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Zaiddodine Pashandi, Maryam Molakarimi, Reza H Sajedi, Majid Taghdir, Hossein Naderi-Manesh
Mnemiopsin, an EF-hand Ca(2+) binding photoprotein isolated from luminous ctenophore Mnemiopsis leidyi, emits blue light from its chromophore, coelenterazine, which is non-covalently bond in its central hydrophobic core. Previous studies have revealed unique biochemical properties for ctenophore photoproteins such as inactivation by light, but only few have focused on photoinactivation process. To understand the nature of photoinactivation process we have investigated the impact of light alone and in the presence of Ca(2+) ion on the structure of this photoprotein...
October 18, 2016: Journal of Photochemistry and Photobiology. B, Biology
Qiong Lu, Monika D Jürgens, Andrew C Johnson, Carola Graf, Andy Sweetman, John Crosse, Paul Whitehead
Some organic pollutants including polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and hexachlorobenzene (HCB) have been banned from production and use in the UK for >30years but due to their toxicity and persistence are still of concern. However, due to their hydrophobicity they are present at very low concentrations and are difficult to measure in water, and so other matrices need to be sampled in order to best assess contamination. This study measured concentrations of ΣICES 7 PCBs (PCB congeners 28, 52, 101, 118, 138, 153 and 180) and Σ6 PBDEs (PBDE congeners 28, 47, 99, 100, 153, 154) and HCB in both bed-sediments and wild roach (a common pelagic fish) in the Thames Basin...
October 22, 2016: Science of the Total Environment
Jakarwan Yostawonkul, Suvimol Surassmo, Tawin Iempridee, Wittaya Pimtong, Kunat Suktham, Warayuth Sajomsang, Pattarapond Gonil, Uracha Rungsardthong Ruktanonchai
A nanostructure lipid carrier (NLC) composed of solid, and liquid lipid as a core has been developed as a delivery system for hydrophobic drug molecules. The aim of this research was to fabricate an oleoyl-quaternized-chitosan (CS)-coated NLC, where the mucoadhesive property of nanoparticles is enhanced for more efficient drug delivery. NLC loaded with alpha-mangostin (AP), a model hydrophobic drug, were fabricated using a high pressure homogenization process and subsequently coated with CS. The fabricated nanoparticles showed particle sizes in the range of 200-400nm, with low polydispersity, high physical stability and excellent encapsulation efficiency (EE>90%)...
September 29, 2016: Colloids and Surfaces. B, Biointerfaces
Francisco Javier Montes Ruiz-Cabello, Tamas Oncsik, Miguel A Rodríguez-Valverde, Plinio Maroni, Miguel A Cabrerizo-Vílchez
Colloidal interactions have been extensively studied due to the wide number of applications where colloids are present. In general, the electric double layer force and the van der Waals interaction dominate the net force acting between two colloids at large separation distances. However, it is well accepted that some other phenomena, especially those acting at short separation distances, might be relevant and induce substantial changes in the force profiles. Within these phenomena, those related to the surface contact angle, the hydration degree of the ions or the pH, may dominate the force profiles features, not only at short distances...
October 25, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Hugh Sherman, Anh V Nguyen, Warren Bruckard
Atomic force microscopy makes it possible to measure the interacting forces between individual colloidal particles and air bubbles, which can provide a measure of the particle hydrophobicity. To indicate the level of hydrophobicity of the particle the contact angle can be calculated, assuming that no interfacial deformation occurs with the bubble retaining a spherical profile. Our experimental results obtained using a modified sphere tensiometry apparatus to detach sub-millimeter spherical particles show that deformation of the bubble interface does occur during particle detachment...
October 25, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Arturo Carranza, María Guadalupe Pérez-García, Kunlin Song, George M Jeha, Zhenyu Diao, Rongying Jin, Nina Bogdanchikova, J Félix Armando Soltero, Mauricio Terrones, Qinglin Wu, John Anthony Pojman, Josue David Mota-Morales
We report an alternative green strategy based on deep-eutectic solvents (DES) to deliver multi-walled carbon nanotubes (MWCNTs) for a bottom-up approach that allowing the selective interfacial functionalization of nonaqueous poly(high internal phase emulsions), poly(HIPEs). The formation and polymerization of methacrylic and styrenic HIPEs were possible through the stabilization with nitrogen doped carbon nanotube (CNX) and surfactant mixtures using a urea-choline chloride DES as a delivering phase. Subtle changes in CNX concentration (less than 0...
October 25, 2016: ACS Applied Materials & Interfaces
Andrea Venturato, Gillian MacFarlane, Jin Geng, Mark Bradley
The development of polymeric materials with cell adhesion abilities requires an understanding of cell-surface interactions which vary with cell type. To investigate the correlation between cell attachment and the nature of the polymer, a series of random and block copolymers composed of 2-(dimethylamino)ethyl acrylate and ethyl acrylate are synthesized through single electron transfer living radical polymerization. The polymers are synthesized with highly defined and controlled monomer compositions and exhibited narrow polydispersity indices...
October 25, 2016: Macromolecular Bioscience
Muhammad Ajaz Hussain, Muhammad Umer Ashraf, Gulzar Muhammad, Muhammad Nawaz Tahir, Syed Nasir Abbas Bukhari
The review summarizes the efforts to fabricate inclusion complexes of different therapeutic agents based on a versatile material . is a macrocyclic nano-basket which is the marvelous host with distinct hydrophobic three dimensional cavities to entrap and encapsulate biologically active guest drugs. and its derivatives are used as carriers (host-guest) for anti-cancer, anti-convulsant, anti-hypertensive, anthelmentic, anti-inflammatory, antimicrobial and anti-psychotic drugs, etc. They are the important biocompatible materials to improve solubility and chemical reactivity, and decrease cytotoxicity of poorly soluble drugs...
September 28, 2016: Current Pharmaceutical Design
Sean Murphy, Sarah Jaber, Cameron Ritchie, Matthias Karg, Paul Mulvaney
Hydrophobic forces play a key role in the processes of collapse and re-swelling of thermoresponsive polymers. However little is known about the dynamics of these processes. Here, thermoresponsive poly(N-isopropylacrylamide) encapsulated gold nanoparticles (Au-PNIPAM) are heated via nanosecond laser flash photolysis. Photothermal heating via excitation of the localized surface plasmon resonance of the Au nanoparticle cores results in rapid PNIPAM shell collapse within the 10 ns pulse width of the laser. Remarkably, re-swelling of the polymer shell takes place in less than 100 nanoseconds...
October 25, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Eun Ji Park, Dong Hee Na
The separation mechanism of PEGylated peptides in reversed-phase high-performance liquid chromatography (RP-HPLC) is complex, because the PEGylated molecules exhibit physicochemical properties that are different from those of the parent molecules and have heterogeneous structure. Since most separation studies have focused on the hydrophobicity of the peptide relative to poly(ethylene glycol) (PEG), the role of PEG in the separation of PEGylated peptides on RP-HPLC is not clear. To elucidate the effect of the attached PEG on the retention of PEGylated peptides on RP-HPLC, the mono-PEGylated forms of collagen pentapeptide and octreotide were fractionated drop-by-drop from the outlet of the HPLC system and each drop was subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)...
October 25, 2016: Analytical Chemistry
Alexander Dundua, Steffen Franzka, Mathias Ulbricht
Nonspecific adsorption of proteins is a challenging problem for the development of biocompatible materials, as well as for antifouling and fouling-release coatings, for instance for the marine industry. The concept of preparing amphiphilic systems based on low surface energy hydrophobic materials via their hydrophilic modification is being widely pursued. This work describes a novel two-step route for the preparation of interpenetrating polymer networks of otherwise incompatible poly(dimethylsiloxane) and zwitterionic polymers...
October 25, 2016: Macromolecular Rapid Communications
Simin Zhang, Yanmei Zheng, Shengyan Yin, Jingzhi Sun, Bao Li, Lixin Wu
In this study, a uniform complex dual micelle bearing gadolinium substituted polyoxometalate core, hydrophobic middle, and biocompatible organic shell, which exhibited a uniform size and definite molecular weight and chemical composition, was constructed for fluorescent and magnetic resonance imaging contrast agent, via a simple two-step preparation. A paramagnetic polyoxometalate cluster K13[Gd(β2-SiW11O39)2] was firstly encapsulated with a cationic dendron in 3-generation (D-3) bearing triethylene glycol monomethyl ether terminal groups through ionic substitution...
October 24, 2016: Chemistry: a European Journal
Hamidreza Kavianpour, Mahdi Vasighi
Nowadays, having knowledge about cellular attributes of proteins has an important role in pharmacy, medical science and molecular biology. These attributes are closely correlated with the function and three-dimensional structure of proteins. Knowledge of protein structural class is used by various methods for better understanding the protein functionality and folding patterns. Computational methods and intelligence systems can have an important role in performing structural classification of proteins. Most of protein sequences are saved in databanks as characters and strings and a numerical representation is essential for applying machine learning methods...
October 24, 2016: Amino Acids
Prabir Khatua, Jaya C Jose, Neelanjana Sengupta, Sanjoy Bandyopadhyay
Accumulation of the amyloid beta (Aβ) peptide in the brain is responsible for debilitating neurodegenerative diseases, such as Alzheimer's disease (AD). We have carried out atomistic molecular dynamics simulations of the full-length Aβ42 peptide monomer with a wide range of conformations at room temperature. Efforts have been made to probe the conformational features of different segments of the peptide, namely the two terminal segments (N-term and C-term), the central hydrophobic regions (hp1 and hp2) and the central turn region joining hp1 and hp2, and their nonuniform influence on the spatial arrangements and binding energies of the surrounding water molecules...
October 25, 2016: Physical Chemistry Chemical Physics: PCCP
M A Malik, H K Sharma, C S Saini
The present study evaluated the effect of removal of polyphenols on the structural properties of protein isolates extracted from sunflower seed and kernel. The structural and thermal changes in protein upon phenolic interaction were studied using circular dichroism, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier Transform Infrared (FT-IR) spectroscopy. Presence of phenolic compounds in proteins decreased the ordered structure content with parallel increase in unordered structure content...
September 2016: Journal of Food Science and Technology
Holjes Salgado-Lugo, Alejandro Sánchez-Arreguín, José Ruiz-Herrera
Chitin synthases are highly important enzymes in nature, where they synthesize structural components in species belonging to different eukaryotic kingdoms, including kingdom Fungi. Unfortunately, their structure and the molecular mechanism of synthesis of their microfibrilar product remain largely unknown, probably because no fungal active chitin synthases have been isolated, possibly due to their extreme hydrophobicity. In this study we have turned to the heterologous expression of the transcript from a small chitin synthase of Rhizopus oryzae (RO3G_00942, Chs1) in Escherichia coli...
October 21, 2016: Fungal Genetics and Biology: FG & B
Jinlan Xu, Xinshuo Fan, Fudi Huang, Xiumin Li
Under the action of hydrogen peroxide, soil organic matter (SOM) can transform dissolved iron (Fe(2+)) into the solid phase. Solid iron is bound to SOM (Fe-SOM), and two components are included: iron oxides bound to SOM (Fe-SOM oxides) and organic iron bound to SOM (organic Fe-SOM). In oil-contaminated soil samples with Fe-SOM, total petroleum hydrocarbon (TPH) was degraded by 67%; however, in oil-contaminated soil samples without Fe-SOM, the degradation of TPH was only 6%. In oil-contaminated soil samples with Fe-SOM, 73-86% of the primary alkanes (C14-C22 composed 67...
October 12, 2016: Journal of Hazardous Materials
Mithun Sarker, Biswa Nath Bhadra, Pill Won Seo, Sung Hwa Jhung
Benzotriazole (BTA) and benzimidazole (BZI) are regarded as water pollutants because of their extensive uses in industry and appreciable water solubility. The adsorption of both BTA and BZI from water over a newly synthesized metal-organic framework, MAF-5(Co), was investigated and compared with zeolitic imidazole frameworks (ZIFs), such as ZIF-8(Zn) and ZIF-67(Co), as well as commercial activated carbon. MAF-5(Co) had the highest adsorption capacities for both BTA and BZI. The maximum adsorption capacities of MAF-5(Co) for BTA and BZI were 389 and 175mgg(-1), respectively...
October 19, 2016: Journal of Hazardous Materials
Lauren Platts, Samuel J Darby, Robert J Falconer
The positively charged amino acids are commonly used excipients in biopharmaceutical formulations for stabilization of therapeutic proteins, yet the mechanisms for their modulation of protein stability are poorly understood. In this study, both lysine and histidine are shown to affect the thermal stability of myoglobin, bovine serum albumin, and lysozyme through a combination of mechanisms governed by their respective functional side chains and glycine, similar to arginine. This study provides evidence that at low concentrations, lysine and histidine interact with proteins by a combination of (1) direct electrostatic interactions with negatively charged side chains, (2) possible binding to high-affinity hydrophobic binding sites, and (3) glycine-mediated weak interactions with peptide backbone and polar side chains...
October 21, 2016: Journal of Pharmaceutical Sciences
Nial J Wheate, Kristie-Ann Dickson, Ryung Rae Kim, Alireza Nematollahi, René B Macquart, Veysel Kayser, Guocan Yu, W Bret Church, Deborah J Marsh
Pillar[n]arenes are a new family of nanocapsules that have shown application in a number of areas, but because of their poor water solubility their biomedical applications are limited. Recently, a method of synthesizing water-soluble pillar[n]arenes was developed. In this study, carboxylated pillar[n]arenes (WP[n], n = 6 or 7) have been examined for their ability to form host-guest complexes with compounds relevant to drug delivery and biodiagnostic applications. Both pillar[n]arenes form host-guest complexes with memantine, chlorhexidine hydrochloride, and proflavine by (1)H nuclear magnetic resonance and modeling...
October 21, 2016: Journal of Pharmaceutical Sciences
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