bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation into omacetaxine solution stability for in vitro study
Authors: Marenah Lamin , Allan Elaine K. , Mountford Joanne C. , Holyoake Tessa L. , Jørgensen Heather G. , Elliott Moira A. 
Published: August 2011

ABSTRACTOmacetaxine is a natural product extract originating from Chinese medicine and finding therapeutic use as a potent myelosuppressive agent in leukemia. When planning in vitro cell biology experiments to assess omacetaxine activity against primary leukemic stem cells, it became apparent that the literature rarely describes the in vitro stability of the molecule, although accessible chromatographic methods have been published. Clearly whole organisms vs their component cells will differ in the way in which they handle xenobiotics, with the latter more dependent on physiochemical parameters such as pH and temperature in the absence of active metabolism or excretion. This could impact on the cells' experience of drug in culture. We therefore report here on examination of a modified, high‐performance liquid chromatography (HPLC) method with assessment of degradant production from a 72 h solution stability study, clearly demonstrating that omacetaxine is highly stable in representative cell culture conditions (37 °C, neutral pH) and persists for many days in marked contrast to its short‐half life in vivo. Copyright © 2011 John Wiley & Sons, Ltd.
Biodegradation of medium chain hydrocarbons by Acinetobacter venetianus 2AW immobilized to hair‐based adsorbent mats
Authors: Luckarift Heather R. , Sizemore Susan R. , Farrington Karen E. , Fulmer Preston A. , Biffinger Justin C. , Nadeau Lloyd J. , Johnson Glenn R. 
Published: August 2011

AbstractThe natural attenuation of hydrocarbons can be hindered by their rapid dispersion in the environment and limited contact with bacteria capable of oxidizing hydrocarbons. A functionalized composite material is described herein, that combines in situ immobilized alkane‐degrading bacteria with an adsorbent material that collects hydrocarbon substrates, and facilitates biodegradation by the immobilized bacterial population. Acinetobacter venetianus 2AW was isolated for its ability to utilize hydrophobic n‐alkanes (C10–C18) as the sole carbon and energy source. Growth of strain 2AW also resulted in the production of a biosurfactant that aided in the dispersion of complex mixtures of hydrophobic compounds. Effective immobilization of strain 2AW to the surface of Ottimat™ adsorbent hair mats via vapor phase deposition of silica provided a stable and reproducible biocatalyst population that facilitates in situ biodegradation of n‐alkanes. Silica‐immobilized strain 2AW demonstrated ca. 85% removal of 1% (v/v) tetradecane and hexadecane within 24 h, under continuous flow conditions. The methodology for immobilizing whole bacterial cells at the surface of an adsorbent, for in situ degradation of hydrocarbons, has practical application in the bioremediation of oil in water emulsions. Published 2011 American Institute of Chemical Engineers Biotechnol Prog., 2011
Evaluation of Escherichia coli proteins that burden nonaffinity‐based chromatography as a potential strategy for improved purification performance
Authors: Bartlow Patrick , Tiwari Neha , Beitle Robert R. , Ataai Mohammad M. 
Published: August 2011

AbstractEscherichia coli is a favored host for rapid, scalable expression of recombinant proteins for academic, commercial, or therapeutic use. To maximize its economic advantages, however, it must be coupled with robust downstream processes. Affinity chromatography methods are unrivaled in their selectivity, easily resolving target proteins from crude lysates, but they come with a significant cost. Reported in this study are preliminary efforts to integrate downstream separation with upstream host design by evaluating co‐eluting host proteins that most severely burden two different nonaffinity‐based column processes. Phosphoenolpyruvate carboxykinase and peptidase D were significant contaminants during serial purification of green fluorescent protein (GFP) by hydrophobic interaction and anion exchange chromatography. Ribosomal protein L25 dominated non‐target binding of polyarginine‐tagged GFP on cation exchange resin. Implications for genetic knockout or site‐directed mutagenesis resulting in diminished column retention are discussed for these and other identified contaminants. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Isolation, Amino Acid Sequence and Biological Activities of Novel Long‐Chain Polyamine‐Associated Peptide Toxins from the Sponge Axinyssa aculeata
Authors: Matsunaga Satoko , Jimbo Mitsuru , Gill Martin B. , Lash‐Van Wyhe L. Leanne , Murata Michio , Nonomura Ken'ichi , Swanson Geoffrey T. , Sakai Ryuichi 
Published: August 2011

AbstractA novel family of functionalized peptide toxins, aculeines (ACUs), was isolated from the marine sponge Axinyssa aculeate. ACUs are polypeptides with N‐terminal residues that are modified by the addition of long‐chain polyamines (LCPA). Aculeines were present in the sponge extract as a complex mixture with differing polyamine chain lengths and peptide structures. ACU‐A and B, which were purified in this study, share a common polypeptide chain but differ in their N‐terminal residue modifications. The amino acid sequence of the polypeptide portion of ACU‐A and B was deduced from 3′ and 5′ RACE, and supported by Edman degradation and mass spectral analysis of peptide fragments. ACU induced convulsions upon intracerebroventricular (i.c.v.) injection in mice, and disrupted neuronal membrane integrity in electrophysiological assays. ACU also lysed erythrocytes with a potency that differed between animal species. Here we describe the isolation, amino acid sequence, and biological activity of this new group of cytotoxic sponge peptides.
Gold‐Catalyzed, Intramolecular, Oxygen‐Transfer Reactions of 2‐Alkynyl‐1,5‐diketones or 2‐Alkynyl‐5‐ketoesters: Scope, Expansion, and Mechanistic Investigations on a New [4+2] Cycloaddition
Authors: Liu Le‐Ping , Malhotra Deepika , Jin Zhuang , Paton Robert S. , Houk K. N. , Hammond Gerald B. 
Published: August 2011

AbstractThe gold‐catalyzed intramolecular oxygen‐transfer reactions of 2‐alkynyl‐1,5‐diketones or 2‐alkynyl‐5‐ketoesters—obtained from tetra‐n‐butylammonium fluoride mediated Michael addition of activated allenes to electron‐deficient olefins—furnished cyclopentenyl ketones under very mild conditions. These reactions proceeded much easier and faster than similar reactions reported in literature, and the corresponding products were obtained in very good yields. Mechanistic investigations on the cycloisomerization were carried out by means of both 18O isotopic experiments and quantum chemical calculations. The results from both, the designed isotopic experiments and theoretical calculations, satisfactorily supported the novel proposed intramolecular [4+2] cycloaddition of a gold‐containing furanium intermediate to a carbonyl group, instead of the previous well‐accepted [2+2] pathway.
Bell‐Like [Ga5] Clusters in Eu3Li5+xGa5–x (x = 0.15)
Authors: Fedorchuk Anatolii , Prots Yurii , Schnelle Walter , Grin Yuri 
Published: August 2011

AbstractThe new ternary gallide Eu3Li5+xGa5–x was synthesized from its constituent elements that were heated at 900 °C and then subsequently annealed at 300 °C for 10 months. The crystal structure was established from single‐crystal diffraction data. A new type of discrete gallium cluster was found inEu3Li5+xGa5–x, namely a bell‐like [Ga5] unit with one single‐,one four‐ and three three‐bonded atoms. On the basis of its structural features, magnetic properties and calculated electronic density of states (DOS), the title compound is represented as [Eu2+]3[Li+]5[(1b)Ga4–]1[(3b)Ga2–]3[(4b)Ga1–]1 (xb = number of bonds, where x = 1–4). The new structural unit observed in this compound is compared with other [Gan] (n = 2–6) clusters found in binary gallium compounds.
Long‐Wavelength Photolysis of Amino Acid 6‐(Methoxy‐2‐oxo‐2H‐naphtho[1,2‐b]pyran‐4‐yl)methyl Esters
Authors: Piloto Ana M. , Soares Ana M. S. , Hungerford Graham , Costa Susana P. G. , Gonçalves M. Sameiro T. 
Published: August 2011

Abstract(6‐Methoxy‐2‐oxo‐2H‐naphtho[1,2‐b]pyran‐4‐yl)methyl esters of valine or phenylalanine as model bifunctional molecules were synthesised to assess its applicability as a photocleavable protecting group for solution phase organic synthesis and in caging applications at longer wavelengths. The behaviour of the corresponding derivatives towards photolysis was evaluated by irradiation at 350 and 419 nm in a mixture of HEPES buffer and acetonitrile or methanol in a photochemical reactor, followed by HPLC/UV monitoring. Time‐resolved fluorescence measurements were used to elucidate the dynamics.
Impact of subsurface rock fragments on runoff and interrill soil loss from cultivated soils
Authors: Smets T. , López‐Vicente M. , Poesen J. 
Published: August 2011

ABSTRACTField and laboratory studies have indicated that rock fragments in the topsoil may have a large impact on soil properties, soil quality, hydraulic, hydrological and erosion processes. In most studies, the rock fragments investigated still remain visible at the soil surface and only properties of these visible rock fragments are used for predicting runoff and soil loss. However, there are indications that rock fragments completely incorporated in the topsoil could also significantly influence the percolation and water distribution in stony soils and therefore, also infiltration, runoff and soil loss rates. Therefore, in this study interrill laboratory experiments with simulated rainfall for 60 min were conducted to assess the influence of subsurface rock fragments incorporated in a disturbed silt loam soil at different depths below the soil surface (i.e. 0.001, 0.01, 0.05 and 0.10 m), on infiltration, surface runoff and interrill erosion processes for small and large rock fragment sizes (i.e. mean diameter 0.04 and 0.20 m, respectively). Although only small differences in infiltration rate and runoff volume are observed between the soil without rock fragments (control) and the one with subsurface rock fragments, considerable differences in total interrill soil loss are observed between the control treatment and both contrasting rock fragments sizes. This is explained by a rapid increase in soil moisture in the areas above the rock fragments and therefore a decrease in topsoil cohesion compared with the control soil profile. The observed differences in runoff volume and interrill soil loss between the control plots and those with subsurface rock fragments is largest after a cumulative rainfall (Pcum) of 11 mm and progressively decreases with increasing Pcum. The results highlight the impacts and complexity of subsurface rock fragments on the production of runoff volume and soil loss and requires their inclusion in process‐based runoff and erosion models. Copyright © 2011 John Wiley & Sons, Ltd.
Spectral and power efficiency of IEEE802.11n MIMO‐OFDM WLAN systems using space‐multimode‐polarization diversity compact stacked circular microstrip antenna arrays
Authors: Yavanoğlu A. , Ertuğ Ö. 
Published: August 2011

ABSTRACTRecent developments in wireless communication systems in indoor environments require high data rates and high transmission qualities especially for multimedia applications in wireless local area network (WLAN) systems. The support of high data rate multiple‐input multiple‐output (MIMO) spatial‐multiplexing communication in orthogonal frequency‐division multiplexing WLAN systems conforming to IEEE802.11n standard requires the use of compact antennas with low correlation ports. In this paper, we analyse a MIMO array consisting of higher‐order space‐multimode‐polarization diversity stacked circular microstrip patch uniform linear antenna arrays (SMP‐SCP‐ULAs) to exploit SMP diversity for use in WLAN systems. Using higher number of antenna ports in lower space and low cross‐polar discrimination values between each transmit and receive antenna, SMP‐SCP‐ULA yields higher multiplexing gain and satisfies more restrictive size constraints in clustered MIMO systems. The performance gains of higher‐order modal SMP‐SCP‐ULA are presented in terms of modal correlation, ergodic spectral efficiency, average bit error rate and compactness gain with respect to dipole and circular microstrip patch uniform linear arrays. Copyright © 2011 John Wiley & Sons, Ltd.
CXCR4 signaling regulates remyelination by endogenous oligodendrocyte progenitor cells in a viral model of demyelination
Authors: Carbajal Kevin S. , Miranda Juan L. , Tsukamoto Michelle R. , Lane Thomas E. 
Published: August 2011

AbstractFollowing intracranial infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV), susceptible mice will develop widespread myelin destruction that results in pathological and clinical outcomes similar to those seen in humans with the demyelinating disease Multiple Sclerosis (MS). Partial remyelination and clinical recovery occurs during the chronic phase following control of viral replication yet the signaling mechanisms regulating these events remain enigmatic. Here we report the kinetics of proliferation and maturation of oligodendrocyte progenitor cells (OPCs) within the spinal cord following JHMV‐induced demyelination and that CXCR4 signaling contributes to the maturation state of OPCs. Following treatment with AMD3100, a specific inhibitor of CXCR4, mice recovering from widespread demyelination exhibit a significant (P < 0.01) increase in the number of OPCs and fewer (P < 0.05) mature oligodendrocytes compared with HBSS‐treated animals. These results suggest that CXCR4 signaling is required for OPCs to mature and contribute to remyelination in response to JHMV‐induced demyelination. To assess if this effect is reversible and has potential therapeutic benefit, we pulsed mice with AMD3100 and then allowed them to recover. This treatment strategy resulted in increased numbers of mature oligodendrocytes, enhanced remyelination, and improved clinical outcome. These findings highlight the possibility to manipulate OPCs in order to increase the pool of remyelination‐competent cells that can participate in recovery. © 2011 Wiley‐Liss, Inc.
Synthesis of new functionalized mono‐ and bisorganophosphorus acids and their derivatives with unsaturated and aromatic fragments
Authors: Prishchenko Andrey A. , Livantsov Mikhail V. , Novikova Olga P. , Livantsova Ludmila I. , Petrosyan Valery S. 
Published: August 2011

AbstractConvenient procedures for the synthesis of functionalized mono‐ and bisorganophosphorus acids and their derivatives with unsaturated and aromatic fragments, starting from the available derivatives of trivalent phosphorus acids, unsaturated and aromatic aldehydes, and carboxylic acid chlorides, are proposed, and some properties of the new unsaturated organophosphorus compounds are presented. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:32–40, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20749
Teasing apart tangrams: Testing hippocampal pattern separation with a collaborative referencing paradigm
Authors: Duff Melissa C. , Warren David E. , Gupta Rupa , Vidal Juan Pablo Benabe , Tranel Daniel , Cohen Neal J. 
Published: August 2011

AbstractThe hippocampus and the medial temporal lobe cortex [medial temporal lobe cortices (MTLC)] both contribute to long‐term memory. Although their contributions are thought to be dissociable, the nature of the representations that each region supports remains unclear. The Complementary Learning Systems (CLS) modeling approach suggests that hippocampus represents overlapping information in a sparser and therefore more separated fashion than MTLC. We tested this prediction using a collaborative referencing paradigm whereby hippocampal amnesic patients and a partner work together to develop and use unique labels for a set of abstract visual stimuli (tangrams) across extended interactions. Previously, we reported that amnesic patients demonstrate intact learning when the tangrams are conceptually dissimilar. Here, we manipulated the degree of visual similarity; half of the stimuli were dissimilar to one another (e.g., camel and giraffe), and half were similar (e.g., birds). We hypothesized that while patients would have little difficulty with the dissimiliar tangrams (quickly arriving at unique and concise labels), they would be unable to rapidly form distinct representations of highly similar visual patterns. Consistent with this prediction, patients and both healthy and brain‐damaged comparison participants showed similar rates of learning for dissimilar tangrams, but the similar tangrams proved more difficult for hippocampal patients as reflected in the greater number of words they used to describe each similar card. This result supports the CLS model's central claim of hippocampal specialization for pattern separation and suggests that our collaborative referencing paradigm may be a useful tool for observing extended encoding of complex representations. © 2011 Wiley Periodicals, Inc.
Mitochondrial DNA mutations in respiratory complex‐I in never‐smoker lung cancer patients contribute to lung cancer progression and associated with EGFR gene mutation
Authors: Dasgupta Santanu , Soudry Ethan , Mukhopadhyay Nitai , Shao Chunbo , Yee John , Lam Stephan , Lam Wan , Zhang Wei , Gazdar Adi F , Fisher Paul B , Sidransky David 
Published: August 2011

AbstractMitochondrial DNA (mtDNA) mutations were reported in different cancers. However, the nature and role of mtDNA mutation in never‐smoker lung cancer patients including patients with epidermal growth factor receptor (EGFR) and KRAS gene mutation are unknown. In the present study, we sequenced entire mitochondrial genome (16.5 kb) in matched normal and tumors obtained from 30 never‐smoker and 30 current‐smoker lung cancer patients, and determined the mtDNA content. All the patients' samples were sequenced for KRAS (exon 2) and EGFR (exon 19 and 21) gene mutation. The impact of forced overexpression of a respiratory complex‐I gene mutation was evaluated in a lung cancer cell line. We observed significantly higher (P = 0.006) mtDNA mutation in the never‐smokers compared to the current‐smoker lung cancer patients. MtDNA mutation was significantly higher (P = 0.026) in the never‐smoker Asian compared to the current‐smoker Caucasian patients' population. MtDNA mutation was significantly (P = 0.007) associated with EGFR gene mutation in the never‐smoker patients. We also observed a significant increase (P = 0.037) in mtDNA content among the never‐smoker lung cancer patients. The majority of the coding mtDNA mutations targeted respiratory complex‐I and forced overexpression of one of these mutations resulted in increased in vitro proliferation, invasion, and superoxide production in lung cancer cells. We observed a higher prevalence and new relationship between mtDNA alterations among never‐smoker lung cancer patients and EGFR gene mutation. Moreover, a representative mutation produced strong growth effects after forced overexpression in lung cancer cells. Signature mtDNA mutations provide a basis to develop novel biomarkers and therapeutic strategies for never‐smoker lung cancer patients. J. Cell. Physiol. 227: 2451–2460, 2012. © 2011 Wiley Periodicals, Inc.
Caveolin‐1 orchestrates fibroblast growth factor 2 signaling control of angiogenesis in placental artery endothelial cell caveolae
Authors: Feng Lin , Liao Wu‐Xiang , Luo Quan , Zhang Hong‐Hai , Wang Wen , Zheng Jing , Chen Dong‐Bao 
Published: August 2011

AbstractFibroblast growth factor (FGF) receptor 1 (FGFR1) protein was expressed as the long and short as well as some truncated forms in ovine fetoplacental artery ex vivo and in vitro. Upon FGF2 stimulation, both the long and short FGFR1s were tyrosine phosphorylated and the PI3K/AKT1 and ERK1/2 pathways were activated in a concentration‐ and time‐ dependent manner in ovine fetoplacental artery endothelial (oFPAE) cells. Blockade of the PI3K/AKT1 pathway attenuated FGF2‐stimulated cell proliferation and migration as well as tube formation; blockade of the ERK1/2 pathway abolished FGF2‐stimulated tube formation and partially inhibited cell proliferation and did not alter cell migration. Both AKT1 and ERK1/2 were co‐fractionated with caveolin‐1 and activated by FGF2 in the caveolae. Disruption of caveolae by methyl‐β‐cyclodextrin inhibited FGF2 activation of AKT1 and ERK1/2. FGFR1 was found in the caveolae where it physically binds to caveolin‐1. FGF2 stimulated dissociation of FGFR1 from caveolin‐1. Downregulation of caveolin‐1 significantly attenuated the FGF2‐induced activation of AKT1 and ERK1/2 and inhibited FGF2‐induced cell proliferation, migration and tube formation in oFPAE cells. Pretreatment with a caveolin‐1 scaffolding domain peptide to mimic caveolin‐1 overexpression also inhibited these FGF2‐induced angiogenic responses. These data demonstrate that caveolae function as a platform for regulating FGF2‐induced angiogenesis through spatiotemporally compartmentalizing FGFR1 and the AKT1 and ERK1/2 signaling modules; the major caveolar structural protein caveolin‐1 interacts with FGFR1 and paradoxically regulates FGF2‐induced activation of PI3K/AKT1 and ERK1/2 pathways that coordinately regulate placental angiogenesis. J. Cell. Physiol. 227: 2480–2491, 2012. © 2011 Wiley Periodicals, Inc.
Ultra‐performance liquid chromatography coupled to mass spectrometry as a sensitive and powerful technology for metabolomic studies
Authors: Wang Xijun , Sun Hui , Zhang Aihua , Wang Ping , Han Ying 
Published: August 2011

AbstractMetabolomics is the comprehensive assessment of endogenous metabolites of a biological system. These large‐scale analyses of metabolites are intimately bound to advancements in ultra‐performance liquid chromatography–electrospray (UPLC) technologies and have emerged in parallel with the development of novel mass analyzers and hyphenated techniques. Recently, the combination of UPLC with MS covers a number of polar metabolites, thus enlarging the number of detected analytes in the widely used separation sciences. This technology has rapidly been accepted by the analytical community and is being gradually applied to various fields such as metabolomics and traditional Chinese medicine (TCM). Given the power of the technology, metabolomics has become increasingly popular in drug development, molecular medicine, traditional medicine and other biotechnology fields, since it profiles directly the phenotype and changes thereof in contrast to other “‐omics” technologies. Hyphenated UPLC/MS technique is becoming a useful tool in the study of body fluids, represents a promising hyphenated microseparation platform in metabolomics and has a strong potential to contribute to disease diagnosis. This review describes the applications of UPLC/MS in metabolomic research, and comparison role of HPLC/MS, NMR and GC/MS, highlights its advantages and limitations with certain characteristic examples in the life and TCM sciences.
Thermoresponsive Gene Carriers Based on Polyethylenimine‐graft‐Poly[oligo(ethylene glycol) methacrylate]
Authors: Zhang Rui , Wang Yang , Du Fu‐Sheng , Wang Ying‐Li , Tan Ying‐Xia , Ji Shou‐Ping , Li Zi‐Chen 
Published: August 2011

AbstractA family of thermoresponsive cationic copolymers (TCPs) that contain branched PEI 25 K as the cationic segment and poly(MEO2MA‐co‐OEGMA475) as the thermosensitive block (TP) is prepared. The DNA binding capability, physicochemical properties, and biological performance of the TCPs are studied. All of these TCPs can condense DNA to form polyplexes with diameters of 150–300 nm and zeta potentials of 7–32 mV at N/P ratios between 12 and 36. The length of TP block is a key factor for shielding the positive surface charge of the polyplexes and protecting them against protein adsorption. TCPs with a higher TP content have a lower cytotoxicity while the best transfection performance is achieved by the TCPs with longest TP length, reaching a level of the intact PEI 25 K in the presence of serum.magnified image