bluuebunny/crossref_metadata_2025 huggingface dataset:
Dephosphorylation of Bcl‐10 by calcineurin is essential for canonical NF‐κB activation in Th cells
Authors: Frischbutter Stefan , Gabriel Christian , Bendfeldt Hanna , Radbruch Andreas , Baumgrass Ria
Published: June 2011

Antigen‐specific stimulation of T helper (Th) cells initiates signaling cascades that ultimately result in the activation of the transcription factors NF‐κB, NFAT, and AP‐1 which regulate, together with other factors, many T‐cell functions such as cytokine production, proliferation, and differentiation. Ordered assembly and different phosphorylation events, along with subcellular translocation of the CARMA1/Bcl‐10/MALT1 complex, determine NF‐κB activation after T‐cell receptor (TCR) triggering. We now provide evidence that inhibition of the Ser/Thr phosphatase calcineurin (CaN) prevents dephosphorylation of Bcl‐10. CaN, in constant interaction with the Bcl‐10/MALT1 complex, is able to dephosphorylate Bcl‐10. The CaN inhibitor cyclosporine A (CsA) converts a transient phosphorylation of Bcl‐10 Ser138 during the immediate early phase of T‐cell activation into a persistent state. Thus, subsequent processes such as IKKβ phosphorylation, IκBα degradation, p65 nuclear translocation, and DNA binding are diminished. Consistently, CsA treatment does not affect the phosphorylation pattern of the upstream kinase PKCθ. Together, our findings demonstrate that CaN functions as a critical signaling molecule during Th cell activation, regulating Bcl‐10 phosphorylation and thereby NF‐κB activation.
IL‐9 is important for T‐cell activation and differentiation in autoimmune inflammation of the central nervous system
Authors: Li Hongmei , Nourbakhsh Bardia , Cullimore Melissa , Zhang Guang‐Xian , Rostami Abdolmohamad
Published: June 2011

Experimental autoimmune encephalomyelitis (EAE) is generally believed to be an autoimmune disease of the central nervous system (CNS) caused by myelin‐specific Th1 and/or Th17 effector cells. The underlying cellular and molecular mechanisms, however, are not fully understood. Using mice deficient in IL‐9 (IL‐9−/−), we showed that IL‐9 plays a critical role in EAE. Specifically, IL‐9−/− mice developed significantly less severe EAE than their WT counterparts following both immunization with myelin proteolipid protein (PLP)180–199 peptide in the presence of Complete Freund's Adjuvant (CFA), and adoptive transfer of PLP180–199 peptide‐specific effector T cells from WT littermates. EAE‐resistant IL‐9−/− mice exhibited considerably fewer infiltrating immune cells in the CNS, with lower levels of IL‐17 and IFN‐γ expression, than their WT littermates. Further studies revealed that null mutation of the IL‐9 gene resulted in significantly lower levels of PLP180–199 peptide‐specific IL‐17 and IFN‐γ production. Moreover, IL‐9−/− memory/activated T cells exhibited decreased C–C chemokine receptors (CCR)2, CCR5, and CCR6 expression. Interestingly, IL‐10 was significantly increased in IL‐9−/− mice compared with WT littermates. Importantly, we found that IL‐9‐mediated Th17‐cell differentiation triggers complex STAT signaling pathways.
Penetration of antibody‐opsonized cells by the membrane attack complex of complement promotes Ca2+influx and induces streamers
Authors: Beum Paul V. , Lindorfer Margaret A. , Peek Elizabeth M. , Stukenberg P. Todd , de Weers Michel , Beurskens Frank J. , Parren Paul W. H. I. , van de Winkel Jan G. J. , Taylor Ronald P.
Published: June 2011

We have reported that during complement‐mediated cytolysis of B cells promoted by the CD20 mAbs rituximab or ofatumumab (OFA), long, thin structures that we call streamers (≥3 cell diameters) are rapidly generated and grow out from the cell surface. Streamers appear before cells are killed and contain opsonizing mAbs and membrane lipids. By exploiting the differential Ca2+requirements of discrete steps in the complement cascade, we determined that mAb‐opsonized cells first tagged with C3b using C5‐depleted serum are killed on addition of serum and EDTA, but the cells do not produce streamers. Also, cells first opsonized with OFA are lysed in serum containing Mg‐EGTA by the alternative complement pathway but streamers are not produced. These findings indicate that Ca2+influx is necessary for streamer formation. Other mAbs that promote complement‐mediated cytolysis also induce streamers on target cells. Streamer‐like structures called nanotubes have been reported in several cellular systems, and are thought to promote intercellular communication/signaling. We tested whether this signaling could influence the susceptibility of neighboring cells contacted by streamers to complement attack and found that complement‐mediated cytolysis of OFA‐opsonized cells increases the resistance of unopsonized indicator cell populations to subsequent lysis when these cells are exposed to OFA and complement.
Direct activation of mTOR in B lymphocytes confers impairment in B‐cell maturation andloss of marginal zone B cells
Authors: Benhamron Sandrine , Tirosh Boaz
Published: June 2011

The tuberous sclerosis complex (TSC), composed of TSC1/TSC2 heterodimers, is inhibitory to the mammalian target of rapamycin (mTOR). Deletion of either TSC1 or TSC2 renders mTOR constitutively active. To directly explore the impact of mTOR activation on B‐cell development, we conditionally deleted TSC1 in murine B cells. This led to impairment in B‐cell maturation. Unexpectedly, and in contrast to Akt activation, marginal zone (MZ) B cells were significantly reduced. Administration of rapamycin partially corrected the MZ defect, indicating a direct role for mTOR in controlling MZ development. When challenged with a T‐cell‐dependent antigen, TSC1 KO mice responded less efficiently. Consistent with the MZ defects, TSC1 KO mice did not respond at all to T‐independent antigens. Because activation of Akt upstream of TSC and mTOR yields the reverse phenotype with respect to MZ development, we conclude that, physiologically, Akt simultaneously emits two opposing signals that counterbalance each other in the control of B‐cell differentiation.
Binuclear Carbonylheptalenechromium Complexes: Partition of Heptalene into a Complexed Heptafulvene Subunit and an Uncomplexed 1,3‐Diene Subunit for Coordination to a Multiply Bonded Pair of Chromium Atoms
Authors: Li Huidong , Feng Hao , Sun Weiguo , Fan Qunchao , Xie Yaoming , King R. Bruce
Published: June 2011

The possibility of extending carbonylchromium chemistry of the bicyclic non‐benzenoid aromatic hydrocarbon heptalene from the known mononuclear (η6‐C12H10)Cr(CO)3 to binuclear derivatives of the type C12H10Cr2(CO)n (n = 6, 5, 4, 3) is examined by density functional theory. The lowest energy C12H10Cr2(CO)6 structures have each heptalene ring bonded to an independent Cr(CO)3 unit as a hexahapto or heptahapto ligand with Cr···Cr distances too long (4.4 to 6.0 Å) for direct bonding. The lowest energy C12H10Cr2(CO)5 structure has an eight‐carbon heptafulvene subunit of the heptalene unit coordinated to a carbonyl‐bridged Cr2(CO)4(μ‐CO) unit as an octahapto ligand leaving an uncomplexed cis‐1,3‐diene subunit in the heptalene ligand. The short Cr≡Cr distance in this structure of ca. 2.36 Å suggests the formal triple bond required to give each chromium atom the favored 18‐electron configuration. A slightly higher energy C12H10Cr2(CO)5 structure by ca. 3 kcal/mol has all 12 heptalene carbon atoms bonded to an unbridged Cr2(CO)5 with a Cr–Cr distance of ca. 3.3 Å corresponding to the formal single bond required to give each chromium atom the favored 18‐electron configuration. The global minima for the more highly unsaturated C12H10Cr2(CO)n (n = 4, 3) complexes are predicted to have a four‐electron donor bridging η2‐μ‐CO group as indicated by short Cr–O distances consistent with a direct bond and a low ν(CO) frequency consistent with a low formal C–O formal bond order.
Syntheses, Structures, and Properties of Trinuclear Copper(I)/Titanium(IV) Thiolate Complexes
Authors: Andrushko Vasyl , Sommer Heino , Himmel Daniel , Fenske Dieter , Eichhöfer Andreas
Published: June 2011

The thiolato‐bridged copper(I)/titanium(IV) complexes [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] (thf = tetrahydrofuran) and [Cu2Ti(SPh)6(PPh3)2] have both been prepared in yields of at least 83 % by reaction of CuCl and TiCl4·2thf with LiSPh in THF in the presence of 15‐crown‐5 or PPh3, respectively. The crystal structures of the trinuclear compounds were determined by X‐ray analysis of single crystals. The dark colored compounds display absorption bands over a wide energy range with absorption onsets lying in the near infrared region at approximately 1350 nm for [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] and 1050 nm for [Cu2Ti(SPh)6(PPh3)2]. Density functional calculations reproduce and explain the energy difference of the lowest energy transitions. Thermal treatment of [Cu2Ti(SPh)6(PPh3)2] up to 500 °C resulted in the cleavage of SPh2 and PPh3 and the formation of a mixture of ternary copper titanium sulfides, namely Cu4TiS4 and the defect thiospinel Cu0.33TiS2. In contrast, reflections of the powder diffraction patterns of the residues from the thermal analysis of [Li(15‐crown‐5)thf]2[Cu2Ti(SPh)8] could only be assigned to the known phases Cu1.8S (Digenite) and Cu1.96S (Djurleit).
Proton Conductivity versus Acidic Strength of One‐Pot Synthesized Acid‐Functionalized SBA‐15 Mesoporous Silica
Authors: Bibent Nicolas , Mehdi Ahmad , Silly Gilles , Henn François , Devautour‐Vinot Sabine
Published: June 2011

This paper reports on the one‐pot synthesis and characterization of the functionalized mesoporous SBA‐15 silica, which contains two loadings of the different acid groups [CO2H, PO(OH)2 and SO3H]. The thermodynamic features of the water that was confined in these porous silicas was investigated by Differential Scanning Calorimetry (DSC). The results showed that the melting behaviour of the confined water was mainly governed by the pore diameter and, as a consequence, indicated that the chemical “decoration” of the porous surface did not play a key role in the water thermodynamics. On the contrary, the proton conductivity of the hydrated mesoporous materials, which was examined under a wide range of temperatures (–100 to 70 °C), was strongly dependent on both the physical state of the confined water and the acidity of the functional groups that were located at the porous surface. The proton conductivity was shown to be directly related to the pKa and the density of the functional groups attached to the mesopore surface. The high conductivity values that were obtained at a low temperature when the confined water is frozen, led us to postulate that the SO3H‐functionalized SBA‐15 sample could be a promising candidate for electrolyte solid applications in fuel cells.
Phenyl–Acetylene Bond Assembly: A Powerful Tool for the Construction of Nanoscale Architectures
Authors: Jenny Nicolas M. , Mayor Marcel , Eaton Thomas R.
Published: June 2011

This microreview summarises fundamental strategies and basic considerations for the design and synthesis of nanoscale architectures assembled through the formation of acetylene‐phenyl bonds. Since its first appearance in 1975 the Sonogashira–Hagihara reaction has allowed the formation of bonds between sp1 and sp2 carbon centres under mild conditions. This palladium‐catalysed cross‐coupling quickly found application in almost every area of synthetic organic chemistry. The biggest impact of this new method was probably observed in nanoscale architectures, giving rise to the new field of “acetylene scaffolding”. Here we present a summary of the underlying concepts and important strategies for the formation of acetylene‐phenyl bonds geared towards the assembly of nanoscale architectures illustrated with a few beautiful examples from the literature. It is not meant to be a comprehensive overview of the Sonogashira cross‐coupling reaction nor of the area of acetylene scaffolding but should serve as guide to the those new to the field. Starting with a short discussion of the reaction mechanism, appropriate choice of precursors is discussed. Introduction of chemoselectivity through the use of various leaving groups or by masking of their reactivity follows. The most common acetylene protection groups are summarised and compared in terms of their functional group tolerances and strategic concepts including orthogonality, sequential deprotection and in situ deprotection. Strategies for quick access to highly functionalised building blocks such as chemoselective halogenations and symmetry breaking are considered. Finally, the potential of the strategies discussed is documented with a few examples from the current literature.
Rapid and Efficient Radiosyntheses of meta‐Substituted [18F]Fluoroarenes from [18F]Fluoride Ion and Diaryliodonium ­Tosylates within a Microreactor
Authors: Chun Joong‐Hyun , Lu Shuiyu , Pike Victor W.
Published: June 2011

Effective methods for the introduction of the short‐lived positron‐emitter fluorine‐18 (t1/2 = 109.7 min) at high specific radioactivity into fluoroarenes are valuable for the development of radiotracers for molecular imaging with positron emission tomography. We have explored the scope of the radiofluorination of diaryliodonium salts with no‐carrier‐added (NCA) [18F]fluoride ion for the preparation of otherwise difficult to access meta‐substituted [18F]fluoroarenes. A microfluidic reaction platform was used to establish optimal radiochemical yields. Rapid, high yielding and selective radiofluorinations were achieved in unsymmetrical diaryliodonium tosylates (ArI+Ar′TsO–), in which Ar carried either a meta electron‐withdrawing (CN, NO2, CF3) or electron‐donating (Me or MeO) group, and in which the partner aryl group (Ar′) was relatively electron‐rich, such as Ph, 3‐MeC6H4, 4‐MeOC6H4, 2‐thienyl, or 5‐Me‐2‐thienyl. The radiofluorination of appropriate diaryliodonium tosylates is therefore a generally useful method for the preparation of simple [18F]m‐fluoroarenes ([18F]ArF).
Voltammetric Determination of 4‐Nitrophenol and 5‐Nitrobenzimidazole Using Different Types of Silver Solid Amalgam Electrodes – A Comparative Study
Authors: Deýlová Dana , Yosypchuk Bogdan , Vyskočil Vlastimil , Barek Jiří
Published: June 2011

The voltammetric behavior of two genotoxic nitro compounds (4‐nitrophenol and 5‐nitrobenzimidazole) has been investigated using direct current voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam electrode (p‐AgSAE), a mercury meniscus modified silver solid amalgam electrode (m‐AgSAE), and a mercury film modified silver solid amalgam electrode (MF‐AgSAE). The optimum conditions have been evaluated for their determination in Britton‐Robinson buffer solutions. The limit of quantification (LQ) for 5‐nitrobenzimidazole at p‐AgSAE was 0.77 µmol L−1 (DCV) and 0.47 µmol L−1 (DPV), at m‐AgSAE it was 0.32 µmol L−1 (DCV) and 0.16 µmol L−1 (DPV), and at MF‐AgSAE it was 0.97 µmol L−1 (DCV) and 0.70 µmol L−1 (DPV). For 4‐nitrophenol at p‐AgSAE, LQ was 0.37 µmol L−1 (DCV) and 0.32 µmol L−1 (DPV), at m‐AgSAE it was 0.14 µmol L−1 (DCV) and 0.1 µmol L−1 (DPV), and at MF‐AgSAE, it was 0.87 µmol L−1 (DCV) and 0.37 µmol L−1 (DPV). Thorough comparative studies have shown that m‐AgSAE is the best sensor for voltammetric determination of the two model genotoxic compounds because it gives the lowest LQ, is easier to prepare, and its surface can be easily renewed both chemically (by new amalgamation) and/or electrochemically (by imposition of cleaning pulses). The practical applicability of the newly developed methods was verified on model samples of drinking water.
Effect of elevated temperatures on mechanical properties of high‐strength concrete containing varying proportions of hematite
Authors: Gencel Osman
Published: June 2011

Aggregates typically constitute 70 to 80 wt% of concrete, and therefore their type, size, and structure play an essential role in modifying the properties of concrete. When concrete is used for shielding nuclear applications, temperature is also a key factor. This study investigates the effects of elevated temperatures (25 °C, 200 °C, 400 °C, 600 °C, and 800 °C), heating durations (1, 2, and 3 h), and cooling regimes (air, and water cooling) on mechanical properties of concrete containing different proportions of hematite. A sample of plain concrete was produced for comparison purposes by using river sand, crushed sand, and crushed aggregates. Replacement ratios of 15%, 30%, 45%, and 60% were used for hematite aggregates. The cement content and water–cement ratio were 450 kg/m3 and 0.38, respectively. Slump values of fresh concretes as well as unit weight, compressive strength, flexural strength, splitting tensile strength, and elasticity modulus values of hardened concrete were determined. The addition of hematite into concrete seems to improve its mechanical properties, and hematite concretes have better thermal stability at elevated temperatures than plain concrete does. Copyright © 2011 John Wiley & Sons, Ltd.
β8 integrin is essential for neuroblast migration in the rostral migratory stream
Authors: Mobley Aaron K. , McCarty Joseph H.
Published: June 2011

Neurogenesis in the post‐natal brain occurs in two primary locations: the subgranular layer of the hippocampal dentate gyrus and the subventricular zone (SVZ) of the lateral ventricles. Following differentiation, neuroblasts within the SVZ migrate several millimeters to the olfactory bulbs (OBs) via a distinct anatomic route, or rostral migratory stream (RMS). The genes that govern neuroblast directional migration, and particularly those encoding cell adhesion and signaling factors, remain largely uncharacterized. Here, we report that the extracellular matrix adhesion receptor, β8 integrin, is essential for proper neuroblast chain formation and directional navigation in the RMS. Primary neuroblasts isolated from the mouse brain express robust levels of β8 integrin protein, and selective ablation of β8 integrin gene expression in neuroblasts leads to aberrant chain migration and size‐reduced OBs. These integrin‐dependent defects can be recapitulated ex vivo using isolated neurospheres or SVZ explants. Collectively, these data identify essential cell‐intrinsic functions for β8 integrin in regulating neuroblast polarity and directional navigation in the mouse forebrain. © 2011 Wiley‐Liss, Inc.
Evidence for intact local connectivity but disrupted regional function in the occipital lobe in children and adolescents with schizophrenia
Authors: White Tonya , Moeller Steen , Schmidt Marcus , Pardo Jose V. , Olman Cheryl
Published: June 2011

It has long been known that specific visual frequencies result in greater blood flow to the striate cortex. These peaks are thought to reflect synchrony of local neuronal firing that is reflective of local cortical networks. Since disrupted neural connectivity is a possible etiology for schizophrenia, our goal was to investigate whether localized connectivity, as measured by aberrant synchrony, is abnormal in children and adolescents with schizophrenia. Subjects included 25 children and adolescents with schizophrenia and 39 controls matched for age and gender. Subjects were scanned on a Siemens 3 Tesla Trio scanner while observing flashing checkerboard presented at either 1, 4, 8, or 12 Hz. Image processing included both a standard GLM model and a Fourier transform analysis. Patients had significantly smaller volume of activation in the occipital lobe compared to controls. There were no differences in the integral or percent signal change of the hemodynamic response function for each of the four frequencies. Occipital activation was stable during development between childhood and late adolescence. Finally, both patients and controls demonstrated an increased response between 4 and 8 Hz consistent with synchrony or entrainment in the neuronal response. Children and adolescents with schizophrenia had a significantly lower volume of activation in the occipital lobe in response to the flashing checkerboard task. However, features of intact local connectivity in patients, such as the hemodynamic response function and maximal response at 8 Hz, were normal. These results are consistent with abnormalities in regional connectivity with preserved local connectivity in early‐onset schizophrenia. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc
Temporally remote destabilization of prediction after rare breaches of expectancy
Authors: Kühn Anne B. , Schubotz Ricarda I.
Published: June 2011

While neural signatures of breaches of expectancy and their immediate effects have been investigated, thus far, temporally more remote effects have been neglected. The present fMRI study explored neural correlates of temporally remote destabilization of prediction following rare breaches of expectancy with a mean delay of 14 s. We hypothesized temporally remote destabilization to be reflected either in an attenuation of areas related to long‐term memory or in an increase of lateral fronto‐parietal loops related to the encoding of new stimuli. Monitoring a deterministic 24‐digit sequence, subjects were asked to indicate occasional sequential omissions by key press. Temporally remote destabilization of prediction was expected to be revealed by contrasting sequential events whose equivalent was omitted in the preceding sequential run n‐1 (destabilized events) with sequential events without such history (nondestabilized events). Temporally remote destabilization of prediction was reflected in an attenuation of activity in the dorsal frontomedian cortex (Brodmann Area (BA) 9) bilaterally. Moreover, activation of the left medial BA 9 was enhanced by contrasting nondestabilized events with breaches. The decrease of dorsal frontomedian activation in the case of destabilized events might be interpreted as a top‐down modulation on perception causing a less expectation‐restricted encoding of the current stimulus and hence enabling the adaptation of expectation and prediction in the long run. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc
The concentration index of a binary outcome revisited
Authors: Wagstaff Adam
Published: June 2011

The binary variable is one of the most common types of variables in the analysis of income‐related health inequalities. I argue that while the binary variable has some unusual properties, it shares many of the properties of the ratio–scale variable and hence lends itself to both relative and absolute inequality analyses, albeit with some qualifications. I argue that criticisms of the normalization I proposed in an earlier paper, and of the use of the binary variable for inequality analysis, stem from a misrepresentation of the properties of the binary variable, as well as a switch of focus away from relative inequality to absolute inequality. I concede that my normalization is not uncontentious, but, in a way, that has not previously been noted. Copyright © 2011 John Wiley & Sons, Ltd.
Novel Compounds with a Viologen Skeleton and N‐Heterocycles on the Peripheries: Electrochemical and Spectroscopic Properties
Authors: Asaftei Simona , Lepadatu Ana Maria , Ciobanu Marius
Published: June 2011

The present article deals with novel compounds comprising a redox‐active group as core and a nucleobase in the peripheries, linked covalently via a spacer. The new derivatives 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[3‐(3,4‐dihydro‐5‐methyl‐2,4‐dioxopyrimidin‐1(2H)‐yl)propyl]‐4,4′‐bipyridinium} hexafluorophosphate (1), 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[2‐(4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidine‐7‐yl)ethyl]‐4,4′‐bipyridinium} hexachloride (2a)

The numbering of the pyrrolo[2,3‐d]pyrimidine system follows the IUPAC rules and is different from that of the purine ring system.

, and 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[2‐(2‐amino‐4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidine‐7‐yl)ethyl]‐4,4′‐bipyridinium} hexabromide (2b)1) were synthesized by nucleobase‐anion alkylation and linked to the 4,4′‐bipyridinium core. UV and CV analyses of these compounds were performed and revealed significantly different properties.
Beilschmiedic Acids F and G, Further Endiandric Acid Derivatives from Beilschmiedia anacardioides
Authors: Chouna Jean Rodolphe , Alango Nkeng‐Efouet Pepin , Ndjakou Lenta Bruno , Duplex Wansi Jean , Neumann Beate , Stammler Hans‐Georg , Fon Kimbu Samuel , Sewald Norbert
Published: June 2011

Two new endiandric acid derivatives, beilschmiedic acid F (1) and beilschmiedic acid G (2), together with three known constituents, beilschmiedic acid A, beilschmiedic acid C, and sitosterol 3‐β‐D‐glucopyranoside, were isolated from the stem bark of Beilschmiedia anacardioides. Their structures were elucidated mainly by using a combination of 1D‐ and 2D‐NMR techniques. The structure and relative configuration of beilschmiedic acid G (2) was also confirmed by X‐ray crystallographic analysis.
Two New Megastigmane Glycosides and a New Iridoid Glycoside from Gelsemium elegans
Authors: Zhang Qiu‐Ping , Zhang Bin‐Feng , Chou Gui‐Xin , Wang Zheng‐Tao
Published: June 2011

Two new megastigmane glycosides, eleganosides A and B (1 and 3, resp.), and one new iridoid glycoside, gouwenoside A (4), together with two known compounds, foliasalacioside B1 (2) and loganin (5), were isolated from the aerial parts of Gelsemium elegans (Gardn. et Champ.) Benth. (Loganiaceae). Their structures were elucidated by spectroscopic methods including 1D‐ and 2D‐NMR techniques. The absolute configuration of 1 was determined by CD spectroscopy.
Oleanane‐Type Triterpenoids from the Endophytic Fungus Pestalotiopsis clavispora Isolated from the Chinese Mangrove Plant Bruguiera sexangula
Authors: Luo Du‐Qiang , Deng Hui‐Ying , Yang Xiao‐Long , Shi Bao‐Zhong , Zhang Jing‐Ze
Published: June 2011

Three new triterpenoid derivatives, named (15α)‐15‐hydroxysoyasapogenol B (1), (7β,15α)‐7,15‐dihydroxysoyasapogenol B (2), and (7β)‐7,29‐dihydroxysoyasapogenol B (3), were isolated from cultures of the plant endophytic fungus Pestalotiopsis clavispora. Their structures and relative configurations were elucidated by extensive spectroscopic analysis and X‐ray crystallography.
One‐Pot Synthesis of 2‐Substituted 4‐Aryl‐4,5‐dihydro‐3,1‐benzoxazepines from 2‐(2‐Aminophenyl)‐1‐arylethanols via Dehydration of the Corresponding Amides
Authors: Fukamachi Shuhei , Konishi Hisatoshi , Kobayashi Kazuhiro
Published: June 2011

An efficient method for the preparation of 2‐substituted 4‐aryl‐4,5‐dihydro‐3,1‐benzoxazepine derivatives under mild conditions has been developed. The reaction of 2‐(2‐aminophenyl)ethanols 1 with acid chlorides in the presence of excess Et3N in THF at room temperature gave the corresponding N‐acylated intermediates 2, which were dehydrated by treatment with POCl3 to give 2‐substituted 4‐aryl‐4,5‐dihydro‐3,1‐benzoxazepines 3 in a one‐pot reaction.
Resveratrol‐induced apoptosis is enhanced in low pH environments associated with cancer
Authors: Shamim Uzma , Hanif Sarmad , Albanyan Abdulmajeed , Beck Frances W.J. , Bao Bin , Wang Zhiwei , Banerjee Sanjeev , Sarkar Fazlul H. , Mohammad Ramzi M. , Hadi Sheikh M. , Azmi Asfar S.
Published: June 2011

Many critical factors such as hypoxia, nutrient deficiency, activation of glycolytic pathway/Warburg effect contribute to the observed low pH in tumors compared to normal tissue. Studies suggest that such tumor specific acidic environment can be exploited for the development of therapeutic strategies against cancer. Independent observations show reduction in pH of mammalian cells undergoing internucleosomal DNA fragmentation and apoptosis. As such, our group has extensively demonstrated that anticancer mechanisms of different plant polyphenols involve mobilization of endogenous copper and consequent internucleosomal DNA breakage. Copper is redox active metal, an essential component of chromatin and is sensitive to subtle pH changes in its microenvironment. Here we explored whether, acidic pH promotes growth inhibition, apoptosis, and DNA damaging capacity of chemopreventive agent resveratrol. Our results reveal that growth inhibition and internucleosomal DNA fragmentation induced apoptosis in Capan‐2 and Panc‐28 pancreatic cancer cell lines (and not in normal HPDE cells) by resveratrol is enhanced at lower pH. Using comet assay, we further demonstrate that DNA breakage by resveratrol is enhanced with acidification. Membrane permeable copper specific chelator neocuproine (and not iron chelator orthophenanthroline) abrogated growth inhibition and apoptosis by resveratrol. Western blot results show enhanced activation of DNA laddering marker H2.aX by resveratrol at acidic pH that was reversed by neocuproine and not by orthophenanthroline. Our findings provide irrevocable proof that low pH environment can be turned into tumor weakness and assist in eradication of cancer cells by resveratrol. J. Cell. Physiol. 227: 1493–1500, 2012. © 2011 Wiley Periodicals, Inc.
Hsp22 (HspB8/H11) knockdown induces sam68 expression and stimulates proliferation of glioblastoma cells
Authors: Modem Suhasini , Chinnakannu Kannagi , Bai Uma , Reddy G. Prem‐Veer , Reddy Thipparthi R.
Published: June 2011

Sam68 (Src‐associated protein in mitosis 68 kDa) is a multifunctional protein, known to govern cellular signal transduction, transcription, RNA metabolism, proliferation, apoptosis, and HIV‐1 replication. Although intrinsic mechanisms that modulate Sam68 function are beginning to emerge, the regulatory events contributing to its expression remain elusive. We previously reported that heat shock protein‐22 (Hsp22) antagonizes Sam68 function in rev‐response element (RRE)‐mediated gene expression. We now demonstrate that Sam68 levels correlate inversely with Hsp22 in a variety of cells, including U87, Jurkat, 293T, and U‐937. In U87 glioblastoma cells, which contained high levels of Hsp22 than other cell lines tested, Hsp22 knockdown dramatically increased both Sam68 mRNA and protein, altered cellular morphology, and enhanced cell proliferation. This heightened proliferation was associated with a sharp decrease in G0/G1 and a corresponding increase in S and G2/M phases in exponentially growing cultures. The increased S phase population in turn correlated with enhanced expression of cell cycle regulatory proteins such as cyclin E, cyclin A, ribonucleotide reductase (RNR), and proliferating cell nuclear antigen (PCNA), which are required for the transition of cells from G1 to S phase. Collectively, our results demonstrate for the first time that Hsp22 regulates Sam68 expression and the ratio of Sam68 to Hsp22 may determine the proliferative potential of glioblastoma cells. J. Cell. Physiol. 226: 2747–2751, 2011. © 2011 Wiley‐Liss, Inc.
Inhibition of human methionine adenosyltransferase 1A transcription by coding region methylation
Authors: Tomasi Maria Lauda , Li Tony W.H. , Li Mei , Mato José M. , Lu Shelly C.
Published: June 2011

Two genes (MAT1A and MAT2A) encode for the essential enzyme methionine adenosyltransferase (MAT). MAT1A is silenced in hepatocellular carcinoma (HCC), and absence of MAT1A leads to spontaneous development of HCC in mice. Previous report correlated promoter methylation to silencing of MAT1A but definitive proof was lacking. Here we investigated the role of methylation in regulating MAT1A expression. There are three MspI/HpaII sites from −1,913 to +160 of the human MAT1A gene (numbered relative to the translational start site) at position −977, +10, and +88. Bisulfite treatment and DNA sequencing, and Southern blot analysis showed that methylation at +10 and +88, but not −977, correlated with lack of MAT1A expression. MAT1A promoter construct methylated at −977, +10 or +88 position has 0.7‐fold, 3‐fold, and 1.6‐fold lower promoter activity, respectively. Methylation at −977 and +10 did not inhibit the promoter more than methylation at +10 alone; while methylation at +10 and +88 reduced promoter activity by 60%. Mutation of +10 and +88 sites also resulted in 40% reduction of promoter activity. Reactivation of MAT1A correlated with demethylation of +10 and +88. In vitro transcription assay showed that methylation or mutation of +10 and +88 sites reduced transcription. In conclusion, our data support the novel finding that methylation of the MAT1A coding region can inhibit gene transcription. This represents a key mechanism for decreased MAT1A expression in HCC and a target for therapy. To our knowledge, this is the first example of coding region methylation inhibiting transcription of a mammalian gene. J. Cell. Physiol. 227: 1583–1591, 2012. © 2011 Wiley Periodicals, Inc.
Molecular characterization of myosin phosphatase in endothelium
Authors: Kim Kyung‐mi , Csortos Csilla , Czikora Istvan , Fulton David , Umapathy Nagavedi S. , Olah Gabor , Verin Alexander D.
Published: June 2011

The phosphorylation status of myosin light chain (MLC) is regulated by both MLC kinases and type 1 Ser/Thr phosphatase (PPase 1), MLC phosphatase (MLCP) activities. The activity of the catalytic subunit of MLCP (CS1β) towards myosin depends on its associated regulatory subunit, namely myosin PPase targeting subunit 1 (MYPT1). Our previously published data strongly suggested the involvement of MLCP in endothelial cell (EC) barrier regulation. In this study, our new data demonstrate that inhibition of MLCP by either CS1β or MYPT1 siRNA‐based depletion results in significant attenuation of purine nucleotide (ATP and adenosine)‐induced EC barrier enhancement. Consistent with the data, thrombin‐induced EC F‐actin stress fiber formation and permeability increase were attenuated by the ectopic expression of constitutively active (C/A) MYPT1. The data demonstrated for the first time direct involvement of MLCP in EC barrier enhancement/protection. Cloning of MYPT1 in human pulmonary artery EC (HPAEC) revealed the presence of two MYPT1 isoforms, long and variant 2 (V2) lacking 56 amino acids from 553 to 609 of human MYPT1 long, which were previously identified in HeLa and HEK 293 cells. Our data demonstrated that in Cos‐7 cells ectopically expressed EC MYPT1 isoforms co‐immunoprecipitated with intact CS1β suggesting the importance of PPase 1 activity for the formation of functional complex of MYPT1/CS1β. Interestingly, MYPT1 V2 shows decreased binding affinity compared to MYPT1 long for radixin (novel MLCP substrate and a member of ERM family proteins). These results suggest functional difference between EC MYPT1 isoforms in the regulation of MLCP activity and cytoskeleton. J. Cell. Physiol. 227: 1701–1708, 2012. © 2011 Wiley Periodicals, Inc.
Microalgae biodiesel via in situ methanolysis
Authors: Carvalho Júnior Rui M. , Vargas José V. C. , Ramos Luiz P. , Marino Cláudia E. B. , Torres Jonas C. L.
Published: June 2011

BACKGROUND: Microalgae have recently been considered a potential feedstock for biodiesel production, since they do not compete with agricultural land, unlike oil crops. However, the production processes must be energetically and economically viable. Therefore, an in situ methanolysis process is proposed for biodiesel production directly from microalgae biomass, to avoid the need for the separation and extraction steps.

RESULTS: Biodiesel was obtained using methanol as the methylation reactant for the transesterification reaction and hydrochloric acid as the catalyst precursor, at 80 °C for 2 h of reaction. A mass return of 23.07 ± 2.76% (m/m) was obtained. Spectrometry in the infrared region showed that the product had equivalent bands of axial deformation of CO, CO and CH, i.e. an ester. Tests showed the chromatographic profile of fatty acids in the sample. A process energetic efficiency value of 1.17 was obtained for microalgae derived biodiesel, which is higher than from soybean and sunflower, reportedly 1.06 and 1.12.

CONCLUSIONS: Industrial sustainability results from low energetic, economic and environmental losses. The microalgae in situ methanolysis process showed greater fuel available energy than energy consumption, therefore is energetically sustainable. Economic and environmental issues should still be addressed. Copyright © 2011 Society of Chemical Industry
Assessing the use of xylanase and laccases in biobleaching stages of a TCF sequence for flax pulp
Authors: Fillat Amanda , Roncero M. Blanca , Vidal Teresa
Published: June 2011

BACKGROUND: In this study, two different laccases were used in combination with various mediators as biobleaching agents in a TCF sequence for flax fibre and pulp. Thus, non‐commercial laccase from Pycnoporus cinnabarinus (PcL) was used with the synthetic mediator violuric acid (VA) or the natural mediator syringaldehyde (SA), and commercial laccase from Myceliophthora thermophila (MtL) was used with the natural mediator methyl syringate (MS). Each laccase–mediator treatment was used in the following TCF bleaching sequence: LQPo (Q denoting a chelating stage and Po a pressurized alkaline peroxide treatment). Also, a xylanase pretreatment was carried out for first time here to assess its effect on flax fibre. Pulp (kappa number, viscosity and brightness) and effluent properties (COD, colour, residual activity and toxicity) were determined after each bleaching stage. The hexenuronic acid (HexA) content of the pulp was also determined to assess its integrity.

RESULTS: The best L stage was PcL + VA, which provided a final brightness and kappa number of 81% ISO and 1.3, respectively. Using a xylanase pretreatment was found to efficiently remove HexA and enhance delignification by laccase (final kappa number 0.7).

CONCLUSIONS: These results warrant upscaling any of these biobleaching sequences for flax pulp as they provide environmentally sustainable flax fibre with a high cellulose content and brightness above 80% ISO. Copyright © 2011 Society of Chemical Industry
Topography of four different endodontic rotary systems, before and after being used for the 12th time
Authors: Yamazaki‐Arasaki Andréa , Cabrales Ricardo , Santos Marcelo Dos , Kleine Brígida , Prokopowitsch Igor
Published: June 2011

Root canal preparation may damage NiTi instruments resulting in wear and deformation. The aim of this study was to make a comparative evaluation of the surface topography of the cervical third of four different rotary systems, before and after being used twelve times, in 1.440 resin blocks with simulated root canals with standardized 45° curvatures, and analyzed by atomic force microscopy – AFM. The blocks were divided into four groups and prepared according to the manufacturers recommendations: Group 1 ‐ K3®; Group 2 ‐ Protaper Universal®; Group 3 ‐ Twisted Files® and Group 4 ‐ Biorace®. After each preparation, the instruments were washed and autoclaved. A total of 240 instruments were selected, being 30 new instruments and 30 after having been used for the 12th time, from each group. These instruments were analyzed by AFM and for quantitative evaluation, the mean RMS (Root mean square) values of the cervical third of the specimens from the four groups were used. The result showed that all the rotary files used for the 12th time suffered wear with change in the topography of the cervical region of the active portion of the file (ANOVA p < 0.01). Classifying the specimens in increasing order, from the least to the greatest wear suffered, Group 3 (2.8993 nm) presented the least wear, followed by Group 4 (12.2520 nm), Group 1 (36.0043 nm) and lastly, Group 2 (59.8750 nm) with the largest amount of cervical surface wear. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Neurotrophin Trk receptors in the brain of a teleost fish, Nothobranchius furzeri
Authors: D'Angelo Livia , de Girolamo Paolo , Cellerino Alessandro , Tozzini Eva Terzibasi , Castaldo Luciana , Lucini Carla
Published: June 2011

Trk neurotrophin receptors are transmembrane tyrosine kinase proteins known as TrkA, TrkB, and TrkC. TrkA is the high affinity receptor for nerve growth factor, TrkB is the one for both brain‐derived neurotrophic factor and neurotrophin‐4, and TrkC is the preferred receptor for neurotrophin‐3. In the adult mammalian brain, neurotrophins are important regulators of neuronal function and plasticity. This study is based on Nothobranchius furzeri, a teleost fish that is becoming an ideal candidate as animal model for aging studies because its life expectancy in captivity is of just 3 months. In adult N. furzeri, all three investigated neurotrophin Trk receptors were immunohistochemically detected in each brain region. TrkA positive neuronal perikarya were localized in the dorsal and ventral areas of the telencephalon and in the cortical nucleus; TrkB immunoreactivity was observed in neuronal perikarya of the dorsal and ventral areas of the telencephalon, the diffuse inferior lobe of the hypothalamus, and Purkinje cells; TrkC positive neuronal perikarya were detected in the most aboral region of the telencephalon, in the magnocellular preoptic nucleus and in few neurons dispersed in the hypothalamus. Numerous positive fibers were widely distributed throughout the brain. Radial glial cells lining the mesencephalic and rhombencephalic ventricles showed immunoreactivity to all three Trks. These findings suggest an involvement of neurotrophins in many aspects of biology of adult N. furzeri. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Enhanced delivery of monomethoxypoly(ethylene glycol)‐poly(lactic‐co‐glycolic acid)‐poly l‐lysine nanoparticles loading platelet‐derived growth factor BB small interfering RNA by ultrasound and/or microbubbles to rat retinal pigment epithelium cells
Authors: Du Jing , Shi Qiu Sheng , Sun Ying , Liu Pei Feng , Zhu Ming Jie , Du Lian Fang , Duan You Rong
Published: June 2011

Background

A novel small interfering RNA (siRNA) delivery method based on the combined use of nanoparticles (NPs) with ultrasound (US) and/or microbubbles (MBs) was introduced in the present study. We investigated the efficacy and safety of US and/or MBs‐enhanced delivery of monomethoxypoly(ethylene glycol)‐poly(lactic‐co‐glycolic acid)‐poly l‐lysine (mPEG‐PLGA‐PLL) NPs loading platelet‐derived growth factor BB (PDGF‐BB) siRNA to rat retinal pigment epithelium (RPE)‐J cells.

Methods

The effect of US and/or MBs on the delivery of NPs containing Cy3‐labeled siRNA was evaluated by fluorescence microscopy and flow cytometry. Potential toxicity of NPs and cell viability under different conditions of US and/or MBs were assessed by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide method.

Results

The results obtained showed that low intensity US or 15–20% MBs could increase the delivery efficiency of a lower concentration of mPEG‐PLGA‐PLL NPs loading siRNA to RPE‐J cells, whereas the combination of US with MBs under the optimal conditions for the enhancement of NPs delivery did not further increase the cellular uptake of NPs compared to either US or MBs alone (p = 0.072 and p = 0.488, respectively). Under the optimal condition for US‐enhanced NPs delivery, the enhanced PDGF‐BB gene silencing with a combination of US and NPs encapsulating siRNA resulted in a significant decrease of mRNA and protein expression levels compared to NPs alone.

Conclusions

US and/or MBs could be used safely to enhance the delivery of NPs loading siRNA to rat RPE‐J cells. A combination of the chemical (mPEG‐PLGA‐PLL NPs loading siRNA) and physical (US) approaches could more effectively downregulate the mRNA and protein expression of PDGF‐BB. Copyright © 2011 John Wiley & Sons, Ltd.
Structural identification of SAR‐943 metabolites generated by human liver microsomes in vitro using mass spectrometry in combination with analysis of fragmentation patterns
Authors: Strom Tobin , Shokati Touraj , Klawitter Jost , Klawitter Jelena , Hoffman Keith , Schiebel Hans‐Martin , Christians Uwe
Published: June 2011

SAR‐943 (32‐deoxo rapamycin) is a proliferation signal inhibitor via interaction with the mammalian target of rapamycin (mTOR). Most importantly, SAR‐943 has improved chemical stability compared to rapamycin (sirolimus) and is currently under investigation as a drug coated on coronary stents. It was the goal of this study to identify the SAR‐943 metabolites generated after incubation with human liver microsomes using high‐resolution mass spectrometry (MS) and MS/iontrap (MSn) and comparison of fragmentation patterns of the metabolites with those of SAR‐943 and other known rapamycin derivatives. Our study showed that SAR‐943 is mainly hydroxylated and/or demethylated by human liver microsomes. The structures of the following metabolites were identified: O‐demethylated metabolites: 39‐O‐desmethyl, 16‐O‐desmethyl and 27‐O‐desmethyl SAR‐943; hydroxylated metabolites: hydroxy piperidine SAR‐943, 11‐hydroxy, 12‐hydroxy, 14‐hydroxy, 23‐hydroxy, 24‐hydroxy, 25‐hydroxy, 46‐hydroxy and 49‐hydroxy SAR‐943; didemethylated metabolites: 16,39‐O‐didesmethyl and 27,39‐O‐didesmethyl SAR‐943; demethylated‐hydroxylated metabolites: 39‐O‐desmethyl, 23‐ or 24‐hydroxy and 39‐O‐desmethyl, hydroxy piperidine SAR‐943 and dihydroxylated metabolites: 12‐,23‐ or 24‐dihydroxy SAR‐943. In addition, several other demethylated‐hydroxylated and dihydroxylated metabolites were detected. However, their exact structures could not be identified. Copyright © 2011 John Wiley & Sons, Ltd.
Low‐level persistence of human papillomavirus 16 DNA in a cohort of closely followed adolescent women
Authors: Weaver B. , Shew M. , Qadadri B. , Tu W. , Tong Y. , Denski C. , Fortenberry J.D. , Ermel A. , Brown D.
Published: June 2011

Most human papillomavirus (HPV) infections in young women become undetectable by standard assays after a few months. It is possible that many HPV infections do not actually clear, but persist at very low levels for years, becoming detected again later in life. The purpose of this study is to describe HPV 16 clearance, reappearance, and low‐level persistence in a cohort of adolescent women. Adolescent women (N = 66), not vaccinated against HPV, were recruited from 1998 to 2008 into a longitudinal study. Self‐collected vaginal samples were obtained quarterly and tested for HPV by Linear Array HPV Genotyping Test (LA‐HPV). To explore low‐level persistence, a type‐specific nested PCR for HPV 16 (TSN‐PCR‐16) was developed. Women with HPV 16 detected by LA‐HPV had their negative swabs retested with TSN‐PCR‐16. Forty‐two participants with HPV 16, followed for a mean of 6.3 years, were analyzed. Using LA‐HPV, the median duration of HPV 16 detection was 428 days (SD 852.5 days). TSN‐PCR‐16 detected HPV 16 during periods of LA‐HPV non‐detection in samples from many women. Using a combination of LA‐HPV and TSN‐PCR‐16 results, the median duration of HPV 16 detection was 1,022.5 days (SD 943.7 days). The durations of detection differed significantly between the two methods (P = 0.0042) with a mean difference of 434.5 days. In adolescent females, duration of HPV 16 detection was significantly longer when TSN‐PCR‐16 was combined with LA‐HPV. Some apparently cleared HPV 16 could be shown to persist at low levels using nested PCR. J. Med. Virol. 83:1362–1369, 2011. © 2011 Wiley‐Liss, Inc.
Characterization of hepatitis B virus in turkish blood donors, and the prevalence of the SP1 splice variant
Authors: Cox Laura E. , Arslan Önder , Allain Jean‐Pierre
Published: June 2011

Hepatitis B is a disease of the liver that can manifest acutely, or persist chronically as a result of infection with the hepatitis B virus (HBV). Turkey has a moderate endemicity level of HBV infection, and all data published to date has shown this to be of genotype D, predominantly of subgenotype D1. However the sequences of very few full genomes have been published. The aim of this study was to characterize the molecular profile of hepatitis B virus in asymptomatic, first‐time Turkish blood donors. The results confirm that genotype D, subgenotype D1 is the most prevalent HBV strain in Turkey, accounting for 94% of cases. Subgenotypes D2 and D3 were present as minority strains (4% and 2%, respectively). A singly spliced HBV variant that is capable of forming defective HBV particles and has been associated with apoptosis and activation of T‐cell responses was also detected in 52.5% of samples screened, co‐circulating with wild type genomes. J. Med. Virol. 83:1321–1325, 2011. © 2011 Wiley‐Liss, Inc.