bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional replacement of the Saccharomyces cerevisiae fatty acid synthase with a bacterial type II system allows flexible product profiles
Authors: Fernandez‐Moya Ruben , Leber Christopher , Cardenas Javier , Da Silva Nancy A. 
Published: June 2015

ABSTRACTThe native yeast type I fatty acid synthase (FAS) is a complex, rigid enzyme, and challenging to engineer for the production of medium‐ or short‐chain fatty acids. Introduction of a type II FAS is a promising alternative as it allows expression control for each discrete enzyme and the addition of heterologous thioesterases. In this study, the native Saccharomyces cerevisiae FAS was functionally replaced by the Escherichia coli type II FAS (eFAS) system. The E. coli acpS + acpP (together), fabB, fabD, fabG, fabH, fabI, fabZ, and tesA were expressed in individual S. cerevisiae strains, and enzyme activity was confirmed by in vitro activity assays. Eight genes were then integrated into the yeast genome, while tesA or an alternate thioesterase gene, fatB from Ricinus communis or TEII from Rattus novergicus, was expressed from a multi‐copy plasmid. Native FAS activity was eliminated by knocking out the yeast FAS2 gene. The strains expressing only the eFAS as de novo fatty acid source grew without fatty acid supplementation demonstrating that this type II FAS is able to functionally replace the native yeast FAS. The engineered strain expressing the R. communis fatB thioesterase increased total fatty acid titer 1.7‐fold and shifted the fatty acid profile towards C14 production, increasing it from <1% in the native strain to more than 30% of total fatty acids, and reducing C18 production from 39% to 8%. Biotechnol. Bioeng. 2015;112: 2618–2623. © 2015 Wiley Periodicals, Inc.
Biosynthesis of Epimers C2 and C2a in the Gentamicin C Complex
Authors: Gu Yawen , Ni Xianpu , Ren Jun , Gao Huiyuan , Wang Da , Xia Huanzhang 
Published: June 2015

AbstractGentamicin is a broad‐spectrum aminoglycoside antibiotic widely used to treat life‐threatening bacterial infections. The gentamicin C complex consists of gentamicin C1, gentamicin C1a, and epimers gentamicin C2 and gentamicin C2a. At present there is a generally accepted pathway of gentamicin biosynthesis, except for detailed understanding of the epimerization process involving gentamicins C2 and C2a. Here we have investigated the biosynthesis of these epimers. JI‐20B—an intermediate in the gentamicin biosynthetic pathway—and its epimer JI‐20Ba were generated by in‐frame deletion within genP, which encodes a phosphotransferase that catalyzes the first step of 3′,4′‐bisdehydroxylation in gentamicin biosynthesis. GenB1 and GenB2 are aminotransferases with different substrate specificities and enantioselectivities. JI‐20Ba, containing a 6′S chiral amine, a precursor of gentamicin C2a, was synthesized from G418 by GenQ/GenB1 through sequential oxidation/transamination at C‐6′. GenQ/GenB2 catalyzed the synthesis of JI‐20B, containing a 6′R chiral amine, a precursor of gentamicin C2, from G418. GenB2 catalyzed the epimerization of JI‐20Ba/JI‐20B and of gentamicins C2a/C2.
Crosstalk of Nataxazole Pathway with Chorismate‐Derived Ionophore Biosynthesis Pathways in Streptomyces sp. Tü 6176
Authors: Cano‐Prieto Carolina , Losada Armando A. , Braña Alfredo F. , Méndez Carmen , Salas José A. , Olano Carlos 
Published: June 2015

AbstractStreptomyces sp. Tü 6176, producer of cytotoxic benzoxazoles AJI9561, nataxazole, and 5‐hydroxy‐nataxazole, has been found to produce a fourth benzoxazole, UK‐1. All derive from 3‐hydroxy‐anthranilate synthesized by the nataxazole biosynthesis machinery. However, biosynthesis of AJI9561, nataxazole, and 5‐hydroxy‐nataxazole requires 6‐methylsalicylic acid also provided by nataxazole biosynthesis pathway, while biosynthesis of UK‐1 utilizes salicylic acid produced by a salicylate synthase from the coelibactin biosynthesis pathway. This clearly suggests crosstalk between nataxazole and coelibactin pathways. Overproduction of UK‐1 was obtained by growing a nataxazole non‐producing mutant (lacking 6‐methylsalicylate synthase, NatPK) in a zinc‐deficient medium. Furthermore, Streptomyces sp. Tü 6176 also produces the siderophore enterobactin in an iron‐free medium. Enterobactin production can be induced in an iron‐independent manner by inactivating natAN, which encodes an anthranilate synthase involved in nataxazole production. The results indicate a close relationship between nataxazole, enterobactin and coelibactin pathways through the shikimate pathway, the source of their common precursor, chorismate.
Comparative Studies of SrCo1−xTaxO3−δ (x=0.05–0.4) Oxides as Cathodes for Low‐Temperature Solid‐Oxide Fuel Cells
Authors: Li Mengran , Zhou Wei , Zhu Zhonghua 
Published: June 2015

AbstractWays to address the sluggish ORR kinetics of cathodes have become an area of great interest and significance for the deployment of solid‐oxide fuel cells (SOFCs) that operate at lower temperatures. A series of Sr(Co,Ta)O3−δ oxides with multilevel substitutions of tantalum (Ta5+) ions have been studied as cathodes for SOFCs in terms of their crystal structures, electrochemical properties, and durability. The effects of doping tantalum on the oxygen reduction reaction (ORR) have been explored and discussed. Not only can the crystallite structure of SrCoO3−δ be stabilized by incorporating Ta5+ at elevated temperatures, but the activity towards ORR can also be significantly enhanced by doping relatively small amounts of Ta5+ (≤20 mol %), which is probably due to the improved oxygen surface exchange that arises from the positive effects of Ta5+ dopants on the oxidation states of cobalt ions.
Solution and Gas‐Phase Acidities of all‐trans (all‐E) Retinoic Acid: An Experimental and Computational Study
Authors: Abboud José‐Luis M. , Koppel Ilmar A. , Uggerud Einar , Leito Ivo , Koppel Ivar , Sekiguchi Osamu , Kaupmees Karl , Saame Jaan , Kütt Karl , Mishima Masaaki 
Published: June 2015

AbstractRetinoic acid is of fundamental biological importance. Its acidity was determined in the gas phase and in acetonitrile solution by means of mass spectrometry and UV/Vis spectrophotometry, respectively. The intrinsic acidity is slightly higher than that of benzoic acid. In solution, the situation is opposite. The experimental systems were described theoretically applying quantum chemical methods (wave function theory and density functional theory). This allowed the determination of the molecular structure of the acid and its conjugate base, both in vacuo and in solution, and for computational estimates of its acidity in both phases.
Phase Coexistence in a Dynamic Phase Diagram
Authors: Gentile Luigi , Coppola Luigi , Balog Sandor , Mortensen Kell , Ranieri Giuseppe A. , Olsson Ulf 
Published: June 2015

AbstractMetastability and phase coexistence are important concepts in colloidal science. Typically, the phase diagram of colloidal systems is considered at the equilibrium without the presence of an external field. However, several studies have reported phase transition under mechanical deformation. The reason behind phase coexistence under shear flow is not fully understood. Here, multilamellar vesicle (MLV)‐to‐sponge (L3) and MLV‐to‐Lα transitions upon increasing temperature are detected using flow small‐angle neutron scattering techniques. Coexistence of Lα and MLV phases at 40 °C under shear flow is detected by using flow NMR spectroscopy. The unusual rheological behavior observed by studying the lamellar phase of a non‐ionic surfactant is explained using 2H NMR and diffusion flow NMR spectroscopy with the coexistence of planar lamellar–multilamellar vesicles. Moreover, a dynamic phase diagram over a wide range of temperatures is proposed.
Hydrogen Production from Aqueous Solutions of Urea with Ruthenium‐based Catalysts
Authors: Furukawa Shinya , Suzuki Ryohei , Ochi Kazuyoshi , Yashima Tatsuaki , Komatsu Takayuki 
Published: June 2015

AbstractInvited for this month′s cover is the group of Takayuki Komatsu at Tokyo Institute of Technology. The image shows that urea molecules can be effectively converted into H2, N2, and CO2 in the presence of water and Ru/Al2O3 as catalyst. The Communication itself is available at 10.1002/cssc.201500112.
Waste Tire Pyrolysis for the Production of Light Hydrocarbons over Layered Catalysts
Authors: Leng Shuai , Wang Xinde , Wang Jianguo , Liu Yue'e , Ma Fengyun , Zhong Xing 
Published: June 2015

AbstractThe pyrolysis of tire waste has attracted widespread attention because valued chemicals (for example aromatic, benzene‐based compounds) can be produced during this process. In this work, a layered catalyst was applied to waste tire pyrolysis to obtain high selectivity for light hydrocarbons (benzene, toluene, xylene, and ethylbenzene). The process was performed in fixed‐bed reactor. The layered catalyst was composed of separate layers of HZSM‐5 (a zeolite‐based catalyst) in the bottom layer and ZnO in the top layer mixed with the tire waste. The layered catalysts showed better performance in the selective production of light hydrocarbons (30.23 %), compared to mixed catalysts and ZnO alone. HZSM‐5 played an important part in secondary cracking of pyrolysis vapors to produce light hydrocarbons. HZMS‐5 could be reused several times and achieve high selectivity of light hydrocarbons over mixture catalysts of regenerated and fresh HZSM‐5 (1:1), and this is proposed a feasible way to achieve successive production.
Three New Phenyl Ether Derivatives from Aspergillus carneus HQ889708
Authors: He Ping , Tian Sha‐Sha , Xu Yan , Yu He , Ji Yan‐Nan , Zhu Hua‐Jie , Li Jian‐Heng 
Published: June 2015

AbstractThree new phenyl ether derivatives, 3‐hydroxy‐5‐(3‐hydroxy‐5‐methylphenoxy)benzoic acid (1), 3,4‐dihydroxy‐5‐(3‐hydroxy‐5‐methylphenoxy)benzoic acid (2), 3‐[3‐hydroxy‐5‐(hydroxymethyl)phenoxy]‐5‐methylphenol (3), and three known compounds 4–6 were obtained from the fermentation broth of Aspergillus carneus HQ889708, which was isolated from sea water from South China Sea. The structures of compounds 1–3 were established on the basis of spectroscopic methods including ESI‐MS and NMR. Compounds 4–6 were reported before as synthesized products, herein, they are reported from nature for the first time.
Palladium Supported on Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for SuzukiMiyaura and Hiyama Reactions under Normal Laboratory Conditions
Authors: Hosseini‐Sarvari Mona , Razmi Zahra 
Published: June 2015

AbstractNanoscale Pd supported on ZnO was prepared by a facile coprecipitation method. Pd/ZnO Nanoparticles were characterized by using XRD, TEM, SEM, XPS, BET specific surface area measurement, and thermogravimetric analysis. This catalyst was used as novel and excellent heterogeneous catalyst for ligand‐free CC bond‐formation particularly in the synthesis of unsymmetrical biaryls by SuzukiMiyaura and Hiyama cross‐coupling reactions under air atmosphere without use of any Ar or N2 flow. The catalyst can be recovered and recycled several times without marked loss of activity.
Characterization of Adducts Formed in the Reactions of Methylglyoxal and Malonaldehyde with Lysine and Histidine Derivatives
Authors: Pluskota‐Karwatka Donata , Pawłowska Agata 
Published: June 2015

AbstractGlycation of biopolymers by α‐oxoaldehydes such as methylglyoxal is believed to play a major role in the complex pathologies associated with diabetes and metabolic diseases. To design strategies that could interfere with the endogenous production of such aldehydes or promote their detoxification or, alternatively, to develop therapeutic procedures that could inhibit the deleterious effects of the oxoaldehydes at the cellular level, it is important to characterize the wide spectrum of reactions between these compounds and biomolecules, and gain insight into their mechanisms. In this study, we investigated the reactivity of endogenous α‐oxoaldehyde, methylglyoxal, and of malonaldehyde towards amino acid derivatives, and we identified new adducts with Nα‐acetyllysine and Nα‐acetylhistidine. In addition, we showed that a structurally analogous adduct is also formed with the model peptide N‐acetylglycyllysine O‐methyl ester. The characterized compounds were most likely derived from the addition of the appropriate nucleophilic center of the studied biomolecules to the CC bond of the initially formed aldehyde conjugate. The resulted adducts contain an electrophilic β‐dicarbonyl moiety and could potentially be involved in the formation of DNAprotein or protein crosslinks.
Exploration of Quantitative StructureReactivity Relationships for the Estimation of Mayr Nucleophilicity
Authors: Latino Diogo A. R. S. , Pereira Florbela 
Published: June 2015

AbstractQuantitative structurereactivity relationships (QSRRs) were investigated for the estimation of the Mayr nucleophilicity parameter N using data sets with 218 nucleophiles (solvent: CH2Cl2) and 88 compounds (solvent: MeCN) extracted from the Mayr's Database of Reactivity Parameters. The best predictions were observed for consensus models of random forests and associative neural networks, trained with empirical 2D and 3D CDK molecular descriptors, which yielded RMSE of 1.54 and 1.97 for independent test sets of the two solvent data sets, respectively. Compounds with silicon atoms were more difficult to predict, as well as classes of compounds with a reduced number of examples in the training set. The models' predictions were consistently more accurate than estimations simply based on the average of the N parameter within the class of the query compound. The possibility of calculating rate constants using the obtained models was also explored.
Sequential Monte Carlo Methods for Estimating Dynamic Microeconomic Models
Authors: Blevins Jason R. 
Published: June 2015

SummaryThis paper develops estimators for dynamic microeconomic models with serially correlated unobserved state variables using sequential Monte Carlo methods to estimate the parameters and the distribution of the unobservables. If persistent unobservables are ignored, the estimates can be subject to a dynamic form of sample selection bias. We focus on single‐agent dynamic discrete‐choice models and dynamic games of incomplete information. We propose a full‐solution maximum likelihood procedure and a two‐step method and use them to estimate an extended version of the capital replacement model of Rust with the original data and in a Monte Carlo study. Copyright © 2015 John Wiley & Sons, Ltd.
Analysis of cytotoxic effects of silver nanoclusters on human peripheral blood mononuclear cells ‘in vitro’
Authors: Orta‐García Sandra Teresa , Plascencia‐Villa Germán , Ochoa‐Martínez Angeles Catalina , Ruiz‐Vera Tania , Pérez‐Vázquez Francisco Javier , Velázquez‐Salazar J Jesús , Yacamán Miguel José , Navarro‐Contreras Hugo Ricardo , Pérez‐Maldonado Iván N. 
Published: June 2015

AbstractThe antimicrobial properties of silver nanoparticles (AgNPs) have made these particles one of the most used nanomaterials in consumer products. Therefore, an understanding of the interactions (unwanted toxicity) between nanoparticles and human cells is of significant interest. The aim of this study was to assess the in vitro cytotoxicity effects of silver nanoclusters (AgNC, < 2 nm diameter) on peripheral blood mononuclear cells (PBMC). Using flow cytometry and comet assay methods, we demonstrate that exposure of PBMC to AgNC induced intracellular reactive oxygen species (ROS) generation, DNA damage and apoptosis at 3, 6 and 12 h, with a dose‐dependent response (0.1, 1, 3, 5 and 30 µg ml–1). Advanced electron microscopy imaging of complete and ultrathin‐sections of PBMC confirmed the cytotoxic effects and cell damage caused by AgNC. The present study showed that AgNC produced without coating agents induced significant cytotoxic effects on PBMC owing to their high aspect ratio and active surface area, even at much lower concentrations (<1 µg ml–1) than those applied in previous studies, resembling what would occur under real exposure conditions to nanosilver‐functionalized consumer products. Copyright © 2015 John Wiley & Sons, Ltd.
Ocular Palatal Tremor Plus Dystonia: New Syndromic Association
Authors: Shaikh Aasef G. , Ghasia Fatema F. , DeLong Mahlon R. , Jinnah Hyder A. , Freeman Alan , Factor Stewart A. 
Published: June 2015

AbstractObjectiveOcular palatal tremor (OPT) typically develops after a breach in the Guillian‐Mollaret triangle. We herein describe a variant of this syndrome in which dystonia is also present, hence called, here, ocular palatal tremor plus dystonia.MethodsWe assessed eye‐head movements and dystonia in 6 patients with ocular palatal plus dystonia.ResultsAmong 6 patients with OPT, 2 had focal dystonia, 3 had multifocal dystonia, and 1 had generalized dystonia. The dystonia affected the upper extremities and neck in 4 patients, the lower extremities in 3, and the face in 2. Three of four cervical dystonia patients had head tremor. Two patients also had speech involvement. Lack of correlation between eye and head oscillations suggested that head oscillations were not compensatory or secondary to the eye oscillations and vice versa.ConclusionsWe describe a novel variant of OPT with dystonia. We speculate that in such a variant, the dystonia possibly could be a result of abnormal cerebellar outflow in patients with a breach in the Guillain‐Mollaret triangle.
Validating administrative records in post‐traumatic stress disorder
Authors: Abrams Thad E. , Vaughan‐Sarrazin Mary , Keane Terence M. , Richardson Kelly 
Published: June 2015

AbstractThere is insufficient data on the accuracy of administrative coding data (ACD) for post‐traumatic stress disorder (PTSD). Medical records were reviewed for (1) a diagnosis of PTSD; (2) treatment for PTSD. The records were compared against the Veterans Health Administration (VHA) data in order to determine the positive predictive value (PPV) and negative predictive value (NPV) of three commonly used approaches. The PPV and NPV varied according to the ACD approach. Relative to a medical records review, the ACD approach of one or two PTSD coded outpatient encounters had a PPV of 78% and an NPV of 91%; whereas the PPV was 97% and the NPV was 98% for three or more PTSD codes. For pharmacotherapy, the ACD approach with one or two codes for PTSD had a PPV of 33% (NPV = 93%), whereas three or more PTSD coded encounters improved the PPV to 85% (NPV = 100%). When using VHA data, we recommend tailoring the identification strategy according to the research aims. An ACD approach identifying one or more PTSD outpatient encounters should be considered sufficient for a diagnosis of PTSD. Assessments for PTSD associated pharmacotherapy require using an ACD approach that identifies veterans with the presence ≥ 3 outpatient PTSD encounters. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
Combination histamine and serotonin treatment after simulated childbirth injury improves stress urinary incontinence
Authors: Song Qi‐Xiang , Balog Brian M. , Lin Dan Li , Jiang Hai‐Hong , Gurel Volkan , Spaulding James , Tobacyk Julia , McMichael John , Damaser Margot S. 
Published: June 2015

AimsHistamine and serotonin‐related pharmaceuticals have the potential to modulate micturition and continence. The aim of this study was to determine if treatment with histamine and/or serotonin improves stress urinary incontinence (SUI) in female rats.MethodsTwenty‐six age‐matched female rats underwent pudendal nerve crush and vaginal distension (PNC + VD), to produce SUI. One week after injury, rats were treated subcutaneously with saline, histamine (1.1 μg), serotonin (2μg), or the combination of both twice daily for another week. A sham injured group received sham PNC + VD and were treated with saline (n = 7). Leak point pressure (LPP) testing with simultaneous external urethral sphincter (EUS) electromyography (EMG) was conducted 2 weeks after injury. The urethra was harvested for qualitative and quantitative histology. Data were analyzed with a one‐way ANOVA and Student‐Newman‐Keuls posthoc test with P < 0.05 indicating statistically significant differences between groups.ResultsCombination treatment significantly increased LPP after PNC + VD compared to injured sham treatment and treatment with either histamine or serotonin alone. Compared to injured sham treated rats, all three treatments significantly increased EUS EMG amplitude at both baseline and peak pressure and EUS EMG firing rate at peak pressure during LPP testing. There were more consistent urethral striated muscle fibers and thicker smooth and striated muscle with combination and histamine treatment. There was a statistically significant shift to a greater proportion of thicker collagen fibers in the urethra in serotonin and combination treated rats compared with injured sham treated rats.ConclusionsCombination treatment was the most effective and may provide an effective therapy for SUI. Neurourol. Urodynam. 35:703–710, 2016. © 2015 Wiley Periodicals, Inc.
Turning Spiroketals Inside Out: A Rearrangement Triggered by an Enol Ether Epoxidation
Authors: Lorenc Chris , Saurí Josep , Moser Arvin , Buevich Alexei V. , Williams Antony J. , Williamson R. Thomas , Martin Gary E. , Peczuh Mark W. 
Published: June 2015

AbstractSpiroketals organize small molecule structures into well‐defined, three‐dimensional configurations that make them good ligands of proteins. We recently discovered a tandem cycloisomerization–dimerization reaction of alkynyl hemiketals that delivered polycyclic, enol‐ether‐containing spiroketals. Here we describe rearrangements of those compounds, triggered by epoxidation of their enol ethers that completely remodel their structures, essentially turning them “inside out”. Due to the high level of substitution on the carbon skeletons of the substrates and products, characterization resorted to X‐ray crystallography and advanced computation and NMR techniques to solve the structures of representative compounds. In particular, a new proton‐detected ADEQUATE NMR experiment (1,1‐HD‐ADEQUATE) enabled the unequivocal assignment of the carbon skeleton of one of the new compounds. Solution of the structures of the representative compounds allowed for the assignment of product structures for the other compounds in two separate series. Both the rearrangement and the methods used for structural determination of the products are valuable tools for the preparation of characterization of new small molecule compounds.
Synthesis of highly nanoporous YBO3 architecture via a co‐precipitation approach and tunable luminescent properties
Authors: Liu Lili , Zhang Xianwen , Chaudhuri Jharna 
Published: June 2015

SummaryWe present a simple co‐precipitation method to prepare highly nanoporous YBO3 architecture using NaBO3 · 4H2O as a boric source and 600°C as the annealing temperature. The reaction was carried out under an aqueous condition without any organic solvent, surfactant, or catalysts. The prepared samples were characterized by powder X‐ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photoluminescence of doped‐nanoporous YBO3:Eu3+ was further investigated. It is expected that highly nanoporous YBO3 architecture can be an ideal candidate for applications in catalysis, adsorption, and optoelectronic devices. SCANNING 37:277–283, 2015. © 2015 Wiley Periodicals, Inc.