which could be used in the development of drug delivery systems.

Structure of the Angiopoietin-2 Receptor Binding Domain and Identification of Surfaces Involved in Tie2 Recognition

The angiopoietins comprise a small class of secreted glycoproteins that play crucial roles in the maturation and maintenance of the mammalian vascular and lymphatic systems. They exert their effects through a member of the tyrosine kinase receptor family, Tie2. Angiopoietin/Tie2 signaling is unique among tyrosine kinase receptor-ligand systems in that distinct angiopoietin ligands, although highly homologous, can function as agonists or antagonists in a context-dependent manner. In an effort to understand this molecular dichotomy, we have crystallized and determined the 2.4 A crystal structure of the Angiopoietin-2 (Ang2) receptor binding region. The structure reveals a fibrinogen fold with a unique C-terminal P domain. Conservation analysis and structure-based mutagenesis identify a groove on the Ang2 molecular surface that mediates receptor recognition.

The N-terminal stem region of bovine and human β1,4-galactosyltransferase I increases the in vitro folding efficiency of their catalytic domain from inclusion bodies

Many recombinant proteins overexpressed in Escherichia coli are generally misfolded, which then aggregate and accumulate as inclusion bodies. The catalytic domain (CD) of bovine and human β1,4-galactosyltransferase (β4Gal-T), expressed in E. coli, it also accumulates as inclusion bodies. We studied the effect of the fusion of the stem region (SR), as an N-terminal extension of the catalytic domain, on the in vitro folding efficiencies of the inclusion bodies. The stem region fused to the catalytic domain (SRCD) increases the folding efficiency of recombinant protein with native fold compared to the protein that contains only the CD. During in vitro folding, also promotes considerably the solubility of the misfolded proteins, which do not bind to UDP–agarose columns and exhibit no galactosyltransferase activity. In contrast, the misfolded proteins that consist of only the CD are insoluble and precipitate out of solution. It is concluded that a protein domain that is produced in a soluble form does not guarantee the presence of the protein molecules in a properly folded and active form. The stem domain has a positive effect on the in vitro folding efficiency of the catalytic domain of both human and bovine β4Gal-T1, suggesting that the stem region acts as a chaperone during protein folding. Furthermore, investigation of the folding conditions of the sulphonated inclusion bodies resulted in identifying a condition in which the presence of PEG-4000 and l-arginine, compared to their absence, increased the yields of native CD and SRCD 7- and 3-fold, respectively.