bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmembrane peptides used to investigate the homo‐oligomeric interface and binding hotspot of latent membrane protein 1
Authors: Sammond Deanne W. , Joce Catherine , Takeshita Ryan , McQuate Sarah E. , Ghosh Nilanjan , Martin Jennifer M. , Yin Hang 
Published: May 2011

AbstractEpstein‐Barr virus (EBV), a human γ‐herpesvirus, establishes lifelong infection by targeting the adaptive immune system of the host through memory B cells. Although normally benign, EBV contributes to lymphoid malignancies and lymphoproliferative syndromes in immunocompromised individuals. The viral oncoprotein latent membrane protein 1 (LMP‐1) is essential for B lymphocyte immortalization by EBV. The constitutive signaling activity of LMP‐1 is dependent on homo‐oligomerization of its six‐spanning hydrophobic transmembrane domain (TMD). However, the mechanism driving LMP‐1 intermolecular interaction is poorly understood. Here, we show that the fifth transmembrane helix (TM5) of LMP‐1 strongly self‐associates, forming a homotrimeric complex mediated by a polar residue embedded in the membrane, D150. Replacement of this aspartic acid residue with alanine disrupts TM5 self‐association in detergent micelles and bacterial cell membranes. A full‐length LMP‐1 variant harboring the D150A substitution is deficient in NFκB activation, supporting the key role of the fifth transmembrane helix in constitutive activation of signaling by this oncoprotein. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 772‐784, 2011.
Changing clinical and pathological features of gastric cancer over time
Authors: Marrelli D , Pedrazzani C , Morgagni P , de Manzoni G , Pacelli F , Coniglio A , Marchet A , Saragoni L , Giacopuzzi S , Roviello F 
Published: May 2011

Abstract

Background
The aim of the present multicentre observational study was to evaluate potential changes in clinical and pathological features of patients with gastric cancer (GC) treated in a 15-year interval.

Methods
A centralized prospective database including clinical, surgical, pathological and follow-up data from 2822 patients who had resection of a primary GC was analysed. The analysis focused on three periods: 1991–1995 (period 1), 1996–2000 (period 2) and 2001–2005 (period 3). Surgical procedure, pathological classification and follow-up were standardized among centres.

Results
The number of resections decreased from 1024 in period 1 to 955 and 843 in periods 2 and 3 respectively. More advanced stages and a smaller number of intestinal-type tumours of the distal third were observed over time. Five-year survival rates after R0 resection (2320 patients) did not change over time (overall: 56·6 and 51·2 per cent in periods 1 and 3; disease-free: 66·8 and 61·1 per cent respectively). Decreases in survival in more recent years were related particularly to more advanced stage, distal tumours and tumours in women. Multivariable analysis showed a lower probability of overall and disease-free survival in the most recent interval: hazard ratio 1·22 (95 per cent confidence interval 1·06 to 1·40) and 1·29 (1·06 to 1·58) respectively compared with period 1. Recurrent tumours were more frequently peritoneal rather than locoregional.

Conclusion
Overall and disease-free survival rates after R0 resection of GC were unchanged over time.
Value of orientation training in laparoscopic cholecystectomy
Authors: Sodergren M H , Orihuela-Espina F , Froghi F , Clark J , Teare J , Yang G Z , Darzi A 
Published: May 2011

Abstract

Background
It is well established that disorientation during laparoscopic operations such as cholecystectomy is associated with increased morbidity and mortality. The aim of the present study was to evaluate whether high-performance orientation strategies could be taught to a cohort without relevant experience of laparoscopic cholecystectomy, resulting in improved performance and spatial awareness, thereby reducing the need for operative experience to command this skill.

Methods
Thirty medical students participated in a randomized controlled trial, with half randomized to a tutorial teaching orientation strategies at specific stages of laparoscopic cholecystectomy and half to a control group without any teaching. Attention as represented by gaze was captured using eye tracking as subjects were presented with 12 images of various stages of the operation, with the task of interpreting the orientation of the image. The primary outcome measure was subject performance in orientation. Secondary outcome measures were gaze dwell time on relevant anatomical structures within the images and comparison of individual behaviour using a visual behaviour profiling algorithm.

Results
The intervention group was significantly more likely to orientate correctly than the control group (mean 75·6 versus 56·1 per cent; P = 0·019). A difference in visual attention behaviour between the two groups was apparent for the majority of images when examining the output of the visual profiling algorithm, in the form of increased homogeneity of visual behaviour and/or an overall difference in orientation strategy. The mean orientation rate of all surgeons under identical conditions in a previously published study was 78·6 per cent.

Conclusion
Training novices in orientation strategies improved their performance significantly and it could reach the level of a surgeon with several years of experience in laparoscopic surgery.
Chemical Constituents of Cordia latifolia and Their Nematicidal Activity
Authors: Begum Sabira , Perwaiz Sobiya , Siddiqui Bina S. , Khan Shazia , Fayyaz Shahina , Ramzan Musarrat 
Published: May 2011

AbstractFollowing nematicidal activity‐guided isolation studies on the fruits, bark, and leaves of Cordia latifolia, two new constituents, cordinoic acid (=11‐oxours‐12‐ene‐23,28‐dioic acid; 1) and cordicilin (=2‐{[(E)‐3‐(3,4‐dihydroxyphenyl)prop‐2‐enoyl]oxy}‐3‐[4‐hydroxy‐3‐(stearoyloxy)phenyl]propanoic acid; 2) were isolated from the stem and leaves, respectively, together with nine known compounds, namely cordioic and cordifolic acid from the stem bark, latifolicin A–D and rosmarinic acid from the fruits, and cordinol and cordicinol from the leaves. Their structures were determined by means of spectroscopic analyses including 1D‐ and 2D‐NMR techniques. The nematicidal activities of these constituents were determined against the root‐knot nematode Meloidogyne incognita. Hundred percent mortality was caused by all of these after 72 h at a 0.125% concentration. Compound 1 and cordioic acid were most active and caused 100% mortality after 24 h at a 0.50% concentration. Furthermore, compound 2, the ester of rosemarinic acid, was found to be more active than the free acid.
Synthesis, DNA Binding, and Cleavage Studies of Novel PNA Binding Cyclen Complexes
Authors: Zhang Yu , Wang Ming‐Qi , Zhang Ji , Zhang Da‐Wei , Lin Hong‐Hui , Yu Xiao‐Qi 
Published: May 2011

AbstractA novel coumarin‐appended PNA binding cyclen derivative ligand, C1, and its copper(II) complex, C2, have been synthesized and characterized. The interaction of these compounds with DNA was systematically investigated by absorption, fluorescence, and viscometric titration, and DNA‐melting and gel‐electrophoresis experiments. DNA Melting and viscometric titration experiments indicate that the binding mode of C1 is a groove binding, and C2 is a multiple binding mode that involves groove binding and electrostatic binding. From the absorption‐titration data, we can state that the primary interaction between CT DNA and the two compounds may be H‐bonds between nucleobases. Fluorescence studies indicate that the binding ability of C1 to d(A)9 is as twice or thrice as that of other oligodeoxynucleotides. Agarose gel‐electrophoresis experiments demonstrate that C2 is an excellent chemical nuclease, which can cleave plasmid DNA completely within 24 h.
Three New Cytochalasins from the Marine‐Derived Fungus Spicaria elegans KLA03 by Supplementing the Cultures with L‐ and D‐Tryptophan
Authors: Wang Fa‐Zuo , Wei Hong‐Juan , Zhu Tian‐Jiao , Li De‐Hai , Lin Zhen‐Jian , Gu Qian‐Qun 
Published: May 2011

AbstractThree new cytochalasins Z21–Z23 (1–3, resp.), together with five analogs, 4–8, were isolated from Spicaria elegans KLA03 by the OSMAC (one strain‐many compounds) approach with adding L‐ and D‐tryptophan during its cultivation. The structures of new cytochalasins were elucidated on the basis of comprehensive 1D‐ and 2D‐NMR and HR‐ESI‐MS analyses. Cytochalasins Z21 and Z22 (1 and 2, resp.), and compound 5 showed cytotoxic activities against A‐549 cell lines with IC50 values of 8.2, 20.0, and 3.1 μM, respectively.
Essential Oils of Medicinal Plants from the Central Andes of Argentina: Chemical Composition, and Antifungal, Antibacterial, and Insect‐Repellent Activities
Authors: Lima Beatriz , López Sandra , Luna Lorena , Agüero María B. , Aragón Liliana , Tapia Alejandro , Zacchino Susana , López María L. , Zygadlo Julio , Feresin Gabriela E. 
Published: May 2011

AbstractThe antifungal, antibacterial, and insect‐repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000 μg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC‐FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli‐1(6)‐en‐5‐one, and terpinen‐4‐ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector‐control.
Phytochemical and Morphological Characterization of Satureja khuzistanicaJamzad Populations from Iran
Authors: Hadian Javad , Hossein Mirjalili Mohammad , Reza Kanani Mohammad , Salehnia Alinazar , Ganjipoor Parvin 
Published: May 2011

AbstractSatureja khuzistanica is an endemic herb growing wild in Iran with interesting pharmacological and biological properties. Here, as an initial step of the domestication process, the variability of phytochemical and morphological traits among 69 individuals of eight natural populations of the plant was studied. The investigated characteristics were the essential oil content and composition, the rosmarinic acid (RA) content, and the leaf and flower morphologies. The Abdanan and Kaver populations showed the highest oil contents. The characterization by GC‐FID and GC/MS analyses of the oils revealed that all 69 sampled individuals had carvacrol as the main component with very high contents (89.59–95.41%). The content of RA of the MeOH extracts of S. khuzistanica showed a high level of variability (coefficient of variation (CV) 50.0%) ranging from 0.59% (w/w) in the Paalam population to 1.81% (w/w) in the Abdanan population. The peduncle length and the leaf surface area (CVs of 47.39 and 47.21%, resp.) were the most variable morphological characteristics among the examined populations. The high level of phytochemical and morphological variability among the studied populations suggests a breeding approach during the domestication, to gain new, promising, and homogenous cultivars, attractive for the industry and agriculture.
On the Terminal Homologation of Physiologically Active Peptides as a Means of Increasing Stability in Human Serum – Neurotensin, Opiorphin, B27‐KK10 Epitope, NPY
Authors: Seebach Dieter , Lukaszuk Aneta , Patora‐Komisarska Krystyna , Podwysocka Dominika , Gardiner James , Ebert Marc‐Olivier , Reubi Jean Claude , Cescato Renzo , Waser Beatrice , Gmeiner Peter , Hübner Harald , Rougeot Catherine 
Published: May 2011

AbstractThe terminal homologation by CH2 insertion into the peptides mentioned in the title is described. This involves replacement of the N‐terminal amino acid residue by a β2‐ and of the C‐terminal amino acid residue by a β3‐homo‐amino acid moiety (β2hXaa and β3hXaa, resp.; Fig. 1). In this way, the structure of the peptide chain from the N‐terminal to the C‐terminal stereogenic center is identical, and the modified peptide is protected against cleavage by exopeptidases (Figs. 2 and 3). Neurotensin (NT; 1) and its C‐terminal fragment NT(8–13) are ligands of the G‐protein‐coupled receptors (GPCR) NT1, NT2, NT3, and NT analogs are promising tools to be used in cancer diagnostics and therapy. The affinities of homologated NT analogs, 2b–2e, for NT1 and NT2 receptors were determined by using cell homogenates and tumor tissues (Table 1); in the latter experiments, the affinities for the NT1 receptor are more or less the same as those of NT (0.5–1.3 vs. 0.6 nM). At the same time, one of the homologated NT analogs, 2c, survives in human plasma for 7 days at 37° (Fig. 6). An NMR analysis of NT(8–13) (Tables 2 and 4, and Fig. 8) reveals that this N‐terminal NT fragment folds to a turn in CD3OH. – In the case of the human analgesic opiorphin (3a), a pentapeptide, and of the HIV‐derived B27‐KK10 (4a), a decapeptide, terminal homologation (→3b and 4b, resp.) led to a 7‐ and 70‐fold half‐life increase in plasma (Fig. 9). With N‐terminally homologated NPY, 5c, we were not able to determine serum stability; the peptide consisting of 36 amino acid residues is subject to cleavage by endopetidases. Three of the homologated compounds, 2b, 2c, and 5c, were shown to be agonists (Fig. 7 and 11). A comparison of terminal homologation with other stability‐increasing terminal modifications of peptides is performed (Fig. 5), and possible applications of the neurotensin analogs, described herein, are discussed.
The Transaldolase Family: New Synthetic Opportunities from an Ancient Enzyme Scaffold
Authors: Samland Anne K. , Rale Madhura , Sprenger Georg A. , Fessner Wolf‐Dieter 
Published: May 2011

AbstractAldol reactions constitute a powerful methodology for carbon–carbon bond formation in synthetic organic chemistry. Biocatalytic carboligation by aldolases offers a green, uniquely regio‐ and stereoselective tool with which to perform these transformations. Recent advances in the field, fueled by both discovery and protein engineering, have greatly improved the synthetic opportunities for the atom‐economic asymmetric synthesis of chiral molecules with potential pharmaceutical relevance. New aldolases derived from the transaldolase scaffold (based on transaldolase B and fructose‐6‐phosphate aldolase from Escherichia coli) have been shown to be unusually flexible in their substrate scope; this makes them particularly valuable for addressing an expanded molecular range of complex polyfunctional targets. Extensive knowledge arising from structural and molecular biochemical studies makes it possible to address the remaining limitations of the methodology by engineering tailored biocatalysts.
Synthesis, Characterization, and DNA‐Binding and ‐Photocleavage Properties of Water‐Soluble Lanthanide Porphyrinate Complexes
Authors: Zhu Xun‐Jin , Wang Ping , Leung Heidi Wing Chi , Wong Wai‐Kwok , Wong Wai‐Yeung , Kwong Daniel W. J. 
Published: May 2011

AbstractA series of cationic lanthanide porphyrinate complexes of the general formula [(Por)Ln(H2O)3]+ (Ln3+=Yb3+ and Er3+) were synthesized in moderate yields through the interaction of meso‐pyridyl‐substituted porphyrin free bases (H2Por) with [Ln{N(SiMe3)2}3]⋅x [LiCl(thf)3], and the corresponding neutral derivatives [(Por)Ln(LOMe)] (LOMe−=[(η5‐C5H5)Co{P(O)(OMe)2}3]−) were also prepared from [(Por)Ln(H2O)3]+ by the addition of the tripodal anion, LOMe−, an effective encapsulating agent for lanthanide ions. Furthermore, the water‐soluble lanthanide(III) porphyrinate complexes—including [(cis‐DMPyDPP)Yb(H2O)3]Cl3 (cis‐DMPyDPP=5,10‐bis(N‐methylpyridinium‐4′‐y1)‐15,20‐di(phenyl)porphyrin), [(trans‐DMPyDPP)Yb(H2O)3]Cl3 (trans‐DMPyDPP=5,15‐bis(N‐methylpyridinium‐4′‐y1)‐10,20‐di(phenyl)porphyrin), [(TMPyP)Yb(LOMe)]I4, and [(TMPyP)Er(LOMe)]I4 (TMPyP=tetrakis(N‐methylpyridinium‐4‐y1)porphyrin)—were obtained by methylation of the corresponding complexes with methyl iodide and unambiguously characterized. The binding interactions and photocleavage activities of the water‐soluble lanthanide(III) porphyrinate complexes towards DNA were investigated by UV‐visible, fluorescence, and near‐infrared luminescence spectroscopy, as well as circular dichroism and gel electrophoresis.
Analysis of Tertiary Phosphanes, Arsanes, and Stibanes as Bridging Ligands in Dinuclear Group 9 Complexes
Authors: Schinzel Sandra , Müller Robert , Riedel Sebastian , Werner Helmut , Kaupp Martin 
Published: May 2011

AbstractThe unusual bridging and semi‐bridging binding mode of tertiary phosphanes, arsanes, and stibanes in dinuclear low‐valent Group 9 complexes have been studied by density functional methods and bonding analyses. The influence of various parameters (bridging and terminal ligands, metal atoms) on the structural preferences and bonding of dinuclear complexes of the general composition [A1 M1(μ‐CH2)2(μ‐EX3)M2 A2] (M1, M2=Co, Rh, Ir; A1, A2=F, Cl, Br, I, κ2‐acac; E=P, As, Sb, X=H, F, CH3) has been analyzed. A number of factors have been identified that favor bridging or semi‐bridging modes for the phosphane ligands and their homologues. A more symmetrical position of the bridging ligand EX3is promoted by more polar EX bonding, but by less electronegative (softer) terminal anionic ligands. Among the Group 9 metal elements Co, Rh, and Ir, the computations clearly show that the 4d element rhodium exhibits the largest preference for a {M1(μ‐EX3)M2} bridge, in agreement with experimental observation. Iridium complexes should be valid targets, whereas cobalt does not seem to support well a symmetric bridging mode. Analyses of the Electron Localization Function (ELF) indicate a competition between a delocalized three‐center bridge bond and direct metal–metal bonding.
Electron Delocalization in Homoconjugated 7,7‐Diarylnorbornane Systems: A Computational and Experimental Study
Authors: Herrero‐García Noelia , Fernández Israel , Osío Barcina José 
Published: May 2011

AbstractA joint computational–experimental study has been carried out to analyze the homoconjugative interactions in 7,7‐diarylnorbornane (DPN) derivatives. The experimentally observed new bands in their UV/Vis have been accurately assigned by means of TD‐DFT calculations. Both experimental data and computations show that aromatic homoconjugation in acyclic systems is an effective mechanism for electron delocalization that resembles the situation described for polyphenylenes and polyenes. The effective homoconjugation length in homoconjugated oligomers is in the range of 6–7 aryl rings. The effect of substituents directly attached to the para carbon atom of the DPN moiety have been also studied. We found that the HOMO→LUMO vertical transitions can indeed be modified by the nature of the aromatic substituents in order to provoke dramatic changes in the electronic properties (i.e., in the absorption spectra) of the studied species.
Synthesis and Characterization of Red‐Luminescent Graphene Oxide Functionalized with Silica‐Coated Eu3+ Complex Nanoparticles
Authors: Zhao Chao , Feng Lingyan , Xu Bailu , Ren Jinsong , Qu Xiaogang 
Published: May 2011

AbstractTraditional dye‐doped fluorescent graphene oxide (GO) reveals a low quantum yield and a short life expectancy. Herein, red‐luminescent silica‐coated Eu3+ complex nanoparticles were synthesized and covalently coupled to GO nanosheets by means of a carbodiimide‐mediated amidation process. SEM and TEM studies demonstrated successful attachment of the silica‐coated Eu3+ complex nanoparticles onto the GO surface. Spectroscopic studies showed that the GO–nanoparticle conjugates exhibit strong luminescence, long lifetimes, as well as good photostability, which suggests that this new type of luminescent nanomaterial has the potential for highly sensitive time‐resolved fluorescence cyto‐ and histochemistry imaging.
Multiplex Detection of Endonucleases by Using a Multicolor Gold Nanobeacon
Authors: Huang Yong , Zhao Shulin , Liang Hong , Chen Zhen‐Feng , Liu Yi‐Ming 
Published: May 2011

AbstractA highly sensitive and selective assay based on a novel enzyme‐responsive multicolor gold nanobeacon has been developed for the multiplex detection of endonucleases, a group of very important nucleases. The nanobeacon takes advantage of the high specificity of DNA cleavage reactions combined with the unique fluorescence‐quenching property of gold nanoparticles (AuNPs). To prepare the nanobeacon, three hairpin DNA reporters, each labeled at the 5′ terminus with a fluorescent dye (i.e., fluorescein amidite (FAM), carboxy‐X‐rhodamine (ROX), cyanine dye (Cy5)), that respond to one of three different endonucleases are co‐assembled at the surface of AuNPs (15 nm). This assembly brings the dyes into very close proximity with the AuNP, which leads to significant quenching of the fluorescence due to the nanosurface energy‐transfer (NSET) effect. When the nanobeacon is exposed to the targeted endonucleases, specific DNA cleavage occurs and pieces of DNA fragments are released from the AuNP surface along with the fluorescent dye, which results in the fluorescence recovery that provides the basis for a quantitative measurement of endonuclease activity. Three endonucleases, namely HaeIII, EcoRI, and EcoRV, were studied as the proof‐of‐concept analytes. These endonucleases in homogeneous mixture solutions were simultaneously quantified by the proposed assay with high sensitivity and specificity. The limits of detection obtained were in the range of 5.0×10−4 U mL−1 to 1.0×10−3 U mL−1 of endonuclease; these limits are at least 100 times more sensitive than the previously reported endonuclease assays. Endonuclease inhibitors impair the DNA cleavage, so it is anticipated that the present method has great potential for screening inhibitors of endonucleases. To demonstrate this application, the inhibitory effects of certain anticancer drugs on HaeIII, EcoRI, and EcoRV activities were studied. The present protocol proved to be sensitive, reliable, and easy to carry out.