bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipid‐like Peptides can Stabilize Integral Membrane Proteins for Biophysical and Structural Studies
Authors: Veith Katharina , Martinez Molledo Maria , Almeida Hernandez Yasser , Josts Inokentijs , Nitsche Julius , Löw Christian , Tidow Henning 
Published: June 2017

AbstractA crucial bottleneck in membrane protein structural biology is the difficulty in identifying a detergent that can maintain the stability and functionality of integral membrane proteins (IMPs). Detergents are poor membrane mimics, and their common use in membrane protein crystallography may be one reason for the challenges in obtaining high‐resolution crystal structures of many IMP families. Lipid‐like peptides (LLPs) have detergent‐like properties and have been proposed as alternatives for the solubilization of G protein‐coupled receptors and other membrane proteins. Here, we systematically analyzed the stabilizing effect of LLPs on integral membrane proteins of different families. We found that LLPs could significantly stabilize detergent‐solubilized IMPs in vitro. This stabilizing effect depended on the chemical nature of the LLP and the intrinsic stability of a particular IMP in the detergent. Our results suggest that screening a subset of LLPs is sufficient to stabilize a particular IMP, which can have a substantial impact on the crystallization and quality of the crystal.
Silica‐Supported Au–Ag Catalysts for the Selective Hydrogenation of Butadiene
Authors: Masoud Nazila , Delannoy Laurent , Calers Christophe , Gallet Jean‐Jacques , Bournel Fabrice , de Jong Krijn P. , Louis Catherine , de Jongh Petra E. 
Published: June 2017

AbstractGold and silver are miscible over the entire composition range, and form an attractive combination for fundamental studies on bimetallic catalysts. Au–Ag catalysts have shown synergistic effects for different oxidation and liquid‐phase hydrogenation reactions, but have rarely been studied for gas‐phase hydrogenation. In this study 3 nm particles of Au, Ag and Au–Ag supported on silica (SBA‐15) were investigated as catalysts for selective hydrogenation of butadiene in an excess of propene. The Au catalyst was over an order of magnitude more active than the Ag catalyst at 120 °C. The initial activity of the Au–Ag catalysts scaled linearly with the Au‐content, suggesting a direct correlation between the surface and overall compositions of the nanoparticles and the absence of synergistic effects. All Au‐containing catalysts were highly selective to butenes (>99.9 %). The Au catalysts were stable, whereas the Au–Ag catalysts lost about half of their activity during 20 h run time at 200 °C, but the initial activity was restored by a consecutive oxidation‐reduction treatment. Near ambient pressure x‐ray photoelectron spectroscopy showed that exposure to H2 at elevated temperatures led to a gradual enrichment of the surface of the Au–Ag nanoparticles by Ag. These observations highlight the importance of considering progressive atomic rearrangements in bimetallic nanocatalysts under reaction conditions.
Organocatalytic Synthesis of Lactones by the Oxidation of Alkenoic Acids
Authors: Triandafillidi Ierasia , Raftopoulou Marianna , Savvidou Anatoli , Kokotos Christoforos G. 
Published: June 2017

AbstractAlong the lines of modern sustainable oxidation, a green and mild organocatalytic synthetic procedure for the synthesis of hydroxylactones from alkenoic acids is described. The reaction includes the activation of H2O2 by an organocatalyst (2,2,2‐trifluoromethylacetophenone), the oxidation of an olefinic group to the corresponding epoxide, and intramolecular lactonization to afford a variety of substituted γ‐ or δ‐lactones with multiple substitution patterns in good to high yields. The product can be obtained with high purity after simple extraction if the conversion is quantitative. Attempts to render the process asymmetric met with limited success.
Application of Microwave Irradiation for Preparation of a KOH/Calcium Aluminate Nanocatalyst and Biodiesel
Authors: Nayebzadeh Hamed , Saghatoleslami Naser , Tabasizadeh Mohammad 
Published: June 2017

AbstractMicrowave combustion was applied for the fabrication of KOH/calcium aluminate for microwave‐enhanced biodiesel production. The effect of calcium nitrate and potassium hydroxide dosages on the properties and activities of samples was assessed. When the Ca/Al ratio was increased, the activity was enhanced probably due to the transformation of the sample to an active mayenite structure. The activity of the sample was reduced by a higher KOH loading as a result of covering the surface and porosity of the support by potassium components. The optimum sample was utilized in the transesterification reaction by two heating systems where the microwave irradiation reduced the reaction time drastically as compared to the conventional heating system. The sample converted canola oil to methyl ester nearly completely and showed high stability via calcination after each usage.
Nanofiber Single‐Ion Conducting Electrolytes: An Approach for High‐Performance Lithium Batteries at Ambient Temperature
Authors: Rohan Rupesh , Kuo Tsung‐Chieh , Chen Meng‐Wei , Lee Jyh‐Tsung 
Published: June 2017

AbstractExploring the benefits of a nanofibrous morphology in electrolyte materials for Li‐battery applications, an approach of fabricating single‐ion conducting electrolyte (SICE) membranes is reported. A nonwoven nanofabric SICE membrane, delivering an outstanding performance, surpassing the conventional liquid electrolyte system at ambient conditions, was fabricated by using an electrospinning technique. When soaked in a carbonate solvent system, the membrane shows high ionic conductivity, electrochemical stability above 5.2 V (vs. Li/Li+) and a lithium transference number (
) close to unity (0.93). Moreover, a LiFePO4|Li cell assembled with this membrane performs charge/discharge up to the 5 C rate under ambient conditions with a coulombic efficiency close to 100%. The discharge capacities of this battery are found to be higher than those of a battery assembled with a commercial separator/dual‐ion salt electrolyte system up to 2 C, which offers significant progress for SICEs. Unlike most of the earlier reported SICEs that performed like a bulk‐material entity, the innovative approach might be valuable for future developments.
Unraveling the Multistimuli Responses of a Complex Dynamic System of Pseudopeptidic Macrocycles
Authors: Valdivielso Angel M. , Puig‐Castellví Francesc , Atcher Joan , Solà Jordi , Tauler Romà , Alfonso Ignacio 
Published: June 2017

AbstractInvited for the cover of this issue is the group of Ignacio Alfonso at the IQAC‐CSIC in Barcelona (Spain). Read the full text of the article at 10.1002/chem.201701294.
Synthesis, DNA Cleavage Activity, Cytotoxicity, Acetylcholinesterase Inhibition, and Acute Murine Toxicity of Redox‐Active Ruthenium(II) Polypyridyl Complexes
Authors: Alatrash Nagham , Narh Eugenia S. , Yadav Abhishek , Kim Mahn‐Jong , Janaratne Thamara , Gabriel James , MacDonnell Frederick M. 
Published: June 2017

AbstractFour mononuclear [(L‐L)2Ru(tatpp)]2+ and two dinuclear [(L‐L)2Ru(tatpp)Ru(L‐L)2]4+ ruthenium(II) polypyridyl complexes (RPCs) containing the 9,11,20,22‐tetraazatetrapyrido[3,2‐a:2′,3′‐c:3′′,2′′‐l:2′′′,3′′′‐n]pentacene (tatpp) ligand were synthesized, in which L‐L is a chelating diamine ligand such as 2,2′‐bipyridine (bpy), 1,10‐phenanthroline (phen), 3,4,7,8‐tetramethyl‐1,10‐phenanthroline (Me4phen) or 4,7‐diphenyl‐1,10‐phenanthroline (Ph2phen). These Ru–tatpp analogues all undergo reduction reactions with modest reducing agents, such as glutathione (GSH), at pH 7. These, plus several structurally related but non‐redox‐active RPCs, were screened for DNA cleavage activity, cytotoxicity, acetylcholinesterase (AChE) inhibition, and acute mouse toxicity, and their activities were examined with respect to redox activity and lipophilicity. All of the redox‐active RPCs show single‐strand DNA cleavage in the presence of GSH, whereas none of the non‐redox‐active RPCs do. Low‐micromolar cytotoxicity (IC50) against malignant H358, CCL228, and MCF7 cultured cell lines was mainly restricted to the redox‐active RPCs; however, they were substantially less toxic toward nonmalignant MCF10 cells. The IC50 values for AChE inhibition in cell‐free assays and the acute toxicity of RPCs in mice revealed that whereas most RPCs show potent inhibitory action against AChE (IC50 values <15 μm), Ru–tatpp complexes as a class are surprisingly well tolerated in animals relative to other RPCs.
Saposin B Binds the Lipofuscin Bisretinoid A2E and Prevents its Enzymatic and Photooxidation
Authors: Tinklepaugh Jay , Smith Britannia M. , Nie Yan , Moody Kelsey , Grohn Kris , Bou‐Abdallah Fadi , Doyle Robert P. 
Published: June 2017

AbstractThe front cover artwork is provided by the group of Prof. Robert P. Doyle at Syracuse University (USA) and collaborators, Prof. Fadi Bou‐Abdallah at SUNY Potsdam (USA) and Kelsey Moody at Ichor Therapeutics. The picture illustrates lipofuscin bisretinoid A2E blue‐light‐induced photooxidation and its protection by the lysosomal protein SapB. Binding of A2E by SapB protects A2E from both enzymatic degradation and photooxidation by blue light. Read the full text of the Communication at 10.1002/cptc.201700039.
Different genetic structures revealed resident populations of a specialist parasitoid wasp in contrast to its migratory host
Authors: Wei Shu‐Jun , Zhou Yuan , Fan Xu‐Lei , Hoffmann Ary A. , Cao Li‐Jun , Chen Xue‐Xin , Xu Zai‐Fu 
Published: June 2017

AbstractGenetic comparisons of parasitoids and their hosts are expected to reflect ecological and evolutionary processes that influence the interactions between species. The parasitoid wasp, Cotesia vestalis, and its host diamondback moth (DBM), Plutella xylostella, provide opportunities to test whether the specialist natural enemy migrates seasonally with its host or occurs as resident population. We genotyped 17 microsatellite loci and two mitochondrial genes for 158 female adults of C. vestalis collected from 12 geographical populations, as well as nine microsatellite loci for 127 DBM larvae from six separate sites. The samplings covered both the likely source (southern) and immigrant (northern) areas of DBM from China. Populations of C. vestalis fell into three groups, pointing to isolation in northwestern and southwestern China and strong genetic differentiation of these populations from others in central and eastern China. In contrast, DBM showed much weaker genetic differentiation and high rates of gene flow. TESS analysis identified the immigrant populations of DBM as showing admixture in northern China. Genetic disconnect between C. vestalis and its host suggests that the parasitoid did not migrate yearly with its host but likely consisted of resident populations in places where its host could not survive in winter.
Phenotyping of gut microbiota: Focus on capillary electrophoresis
Authors: Ferrer Manuel , Raczkowska Beata Anna , Martínez‐Martínez Mónica , Barbas Coral , Rojo David 
Published: June 2017

AbstractThe analysis of the microbial metabolome is crucial to fully understand the symbiotic relation between humans and microbes. That is why an explosion of metabolomics took place in the area. So far, at least several hundreds of microbial metabolites have been shown to be statistically altered when humans undergo a plethora of commonly faced perturbations. NMR and MS, usually coupled with GC, LC and CE have revealed their identities. CE is a robust analytical platform for the analysis of polar and ionic metabolites that are essential in order to assess the cells’ activity. Due to its novelty, only 5% of the metabolomics studies investigate gut microbiota using CE, even though the metabolites found by CE as being significantly altered in human microbiota represent around 23% of the total number of metabolites identified by metabolomics tools. Herein, we discuss the advances of metabolomics in the frame of other OMICS techniques for human gut microbiota analysis. Afterwards, we focus on sample treatment, analytical methods and data processing in CE coupled to any detector that have been reported to date in order to enhance metabolite coverage in the art, and to identify metabolite markers that cannot be covered by other platforms but are of key importance for determining microbial activity and human health.
A robust protocol for the isolation of cellular proteins from Xanthomonas campestris to analyze the methionine effect in 2D‐gel experiments
Authors: Schulte Fabian , Hardt Markus , Niehaus Karsten 
Published: June 2017

AbstractTwo‐dimensional PAGE (2D‐PAGE) is a key technique for the separation of complex protein samples to survey the protein inventory of prokaryotic microorganisms. Although the preparation of proteins is a critical step in 2D gel experiments, its effect on the outcome of proteome data is often underestimated. In this work, we show that the choice of protein isolation method can have a profound impact on the quality of 2D gels of protein extracts from prokaryotes. Based on Xanthomonas campestris, a commercially relevant producer of the thickening agent xanthan, we validated a phenol extraction protocol for the purification of bacterial proteins that provides excellent 2D gel separation. As a proof of concept, this method was used to study the effect of methionine—a medium compound that reduces the xanthan output of industrial fermentations—on the cellular proteome of Xanthomonas. The detection of nine regulated proteins associated with sulfur metabolism (Cgl, CysI, CysJ, CysK, MetH1, MetY) and sugar nucleotide biosynthesis (Pgi, Ugd, XanA) proved the efficiency of phenol extraction for the screening of statistically significant abundance changes in 2D gel spots and MALDI‐TOF‐MS based identification in bacteria. Since this method is very robust, it may be useful for the study of other prokaryotes that are relevant in industrial biotechnology.
Microtiter plate‐based cultivation to investigate the growth of filamentous fungi
Authors: Huth Ina , Schrader Jens , Holtmann Dirk 
Published: June 2017

AbstractMicroscale bioprocessing techniques are rapidly emerging as a means to increase the speed of bioprocess design and to reduce material consumption. However, there is still a lack of suitable parallelized techniques to investigate the industrially important group of filamentous bacteria and fungi. Cultivation of filamentous organisms in shake flasks is still the favored technique for comparing and optimizing cultivation conditions of production strains at mL‐scale. In this paper, the application of a microtiter plate‐based cultivation system in combination with the filamentous fungus Aspergillus niger was investigated. A protocol for reproducible cultivation was developed and evaluated. Productivity of A. niger concerning the rose‐like aroma compound 2‐phenylethanol showed low standard deviations while regular and consistent morphologies appeared in the parallelized system. Furthermore, the effect of addition of microparticles on the morphology was investigated. The results can be used to accelerate the process development with A. niger and other filamentous organisms.
Surfactant‐Free One‐Pot Synthesis of Low‐Density Cerium Oxide Nanoparticles for Adsorptive Removal of Arsenic Species
Authors: Mishra Prashant Kumar , Saxena Amit , Rawat Ashok Singh , Dixit Pradeep Kumar , Kumar Rakesh , Rai Pramod Kumar 
Published: June 2017

Cerium oxide (CeO2) nanoparticles of size 3–5 nm and surface area 257 m2 g−1 were synthesized using simple, single‐pot, and surfactant‐free aerogel process. Efforts were made to tune the surface area and porosity of CeO2 nanoparticles by changing the concentration of precursors. CeO2 nanoparticles were characterized by TEM, SEM, XRD, N2‐BET, and FTIR. Prepared CeO2 was used to remove As(III) and As(V) from water at variable contaminant concentrations (25–100 ppm) and pH (3–10). The adsorption process found extremely fast for the first few minutes of exposure. CeO2 nanoparticles indicated adsorption capacities of 71.9 and 36.8 mg g−1 against As(III) and As(V), respectively. The adsorption data best fitted with Redlich–Peterson model, depicting monolayer adsorption. The adsorption followed pseudo‐second‐order kinetics and intraparticle diffusion with three‐step diffusion process. The effect of co‐existing anions (H2
,
, and
) indicated 80–96% reduction in adsorption capacity. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 221–231, 2018
Role of ion‐exchange resins as catalyst in the reaction‐network of transformation of biomass into biofuels
Authors: Ramírez Eliana , Bringué Roger , Fité Carles , Iborra Montserrat , Tejero Javier , Cunill Fidel 
Published: June 2017

AbstractThe use of acidic ion exchange resins in the transformation of biomass into biofuels is revised and their potential application is presented. Relationships between morphology and structure of resins and their catalytic activity for some existing reactions of the transformation network from sugars to biofuels are observed. In the synthesis of 5‐hydroxymethyfurfural and levulinic acid, catalytic activity of resins increases when the crosslinking content is decreased for both macroreticular and gel‐type resins. Gel‐type resins with low crosslinking were found to be the most suitable resins for direct esterification of levulinic acid with linear alcohols. However, for the alcoholysis of furfuryl alcohol, macroreticular resins are better than gel‐type ones. Deactivation probably due to humins formation is the main drawback for industrial application. © 2017 Society of Chemical Industry
New frontiers of land and water commodification: socio‐environmental controversies of large‐scale land acquisitions
Authors: D'Odorico Paolo , Rulli Maria Cristina , Dell'Angelo Jampel , Davis Kyle Frankel 
Published: June 2017

AbstractA growing number of regions in the developing world are targeted by transnational investors who are acquiring large amounts of land and natural resources. Driven by the increasing global demand for agricultural products, such investments are often considered an opportunity for economic development in the target country. However, there are concerns about the social and environmental impacts on local communities. In this brief review, we discuss some key socio‐environmental controversies surrounding large‐scale land acquisitions (LSLAs). LSLAs often target common property systems and lead to privatization and commodification of land through long‐term land concessions. There is a debate between supporters of foreign land investments as a means to attract modern agricultural technology that would decrease the yield gap in underperforming agricultural land and those who question such a development model because it is seldom coupled with policy instruments that would ensure that the benefits improve food security in local populations. Large‐scale land investments displace a variety of systems of production ranging from small‐scale farming to (arguably) “unused” land such as forests and savannas on which local communities often depend. Moreover, LSLAs entail an appropriation of water resources that may negatively impact local farmers or downstream human and natural systems. In most cases, investors keep the land fallow but, when they put it under productive use, they typically change land cover and land use to start intensified commercial farming, often for nonfood crops. Copyright © 2017 John Wiley & Sons, Ltd.
All‐Aqueous Nanoprecipitation: Spontaneous Formation of Hydrogen‐Bonded Nanoparticles and Nanocapsules Mediated by Phase Separation of Poly(N‐Isopropylacrylamide)
Authors: Wang Yuhao , Sukhishvili Svetlana A. 
Published: June 2017

Spontaneous formation of polymer nanoparticles of well‐defined, <100 nm sizes with controlled solid/hollow morphology and fluorescent properties is reported. The nanoparticle formation is assisted by temperature‐triggered nucleation of an amphiphilic polymer—poly(N‐isopropylacrylamide) (PNIPAM)—and mediated by hydrogen bonding of the emerged nuclei with tannic acid (TA). The pH of solution and TA/PNIPAM ratios are explored as parameters that define TA/PNIPAM assembly. Well‐defined nanoparticles are formed in a wide range of neutral pH when the TA/PNIPAM ratio exceeds its critical, pH‐dependent value. Dynamic light scattering and zeta potential measurements as well as atomic force microscopy and electron energy loss spectroscopy indicate that solid nanoparticles or nanocapsules are formed depending on the solution pH and that enhanced ionization of TA favors hollow morphology. Nanocapsules exhibit label‐free fluorescence at neutral pH values and therefore can be useful in imaging applications.
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Microfluidic Programming of Compositional Hydrogel Landscapes
Authors: Allazetta S. , Negro A. , Lutolf M. P. 
Published: June 2017

A droplet microfluidics strategy to rapidly synthesize, process, and screen up to hundreds of thousands of compositionally distinct synthetic hydrogels is presented. By programming the flow rates of multiple microfluidic inlet channels supplying individual hydrogel building blocks, microgel compositions and properties are systematically modulated. The use of fluorescent labels as proxies for the physical and chemical properties of the microgel permits the rapid screening and discovery of specific formulations through fluorescence microscopy or flow cytometry. This concept should accelerate the discovery of new hydrogel formulations for various novel applications.
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Pharmacoinformatic Study on the Selective Inhibition of the Protozoan Dihydrofolate Reductase Enzymes
Authors: Sharma Vishnu K. , Abbat Sheenu , Bharatam P. V. 
Published: June 2017

AbstractDihydrofolate reductase (DHFR) is an essential enzyme of the folate metabolic pathway in protozoa and it is a validated, potential drug target in many infectious diseases. Information about unique conserved residues of the DHFR enzyme is required to understand residual selectivity of the protozoan DHFR enzyme. The three dimensional crystal structures are not available for all the protozoan DHFR enzymes. Enzyme‐substrate/inhibitor interaction information is required for the binding mode characterization in protozoan DHFR for selective inhibitor design. In this work, multiple sequence analysis was carried out in all the studied species. Homology models were built for protozoan DHFR enzymes, for which 3D structures are not available in PDB. The molecular docking and Prime‐MMGBSA calculations of the natural substrate (dihydrofolate, DHF) and classical DHFR inhibitor (methotrexate, MTX) were performed in protozoan DHFR enzymes. Comparative sequence analysis showed that an overall sequence identity between the studied species ranging from 22.94 % (CfDHFR‐BgDHFR) to 94.61 % (LdDHFR‐LmDHFR). Interestingly, it was observed that most of the active site residues were conserved in all the cases and all the enzymes exhibit similar key binding interactions with DHF and MTX in molecular docking analysis, but there are a few key binding residues which differ in protozoan species that makes it suitable for target selectivity. This information can be used to design selective and potent protozoan DHFR enzyme inhibitors.