bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plugging a Molecular Wire into Photosystem I: Reconstitution of the Photoelectric Conversion System on a Gold Electrode
Authors: Terasaki Nao , Yamamoto Noritaka , Hiraga Takashi , Yamanoi Yoshinori , Yonezawa Tetsu , Nishihara Hiroshi , Ohmori Tsutomu , Sakai Makoto , Fujii Masaaki , Tohri Akihiko , Iwai Masako , Inoue Yasunori , Yoneyama Satoshi , Minakata Makoto , Enami Isao 
Published: January 2009

AbstractNach Anregung mit Licht überträgt das P700 des Photosystems I (PS I) Elektronen auf eine Goldoberfläche (siehe Bild). Dabei kommt ein neuartiges molekulares Verbindersystem zum Einsatz, in dem ein künstlicher molekularer Draht, der auf der Goldoberfläche angeordnet ist, durch Rekonstitution mit PS I verbunden wurde. Die Analyse der Kinetik des Photoelektronentransfers belegt die Abgabe von Elektronen aus PS I sowie die Effektivität des molekularen Drahts.magnified image
Electronic Absorption Spectra and Redox Properties of C Type Cytochromes in Living Microbes
Authors: Nakamura Ryuhei , Ishii Kazuyuki , Hashimoto Kazuhito 
Published: January 2009

AbstractShewanella is an electrogenic microbe that has significant content of c type cytochromes (ca. 0.5 mM). This feature allows the optical absorption spectra of the cell‐membrane‐associated proteins to be monitored in vivo in the course of extracellular respiratory electron‐transfer reactions. The results show significant differences to those obtained in vitro with purified proteins.magnified image
Bridging the Materials Gap in Catalysis: Entrapment of Molecular Catalysts in Functional Supports and Beyond
Authors: Thomas Arne , Driess Matthias 
Published: January 2009

AbstractRising sun of the materials world: Tremendous efforts are being made to combine the potential of molecular catalysts with that of functional supports. An approach towards unifying homogeneous and heterogeneous catalysis is the entrapment of organometallic catalysts in a metal matrix, which leads to well‐defined composites that are suitable as heterogeneous catalysts for hydrogenation of styrene and diphenylacetylene.magnified image
A Palladium(II)‐Catalyzed Synthesis of Spiroacetals through a One‐Pot Multicomponent Cascade Reaction
Authors: Barluenga José , Mendoza Abraham , Rodríguez Félix , Fañanás Francisco J. 
Published: January 2009

AbstractFunctionalized spiroacetals have been easily prepared in a one‐pot three‐component coupling process that involves the reaction of pentynol derivatives, salicylaldehydes, and amines in the presence of catalytic amounts of a palladium(II) complex (see scheme). Alternatively, oxygen‐substituted spiroacetals can be obtained by using orthoesters as the third component.magnified image
Direct CH Metalation with Chromium(II) and Iron(II): Transition‐Metal Host / Benzenediide Guest Magnetic Inverse‐Crown Complexes
Authors: Alborés Pablo , Carrella Luca M. , Clegg William , García‐Álvarez Pablo , Kennedy Alan R. , Klett Jan , Mulvey Robert E. , Rentschler Eva , Russo Luca 
Published: January 2009

AbstractCheck M(etal)ate: The chessboard and the figures represent a special reaction in which different low‐polarity metals can metalate arenes directly when they are brought into the right position. In a combination of queen (sodium) and knight (chromium or iron), it is possible for the knight (usually the weaker piece) to make a direct deadly hit on the king (benzene) in this game of elemental chess.magnified image
A sheep in wolf's clothing: do carrion and dung odours of flowers not only attract pollinators but also deter herbivores?
Authors: Lev‐Yadun Simcha , Ne'eman Gidi , Shanas Uri 
Published: January 2009

AbstractCarrion and dung odours of various flowers have traditionally been considered an adaptation for attracting the flies and beetles that pollinate them. While we accept the role of such odours in pollinator attraction, we propose that they may also have another, overlooked, anti‐herbivore defensive function. We suggest that such odours may deter mammalian herbivores, especially during the critical period of flowering. Carrion odour is a good predictor for two potential dangers to mammalian herbivores: (1) pathogenic microbes, (2) proximity of carnivores. Similarly, dung odour predicts faeces‐contaminated habitats that present high risks of parasitism. These are two new types of repulsive olfactory aposematic mimicry by plants: (1) olfactory feigning of carcass (thanatosis), a well‐known behavioural defensive strategy in animals, (2) olfactory mimicry of faeces, which also has a defensive visual parallel in animals.
Quantitative regulation of alternative splicing in evolution and development
Authors: Irimia Manuel , Rukov Jakob L. , Roy Scott W. , Vinther Jeppe , Garcia‐Fernandez Jordi 
Published: January 2009

AbstractAlternative splicing (AS) is a widespread mechanism with an important role in increasing transcriptome and proteome diversity by generating multiple different products from the same gene. Evolutionary studies of AS have focused primarily on the conservation of alternatively spliced sequences or of the AS pattern of those sequences itself. Less is known about the evolution of the regulation of AS, but several studies, working from different perspectives, have recently made significant progress. Here, we categorize the different levels of AS evolution, and summarize the studies on evolution of AS regulation, which point to a high level of evolutionary conservation of the regulation of AS events conserved between related species. This suggests that the quantitative regulation of AS is an intrinsic part of AS function. We discuss the potential role of changes in developmental regulation of AS as an additional layer in complex gene regulatory networks and in the emergence of genetic novelties.
Quantitative analysis of intracellular sugar phosphates and sugar nucleotides in encapsulated streptococci using HPAEC‐PAD
Authors: Marcellin Esteban , Nielsen Lars K. , Abeydeera Peter , Krömer Jens O. 
Published: January 2009

AbstractMetabolomics is a powerful tool for the study of biological systems. Besides analytical techniques, cell harvest and extraction are critical steps, especially when studying encapsulated streptococci. We have compared four different harvesting techniques for biomass from liquid culture of the hyaluronic acid (HA)‐producing bacterium Streptococcus zooepidemicus. The best method for cell separation was quick (2 min) centrifugation, which allowed efficient medium removal and enabled quantification of the broadest range of sugar metabolites. Unlike observations for other microbes, changes in metabolite pools due to a delay of extraction by the centrifugation were not observed, so metabolite levels accurately reflected the metabolome at the point of cell harvest. A hypothesis is that the capsule itself isolates the cells from the surroundings and still supports it with nutrients during the harvest. Quantification of sugar phosphates and nucleotide sugars was performed using high‐performance anion exchange chromatography combined with pulsed amperometric detection, achieving limits of quantification of 2.5 pmol for sugar phosphates and 5 pmol on column for nucleotide sugars. Intracellular pool sizes for intermediates of the HA pathway under production conditions ranged from 0.2 to 0.5 μmol/g cell dry weight.
Production of random DNA oligomers for scalable DNA computing
Authors: Wang Sixue S. L. , Johnson John J. X. , Hughes Bradley S. T. , Karabay Dundar A. O. , Bader Karson D. W. , Austin Alan , Habib Aisha , Hatef Husnia , Joshi Megha , Nguyen Lawrence , Mills Allen P. 
Published: January 2009

AbstractWhile remarkably complex networks of connected DNA molecules can form from a relatively small number of distinct oligomer strands, a large computational space created by DNA reactions would ultimately require the use of many distinct DNA strands. The automatic synthesis of this many distinct strands is economically prohibitive. We present here a new approach to producing distinct DNA oligomers based on the polymerase chain reaction (PCR) amplification of a few random template sequences. As an example, we designed a DNA template sequence consisting of a 50‐mer random DNA segment flanked by two 20‐mer invariant primer sequences. Amplification of a dilute sample containing about 30 different template molecules allows us to obtain around 1011 copies of these molecules and their complements. We demonstrate the use of these amplicons to implement some of the vector operations that will be required in a DNA implementation of an analog neural network.
Rapid prototyping of scaphoid and lunate bones
Authors: Gittard Shaun D. , Narayan Roger , Lusk Jason , Morel Pierre , Stockmans Filip , Ramsey Michael , Laverde Claire , Phillips Jack , Monteiro‐Riviere Nancy A. , Ovsianikov Aleksandr , Chichkov Boris N. 
Published: January 2009

AbstractIn this study, a novel rapid prototyping technology was used to fabricate scaphoid and lunate bone prostheses, two carpal bones that are prone to avascular necrosis. Carpal prostheses were fabricated with an Envisiontec Perfactory® SXGA stereolithography system using Envisiontec eShell 200 photocurable polymer. Fabrication was guided using 3‐D models, which were generated using Mimics software (Materialise NV, Leuven, Belgium) from patient computer tomography data. The prostheses were fabricated in a layer‐by‐layer manner; ∼ 50‐μm thick layers were observed in the prostheses. Hardness and Young's modulus values of polymerized eShell 200 material were 93.8 ± 7.25 MPa and 3050 ± 90 MPa, respectively. The minimum compressive force required for fracture was 1360 N for the scaphoid prosthesis and 1248 N for the lunate prosthesis. Polymerized Envisiontec eShell material exhibited high human neonatal epidermal keratinocyte cell viability rate in an MTT assay. The results of this study indicate that small bone prostheses fabricated by stereolithography using eShell 200 polymer may have suitable geometry, mechanical properties, and cytocompatibility properties for in vivo use.
Fully in vitro selection of recombinant antibodies
Authors: Moutel Sandrine , Vielemeyer Ole , Jin Hulin , Divoux Séverine , Benaroch Philippe , Perez Franck 
Published: January 2009

AbstractAntibodies are essential for the identification and characterization of proteins. In the current postgenomic era the need for highly specific antibodies has further increased not only for research applications but also because they represent one of the most promising therapeutic options, especially in the field of cancer treatment. One appealing approach for rapid and inexpensive antibody generation is the use of phage display. This technique allows for a fast and animal‐free selection of highly functional alternatives to classical antibodies. However, one strong limitation of this recombinant approach has been the difficulty in producing and purifying antigens. These steps have to be adjusted for each new target, are time consuming and sometimes present an insurmountable obstacle. Here we report the development of new antibody selection approach where antigens are produced through in vitro translation and are used directly and without the need for purification. With this approach we were able to rapidly select recombinant antibodies directed against GFP and the mammalian protein tsg101, respectively. We believe that our method greatly facilitates antigen preparation and thus may broaden the use of the recombinant approach for antibody generation, especially since the technique could in the future be adapted to a high‐throughput technology, thus further accelerating antibody selection.
Expression system of CotA‐laccase for directed evolution and high‐throughput screenings for the oxidation of high‐redox potential dyes
Authors: Brissos Vânia , Pereira Luciana , Munteanu Florentina‐Daniela , Cavaco‐Paulo Artur , Martins Lígia O. 
Published: January 2009

AbstractLaccases are useful biocatalysts for many diverse biotechnological applications. In this study we have established efficient and reliable expression systems and high‐throughput screenings for the recombinant CotA‐laccase fromBacillus subtilis. The expression levels ofcotA‐laccasewere compared in five differentEscherichia colihost strains growing in 96‐well microtiter plates under different culture conditions. Lower coefficients of variance (around 15%) were achieved using crude cell lysates of BL21 and KRX host strains growing under microaerobic conditions. Reproducible high‐throughput screenings for the decolorization of high redox potential azo and anthraquinonic dyes were developed and optimized for identification of variants with increased redox potential. The enzymatic assays developed were tested for the screening of one mutant library from CotA‐laccase created by error‐prone PCR.
Transient protein expression in three Pisum sativum (green pea) varieties
Authors: Green Brian J. , Fujiki Masaaki , Mett Valentina , Kaczmarczyk Jon , Shamloul Moneim , Musiychuk Konstantin , Underkoffler Susan , Yusibov Vidadi , Mett Vadim 
Published: January 2009

AbstractThe expression of proteins in plants both transiently and via permanently transformed lines has been demonstrated by a number of groups. Transient plant expression systems, due to high expression levels and speed of production, show greater promise for the manufacturing of biopharmaceuticals when compared to permanent transformants. Expression vectors based on a tobacco mosaic virus (TMV) are the most commonly utilized and the primary plant used, Nicotiana benthamiana, has demonstrated the ability to express a wide range of proteins at levels amenable to purification. N. benthamiana has two limitations for its use; one is its relatively slow growth, and the other is its low biomass. To address these limitations we screened a number of legumes for transient protein expression. Using the alfalfa mosaic virus (AMV) and the cucumber mosaic virus (CMV) vectors, delivered via Agrobacterium, we were able to identify three Pisum sativum varieties that demonstrated protein expression transiently. Expression levels of 420 ( 26.24 mg GFP/kgFW in the green pea variety speckled pea were achieved. We were also able to express three therapeutic proteins indicating promise for this system in the production of biopharmaceuticals.
A strained DNA binding helix is conserved for site recognition, folding nucleation, and conformational modulation
Authors: Wetzler Diana E. , Gallo Mariana , Melis Riccardo , Eliseo Tomasso , Nadra Alejandro D. , Ferreiro Diego U. , Paci Maurizio , Sánchez Ignacio E. , Cicero Daniel O. , de Prat Gay Gonzalo 
Published: January 2009

AbstractNucleic acid recognition is often mediated by α‐helices or disordered regions that fold into α‐helix on binding. A peptide bearing the DNA recognition helix of HPV16 E2 displays type II polyproline (PII) structure as judged by pH, temperature, and solvent effects on the CD spectra. NMR experiments indicate that the canonical α‐helix is stabilized at the N‐terminus, while the PII forms at the C‐terminus half of the peptide. Re‐examination of the dihedral angles of the DNA binding helix in the crystal structure and analysis of the NMR chemical shift indexes confirm that the N‐terminus half is a canonical α‐helix, while the C‐terminal half adopts a 310helix structure. These regions precisely match two locally driven folding nucleii, which partake in the native hydrophobic core and modulate a conformational switch in the DNA binding helix. The peptide shows only weak and unspecific residual DNA binding, 104‐fold lower affinity, and 500‐fold lower discrimination capacity compared with the domain. Thus, the precise side chain conformation required for modulated and tight physiological binding by HPV E2 is largely determined by the noncanonical strained α‐helix conformation, “presented” by this unique architecture. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 432–443, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Deterring malingered psychopathology: The effect of warning simulating malingerers
Authors: King Joanne , Sullivan Karen A. 
Published: January 2009

AbstractThe utility of a warning to deter malingering on measures of personality and psychopathology was examined. Sixty‐seven first year psychology students were randomly assigned to one of three conditions: unwarned malingerers, warned malingerers, and controls. Participants in the two malingering groups were given a financial incentive to simulate believable psychological impairment. Warned malingerers received an additional warning that the tests could detect malingering and that detection would result in loss of course credit. Controls received standardized test instructions. It was hypothesized that the malingering incentive would be sufficient to induce malingering, but that a deterrence theory warning would have a subsequent deterrent effect. Between‐groups analyses indicated that the warning used in this study significantly altered test performance on the Personality Assessment Inventory (PAI) and revised Symptom Checklist 90 (SCL‐90‐R). Warned malingerers scored significantly lower (faked less) than unwarned malingerers on the majority of the psychopathology scales and frequently approximated control group performances. These results support the effectiveness of a warning to complement existing malingering detection methods. Copyright © 2009 John Wiley & Sons, Ltd.
A latent class factor approach to identifying subtypes of juvenile diversion youths based on psychopathic features
Authors: Wareham Jennifer , Dembo Richard , Poythress Norman G. , Childs Kristina , Schmeidler James 
Published: January 2009

AbstractLatent class factor analysis allows for the estimation of a dimensional construct such as psychopathy through factor analysis while also examining the heterogeneity of the sample. We report the results of a latent class factor analysis examining the psychometric structure of a widely used measure of psychopathy, as well as internalizing (i.e. anxiety) and externalizing indices, among diversion program youths involved in an intervention study. The results indicated that four subgroups of adolescents existed in the data: one with high psychopathic features and externalizing problems, but low anxiety; one with moderately high affective and behavioral psychopathic features and externalizing problems, but low anxiety; one with moderately high interpersonal and behavioral psychopathic features, externalizing problems, and anxiety; and one with very low psychopathy scores, anxiety, and externalizing problems. The validity of these subgroups was assessed comparing prior family problems, substance use, and offending measures, and one‐year follow‐up measures of recidivism, detention days, substance use, and program completion. This study offers partial support for the existence of psychopathy subgroups and has implications for future studies of psychopathy typologies. In addition, this study employed a methodology for classification that permits consideration of the dimensional nature of a construct, and as such has implications for a variety of research areas. Copyright © 2009 John Wiley & Sons, Ltd.
Heparin Antagonism by Polyvalent Display of Cationic Motifs on Virus‐Like Particles
Authors: Udit Andrew K. , Everett Chris , Gale Andrew J. , Reiber Kyle Jennifer , Ozkan Mihri , Finn M. G. 
Published: January 2009

AbstractParticles to the rescue! The construction of cationic amino acid motifs on the surface of bacteriophage Qβ by genetic engineering or chemical conjugation gives particles that are potent inhibitors of the anticoagulant action of heparin, which is a common anticlotting agent subject to clinical overdose.magnified imagePolyvalent interactions allow biological structures to exploit low‐affinity ligand–receptor binding events to affect physiological responses. We describe here the use of bacteriophage Qβ as a multivalent platform for the display of polycationic motifs that act as heparin antagonists. Point mutations to the coat protein allowed us to generate capsids bearing the K16M, T18R, N10R, or D14R mutations; because 180 coat proteins form the capsid, the mutants provide a spectrum of particles differing in surface charge by as much as +540 units (K16M vs. D14R). Whereas larger poly‐Arg insertions (for example, C‐terminal Arg8) did not yield intact virions, it was possible to append chemically synthesized oligo‐Arg peptides to stable wild‐type (WT) and K16M platforms. Heparin antagonism by the particles was evaluated by using the activated partial thrombin time (aPTT) clotting assay; this revealed that T18R, D14R, and WT‐(R8G2)95 were the most effective at disrupting heparin‐mediated anticoagulation (>95 % inhibition). This activity agreed with measurements of ζ potential (ZP) and retention time on cation exchange chromatography for the genetic constructs, which distribute their added positive charge over the capsid surface (+180 and +360 for T18R and D14R relative to WT). The potent activity of WT‐(R8G2)95, despite its relatively diminished overall surface charge is likely a consequence of the particle's presentation of locally concentrated regions with high positive charge density that interact with heparin's extensively sulfated domains. The engineered cationic capsids retained their ability to inhibit heparin at high concentrations and showed no anticlotting activity of the kind that limits the utility of antiheparin polycationic agents that are currently in clinical use.
Synthesis of Sulfated Glucosaminides for Profiling Substrate Specificities of Sulfatases and Fungal β‐N‐Acetylhexosaminidases
Authors: Loft Karen J. , Bojarová Pavla , Slámová Kristýna , Křen Vladimír , Williams Spencer J. 
Published: January 2009

AbstractSystematic sulfation: Sulfated glycoconjugates are degraded either by desulfation followed by glycoside cleavage, or by glycoside cleavage followed by desulfation. To study these processes, here we report the synthesis of four regioisomerically sulfated p‐nitrophenyl glucosaminides from the common precursor p‐nitrophenyl N‐acetyl‐β‐D‐glucosaminide. These substrates allowed the rapid analysis of the substrate preferences of a set of four sulfatases and 24 hexosaminidases.magnified imageSulfated carbohydrates are components of many glycoconjugates, and are degraded by two major processes: cleavage of the sulfate ester by a sulfatase, or en bloc removal of a sulfated monosaccharide by a glycoside hydrolase. However, these processes have proved difficult to study owing to a lack of homogeneous, defined substrates. We describe here the synthesis of a series of p‐nitrophenyl β‐D‐glucosaminides bearing sulfate esters at the 2‐, 3‐, 4‐ or 6‐positions, by divergent routes starting with p‐nitrophenyl 2‐acetamido‐2‐deoxy‐β‐D‐glucopyranoside. The sulfated p‐nitrophenyl β‐D‐glucosaminides were used to study the substrate specificity of four sulfatases (from Helix pomatia, Patella vulgata, abalone, and Pseudomonas aeruginosa), and revealed significant differences in the preference of each of these enzymes for desulfation at different positions around the sugar ring. The 3‐, 4‐ and 6‐sulfated p‐nitrophenyl 2‐acetamido‐2‐deoxy‐β‐D‐glucosaminides were screened against a panel of 24 fungal β‐N‐acetylhexosaminidases to assess their substrate specificity. While the 4‐ and 6‐sulfates were substrates for many of the fungal enzymes investigated, only a single β‐N‐acetylhexosaminidase, that from Penicillium chrysogenum, could hydrolyze the 3‐sulfated p‐nitrophenyl glycoside. Together these results demonstrate the utility of sulfated p‐nitrophenyl β‐D‐glucosaminides for the study of both sulfatases and glycoside hydrolases.