bluuebunny/crossref_metadata_2025_split huggingface dataset:
New criteria for selecting the origin of DNA replication in Wolbachia and closely related bacteria
Authors: Ioannidis Panagiotis , Hotopp Julie C Dunning , Sapountzis Panagiotis , Siozios Stefanos , Tsiamis Georgios , Bordenstein Seth R , Baldo Laura , Werren John H , Bourtzis Kostas 
Published: June 2007

AbstractBackgroundThe annotated genomes of two closely related strains of the intracellular bacteriumWolbachia pipientishave been reported without the identifications of the putative origin of replication (ori). Identifying theoriof these bacteria and related alpha-Proteobacteria as well as their patterns of sequence evolution will aid studies of cell replication and cell density, as well as the potential genetic manipulation of these widespread intracellular bacteria.ResultsUsing features that have been previously experimentally verified in the alpha-ProteobacteriumCaulobacter crescentus, the origin of DNA replication (ori) regions were identifiedin silicoforWolbachiastrains and eleven other related bacteria belonging toEhrlichia,Anaplasma, andRickettsiagenera. These features include DnaA-, CtrA- and IHF-binding sites as well as the flanking genes inC. crescentus. TheWolbachia oriboundary genes were found to behemEand COG1253 protein (CBS domain protein). Comparisons of the putativeoriregion among relatedWolbachiastrains showed higher conservation of bases within binding sites.ConclusionThe sequences of theoriregions described here are only similar among closely related bacteria while fundamental characteristics like presence of DnaA and IHF binding sites as well as the boundary genes are more widely conserved. The relative paucity of CtrA binding sites in theoriregions, as well as the absence of key enzymes associated with DNA replication in the respective genomes, suggest that several of these obligate intracellular bacteria may have altered replication mechanisms. Based on these analyses, criteria are set forth for identifying theoriregion in genome sequencing projects.
Cocaine reward and locomotion stimulation in mice with reduced dopamine transporter expression
Authors: Tilley Michael R , Cagniard Barbara , Zhuang Xiaoxi , Han Dawn D , Tiao Narry , Gu Howard H 
Published: June 2007

AbstractBackgroundThe dopamine transporter (DAT) plays a critical role in regulating dopamine neurotransmission. Variations in DAT or changes in basal dopaminergic tone have been shown to alter behavior and drug responses. DAT is one of the three known high affinity targets for cocaine, a powerful psychostimulant that produces reward and stimulates locomotor activity in humans and animals. We have shown that cocaine no longer produces reward in knock-in mice with a cocaine insensitive mutant DAT (DAT-CI), suggesting that cocaine inhibition of DAT is critical for its rewarding effect. However, in DAT-CI mice, the mutant DAT has significantly reduced uptake activity resulting in elevated basal dopaminergic tone, which might cause adaptive changes that alter responses to cocaine. Therefore, the objective of this study is to determine how elevated dopaminergic tone affects how mice respond to cocaine.ResultsWe examined the cocaine induced behavior of DAT knockdown mice that have DAT expression reduced by 90% when compared to the wild type mice. Despite a dramatic reduction of DAT expression and marked elevation in basal dopamine tone, cocaine produced reward, as measured by conditioned place preference, and stimulated locomotor activity in these mice.ConclusionA reduction in DAT expression and elevation of dopaminergic tone do not lead to adaptive changes that abolish the rewarding and stimulating effects of cocaine. Therefore, the lack of reward to cocaine observed in DAT-CI mice is unlikely to have resulted from the reduced DAT activity but instead is likely due to the inability of cocaine to block the mutated DAT and increase extracellular dopamine. This study supports the conclusion that the blockade of DAT is required for cocaine reward and locomotor stimulation.
Phosphorylation of Irs1 at SER-522 Inhibits Insulin Signaling
Authors: Giraud Jodel , Haas Michael , Feener Edward P. , Copps Kyle D. , Dong Xiaocheng , Dunn Sarah L. , White Morris F. 
Published: June 2007

AbstractMultisite phosphorylation of Irs1 on serine and threonine residues regulates insulin signaling that can contribute to insulin resistance. We identified by mass spectrometry the phosphorylation of Ser522 in rat Irs1 (S522Irs1). The functional effects of this phosphorylation site were investigated in cultured cells using a sequence-specific phosphoserine antibody. Insulin stimulated the phosphorylation of S522Irs1 in L6 myoblasts and myotubes. S522Irs1 phosphorylation was inhibited by wortmannin, whereas PD98059, rapamycin, or glucose-starvation had no effect. Reducing Akt expression with small interfering RNA inhibited insulin-stimulated phosphorylation of S522Irs1, suggesting the involvement of the phosphatidylinositol 3-kinase→ Akt cascade. A S522Irs1→A522Irs1 substitution increased insulin-stimulated tyrosine phosphorylation of Irs1 and signaling, whereas a S522Irs1→E522Irs1 substitution reduced insulin-stimulated Irs1 tyrosine phosphorylation. Together, these results suggest the phosphatidylinositol 3-kinase→Akt cascade can inhibit insulin signaling through the phosphorylation of S522Irs1.
Subcellular Localization Modulates Activation Function 1 Domain Phosphorylation in the Androgen Receptor
Authors: Kesler Cristina T. , Gioeli Daniel , Conaway Mark R. , Weber Michael J. , Paschal Bryce M. 
Published: June 2007

AbstractAlthough the steady-state distribution of the androgen receptor (AR) is predominantly nuclear in androgen-treated cells, androgen-bound AR shuttles between the nucleus and the cytoplasm. In the present study we have addressed how nucleocytoplasmic shuttling contributes to the regulation of AR. Nuclear transport signal fusions were used to force AR localization to the nucleus or cytoplasm of prostate cancer cells, and the effect of localization on shuttling, transcription, androgen binding, and phosphorylation was determined. Fusing the simian virus 40 nuclear localization signal or c-Abl nuclear export signal to AR resulted in androgen-independent localization to the nucleus or cytoplasm, respectively. AR forced to the nucleus was transcriptionally active on prostate-specific antigen and mouse mammary tumor virus promoters driving reporter genes. AR forced to the cytoplasm was largely inactive on the prostate-specific antigen promoter, but, surprisingly, AR was active on the mouse mammary tumor virus promoter and on two endogenous genes examined. Thus, highly transient nuclear localization of AR is sufficient to activate transcription. Androgen dissociation rates and the dissociation constant (KD) of AR for androgen were similar whether AR was localized to the cytoplasm or the nucleus, suggesting the ligand-binding cycle of AR is not strictly linked to its compartmentalization. Using phosphosite antibodies, we found that compartmentalization influences the phosphorylation state of AR. We show there is a bias for androgen-dependent phosphorylation of Ser81, Ser256, and Ser308 in the nucleus and androgen-independent phosphorylation of Ser94 in the cytoplasm. We propose that one function of nucleocytoplasmic shuttling is to integrate the signaling environment in the cytoplasm with AR activity in the nucleus.
Topics and topicalization in Amharic
Authors: Demeke Girma A , Meyer Ronny 
Published: June 2007

Abstract
The paper examines the information structure of Amharic sentences with regard to topicalization. The morphemes -mma, -ss, and -mm in Amharic have been ascribed a function as topic markers (cf. Blejer 1986, Gasser 1983, Hetzron 1973, Kapeliuk 1978, Leslau 1995, etc.). From a synchronic point of view we disagree with Leslau's (1995) analysis of -mma as a combination of -mm ‘TOP:N’ and -a(a) ‘TOP:E’. Further, we argue that only the morphemes -mma and -ss can be considered topic markers while -mm is rather a focus marker. Topics in Amharic are generally marked by fronting the constituent in question to the sentence-initial position. Those which are additionally marked by the morphemes
-mma and -ss are contrastive, i.e., ‘as for’-topics, while topics only marked by fronting are non-contrastive.
A Critique and Improvement of the CL Common Language Effect Size Statistics of McGraw and Wong
Authors: Vargha András , Delaney Harold D. 
Published: June 2007

McGraw and Wong (1992) described an appealing index of effect size, called CL, which measures the difference between two populations in terms of the probability that a score sampled at random from the first population will be greater than a score sampled at random from the second. McGraw and Wong introduced this "common language effect size statistic" for normal distributions and then proposed an approximate estimation for any continuous distribution. In addition, they generalized CL to the n-group case, the correlated samples case, and the discrete values case. In the current paper a different generalization of CL, called the A measure of stochastic superiority, is proposed, which may be directly applied for any discrete or continuous variable that is at least ordinally scaled. Exact methods for point and interval estimation as well as the significance tests of the A = .5 hypothesis are provided. New generalizations ofCL are provided for the multi-group and correlated samples cases.
Optimal Calibration Designs for Tests of Polytomously Scored Items Described by Item Response Theory Models
Authors: Holman Rebecca , Berger Martijn P. F. 
Published: June 2007

This article examines calibration designs, which maximize the determinant of Fisher’s information matrix on the item parameters (D-optimal), for sets of polytomously scored items. These items were analyzed using a number of item response theory (IRT) models, which are members of the “divide-by-total” family, including the nominal categories model, the rating scale model, the unidimensional polytomous Rasch model and the partial credit model. We extend the known results for dichotomous items, both singly and in tests to polytomous items. The structure of Fisher’s information matrix is examined in order to gain insights into the structure of D-optimal calibration designs for IRT models. A theorem giving an upper bound for the number of support points for such models is proved. A lower bound is also given. Finally, we examine a set of items, which have been analyzed using a number of different models. The locally D-optimal calibration design for each analysis is calculated using an exact numerical and a sequential procedure. The results are discussed both in general and in relation to each other.
A dual extremum principle in thermodynamics
Authors: Mitsos Alexander , Barton Paul I. 
Published: June 2007

AbstractPhase equilibria of multicomponent mixtures are considered and a reinterpretation of the Gibbs tangent plane stability criterion is proposed via Lagrangian duality. The starting point is the natural primal problem of minimizing the Gibbs free energy subject to material balance. The stable phase split is the solution of the corresponding dual problem, providing a necessary and sufficient dual extremum principle. Only in the absence of duality gap is the physical phase split also the solution of the primal problem. The only requirements are continuity of the Gibbs free energy and the trivial requirement that each species is present in the overall composition. The number of phases is permitted to be infinite, and does not need to be known a priori. No assumption is made on the presence of all species in all phases. Case studies are presented based on the NRTL and UNIQUAC activity coefficient model. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Polyferrocenylsilan‐basierte Polymersysteme
Authors: Bellas Vasilios , Rehahn Matthias 
Published: June 2007

AbstractMetallopolymere haben sich in den letzten Jahrzehnten zu einem ergiebigen Forschungsgebiet entwickelt. Besonders die Polyferrocenylsilan(PFS)‐Chemie hat sich dabei rasant entwickelt. Nach Entdeckung der thermischen Ringöffnungspolymerisation (ROP) von Sila[1]ferrocenophanen konnten Polyferrocenylsilane bald auch durch anionische, kationische, übergangsmetallkatalysierte und photolytische anionische ROP zugänglich gemacht werden. Hiervon ausgehend wurden unterschiedlichste weiterführende Synthesestrategien ausgearbeitet, die Zugang zu einer breiten Palette an Copolymeren, Polyelektrolyten und nanostrukturierten Materialien eröffnen. Die physikalischen Eigenschaften PFS‐basierter Polymere sowie die mit ihnen realisierbaren Funktionen wurden erforscht und können jetzt in technischen Anwendungen genutzt werden.
Strained Metallocenophanes and Related Organometallic Rings Containing π‐Hydrocarbon Ligands and Transition‐Metal Centers
Authors: Herbert David E. , Mayer Ulrich F. J. , Manners Ian 
Published: June 2007

AbstractThe structures, bonding, and ring‐opening reactions of strained cyclic carbon‐based molecules form a key component of standard textbooks. In contrast, the study of strained organometallic molecules containing transition metals is a much more recent development. A wealth of recent research has revealed fascinating nuances in terms of structure, bonding, and reactivity. Building on initial work on strained ferrocenophanes, a broad range of strained organometallic rings composed of a variety of different metals, π‐hydrocarbon ligands, and bridging elements has now been developed. Such strained species can potentially undergo ring‐opening reactions to functionalize surfaces and ring‐opening polymerization to form easily processed metallopolymers with properties determined by the presence of the metal and spacer. This Review summarizes the current state of knowledge on the preparation, structural characterization, electronic structure, and reactivity of strained organometallic rings with π‐hydrocarbon ligands and d‐block metals.
Synthesis of bis‐N‐acyllactams type chain extenders for polyesters and polyamides
Authors: Stier Ulli , Schweizer Michael 
Published: June 2007

AbstractThis article shows the synthesis of chain extenders derived from the group of bis‐N‐acyllactams. These chain extenders may not only increase the molecular weight of polyesters or polyamides but also permit a flexible modification at the same time by incorporating an arbitrary functionality in the polymer chains. The chain extenders are synthesized by a two step process starting from terephthaloyl chloride, ε‐caprolactam, and the functional moiety R which derives from a diol HOROH or diamine H2NRNH2. For five chain extenders varying in the moiety R, the synthesis is explicitly shown and the thermal stability is investigated. It can be shown that the chain extenders are thermal stable up to 260°C at least. The chain extenders may thus be useful to increase the molecular weight and to modify many important thermoplastic polyesters and polyamides during the melt extrusion process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
An HPLC method for the determination of the free cortisol/cortisone ratio in human urine
Authors: Sharef O. Al , Feely J. , Kavanagh P. V. , Scott K. R. , Sharma S. C. 
Published: June 2007

AbstractThe measurement of the urinary free cortisol–cortisone ratio has been reported to be a sensitive indicator of renal 11 β‐hydroxysteroid dehydrogenase type 2 (11 β‐HSD 2) activity. This converts biologically active cortisol to inactive cortisone. A decrease in its activity (e.g. through disease or inhibition caused by a therapeutic agent or a foodstuff) may increase cortisol levels and susceptibility towards hypertension. The method presented here uses a simple isocratic tandem column HPLC system. The method has been validated and found to be robust and reproducible. The lower limit of quantification (LLOQ) was found to be 10 ng/mL for both cortisol and cortisone. Samples of urine (n = 99) from patients, most of whom were on complex combinations of drugs, were analyzed and 92% of samples were found to give successful results with this method (cortisol and cortisone above LLOQ). The ratio ranged from 0.07 to 5.61. No interferences were noted from the drugs that the patients were taking. It was also found that a morning spot urine sample gave comparable results to 24 h collection samples, thus making sample collection much easier. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of benzofurazan derivatization reagents for carboxylic acids in liquid chromatography/electrospray ionization–tandem mass spectrometry
Authors: Santa Tomofumi , Al‐Dirbashi Osama Y , Ichibangase Tomoko , Fukushima Takeshi , Rashed Mohamed S , Funatsu Takashi , Imai Kazuhiro 
Published: June 2007

AbstractThe applicability of benzofurazan derivatization regents to carboxylic acids analysis in LC/ESI‐MS/MS (high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry) was examined. The product ion spectra of DAABD‐AE {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐(2‐aminoethylamino)‐2,1,3‐benzoxadiazole}, DAABD‐PZ {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐N‐piperazino‐2,1,3‐benzoxadiazole}, DAABD‐PiCZ {4‐[4‐carbazoylpiperidin‐1‐yl]‐7‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐2,1,3‐benzoxadiazole}, DAABD‐ProCZ {4‐[2‐carbazoylpyrrolidin‐1‐yl]‐7‐[2‐(N,N‐dimethylamino) ethylaminosulfonyl]‐2,1,3‐benzoxadiazole} and DAABD‐Apy {4‐[2‐(N,N‐dimethylamino)ethylaminosulfonyl]‐7‐(3‐aminopyrrolidin‐1‐yl)‐2,1,3‐benzoxadiazole}, and their acetylated compounds were obtained. An intense fragment ion at m/z 151 corresponding to (dimethylamino)ethylaminosulfonyl moiety was observed in each spectra, suggesting that these reagents were suitable for ESI‐MS/MS analysis. DAABD‐AE, DAABD‐APy and DAABD‐PZ were applied to the analysis of octanoic acid and it was found that DAABD‐AE and DAABD‐APy gave high signal intensity suitable for LC/ESI‐MS/MS. Copyright © 2007 John Wiley & Sons, Ltd.
Peptaibiotics and Peptaibols: An Alternative to Classical Antibiotics?
Authors: Duclohier Hervé 
Published: June 2007

AbstractThe development and antimicrobial properties of peptaibiotics and peptaibols are discussed. Also, the role of emerging peptaibol analogues, of alamethicin, e.g., harzianins HC, trichotoxin, and antiamoebin, is outlined.
Peptaibols: Stable Markers of Fungal Development in the Marine Environment
Authors: Poirier Laurence , Montagu Monique , Landreau Anne , Mohamed‐Benkada Mustapha , Grovel Olivier , Sallenave‐Namont Claire , Biard Jean‐François , Amiard‐Triquet Claude , Amiard Jean‐Claude , Pouchus Yves François 
Published: June 2007

AbstractDifferent peptaibols were observed in both fresh and frozen marine sediments collected from a marine area devoted to bivalve culture (Fier d'Ars, Atlantic coast, France). The identification of the peptaibols was based on a three‐step mass‐spectrometric analysis: observation of doubly charged ions with a characteristic isotopic profile, cleavage and observation of C‐ and N‐terminal fragments, and partial sequencing of the N‐terminal segments. The MS characteristics indicated numerous similarities between the peptaibols detected and those produced by different strains of Trichoderma species isolated from fresh sediments. Peptaibols were also detected in mussel samples collected at the same site. This constitutes the first observation of contamination of the marine human‐food chain by fungal metabolites. Since peptaibols were readily observed both in fresh sediments and in samples kept frozen for several years, these compounds can be considered as stable markers of the development of Trichoderma in the marine environment.
The ‘Azirine/Oxazolone Method’ in Peptaibol Synthesis: Preparation of a Derivative of Trichotoxin A‐50 (G)
Authors: Altherr Werner , Linden Anthony , Heimgartner Heinz 
Published: June 2007

AbstractThe synthesis of a mixture of epimeric derivatives of the peptaibol trichotoxin A‐50 (G) is described. The ‘azirine/oxazolone method’ has been used as a superior method for the introduction of the Aib as well as the Iva units into the peptide chain. In this protocol, 2,2‐disubstituted 2H‐azirin‐3‐amines are the synthons for 2,2‐disubstituted glycines, which undergo coupling with N‐protected amino or peptide acids in high yield, and without any need of coupling reagents. The problem of the instability of the amide function of the Gln side chain under the conditions of the acid‐catalyzed hydrolysis of Z‐Gln‐(Aib)n‐N(Me)Ph was solved by using an appropriate protecting group for the amide function of the Gln side chain, e.g., the triphenylmethyl (trityl; Tr) group. The structures of two intermediate peptides, i.e., the segments comprising residues 1–5 and 10–13, resp., were established by X‐ray crystallography.
Multinuclear Solid‐State‐NMR and FT‐IR‐Absorption Investigations on Lipid/Trichogin Bilayers
Authors: Heuber Christiane , Formaggio Fernando , Baldini Chiara , Toniolo Claudio , Müller Klaus 
Published: June 2007

AbstractSolid‐state NMR and FT‐IR absorption spectroscopy are employed to study the molecular properties of 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (DMPC) lipids as a function of trichogin‐OMe content, a membrane‐active analogue of the peptaibol trichogin GA IV. Variable‐temperature NMR studies are performed, comprising 13C‐, 31P‐, and 14N‐NMR line‐shape and relaxation experiments, to provide information about the mobility and ordering of the phospholipid head group and the acyl‐chain region in the absence and presence of trichogin‐OMe. Likewise, variable‐temperature FT‐IR‐absorption studies are performed, and the conformation‐sensitive CH2 stretching bands are analyzed to examine the conformational state of the acyl chain.At lower trichogin‐OMe concentrations, the peptide exhibits no remarkable influence on the dynamics and ordering features of the phospholipid molecules. It is concluded that, in this case, trichogin‐OMe is embedded in the lipid bilayer, with its helix axis laying parallel to the bilayer plane, the more hydrophobic part pointing towards the inner part of the bilayer (‘carpet‐like’ superstructure). The lipid dynamics are probed by rotating‐frame spin–lattice‐relaxation (T1ρ) experiments for the 13C and 31P nuclei, which are assumed to be dominated by collective‐order fluctuations. Variation of T1ρ with sample composition is attributed to changes of the membrane stiffness.For the sample with the highest lipid/peptide (L/P) molar ratio, i.e., L/P 5 : 1, phase separation as a result of membrane disruption occurs. In this case, a second spectroscopic component can be separated in the 31P‐NMR spectra. In addition, the (motionally averaged) magnetic interactions are greatly reduced, the actual values differing for both components. The second spectroscopic component refers to membrane components with high trichogin‐OMe concentration and to strong lipid–trichogin‐OMe interactions, as reflected by significant changes of the head‐group orientation (toroidal model). At the same time, DMPC molecules exist with minor lipid–trichogin‐OMe interactions, most probably in smaller liposomes, trichogin‐OMe being embedded in a ‘carpet‐like’ manner. Moreover, lipid ordering is generally reduced for the highly concentrated sample, which may result from fast lateral lipid motion along the curved bilayer surface.