bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Resolution Quantitative Trait Locus Mapping Reveals Sign Epistasis Controlling Ovariole Number Between Two Drosophila Species
Authors: Orgogozo Virginie , Broman Karl W , Stern David L 
Published: February 2006

Abstract
Identifying the genes underlying genetically complex traits is of fundamental importance for medicine, agriculture, and evolutionary biology. However, the level of resolution offered by traditional quantitative trait locus (QTL) mapping is usually coarse. We analyze here a trait closely related to fitness, ovariole number. Our initial interspecific mapping between Drosophila sechellia (8 ovarioles/ovary) and D. simulans (15 ovarioles/ovary) identified a major QTL on chromosome 3 and a minor QTL on chromosome 2. To refine the position of the major QTL, we selected 1038 additional recombinants in the region of interest using flanking morphological markers (selective phenotyping). This effort generated approximately one recombination event per gene and increased the mapping resolution by approximately seven times. Our study thus shows that using visible markers to select for recombinants can efficiently increase the resolution of QTL mapping. We resolved the major QTL into two epistatic QTL, QTL3a and QTL3b. QTL3a shows sign epistasis: it has opposite effects in two different genetic backgrounds, the presence vs. the absence of the QTL3b D. sechellia allele. This property of QTL3a allows us to reconstruct the probable order of fixation of the QTL alleles during evolution.
Male Demography in East Asia: A North–South Contrast in Human Population Expansion Times
Authors: Xue Yali , Zerjal Tatiana , Bao Weidong , Zhu Suling , Shu Qunfang , Xu Jiujin , Du Ruofu , Fu Songbin , Li Pu , Hurles Matthew E , Yang Huanming , Tyler-Smith Chris 
Published: February 2006

Abstract
The human population has increased greatly in size in the last 100,000 years, but the initial stimuli to growth, the times when expansion started, and their variation between different parts of the world are poorly understood. We have investigated male demography in East Asia, applying a Bayesian full-likelihood analysis to data from 988 men representing 27 populations from China, Mongolia, Korea, and Japan typed with 45 binary and 16 STR markers from the Y chromosome. According to our analysis, the northern populations examined all started to expand in number between 34 (18–68) and 22 (12–39) thousand years ago (KYA), before the last glacial maximum at 21–18 KYA, while the southern populations all started to expand between 18 (6–47) and 12 (1–45) KYA, but then grew faster. We suggest that the northern populations expanded earlier because they could exploit the abundant megafauna of the “Mammoth Steppe,” while the southern populations could increase in number only when a warmer and more stable climate led to more plentiful plant resources such as tubers.
Analysis of Core Housekeeping and Virulence Genes Reveals Cryptic Lineages ofClostridium perfringensThat Are Associated With Distinct Disease Presentations
Authors: Rooney Alejandro P , Swezey James L , Friedman Robert , Hecht David W , Maddox Carol W 
Published: February 2006

AbstractClostridium perfringens is an important human and animal pathogen that causes a number of diseases that vary in their etiology and severity. Differences between strains regarding toxin gene composition and toxin production partly explain why some strains cause radically different diseases than others. However, they do not provide a complete explanation. The purpose of this study was to determine if there is a phylogenetic component that explains the variance in C. perfringens strain virulence by assessing patterns of genetic polymorphism in genes (colA gyrA, plc, pfoS, and rplL) that form part of the core genome in 248 type A strains. We found that purifying selection plays a central role in shaping the patterns of nucleotide substitution and polymorphism in both housekeeping and virulence genes. In contrast, recombination was found to be a significant factor only for the virulence genes plc and colA and the housekeeping gene gyrA. Finally, we found that the strains grouped into five distinct evolutionary lineages that show evidence of host adaptation and the early stages of speciation. The discovery of these previously unknown lineages and their association with distinct disease presentations carries important implications for human and veterinary clostridial disease epidemiology and provides important insights into the pathways through which virulence has evolved in C. perfringens.
A Deficiency in the Region Homologous to Human 17q21.33–q23.2 Causes Heart Defects in Mice
Authors: Yu Y Eugene , Morishima Masae , Pao Annie , Wang Ding-Yan , Wen Xiao-Yan , Baldini Antonio , Bradley Allan 
Published: February 2006

AbstractSeveral constitutional chromosomal rearrangements occur on human chromosome 17. Patients who carry constitutional deletions of 17q21.3–q24 exhibit distinct phenotypic features. Within the deletion interval, there is a genomic segment that is bounded by the myeloperoxidase and homeobox B1 genes. This genomic segment is syntenically conserved on mouse chromosome 11 and is bounded by the mouse homologs of the same genes (Mpo and HoxB1). To attain functional information about this syntenic segment in mice, we have generated a 6.9-Mb deletion [Df(11)18], the reciprocal duplication [Dp(11)18] between Mpo and Chad (the chondroadherin gene), and a 1.8-Mb deletion between Chad and HoxB1. Phenotypic analyses of the mutant mouse lines showed that the Dp(11)18/Dp(11)18 genotype was responsible for embryonic or adolescent lethality, whereas the Df(11)18/+ genotype was responsible for heart defects. The cardiovascular phenotype of the Df(11)18/+ fetuses was similar to those of patients who carried the deletions of 17q21.3–q24. Since heart defects were not detectable in Df(11)18/Dp(11)18 mice, the haplo-insufficiency of one or more genes located between Mpo and Chad may be responsible for the abnormal cardiovascular phenotype. Therefore, we have identified a new dosage-sensitive genomic region that may be critical for normal heart development in both mice and humans.
Cotransport of the Heterodimeric Small Subunit of the Saccharomyces cerevisiae Ribonucleotide Reductase Between the Nucleus and the Cytoplasm
Authors: An Xiuxiang , Zhang Zhen , Yang Kui , Huang Mingxia 
Published: February 2006

Abstract
Ribonucleotide reductase (RNR) catalyzes the rate-liming step in de novo deoxyribonucleotide biosynthesis and is essential in DNA replication and repair. Cells have evolved complex mechanisms to modulate RNR activity during normal cell cycle progression and in response to genotoxic stress. A recently characterized mode of RNR regulation is DNA damage-induced RNR subunit redistribution. The RNR holoenzyme consists of a large subunit, R1, and a small subunit, R2. The Saccharomyces cerevisiae R2 is an Rnr2:Rnr4 heterodimer. Rnr2 generates a diferric–tyrosyl radical cofactor required for catalysis; Rnr4 facilitates cofactor assembly and stabilizes the resulting holo-heterodimer. Upon DNA damage, Rnr2 and Rnr4 undergo checkpoint-dependent, nucleus-to-cytoplasm redistribution, resulting in colocalization of R1 and R2. Here we present evidence that Rnr2 and Rnr4 are transported between the nucleus and the cytoplasm as one protein complex. Tagging either Rnr2 or Rnr4 with a nuclear export sequence causes cytoplasmic localization of both proteins. Moreover, mutations at the Rnr2:Rnr4 heterodimer interface can affect the localization of both proteins without disrupting the heterodimeric complex. Finally, the relocalization of Rnr4 appears to involve both active export and blockage of nuclear import. Our findings provide new insights into the mechanism of DNA damage-induced RNR subunit redistribution.
Selective Male Mortality in the Red Imported Fire Ant, Solenopsis invicta
Authors: Fritz Gary N , Vander Meer Robert K , Preston Catherine A 
Published: February 2006

Abstract
Males in polygyne populations of Solenopsis invicta are primarily sterile diploids and thought to not express the Gp-9 gene coding for a pheromone-binding protein affecting complex social behavior. We examined an aspect of the breeding system hitherto not considered—male Gp-9 genotypes in relation to sperm stored in queens. Four sites with varying frequencies of sympatric monogyne and polygyne colonies were sampled, including sexuals, workers, and broods from four colonies. Most queens were heterozygotes storing B sperm. Although predicted to be common, only 14 of 504 males were B or BB genotypes, suggesting strong selection. Increased frequency of polygyne colonies at each site paralleled increases in queens with b sperm (1.9–32.8%) and of noninseminated queens. The presence of both B and b sperm in 1.9–18.9% of queens, genotype profiles of colonies, and genotypes of offspring from individual queens suggest some frequency of multiple mating. The bb genotype, rather than an obligate, developmental lethal, was present in some queens and common in alates, workers, and brood. Selective mortality of sexuals may affect multiple aspects of the breeding system, including female-mediated dispersal, mating success, and gene flow.
Localization of Müllerian Mimicry Genes on a Dense Linkage Map ofHeliconius erato
Authors: Kapan Durrell D , Flanagan Nicola S , Tobler Alex , Papa Riccardo , Reed Robert D , Acevedo Gonzalez Jenny , Ramirez Restrepo Manuel , Martinez Lournet , Maldonado Karla , Ritschoff Clare , Heckel David G , McMillan W Owen 
Published: February 2006

AbstractWe report a dense genetic linkage map of Heliconius erato, a neotropical butterfly that has undergone a remarkable adaptive radiation in warningly colored mimetic wing patterns. Our study exploited natural variation segregating in a cross between H. erato etylus and H. himera to localize wing color pattern loci on a dense linkage map containing amplified fragment length polymorphisms (AFLP), microsatellites, and single-copy nuclear loci. We unambiguously identified all 20 autosomal linkage groups and the sex chromosome (Z). The map spanned a total of 1430 Haldane cM and linkage groups varied in size from 26.3 to 97.8 cM. The average distance between markers was 5.1 cM. Within this framework, we localized two major color pattern loci to narrow regions of the genome. The first gene, D, responsible for red/orange elements, had a most likely placement in a 6.7-cM region flanked by two AFLP markers on the end of a large 87.5-cM linkage group. The second locus, Sd, affects the melanic pattern on the forewing and was found within a 6.3-cM interval between flanking AFLP loci. This study complements recent linkage analysis of H. erato's comimic, H. melpomene, and forms the basis for marker-assisted physical mapping and for studies into the comparative genetic architecture of wing-pattern mimicry in Heliconius.
Polymer flocculation of calcite: Relating the aggregate size to the settling rate
Authors: Heath Alex R. , Bahri Parisa A. , Fawell Phillip D. , Farrow John B. 
Published: February 2006

AbstractThe initial hindered settling velocities of flocculated calcite suspensions have been related to the mean aggregate sizes and solid fraction under a range of flocculation conditions that are similar to those occurring within a mineral processing thickener. Calcite particles were flocculated in turbulent pipe flow and the aggregates sized with an in situ probe (Lasentec FBRM). The flocculated suspension then flowed into vertical column used to measure the hindered settling velocity. This allowed the investigation of key flocculation parameters — the flocculant dosage, the primary particle size, the suspension solid fraction and the fluid shear rate. The hindered settling velocity was related to the mean aggregate size using a relationship based on Richardson and Zaki's extension of Stokes' law. The effect of aggregate porosity was incorporated using fractal geometry, allowing the estimation of the fractal dimension (2.4) from experimental data. It is an important step toward the development of a link between the size of aggregates produced by flocculation, and their settling and dewatering characteristics. This is also an essential step in the development of robust process models describing the performance of gravity thickeners which are widely used throughout the minerals and other industries. © 2006 American Institute of Chemical Engineers AIChE J, 2006
An equation of state contribution for polar components: Polarizable dipoles
Authors: Kleiner Matthias , Gross Joachim 
Published: February 2006

AbstractThe renormalized perturbation theory for polarizable polar fluids of Wertheim is applied in combination with a dipole contribution for non‐spherical molecules to account for the non‐additive induction interactions due to the polarization of molecules. A comparison to simulation data of pure polarizable dipolar fluids and mixtures reveals a good to excellent agreement between the renormalized perturbation theory and the simulations. The model framework is applied with the Perturbed‐Chain SAFT equation of state to model phase equilibria of mixtures containing strongly polar components. The considered values of dipole moments and of average molecular polarizabilities stem from independent sources, and there is thus no additional adjustable parameter introduced along with the polar contributions to the equation of state. It is confirmed that accounting for dipolar interactions not only reduces the value of the binary interaction parameter, but in many cases significantly improves the description of pure‐component and mixture phase equilibria. Accounting for molecular polarizability and the dipole induction effects only leads to slightly improved results compared to the case where a permanent dipole moment is considered in the calculations. © 2006 American Institute of Chemical Engineers AIChE J, 2006
New Purines with Antiplatelet Activity
Authors: Märschenz Katrin , Rehse Klaus 
Published: February 2006

AbstractFour purine‐2,6‐diamines, 4a, b, 5a, b, nineteen N‐(purin‐2‐yl)benzenecarboxamides 6a–q, 7b, and one N‐(purin‐2‐yl)‐2‐furanecarboxamide 8 were prepared for the first time and tested for their inhibition of blood platelet aggregation. Six compounds, 6a, b, h, m, o, p, inhibited the platelet aggregation induced by collagen with IC50 values between 3 and 10 μmol/L in the Born test. ADP, PAF, and adrenaline were used as specific aggregation inducers to examine the mechanism of the anti‐aggregating activity. An astonishing pattern of activities in the nanomolar, with 6m, 7b, 8 and even subnanomolar range, with 6b, was observed. Compound 6b inhibited the platelet aggregation induced by ADP with an IC50 = 0.45 nM (6m: 3.5 nM; 8: 30 nM). Compound 7b showed an antagonism against the inducer adrenaline with an IC50 = 1.8 nM (6o: 20 nM; 8: 30 nM). The strongest antagonism against PAF was observed with 7b showing an IC50 = 1 nM (6b: 35 nM; 8: 74 nM).
Yeast as a tool to uncover the cellular targets of drugs
Authors: Sturgeon Christopher M. , Kemmer Danielle , Anderson Hilary J. , Roberge Michel 
Published: February 2006

AbstractKnowledge of the spectrum of cellular proteins targeted by experimental therapeutic agents would greatly facilitate drug development. However, identifying the targets of drugs is a daunting challenge. The yeast Saccharomyces cerevisiae is a valuable model organism for human diseases and pathways because it is genetically tractable and shares many functional homolog with humans. In yeast, it is possible to increase or decrease the expression level of essentially every gene and measure changes in drug sensitivity to uncover potential targets. It is also possible to infer mechanism of action from comparing the changes in mRNA expression elicited by drug treatment with those induced by gene deletions or by other drugs. Proteins that bind drugs directly can be identified using yeast protein chips. This review of the use of yeast for discovering targets of drugs discusses the advantages and drawbacks of each approach and how combining methods may reveal targets more efficiently.
Psychopathy, aggression, and the processing of emotional stimuli in non‐referred girls and boys
Authors: Kimonis Eva R. , Frick Paul J. , Fazekas Holly , Loney Bryan R. 
Published: February 2006

AbstractResearch shows that individuals with psychopathic traits differ in how they process negative emotional stimuli. However, it is unclear whether these differences are specific to certain types of negative emotional stimulus and whether they are more strongly associated with psychopathic traits or aggression. Further, it is not clear whether or not deficits in emotional processing generalize to females and ethnic minority individuals with psychopathic traits. In this study, we examined the emotional processing of visual stimuli using a dot‐probe task in 50 non‐referred girls and boys (mean age of 9.30; SD = 2.00). Overall, there was a significant association between proactive aggression and reduced responsiveness to distressing stimuli. In addition, the predicted association between psychopathic traits and reduced responsiveness to distressing stimuli was only found for children high on aggression. Also, the associations among aggression, psychopathic traits, and responsiveness to distressing stimuli did not differ for boys and girls. Copyright © 2006 John Wiley & Sons, Ltd.
Chemical‐Reaction‐Based Site‐Selective DNA Cutter for PCR‐Free Gene Manipulation
Authors: Yamamoto Yoji , Uehara Akihiko , Watanabe Akira , Aburatani Hiroyuki , Komiyama Makoto 
Published: February 2006

AbstractAn artificial restriction DNA cutter (ARCUT), recently developed by the authors, was used to construct a fusion protein. The gene of WW‐domain‐containing oxidoreductase (WWOX) was cut by ARCUT just before its stop codon, and ligated to fuse the gene of enhanced green fluorescent protein (EGFP). The reading frames of two genes were adjusted to coincide each other. Throughout the manipulation, no PCR was employed. The fluorescent fusion protein was successfully expressed in mammalian cells, and showed entirely different subcellular localization from EGFP itself. Apparently, the DNA was kept completely intact during the manipulation. The man‐made tool ARCUT has promising features for future biotechnology and molecular biology.
Remote Interactions Explain the Unusual Regioselectivity of Lipase from Pseudomonas cepacia toward the Secondary Hydroxyl of 2′‐Deoxynucleosides
Authors: Lavandera Iván , Fernández Susana , Magdalena Julia , Ferrero Miguel , Grewal Harjap , Savile Christopher K. , Kazlauskas Romas J. , Gotor Vicente 
Published: February 2006

AbstractLipase from Pseudomonas cepacia (PCL) surprisingly favors acylation of the secondary hydroxyl at the 3′‐position over the primary hydroxyl at the 5′‐position in 2′‐deoxynucleosides by up to >98:1. Catalytically productive tetrahedral intermediate analogues for both orientations were found by molecular modeling. However, acylation of the 3′‐hydroxyl places the thymine base in the alternate hydrophobic pocket of PCL's substrate‐binding site where it can hydrogen bond to the side‐chain hydroxyls of Tyr23 and Tyr29 and the main chain carbonyl of Leu17. Conversely, acylation of the 5′‐hydroxyl leaves the thymine base in the solvent where there is no favorable binding to the enzyme. We propose that these remote stabilizing interactions between the thymine base and PCL's substrate‐binding site stabilize the 3′‐acylation transition state and thus account for the unusual regioselectivity.
Density Control of Dodecamanganese Clusters Anchored on Silicon(100)
Authors: Condorelli Guglielmo G. , Motta Alessandro , Favazza Maria , Nativo Paola , Fragalà Ignazio L. , Gatteschi Dante 
Published: February 2006

AbstractA synthetic strategy to control the density of Mn12 clusters anchored on silicon(100) was investigated. Diluted monolayers suitable for Mn12 anchoring were prepared by Si‐grafting mixtures of the methyl 10‐undecylenoate precursor ligand with 1‐decene spectator spacers. Different ratios of these mixtures were tested. The grafted surfaces were hydrolyzed to reveal the carboxylic groups available for the subsequent exchange with the [Mn12O12(OAc)16(H2O)4]⋅4 H2O⋅2 AcOH cluster. Modified surfaces were analyzed by attenuated total reflection (ATR)‐FTIR spectroscopy, X‐ray photoemission spectroscopy (XPS), and AFM imaging. Results of XPS and ATR‐FTIR spectroscopy show that the surface mole ratio between grafted ester and decene is higher than in the source solution. The surface density of the Mn12 cluster is, in turn, strictly proportional to the ester mole fraction. Well‐resolved and isolated clusters were observed by AFM, using a diluted ester/decene 1:1 solution.
Bis(trifluoromethyl)phosphinous Acid (CF3)2P‐O‐H: An Example of a Thermally Stable Phosphinous Acid—Synthesis, Gas‐Phase Structure, and Rotational Isomers
Authors: Hoge Berthold , Garcia Placido , Willner Helge , Oberhammer Heinz 
Published: February 2006

AbstractThe bis(trifluoromethyl)phosphinous acid, (CF3)2POH, is the only known example of a thermally stable phosphinous acid. Although this compound has been known since 1960, little is known about the chemistry of this extraordinary compound; this might be due to the tedious, and in some part risky, synthesis that was originally published. An improved, simple, and safe synthesis that is based on the treatment of the easily accessible (CF3)2PNEt2, with at least three equivalents of p‐toluene sulfonic acid, is presented. The reaction results in a complete conversion to the phosphinous acid, which is isolated in almost 90 % yield. The compound exists in an equilibrium of two POH rotational isomers, a fact which is supported by quantum chemical calculations. The relative enthalpy difference of 6.4 kJ mol−1, calculated at the B3PW91/6‐311G(3d,p) level, is in excellent agreement with the experimental value of 5.9 kJ mol−1, which was determined from the temperature dependence of the $\tilde \nu $(OH) bands of the two rotational isomers. The complete experimental vibrational spectra of both rotamers, their predicted vibrational spectra obtained by using quantum chemical calculations, and an attempt at photoinduced isomerization of matrix‐isolated (CF3)2POH is presented. The experimental structure, obtained from an electron‐diffraction study in the gas phase, is reproduced very well by ab initio and density functional theory (DFT) methods.
Self‐Assembly of Chiral Depsipeptide Dendrimers
Authors: Hager Kristine , Franz Alexander , Hirsch Andreas 
Published: February 2006

AbstractThe self‐assembly of chiral depsipeptide dendrons 4, which contain a cyanuric acid building block at their focal point, with the homotritopic Hamilton receptor 1 is reported. The 1:3 compositions of the resulting chiral supramolecular dendrimers, the association constants Kn, and the cooperativity of binding expressed by Scatchard plots and the Hill coefficients nH was determined by NMR titration experiments. The most pronounced positive cooperativity was found for the complexes 1 L3 with L being the second‐generation dendrons 4 c–e. The least stable complexes are formed with the bulky third‐generation dendrons 4 f–h. Similar results are obtained by the corresponding complexation of the achiral Frechét‐type first‐ to third‐generation dendrons 3 with 1. Chiroptical investigations of 1:3 complexes of 1 and 4 reveal chirality transfer from the dendron to the Hamilton receptor as demonstrated by the appearance of new CD absorption bands at 310 nm.