bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large multiple transmembrane domain fragments of a G protein‐coupled receptor: Biosynthesis, purification, and biophysical studies
Authors: Potetinova Zhanna , Tantry Subramanyam , Cohen Leah S. , Caroccia Katrina E. , Arshava Boris , Becker Jeffrey M. , Naider Fred 
Published: July 2012

AbstractTo conduct biophysical analyses on large domains of GPCRs, multimilligram quantities of highly homogeneous proteins are necessary. This communication discusses the biosynthesis of four transmembrane and five transmembrane‐containing fragments of Ste2p, a GPCR recognizing the Saccharomyces cerevisiae tridecapeptide pheromone α‐factor. The target fragments contained the predicted four N‐terminal Ste2p[G31‐A198] (4TMN), four C‐terminal Ste2p[T155‐L340] (4TMC), or five C‐terminal Ste2p[I120‐L340] (5TMC) transmembrane segments of Ste2p. 4TMN was expressed as a fusion protein using a modified pMMHa vector in L‐arabinose‐induced Escherichia coli BL21‐AI, and cleaved with cyanogen bromide. 4TMC and 5TMC were obtained by direct expression using a pET21a vector in IPTG‐induced E. coli BL21(DE3) cells. 4TMC and 5TMC were biosynthesized on a preparative scale, isolated in multimilligram amounts, characterized by MS and investigated by biophysical methods. CD spectroscopy indicated the expected highly α‐helical content for 4TMC and 5TMC in membrane mimetic environments. Tryptophan fluorescence showed that 5TMC integrated into the nonpolar region of 1‐stearoyl‐2‐hydroxy‐sn‐glycero‐3‐phospho‐(1′‐rac‐glycerol) micelles. HSQC‐TROSY investigations revealed that [15N]‐labeled 5TMC in 50% trifluoroethanol‐d2/H2O/0.05%–trifluoroacetic acid was stable enough to conduct long multidimensional NMR measurements. The entire Ste2p GPCR was not readily reconstituted from the first two and last five or first three and last four transmembrane domains. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 485–500, 2012.
The many facets of MLL1 regulation
Authors: Zhang Pamela , Bergamin Elisa , Couture Jean‐François 
Published: July 2012

AbstractIn the last 20 years, we have witnessed an exponential number of evidences linking the human mixed lineage leukemia‐1 (MLL1) gene to several acute and myelogenous leukemias. MLL1 is one of the founding members of the SET1 family of lysine methyltransferases and is key for the proper control of developmentally regulated gene expression. MLL1 is a structurally complex protein composed of several functional domains. These domains play pivotal roles for the recruitment of regulatory proteins. These MLL1 regulatory proteins (MRPs) dynamically interact with MLL1 and consequently control gene expression. In this review, we summarize recent structural and functional studies of MRPs and discuss emergent structural paradigms for the control of MLL1 activity. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 136–145, 2013.
New biocomposites based on bioplastic flax fibers and biodegradable polymers
Authors: Wróbel‐Kwiatkowska Magdalena , Czemplik Magdalena , Kulma Anna , Żuk Magdalena , Kaczmar Jacek , Dymińska Lucyna , Hanuza Jerzy , Ptak Maciej , Szopa Jan 
Published: July 2012

AbstractA new generation of entirely biodegradable and bioactive composites with polylactic acid (PLA) or poly‐ε‐caprolactone (PCL) as the matrix and bioplastic flax fibers as reinforcement were analyzed. Bioplastic fibers contain polyhydroxybutyrate and were obtained from transgenic flax. Biochemical analysis of fibers revealed presence of several antioxidative compounds of hydrophilic (phenolics) and hydrophobic [cannabidiol (CBD), lutein] nature, indicating their high antioxidant potential. The presence of CBD and lutein in flax fibers is reported for the first time. FTIR analysis showed intermolecular hydrogen bonds between the constituents in composite PLA+flax fibers which were not detected in PCL‐based composite. Mechanical analysis of prepared composites revealed improved stiffness and a decrease in tensile strength. The viability of human dermal fibroblasts on the surface of composites made of PLA and transgenic flax fibers was the same as for cells cultured without composites and only slightly lower (to 9%) for PCL‐based composites. The amount of platelets and Escherichia coli cells aggregated on the surface of the PLA based composites was significantly lower than for pure polymer. Thus, composites made of PLA and transgenic flax fibers seem to have bacteriostatic, platelet anti‐aggregated, and non‐cytotoxic effect. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Cardiotoxin‐I: An Unexpectedly Potent Insulinotropic Agent
Authors: Nguyen Thi Tuyet Nhung , Folch Benjamin , Létourneau Myriam , Vaudry David , Truong Nam Hai , Doucet Nicolas , Chatenet David , Fournier Alain 
Published: July 2012

AbstractInsulin secretion from pancreatic β‐cells is a complex process, involving the integration and interaction of multiple external and internal stimuli, in which glucose plays a major role. Understanding the physiology leading to insulin release is a crucial step toward the identification of new targets. In this study, we evaluated the presence of insulinotropic metabolites in Naja kaouthia snake venom. Only one fraction, identified as cardiotoxin‐I (CTX‐I) was able to induce insulin secretion from INS‐1E cells without affecting cell viability and integrity, as assessed by MTT and LDH assays. Interestingly, CTX‐I was also able to stimulate insulin secretion from INS‐1E cells even in the absence of glucose. Although cardiotoxins have been characterized as potent hemolytic agents and vasoconstrictors, CTX‐I was unable to induce direct hemolysis of human erythrocytes or to induce potent vasoconstriction. As such, this newly identified insulin‐releasing toxin will surely enrich the pool of existing tools to study β‐cell physiology or even open a new therapeutic avenue.
Sulfur‐Containing Secondary Metabolites from Arabidopsis thaliana and other Brassicaceae with Function in Plant Immunity
Authors: Bednarek Paweł 
Published: July 2012

AbstractBiosynthesis of antimicrobial secondary metabolites in response to microbial infection is one of the features of the plant immune system. Particular classes of plant secondary metabolites involved in plant defence are often produced only by species belonging to certain phylogenetic clades. Brassicaceae plants have evolved the ability to synthesise a wide range of sulfur‐containing secondary metabolites, including glucosinolates and indole‐type phytoalexins. A subset of these compounds is produced by the model plant Arabidopsis thaliana. Genetic tools available for this species enabled verification of immune functions of glucosinolates and camalexin (A. thaliana phytoalexin), as well as characterisation of their respective biosynthetic pathways. Current knowledge of the biosynthesis of Brassicaceae sulfur‐containing metabolites suggests that the key event in the evolution of these compounds is the acquisition of biochemical mechanisms originating from detoxification pathways into secondary metabolite biosynthesis. Moreover, it is likely that glucosinolates and Brassicaceae phytoalexins, traditionally considered as separate groups of compounds, have a common evolutionary origin and are interconnected on the biosynthetic level. This suggests that the diversity of Brassicaceae sulfur‐containing phytochemicals reflect phylogenetic clade‐specific branches of an ancient biosynthetic pathway.
Polycyclic Azoniahetarenes: Assessing the Binding Parameters of Complexes between Unsubstituted Ligands and G‐Quadruplex DNA
Authors: Jäger Katharina , Bats Jan W. , Ihmels Heiko , Granzhan Anton , Uebach Sandra , Patrick Brian O. 
Published: July 2012

AbstractPolycyclic azoniahetarenes were employed to determine the effect of the structure of unsubstituted polyaromatic ligands on their quadruplex‐DNA binding properties. The interactions of three isomeric diazoniadibenzo[b,k]chrysenes (4 a–c), diazoniapentaphene (5), diazoniaanthra[1,2‐a]anthracene (6), and tetraazoniapentapheno[6,7‐h]pentaphene (3) with quadruplex DNA were examined by DNA melting studies (FRET melting) and fluorimetric titrations. In general, penta‐ and hexacyclic azoniahetarenes bind to quadruplex DNA (Kb≈106 M−1) even in the absence of additional functional side chains. The binding modes of 4 a–c and 3 were studied in more detail by ligand displacement experiments, isothermal titration calorimetry, and CD and NMR spectroscopy. All experimental data indicate that terminal π stacking of the diazoniachrysenes to the quadruplex is the major binding mode; however, because of different electron distributions of the π systems of each isomer, these ligands align differently in the binding site to achieve ideal binding interactions. It is proposed that tetraazonia ligand 3 binds to the quadruplex by terminal stacking with a small portion of its π system, whereas a significant part of the bulky ligand most likely points outside the quadruplex structure, and is thus partially placed in the grooves. Notably, 3 and the known tetracationic porphyrin TMPyP4 exhibit almost the same binding properties towards quadruplex DNA, with 3 being more selective for quadruplex than for duplex DNA. Overall, studies on azonia‐type hetarenes enable understanding of some parameters that govern the quadruplex‐binding properties of parent ligand systems. Since unsubstituted ligands were employed in this study, complementary and cooperative effects of additional substituents, which may interfere with the ligand properties, were eliminated.
Tetrasubstituted Phenanthrolines as Highly Potent, Water‐Soluble, and Selective G‐Quadruplex Ligands
Authors: Larsen Anders Foller , Nielsen Mads Corvinius , Ulven Trond 
Published: July 2012

AbstractSmall molecules capable of stabilizing the G‐quadruplex (G4) structure are of interest for the development of improved anticancer drugs. Novel 4,7‐diamino‐substituted 1,10‐phenanthroline‐2,9‐dicarboxamides that represent hybrid structures of known phenanthroline‐based ligands have been designed. An efficient synthetic route to the compounds has been developed and their interactions with various G4 sequences have been evaluated by Förster resonance energy transfer (FRET) melting assays, fluorescent intercalator displacement (FID), electrospray ionization mass spectrometry (ESI‐MS), and circular dichroism (CD) spectroscopy. The preferred compounds have high aqueous solubility and are strong and potent G4 binders with a high selectivity over duplex DNA; thus, they represent a significant improvement over the lead compounds. Two of the compounds are inhibitors of HeLa and HT1080 cell proliferation.
Viability of Möbius Topologies in [26]‐ and [28]Hexaphyrins
Authors: Alonso Mercedes , Geerlings Paul , de Proft Frank 
Published: July 2012

AbstractRecently, hexaphyrins have emerged as a promising class of π‐conjugated molecules that display a range of interesting electronic, optical, and conformational properties, including the formation of stable Möbius aromatic systems. Besides the Möbius topology, hexaphyrins can adopt a variety of conformations with Hückel and twisted Hückel topologies, which can be interconverted under certain conditions. To determine the optimum conditions for viable Möbius topologies, the conformational preferences of [26]‐ and [28]hexaphyrins and the dynamic interconversion between the Möbius and Hückel topologies were investigated by density functional calculations. In the absence of meso substituents, [26]hexaphyrin prefers a planar dumbbell conformation, strongly aromatic and relatively strain free. The Möbius topology is highly improbable: the most stable tautomer is 33 kcal mol−1 higher in energy than the global minimum. On the other hand, the Möbius conformer of [28]hexaphyrin is only 6.5 kcal mol−1 higher in energy than the most stable dumbbell conformation. This marked difference is due to aromatic stabilization in the Möbius 4n electron macrocycle as opposed to antiaromatic destabilization in the 4n+2 electron system, as revealed by several energetic, magnetic, structural, and reactivity indices of aromaticity. For [28]hexaphyrins, the computed activation barrier for interconversion between the Möbius aromatic and Hückel antiaromatic conformers ranges from 7.2 to 10.2 kcal mol−1, in very good agreement with the available experimental data. The conformation of the hexaphyrin macrocycle is strongly dependent on oxidation state and solvent, and this feature creates a promising platform for the development of molecular switches.
ChemInform Abstract: Synthesis and Tuberculostatic Activity of Novel Diverse Heterocyclic Compounds Derived from Heterocyclic Carbohydrazides and Methyl 2‐Heteroaroylhydrazinecarbodithioates.
Authors: Gobis Katarzyna , Foks Henryk , Augustynowicz‐Kopec Ewa , Napiorkowska Agnieszka 
Published: July 2012

AbstractOxadiazoles, thiadiazoles, and triazoles are synthesized by exploiting the high reactivity of methyl heteroaroylhydrazinecarbodithioates such as (IV) which undergo cyclization in alkaline or acidic solution.
ChemInform Abstract: Au‐Catalyzed Asymmetric Formal [3 + 2] Cycloaddition of Isocyanoacetates with Maleimides.
Authors: Padilla Silvia , Adrio Javier , Carretero Juan C. 
Published: July 2012

AbstractThe procedure allows the efficient access to chiral pyrrolopyrrole compounds which can be converted into various derivatives such as (IV) and (VI).
ChemInform Abstract: Efficient Synthesis of 5′‐Fluoroalkoxythiazoles via α‐Bromo‐α‐fluoroalkoxyacetophenones Hantzsch Type Cyclization with Thioureas or Thioamides.
Authors: Sokolenko Taras M. , Davydova Yulia A. , Yagupolskii Yurii L. 
Published: July 2012

AbstractAddition of dimethoxyphenylethanol (I) to fluoroolefins (II) followed by deprotection of the carbonyl function, α‐bromination, and subsequent treatment of the α‐bromo‐α‐fluoroalkoxyacetophenones (V) with thioureas or thioamides provides access to thiazoles with fluoroalkoxy groups at the 5‐position by means of Hantzsch‐type cyclization.
ChemInform Abstract: Interaction of Quinolines Polyfluorinated on the Benzene Moiety with Sodium and Potassium Amides in Liquid Ammonia.
Authors: Gurskaya Larisa Yu. , Selivanova Galina A. , Shteingarts Vitalij D. 
Published: July 2012

AbstractQuinolines (I) and (III) react with potassium or sodium amides by adding the NH2‐ ion at the 2‐position of the pyridine fragment to afford the quinolineamines (II) and (IV), resp., upon oxidation of the adducts formed.
ChemInform Abstract: Synthesis of 3‐Substituted 4‐Sulfanyl‐8‐methoxyisoquinolin‐1(2H)‐ones by the Reaction of Ethyl 2‐[Lithio(sulfanyl)methyl]‐6‐methoxybenzoates with Aliphatic and Aromatic Nitriles.
Authors: Kobayashi Kazuhiro , Hashimoto Hiroo , Nakagawa Kazuhiro 
Published: July 2012

AbstractIntermediates (III), obtained by reaction of ethyl halomethylmethoxybenzoates (I) with sodium thiolates, are deprotonated upon treatment with lithium diisopropylamide to generate the corresponding benzyl anions, which react smoothly with a variety of nitriles to afford satisfactory to very good yields of the desired isoquinolinones (V) and (VII).
ChemInform Abstract: Monoterpene Glucosides from Ziziphora clinopodioides (Labiatae).
Authors: Furukawa Megumi , Oikawa Naoki , Imohata Toru , Makino Mitsuko , Ogawa Shoujiro , Iida Takashi , Fujimoto Yasuo , Kitanaka Susumu 
Published: July 2012

AbstractThe three new monoterpene glucosides ziziphoroside A (I), B (II) and C (III) exhibit only weak inhibitory activity against nitric oxide production by lipopolysaccharide and interferon‐γ activated macrophages, RAW 264.7.
ChemInform Abstract: Search for New Natural Leads. Part 10. Galactolipids from Bauhinia racemosa as a New Class of Antifilarial Agents Against Human Lymphatic Filarial Parasite, Brugia malayi.
Authors: Sashidhara Koneni V. , Singh Suriya P. , Misra Sweta , Gupta Jyoti , Misra‐Bhattacharya Shailja 
Published: July 2012

AbstractAmong the active galactolipids, compound (I) emerge as lead structure active on both forms of lymphatic filarial parasite, Brugia malayi.
Antibacterial Behavior of Pyridinecarboxylatesilver(I) Complexes
Authors: Abarca Romina , Gomez Grace , Velasquez Carla , Paez Maritza A. , Gulppi Miguel , Arrieta Abel , Azocar Manuel I. 
Published: July 2012

AbstractFT‐IR spectroscopy of carboxylic groups and viability tests were useful to understand the antibacterial properties of six highly efficient silver(I) pyridinecarboxylate (nicotinic, picolinic and isonicotinic acids) and bipiridinecarboxylate (pyridine‐2,3‐dicarboxylic, pyridine‐2,4‐dicarboxylic and pyridine‐2,5‐dicarboxylic acids) complexes with AgO and AgN bonds against E. coli (ATCC 25922) and Streptococcus agalactiae (ISP 329‐09). The results show a tendency between the nature of AgX (X=oxygen and nitrogen) bonds and the rate or efficiency of antibacterial behavior.
Terpenoids from a Chinese Gorgonian Anthogorgia sp. and Their Antifouling Activities
Authors: Chen Dawei , Liu Dong , Shen Shi , Cheng Wei , Lin Wenhan 
Published: July 2012

AbstractChemical examination of a Chinese gorgonian Anthogorgia sp. resulted in the isolation of seven terpenoids, including two new compounds, an rearranged serrulatane‐type diterpenoid anthogorgiene P (1) and a guaiazuene‐based terpenoid anthogorgiene Q (2). Anthogorgiene P (1) contains an unprecedented cubebane nucleus which is rarely found from nature. The structures of new compounds were elucidated on the basis of extensive spectroscopic methods (IR, UV, MS, CD and NMR). Compound 7 showed potent antifouling activity against the larval settlement of Balanus amphitrite, while 1 and 4 possessed moderate inhibition.
Preparation of Ionic Liquid‐based Vilsmier Reagent from Novel Multi‐purpose Dimethyl Formamide‐like Ionic Liquid and Its Application
Authors: Hullio Ahmed Ali , Mastoi G. M. 
Published: July 2012

AbstractIn continuation of research to explore the applied potential of DMF‐like ionic liquid, the ionic liquid version of N,N‐dimethyliminiumchloride (Vilsmier reagent) has been synthesized from DMF‐like ionic liquid and tested effectively for its capacity to achieve more useful organic transformations. The results show that DMF‐like ionic liquid is world's first task specific ionic liquid which has catalyzed numerous diverse type of reaction and is multipurpose in its application. Thus a new term for this DMF‐like ionic liquid has been coined that is DMF‐like "multipurpose" ionic liquid.
On testing for independence between the innovations of several time series
Authors: Duchesne Pierre , Ghoudi Kilani , Rémillard Bruno 
Published: July 2012

AbstractTest statistics for checking the independence between the innovations of several time series are developed. The time series models considered allow for general specifications for the conditional mean and variance functions that could depend on common explanatory variables. In testing for independence between more than two time series, checking pairwise independence does not lead to consistent procedures. Thus a finite family of empirical processes relying on multivariate lagged residuals are constructed, and we derive their asymptotic distributions. In order to obtain simple asymptotic covariance structures, Möbius transformations of the empirical processes are studied, and simplifications occur. Under the null hypothesis of independence, we show that these transformed processes are asymptotically Gaussian, independent, and with tractable covariance functions not depending on the estimated parameters. Various procedures are discussed, including Cramér–von Mises test statistics and tests based on non‐parametric measures. The ranks of the residuals are considered in the new methods, giving test statistics which are asymptotically margin‐free. Generalized cross‐correlations are introduced, extending the concept of cross‐correlation to an arbitrary number of time series; portmanteau procedures based on them are discussed. In order to detect the dependence visually, graphical devices are proposed. Simulations are conducted to explore the finite sample properties of the methodology, which is found to be powerful against various types of alternatives when the independence is tested between two and three time series. An application is considered, using the daily log‐returns of Apple, Intel and Hewlett‐Packard traded on the Nasdaq financial market.The Canadian Journal of Statistics40: 447–479; 2012 © 2012 Statistical Society of Canada
Synthesis and Antimicrobial Activities of Oximes Derived from O‐Benzylhydroxylamine as FabH Inhibitors
Authors: Luo Yin , Zhang Li‐Rong , Hu Yang , Zhang Shuai , Fu Jie , Wang Xiao‐Ming , Zhu Hai‐Liang 
Published: July 2012

AbstractForty‐three oxime derivatives were synthesized by allowing O‐benzylhydroxylamines to react with primary benzaldehydes or salicylaldehydes; these products were gauged as potential inhibitors of β‐ketoacyl‐(acyl‐carrier‐protein) synthase III (FabH). Among the 43 compounds, 38 are reported herein for the first time. These compounds were assayed for antimicrobial activities against Escherichia coli, Pseudomonas aeruginosa, Pseudomonas fluorescens, Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis. Compounds with prominent antibacterial activities were tested for their E. coli FabH inhibitory activities. 3‐((2,4‐Dichlorobenzyloxyimino)methyl)benzaldehyde O‐2,4‐dichlorobenzyl oxime (44) showed the best antibacterial activity, with minimum inhibitory concentrations of 3.13–6.25 μg mL−1 against the tested bacterial strains, exhibiting the best E. coli FabH inhibitory activity, with an IC50 value of 1.7 mM. Docking simulations were performed to position compound 44 into the E. coli FabH active site in order to determine the most probable binding conformation.
Cellular components of the human medial amygdaloid nucleus
Authors: Dall'Oglio Aline , Xavier Léder L. , Hilbig Arlete , Ferme Denise , Moreira Jorge E. , Achaval Matilde , Rasia‐Filho Alberto A. 
Published: July 2012

AbstractThe medial nucleus (Me) is a superficial component of the amygdaloid complex. Here we assessed the density and morphology of the neurons and glial cells, the glial fibrillary acidic protein (GFAP) immunoreactivity, and the ultrastructure of the synaptic sites in the human Me. The optical fractionator method was applied. The Me presented an estimated mean neuronal density of 1.53 × 105neurons/mm3(greater in the left hemisphere), more glia (72% of all cells) than neurons, and a nonneuronal:neuronal ratio of 2.7. Golgi‐impregnated neurons had round or ovoid, fusiform, angular, and polygonal cell bodies (10–30 μm in diameter). The length of the dendrites varied, and pleomorphic spines were found in sparsely spiny or densely spiny cells (1.5–5.2 spines/dendritic μm). The axons in the Me neuropil were fine or coarsely beaded, and fibers showed simple or notably complex collateral terminations. The protoplasmic astrocytes were either isolated or formed small clusters and showed GFAP‐immunoreactive cell bodies and multiple branches. Furthermore, we identified both asymmetrical (with various small, clear, round, electron‐lucent vesicles and, occasionally, large, dense‐core vesicles) and symmetrical (with small, flattened vesicles) axodendritic contacts, also including multisynaptic spines. The astrocytes surround and may compose tripartite or tetrapartite synapses, the latter including the extracellular matrix between the pre‐ and the postsynaptic elements. Interestingly, the terminal axons exhibited a glomerular‐like structure with various asymmetrical contacts. These new morphological data on the cellular population and synaptic complexity of the human Me can contribute to our knowledge of its role in health and pathological conditions. J. Comp. Neurol. 521:589–611, 2013. © 2012 Wiley Periodicals, Inc.