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https://www.readbyqxmd.com/read/28075582/the-form-in-which-nitrogen-is-supplied-affects-the-polyamines-amino-acids-and-mineral-composition-of-sweet-pepper-fruit-under-an-elevated-co2-concentration
#1
Maria C Piñero, Ginés Otálora, Manuel E Porras, Mari C Sánchez-Guerrero, Pilar Lorenzo, Evangelina Medrano, Francisco M Del Amor
We investigated the effect of supplying nitrogen, as NO3(-) or as NO3(-)/NH4(+), on the composition of fruits of sweet pepper (Capsicum annuum L. cv. Melchor) plants grown with different CO2 concentrations ([CO2]): ambient or elevated (800 μmol mol(-1)). The results show that the application of NH4(+) and high [CO2] affected the chroma related to the concentrations of chlorophylls. The concentrations of Ca, Cu, Mg, P, and Zn were significantly reduced in the fruits of plants nourished with NH4(+), the loss of Fe being more dramatic at increased [CO2], which was also the case with the protein concentration...
January 17, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28068080/effect-of-the-southeast-asian-ovalocytosis-deletion-on-the-conformational-dynamics-of-the-signal-anchor-transmembrane-segment-1-of-the-red-cell-anion-exchanger-1-ae1-band-3-slc4a1
#2
Philip W Fowler, Mark S P Sansom, Reinhart A F Reithmeier
The first transmembrane (TM1) helix in the red cell anion exchanger (AE1, Band 3, SLC4A1) acts as an internal signal anchor that binds the signal recognition particle and directs the nascent polypeptide chain to the endoplasmic reticulum (ER) membrane where it moves from the translocon laterally into the lipid bilayer. The sequence N-terminal to TM1 forms an amphipathic helix that lies at the membrane interface connected to TM1 by a bend at Pro403. Southeast Asian Ovalocytosis (SAO) is a red cell abnormality caused by a nine-amino acid deletion (Ala400-Ala408) at the N-terminus of TM1...
January 9, 2017: Biochemistry
https://www.readbyqxmd.com/read/28065835/nmr-investigation-of-the-isolated-second-voltage-sensing-domain-of-human-nav1-4-channel
#3
A S Paramonov, E N Lyukmanova, M Yu Myshkin, M A Shulepko, D S Kulbatskii, N S Petrosian, A O Chugunov, D A Dolgikh, M P Kirpichnikov, A S Arseniev, Z O Shenkarev
Voltage-gated Na(+) channels are essential for the functioning of cardiovascular, muscular, and nervous systems. The α-subunit of eukaryotic Na(+) channel consists of ~2000 amino acid residues and encloses 24 transmembrane (TM) helices, which form five membrane domains: four voltage-sensing (VSD) and one pore domain. The structural complexity significantly impedes recombinant production and structural studies of full-sized Na(+) channels. Modular organization of voltage-gated channels gives an idea for studying of the isolated second VSD of human skeletal muscle Nav1...
January 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28064143/production-of-trihalomethanes-haloacetaldehydes-and-haloacetonitriles-during-chlorination-of-microcystin-lr-and-impacts-of-pre-oxidation-on-their-formation
#4
Wenhai Chu, Dechang Yao, Yang Deng, Minghao Sui, Naiyun Gao
Microcystins (MCs) in drinking water have gained much attention due to their adverse health effects. However, little is known about the impact of pre-oxidation in the formation of disinfection by-products (DBPs) during the downstream chlorination of MCs. The present study examined the formation of both carbonaceous and nitrogenous DBPs from chlorination of MC-LR (the most abundant MC species) and evaluated the impact of permanganate (PM), hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) pre-oxidation on the DBP formation in chlorination...
December 29, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28060291/optimization-of-a-quantitative-micro-neutralization-assay
#5
Yipu Lin, Yan Gu, John W McCauley
The micro-neutralization (MN) assay is a standard technique for measuring the infectivity of the influenza virus and the inhibition of virus replication. In this study, we present the protocol of an imaging-based MN assay to quantify the true antigenic relationships between viruses. Unlike typical plaque reduction assays that rely on visible plaques, this assay quantitates the entire infected cell population of each well. The protocol matches the virus type or subtype with the selection of cell lines to achieve maximum infectivity, which enhances sample contrast during imaging and image processing...
December 14, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28049867/elephant-s-breast-milk-contains-large-amounts-of-glucosamine
#6
Zenta Takatsu, Muneya Tsuda, Akio Yamada, Hiroshi Matsumoto, Akira Takai, Yasuhiro Takeda, Mitsunori Takase
Hand-reared elephant calves that are nursed with milk substitutes sometimes suffer bone fractures, probably due to problems associated with nutrition, exercise, sunshine levels and/or genetic factors. As we were expecting the birth of an Asian elephant (Elephas maximus), we analyzed elephant's breast milk to improve the milk substitutes for elephant calves. Although there were few nutritional differences between conventional substitutes and elephant's breast milk, we found a large unknown peak in the breast milk during high-performance liquid chromatography-based amino acid analysis and determined that it was glucosamine (GlcN) using liquid chromatography/mass spectrometry...
December 31, 2016: Journal of Veterinary Medical Science
https://www.readbyqxmd.com/read/28045057/conformational-transition-of-fgfr-kinase-activation-revealed-by-site-specific-unnatural-amino-acid-reporter-and-single-molecule-fret
#7
Louis Perdios, Alan R Lowe, Giorgio Saladino, Tom D Bunney, Nethaji Thiyagarajan, Yuriy Alexandrov, Christopher Dunsby, Paul M W French, Jason W Chin, Francesco Luigi Gervasio, Edward W Tate, Matilda Katan
Protein kinases share significant structural similarity; however, structural features alone are insufficient to explain their diverse functions. Thus, bridging the gap between static structure and function requires a more detailed understanding of their dynamic properties. For example, kinase activation may occur via a switch-like mechanism or by shifting a dynamic equilibrium between inactive and active states. Here, we utilize a combination of FRET and molecular dynamics (MD) simulations to probe the activation mechanism of the kinase domain of Fibroblast Growth Factor Receptor (FGFR)...
January 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28040472/proatherogenic-effects-of-4-hydroxynonenal
#8
Anne Nègre-Salvayre, Sandra Garoby-Salom, Audrey Swiader, Myriam Rouahi, Mélanie Pucelle, Robert Salvayre
4-hydroxy-2-nonenal (HNE) is a α,β-unsaturated hydroxyalkenal generated by peroxidation of n-6 polyunsaturated fatty acid. This reactive carbonyl compound exhibits a huge number of biological properties that result mainly from the formation of HNE-adducts on free amino groups and thiol groups in proteins. In the vascular system, HNE adduct accumulation progressively leads to cellular dysfunction and tissue damages that are involved in the progression of atherosclerosis and related diseases. HNE contributes to the atherogenicity of oxidized LDL, by forming HNE-apoB adducts that deviate the LDL metabolism to the scavenger receptor pathway of macrophagic cells, and lead to the formation of foam cells...
December 28, 2016: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28025326/dysfunction-of-cgmp-signalling-in-photoreceptors-by-a-macular-dystrophy-related-mutation-in-the-calcium-sensor-gcap1
#9
Farina Vocke, Nicole Weisschuh, Valerio Marino, Silvia Malfatti, Samuel G Jacobson, Charlotte M Reiff, Daniele Dell'Orco, Karl-Wilhelm Koch
Macular dystrophy leads to progressive loss of central vision and shows symptoms similar to age-related macular degeneration. Genetic screening of patients diagnosed with macular dystrophy disclosed a novel mutation in the GUCA1A gene, namely a c.526C > T substitution leading to the amino acid substitution p.L176F in the guanylate cyclase-activating protein 1 (GCAP1). The same variant was found in three families showing an autosomal dominant mode of inheritance. For a full functional characterization of the L176F mutant we expressed and purified the mutant protein and measured key parameters of its activating properties, its Ca(2+)/Mg(2+)-binding, and its Ca(2+)-induced conformational changes in comparison to the wildtype protein...
December 26, 2016: Human Molecular Genetics
https://www.readbyqxmd.com/read/28017522/structural-basis-for-ligand-binding-to-the-guanidine-i-riboswitch
#10
Caroline W Reiss, Yong Xiong, Scott A Strobel
The guanidine-I riboswitch is a conserved RNA element with approximately 2,000 known examples across four phyla of bacteria. It exists upstream of nitrogen metabolism and multidrug resistance transporter genes and alters expression through the specific recognition of a free guanidinium cation. Here we report the structure of a guanidine riboswitch aptamer from Sulfobacillus acidophilus at 2.7 Å resolution. Helices P1, P1a, P1b, and P2 form a coaxial stack that acts as a scaffold for ligand binding. A previously unidentified P3 helix docks into P1a to form the guanidinium binding pocket, which is completely enclosed...
December 18, 2016: Structure
https://www.readbyqxmd.com/read/28012919/ilex-paraguariensis-and-its-main-component-chlorogenic-acid-inhibit-fructose-formation-of-advanced-glycation-endproducts-with-amino-acids-at-conditions-compatible-with-those-in-the-digestive-system
#11
Yasmin Bains, Alejandro Gugliucci
We have previously shown that Ilex paraguariensis extracts have potent antiglycation actions. Associations of excess free fructose consumption with inflammatory diseases have been proposed to be mediated through in situ enteral formation of fructose AGEs, which, after being absorbed may contribute to inflammatory diseases via engagement of RAGE. In this proof of principle investigation we show fluorescent AGE formation between amino acids (Arg, Lys, Gly at 10-50mM) and fructose (10-50mM) under time, temperature, pH and concentrations compatible with the digestive system lumen and its inhibition by Ilex paraguariensis extracts...
December 22, 2016: Fitoterapia
https://www.readbyqxmd.com/read/28011956/repeated-cures-with-paracetamol-worsen-sarcopenia-in-old-rats-with-suboptimal-food-intake
#12
C Mast, I Savary-Auzeloux, D Remond, C Pouyet, D Centeno, G Voyard, L Combaret, D Dardevet, I Papet
The availability of all amino acids is of prime importance to prevent the ageing-associated decrease in skeletal muscle mass i.e. sarcopenia. Cysteine is the precursor of sulfate and glutathione that are both utilized in the liver to detoxify paracetamol (APAP). Cysteine availability could become limiting under repeated cures with APAP, especially when food intake is suboptimal. The aim of the study was to determine whether repeated cures with APAP could worsen sarcopenia. Twenty-two-month-old male Wistar rats received 3 two-week-long cures of APAP (1% of the diet) intercalated with washout periods of two weeks (APAP group)...
October 2016: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
https://www.readbyqxmd.com/read/28004569/strategies-for-the-activation-and-release-of-the-membranolytic-peptide-melittin-from-liposomes-using-endosomal-ph-as-a-trigger
#13
Erik Oude Blenke, Malgorzata Sleszynska, Martijn Evers, Gert Storm, Nathaniel I Martin, Enrico Mastrobattista
Endosomolytic peptides are often coupled to drug delivery systems to enhance endosomal escape, which is crucial for the delivery of macromolecular drugs that are vulnerable to degradation in the endolysosomal pathway. Melittin is a 26 amino acid peptide derived from bee venom that has a very high membranolytic activity. However, such lytic peptides also impose a significant safety risk when applied in vivo as they often have similar activity against red blood cells and other non-target cell membranes. Our aim is to control the membrane-disrupting capacity of these peptides in time and space by physically constraining them to a nanocarrier surface in such a way that they only become activated when delivered inside acidic endosomes...
December 22, 2016: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28000995/ribonucleotides-and-rna-promote-peptide-chain-growth
#14
Helmut Griesser, Peter Tremmel, Eric Kervio, Camilla Pfeffer, Ulrich E Steiner, Clemens Richert
All known forms of life use RNA-mediated polypeptide synthesis to produce the proteins encoded in their genes. Because the principal parts of the translational machinery consist of RNA, it is likely that peptide synthesis was achieved early in the prebiotic evolution of an RNA-dominated molecular world. How RNA attracted amino acids and then induced peptide formation in the absence of enzymes has been unclear. Herein, we show that covalent capture of an amino acid as a phosphoramidate favors peptide formation...
December 21, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27996252/the-formation-and-occurrence-of-n-chloro-2-2-dichloroacetamide-a-previously-overlooked-nitrogenous-disinfection-byproduct-in-chlorinated-drinking-waters
#15
Yun Yu, David A Reckhow
Haloacetamides (HAMs) are a class of newly identified nitrogenous disinfection byproducts (N-DBPs) whose occurrence in drinking waters has recently been reported in several DBP surveys. As the most prominent HAM species, it is commonly acknowledged that 2,2-dichloroacetamide (DCAM) is mainly generated from dichloroacetonitrile (DCAN) hydrolysis because the concentrations of these two compounds are often well correlated. Instead of DCAM, a previously unreported N-DBP, N-chloro-2,2-dichloroacetamide (N-Cl-DCAM), was confirmed in this study as the actual DCAN degradation product in chlorinated drinking waters...
December 20, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27992223/revealing-the-mechanistic-pathway-of-acid-activation-of-proton-pump-inhibitors-to-inhibit-the-gastric-proton-pump-a-dft-study
#16
Kalyanashis Jana, Tusar Bandyopadhyay, Bishwajit Ganguly
Acid-related gastric diseases are associated with disorder of digestive tract acidification due to the acid secretion by gastric proton pump, H(+),K(+)-ATPase. Omeprazole is one of the persuasive irreversible inhibitor of the proton pump H(+),K(+)-ATPase. However, the reports on the mechanistic pathway of irreversible proton pump inhibitors (PPIs) on the acid activation and formation of disulfide complex are scarce in the literature. We have examined the acid activation PPIs, i.e., timoprazole, S-omeprazole and R-omeprazole using M062X/6-31++G(d,p) in aqueous phase with SMD solvation model...
December 29, 2016: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27977182/effects-of-fungicide-treatment-on-free-amino-acid-concentration-and-acrylamide-forming-potential-in-wheat
#17
Tanya Y Curtis, Stephen J Powers, Nigel G Halford
Acrylamide forms from free asparagine and reducing sugars during frying, baking, roasting, or high-temperature processing, and cereal products are major contributors to dietary acrylamide intake. Free asparagine concentration is the determining factor for acrylamide-forming potential in cereals, and this study investigated the effect of fungicide application on free asparagine accumulation in wheat grain. Free amino acid concentrations were measured in flour from 47 varieties of wheat grown in a field trial in 2011-2012...
December 28, 2016: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/27973834/experimental-and-theoretical-investigations-of-infrared-multiple-photon-dissociation-spectra-of-asparagine-complexes-with-zn-2-and-cd-2-and-their-deamidation-processes
#18
Georgia C Boles, Rebecca A Coates, Giel Berden, Jos Oomens, P B Armentrout
Complexes of asparagine (Asn) cationized with Zn(2+) and Cd(2+) were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light generated from a free electron laser. Electrospray ionization yielded complexes of deprotonated Asn with Zn(2+), [Zn(Asn-H)](+), and intact Asn with CdCl(+), CdCl(+)(Asn). Series of low energy conformers for each complex were found using quantum chemical calculations in order to identify the structures formed experimentally. The experimentally obtained spectra were compared to those calculated from optimized structures at the B3LYP/6-311+G(d,p) level for [Zn(Asn-H)](+) and the B3LYP/def2-TZVP level with an SDD effective core potential on cadmium for the CdCl(+)(Asn) system...
December 15, 2016: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27966891/combining-sense-and-nonsense-codon-reassignment-for-site-selective-protein-modification-with-unnatural-amino-acids
#19
Zhenling Cui, Sergey Mureev, Mark E Polinkovsky, Zhong Guo, Zakir Tnimov, Thomas Durek, Alun Jones, Kirill Alexandrov
Incorporation of unnatural amino acids (uAAs) via codon reassignment is a powerful approach for introducing novel chemical and biological properties to synthesized polypeptides. However, the site-selective incorporation of multiple uAAs into polypeptides is hampered by the limited number of reassignable nonsense codons. This challenge is addressed in the current work by developing Escherichia coli in vitro translation system depleted of specific endogenous tRNAs. The translational activity in this system is dependent on the addition of synthetic tRNAs for the chosen sense codon...
December 30, 2016: ACS Synthetic Biology
https://www.readbyqxmd.com/read/27966355/accurate-three-states-model-for-amino-acids-with-two-chemically-coupled-titrating-sites-in-explicit-solvent-atomistic-constant-ph-simulations-and-pka-calculations
#20
Plamen Dobrev, Serena Donnini, Gerrit Groenhof, Helmut Grubmüller
Correct protonation of titratable groups in biomolecules is crucial for their accurate description by molecular dynamics simulations. In the context of constant pH simulations, an additional protonation degree of freedom is introduced for each titratable site, allowing the protonation state to change dynamically with changing structure or electrostatics. Here, we extend previous approaches for an accurate description of chemically coupled titrating sites. A second reaction coordinate is used to switch between two tautomeric states of an amino acid with chemically coupled titratable sites, such as aspartate (Asp), glutamate (Glu), and histidine (His)...
December 14, 2016: Journal of Chemical Theory and Computation
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