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Zhengrong Yang, Qingxian Zhou, Leo Mok, Anukriti Singh, Douglas J Swartz, Ina L Urbatsch, Christie G Brouillette
Structural changes in mouse P-glycoprotein (Pgp) induced by thermal unfolding were studied by differential scanning calorimetry (DSC), circular dichroism and fluorescence spectroscopy to gain insight into the solution conformation(s) of this ABC transporter that may not be apparent from current crystal structures. DSC of reconstituted Pgp showed two thermal unfolding transitions in the absence of MgATP, suggesting that each transition involved the cooperative unfolding of two or more interacting structural domains...
October 23, 2016: Biochimica et Biophysica Acta
Leonardo Miziara Barboza Ferreira, Suzy Sayuri Sassamoto Kurokawa, Jovan Duran Alonso, Douglas Lopes Cassimiro, Ana Luiza Ribeiro de Souza, Mariana Fonseca, Victor Hugo Vitorino Sarmento, Luis Octavio Regasini, Clóvis Augusto Ribeiro
Supra-amphiphiles are a new class of building blocks that are fabricated by means of non-covalent forces. In this work, we studied the formation of supra-amphiphiles by combining hydrophilic meglumine (MEG) with hydrophobic maleated castor oils (MACO). Spectroscopic analysis demonstrated that ionic interactions are the main driving force in the fabrication of these materials. Subsequently, supra-amphiphile/water systems were examined for their structure and water behavior by polarized optical microscopy (POM), small angle x-ray scattering (SAXS), and differential scanning calorimetry (DSC)...
October 26, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Svenja Winzen, James Ciro Schwabacher, Julius Mueller, Katharina Landfester, Kristin Mohr
Surfactants, even in miniscule amounts, are often used for the synthesis and especially the stabilization of nanomaterials, which is essential for in vivo applications. In this study, we show that the interaction between nanoparticles and proteins strongly depends on the type of stabilizing surfactants and their (small) concentration changes. The reaction between human serum albumin (HSA) and polystyrene nanoparticles (PS-NPs) stabilized by an ionic or nonionic surfactant - sodium dodecyl sulfate (SDS) or Lutensol AT50, respectively - was monitored using isothermal titration calorimetry (ITC)...
October 26, 2016: Biomacromolecules
Wynton C McClary, John Paul Sumida, Michele Scian, Lorela Paco, William M Atkins
Cytochrome P4503A4 (CYP3A4) is a peripheral membrane protein that plays a major role in enzymatic detoxication of many drugs and toxins. CYP3A4 has an integral membrane N-terminal helix and a localized patch comprised of the G'- and F'-helix regions that are embedded in the membrane, but the effects of membrane composition on CYP3A4 function are unknown. Here, circular dichroism and differential scanning calorimetry were used to compare the stability of CYP3A4 in lipid bilayer nanodiscs with varying ratios of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC): 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)...
October 26, 2016: Biochemistry
Zhaoqi Guo, Yunlong Wu, Chongqing Deng, Guoping Yang, Jiangong Zhang, Zhihua Sun, Haixia Ma, Chao Gao, Zhongwei An
Two new energetic coordination polymers (CPs) [Pb(BT)(H2O)3]n (1) and [Pb3(DOBT)3(H2O)2]n·(4H2O)n (2) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1'H-5,5'-bitetrazole (H2BT) and 1H,1'H-[5,5'-bitetrazole]-1,1'-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of 2 which has higher thermal stability and lower sensitivity than that of 1. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of 2 is derived to be much higher than that of 1 as well as the reported CPs...
October 26, 2016: Inorganic Chemistry
Jianghui Xu, Vikramjeet Singh, Xianzhen Yin, Parbeen Singh, Li Wu, Xiaonan Xu, Tao Guo, Lixin Sun, Shuangying Gui, Jiwen Zhang
β-artemether (ARM) is a widely used anti-malarial drug isolated from the Chinese antimalarial plant, Artemisia annua. The solvent effects on crystal habits and dissolution of ARM were thoroughly investigated and discussed herein. The ARM was recrystallized in 9 different solvents of varied polarity, namely, methanol, ethanol, isopropanol, tetrahydrofuran, dichloromethane, trichloromethane, ethyl acetate, acetone and hexane by solvent evaporation method. The obtained crystals were morphologically characterized using scanning electron microscope (SEM)...
October 26, 2016: Drug Development and Industrial Pharmacy
Mark Steinmann, Manfred Wagner, Frederik R Wurm
Degradable polymers are a currently growing field of research for biomedical and materials science applications. The majority of such compounds are based on polyesters and polyamides. In contrast, their phosphorus-containing counterparts are much less studied, in spite of their potential precise degradation profile and biocompatibility. Herein, the first library of poly(phosphorodiamidate)s (PPDAs) with two P-N bonds forming the polymer backbone and a pendant P-OR group is prepared through acyclic diene metathesis polymerization...
October 26, 2016: Chemistry: a European Journal
Pakkawat Detchewa, Masubon Thongngam, Jay-Lin Jane, Onanong Naivikul
The objective of this study was to investigate the effect of soy protein isolate on functional properties and consumer acceptance of gluten-free rice spaghetti (GFRS) made from rice flour. Dry-milled high-amylose (Chai Nat 1) rice flour was premixed with dry-milled waxy (RD 6) rice flour at a ratio of 90:10 (w/w) with the soy protein isolate (SPI) concentration varying between 0, 2.5, 5.0, 7.5, 10.0 %, db. The GFRS formulation was processed using a co-rotating twin-screw extruder up to 95 °C with a screw speed of 220 rpm, 32 % moisture content, and then dried at 40 °C...
September 2016: Journal of Food Science and Technology
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
Zahra Zarekhalili, S Hajir Bahrami, M Ranjbar-Mohammadi, Peiman Brouki Milan
In this work three dimensional biodegradable nanofiberous scaffolds containing poly(ε-caprolactone) (PCL), poly(vinyl alcohol) (PVA) and gum tragacanth (GT) were successfully fabricated through two nozzles electrospinning process. For this purpose, PVA/GT blend (Blend: B) solution (60:40wt %) was injected from one syringe and poly(ε-caprolactone) solution from the other one. Presence of PVA and PCL in the formulation improved the electrospinning process of GT solution and mechanical properties of the fabricated nanofibers...
October 21, 2016: International Journal of Biological Macromolecules
Samuel A Sakyi, Samuel Yaw Aboagye, Isaac Darko Otchere, Albert M Liao, Thomas G Caltagirone, Dorothy Yeboah-Manu
BACKGROUND: Buruli ulcer (BU) is a subcutaneous skin disease listed among the neglected tropical diseases by the World Health Organization (WHO). Early case detection and management is very important to reduce morbidity and the accompanied characteristic disfiguring nature of BU. Since diagnosis based on clinical evidence can lead to misdiagnosis, microbiological confirmation is essential to reduce abuse of drugs; since the anti-mycobacterial drugs are also used for TB treatment. The current WHO gold standard PCR method is expensive, requires infrastructure and expertise are usually not available at the peripheral centers where BU cases are managed...
October 2016: PLoS Neglected Tropical Diseases
Yana K Rennie, Patrick J McIntyre, Tito Akindele, Richard Bayliss, Andrew G Jamieson
Inhibition of protein kinases using ATP-competitive compounds is an important strategy in drug discovery. In contrast, the allosteric regulation of kinases through the disruption of protein-protein interactions has not been widely adopted, despite the potential for selective targeting. Aurora-A kinase regulates mitotic entry and mitotic spindle assembly, and is a promising target for anti-cancer therapy. The microtubule-associated protein TPX2 activates Aurora-A through binding to two sites. Aurora-A recognition is mediated by two motifs within the first 43 residues of TPX2, connected by a flexible linker...
October 24, 2016: ACS Chemical Biology
Van-Chien Bui, Thi-Huong Nguyen
Knowledge about the mechanism by which some antibodies can block HIV-1 entry is critical to our understanding of their function and may offer new avenues for controlling the adhesion of HIV-1 to the host cells. While much progress has been made, this mechanism remains unclear. Here, atomic force microscopy, isothermal titration calorimetry (ITC), and circular dichroism spectroscopy were used to measure some biophysical characteristics of the interaction of four-domains (D1-D4) membrane protein CD4 with anti-D3 antibody OKT4 and with HIV-1 entry blocking anti-D1 antibody Leu3a...
October 17, 2016: Immunobiology
M Teresa Viciosa, Joaquim J Moura Ramos, Hermínio P Diogo
The slow molecular mobility in the amorphous solid state of 3 active pharmaceutical drugs (cimetidine, nizatidine, and famotidine) has been studied using differential scanning calorimetry and the 2 dielectric-related techniques of dielectric relaxation spectroscopy and thermally stimulated depolarization currents. The glass-forming ability, the glass stability, and the tendency for crystallization from the equilibrium melt were investigated by differential scanning calorimetry, which also provided the characterization of the main relaxation of the 3 glass formers...
October 20, 2016: Journal of Pharmaceutical Sciences
Babak Mirtamizdoust, Zdeněk Trávníček, Younes Hanifehpour, Pejman Talemi, Hassan Hammud, Sang Woo Joo
A sonochemical method was used to synthesize nano-peanuts of a new lead(II) coordination 1D polymer, [Pb(qcnh)(NO3)2]n (1), where qcnh=2-quinolincarbaldehyde nicotinohydrazide. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and single crystal X-ray analysis. The X-ray structure revealed that the Pb(II) atom is coordinated by one oxygen and three nitrogen atoms from two qcnh ligands and five oxygen atoms from three nitrate ligands in an 8+1 fashion with a PbN3O6 donor set...
January 2017: Ultrasonics Sonochemistry
Anas Shamsi, Azaj Ahmed, Bilqees Bano
Nanotechnology is one of the fastest growing fields of science owing to use of nanomaterials in industries and medicine across the globe. Currently silicon dioxide nanoparticles (SiO2 NPs) are one of the most popular nanomaterials owing to their inert toxicity profile and hence exposure to SiO2 nanoparticles is on the increase. Cystatins are thiol proteinase inhibitors (TPIs) ubiquitously distributed in plants and animals and they are now at the heed of a number of normal and pathological conditions and shouldn't be regarded solely as TPIs...
October 19, 2016: International Journal of Biological Macromolecules
Biao Huang, Mingxian Liu, Zheru Long, Yan Shen, Changren Zhou
Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100-250μm is found in the hydrogels, which can provide a space for cell growth and migration...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Michael Karlsson, Johannes K Ehinger, Sarah Piel, Fredrik Sjövall, Johanna Henriksnäs, Urban Höglund, Magnus J Hansson, Eskil Elmér
Metabolic crisis is a clinical condition primarily affecting patients with inherent mitochondrial dysfunction in situations of augmented demand. To model this, ten pigs received an infusion of rotenone, a mitochondrial complex I inhibitor, or vehicle. Clinical parameters, blood gases, continuous indirect calorimetry, in vivo muscle oxygen tension, ex vivo mitochondrial respiration and metabolomics were assessed. Rotenone induced a progressive increase in lactate which was paralleled by an increase in oxygen tension in venous blood and skeletal muscle...
October 18, 2016: Mitochondrion
Chagam Koteswara Reddy, M Suriya, P V Vidya, Sundaramoorthy Haripriya
This study describes a simple method of preparation and physico-chemical properties of modified starches (type-3 resistant starches) from banana (Musa AAB), and the modified starches investigated as functional food with a beneficial effect on type-2 diabetes. RS3 was prepared using a method combined with debranching modification and physical modification; native and modifies starches were characterized by scanning electron microscope (SEM), powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and rapid visco analyzer (RVA)...
October 18, 2016: International Journal of Biological Macromolecules
Michaela L Sundqvist, Jon O Lundberg, Eddie Weitzberg
The nitrate-nitrite-nitric oxide pathway has emerged as a significant source of nitric oxide (NO) bioactivity. Dietary intake of inorganic nitrate has a number of cardiovascular effects as well as a decrease in oxygen cost during exercise and a reduction in resting metabolic rate (RMR). Oral bacteria have a key role in bioactivation of inorganic nitrate since they catalyse the conversion of salivary nitrate to the more reactive nitrite anion. Recent studies demonstrate that blood pressure increases with the use of an antiseptic mouthwash, indicating that endogenous, NO-synthase derived nitrate is recycled into nitrite and NO, sufficiently to modulate cardiovascular function...
October 18, 2016: Nitric Oxide: Biology and Chemistry
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