bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic instability in the lower thermosphere inferred from irregular sporadic E layers
Authors: Hysell D. L. , Nossa E. , Larsen M. F. , Munro J. , Smith S. , Sulzer M. P. , González S. A.
Published: June 2012

Simultaneous observations of an irregular sporadic Elayer from the Arecibo incoherent scatter radar and a coherent scatter radar located on St. Croix are presented. The layers exhibit periodic structuring which is attributed to shear instability in the neutral flow. Estimates of the time‐varying vector neutral wind profiles in which the layer was embedded are analyzed and shown to be shear unstable in the Richardson number sense. In addition to the calculation of the Richardson number values, we present an eigenvalue analysis of the model of Miles (1961) and Howard (1961) for the observed wind profiles. The calculated eigenmodes have dominant Kelvin‐Helmholtz modes for the estimated flow that are propagating to the southwest with phase speeds near 50 m/s and horizontal wavelengths between 10–15 km. The growth times for the waves would have been as little as about 1 min. These features are in reasonable agreement with the observed of Es‐layer structure. The Miles‐Howard model has been analyzed extensively in the past using both analytic and numerical techniques, but calculations of eigenmodes for the equations in a case with background winds that have turning and speed shear have not been carried out previously, as far as we know. The difficulties associated with the calculation are related to identifying the fastest growing modes among the large number of modes that satisfy the equations. The technique and the relationship of the solutions to the observed sporadicE layer wave structure are described.
Ferrous iron partitioning between magnesium silicate perovskite and ferropericlase and the composition of perovskite in the Earth's lower mantle
Authors: Nakajima Yoichi , Frost Daniel J. , Rubie David C.
Published: June 2012

We have investigated the exchange of Fe and Mg between magnesium silicate perovskite (Mg‐Pv) and ferropericlase (Fp) at 25 GPa and 2400 to 2600 K using a Kawai‐type multianvil apparatus. Each experiment was performed with coexisting metallic Fe, which buffered the oxygen fugacity at the lowest possible level. As the system was Al‐free the presence of metallic Fe ensures low ferric iron (Fe3+) contents in all phases. The results are used to extract thermodynamic data to describe Fe2+‐Mg partitioning. A thermodynamic assessment and modeling of the available high‐pressure partitioning data indicates that the influence of a Fe‐spin transition in Fp on Fe‐Mg partitioning may be more subtle than previously proposed. Furthermore, we demonstrate that a comparison between perovskite Fe2+ contents predicted by the thermodynamic model and previously reported perovskite analyses can be used to estimate Mg‐Pv Fe3+ concentrations of both Al‐bearing and Al‐free phases in the previous studies. These estimates show that the Fe3+ content of Al‐free Mg‐Pv depends strongly on oxygen fugacity, and varies accordingly with the capsule materials used in experiments. The relationship between Fe3+ and Al concentrations in Al‐bearing Mg‐Pv indicates that the substitution mechanism of Fe3+ and Al changes with Al content. Chemical heterogeneities in the lower mantle will result in the formation of Mg‐Pv with quite different Al and bulk Fe concentrations, which will cause important differences in Fe3+ and oxygen vacancy concentrations in Mg‐Pv.
The scaling of temporal rainfall
Authors: Veneziano Daniele , Lepore Chiara
Published: June 2012

The scaling analysis of temporal rainfall produces very different results if one uses the entire rainfall record inclusive of rainstorms and dry interstorm periods (continuous analysis) or only intrastorm data (within‐storm analysis). We show that the continuous results reflect mainly the alternation of dry and wet periods and that the rain support is not fractal. Therefore, the continuous results are spurious. This conclusion is significant since continuous analysis is the most popular scaling analysis method for rainfall. The literature on within‐storm analysis is much more limited, and standard methods do not exist. We develop such methods and show how their bias can be corrected and the accuracy maximized. The results from within‐storm analysis show higher intermittency (higher‐intensity fluctuations) than continuous analysis. This result has important implications on downscaling and the evaluation of rainfall extremes. Frequently used multifractal models for rainfall are of the log‐Levy (“universal”) type. A key parameter of those models is the stability index 0 <α ≤ 2, with α= 2 corresponding to lognormal models. To account for the alternation of dry and wet periods (also inside the storms), one can add a “beta component,” obtaining beta‐log‐Levy and beta‐lognormal models. By using simulations withα = 2, we show that standard estimators of αare negatively biased and that the hypothesis of beta‐lognormal multifractality inside the storms is statistically acceptable.
Incisives centrales maxillaires et symétrie : un enjeu
orthodontique majeur
Authors: Moreau Alexis , Bocquet Emmanuelle
Published: June 2012

Les incisives centrales maxillaires jouent un rôle déterminant dans le rendu esthétique
du sourire. La correction de leur malposition et notamment de leur asymétrie est
d’ailleurs l’un des principaux motifs de consultation des patients qui souhaitent
bénéficier d’un traitement orthodontique. L’étiologie de cette asymétrie qui peut être
verticale (une incisive centrale vis-à-vis de son homologue contro-latérale) ou
horizontale (milieu inter-incisif par rapport au plan sagittal médian) sera objectivée au
moyen de l’examen clinique et des examens complémentaires, en particulier radiologiques,
afin de choisir le plan de traitement le plus adapté. En fonction de l’étiopathogénie
(traumatisme alvéolo-dentaire, asymétrie squelettique, asymétrie d’arcade...), le
traitement orthodontique interviendra ensuite à trois niveaux : localement au niveau des
dents elles-mêmes (ingression, égression), globalement au niveau de l’arcade (translation,
recul en masse) et régionalement au niveau squelettique (chirurgie maxillo-faciale). La
complexité de certains traitements liée à la coordination des différents niveaux d’action
thérapeutique est parfois accrue par la nécessité de faire intervenir d’autres spécialités
(chirurgien-dentiste, parodontiste, chirurgien maxillo-facial). La planification initiale
détaillée revêt ici toute son importance, de même que le choix des praticiens associés à
la thérapeutique. Ces traitements, une fois terminés, sont cependant une source de grande
satisfaction pour le praticien et son patient en raison de l’amélioration esthétique très
probante obtenue.
Apport de la parodontologie dans l’esthétique du sourire
Authors: Monnet-Corti Virginie , Barrin Arnaud , Goubron Cyril
Published: June 2012

L’objectif de cet article est de faire le point sur les différents défauts inesthétiques parodontaux et leurs traitements afin d’établir des conduites à tenir pour la prise en charge des défauts parodontaux. L’interrelation entre la discipline orthodontique et parodontale n’est plus à démontrer. Le parodonte évolue tout au long de la vie ; il en est de même pour le sourire. Le parodonte s’intègre dans le cadre facial, mais aussi dans le cadre labial. Ce sont des critères esthétiques dynamiques. La gencive et l’agencement dentaire, statique, conditionnent également le sourire. Pour qu’un traitement orthodontique soit réalisé dans les meilleures conditions, il est essentiel de respecter un parcours coordonné entre l’orthodontiste et le parodontiste. Dans un premier temps, il faut établir un diagnostic étiologique du défaut esthétique afin d’apporter le traitement approprié (parodontal ou orthodontique) au bon moment.
Le concept du déplacement dentaire accéléré par corticotomie ou
par piézocision
Authors: Strippoli Julien , Aknin Jean-Jacques
Published: June 2012

Les corticotomies et la piézocision, plus récemment, permettent d’accélérer le
déplacement dentaire provoqué et donc de réduire la durée du traitement orthodontique. Les
mécanismes biologiques sous-jacents à ces thérapeutiques font l’objet de débats entre les
auteurs défendant un concept « mécanistique » et ceux défendant un concept « biologique ». À
travers l’analyse des différentes publications sur le sujet, il semble que l’explication
biologique soit la bonne, avec comme élément central le « Phénomène d’Activation Régional »
(PAR). Mais la plupart des études ne sont pas fondées sur les principes de l’
« evidence-based-medecine » (EBM).
Resistance at the Limits: Feminist Activism and Conscientious Objection in Israel
Authors: Natanel Katherine
Published: June 2012

This article investigates the relationship between feminism and conscientious objection in Israel, evaluating the efficacy of feminist resistance in the organised refusal movement. While recent feminist scholarship on peace, anti-occupation and anti-militarism activism in Israel largely highlights women's collective action, it does so at the risk of eliding the relations of power within these groups. Expanding the scope of consideration, I look to the experiences of individual feminist conscientious objectors who make visible significant tensions through their accounts of military refusal and participation in the organised conscientious objection movement. Drawing on original ethnographic research, this article problematises feminist activism in the organised Israeli refusal movement through three primary issues: political voice; privilege; and the realisation of gender agendas. Using Michel Foucault's conceptualisation of power as it has been critiqued and qualified by feminist scholars, I consider the ways in which resistance may be both multiple and a diagnostic of power, allowing activists and academics not only to envision new avenues for social change, but also to recognise their constraints. Critically, feminist theories of intersectionality enrich and complicate this Foucauldian approach to power, providing further modes of critique and strategy in the context of feminist activism in Israel. Ultimately, I argue not only for engagement with the limits of power, but also attention to their function, as in theory and praxis these boundaries critically inform our theorising on gender and resistance.
Militarism, Conflict and Women's Activism in the Global Era: Challenges and Prospects for Women in Three West African Contexts
Authors: Mama Amina , Okazawa-Rey Margo
Published: June 2012

This article develops a feminist perspective on militarism in Africa, drawing examples from the Nigerian, Sierra Leonean and Liberian civil wars spanning several decades to examine women's participation in the conflict, their survival and livelihood strategies, and their activism. We argue that postcolonial conflicts epitomise some of the worst excesses of militarism in the era of neoliberal globalisation, and that the economic, organisational and ideological features of militarism undermine the prospects for democratisation, social justice and genuine security, especially for women, in post-war societies. Theorisations of ‘new wars’ and the war economy are taken as entry points to a discussion of the conceptual and policy challenges posed by the enduring and systemic cultural and material aspects of militarism. These include the contradictory ways in which women are affected by the complex relationship between gendered capitalist processes and militarism, and the manner in which women negotiate their lives through both. Finally, we highlight the potential of transnational feminist theorising and activism for strengthening intellectual and political solidarities and argue that the globalised military security system can be our ‘common context for struggle' 1 as contemporary feminist activist scholars.

1 Mohanty, 2003.
Site-controlled formation of InAs/GaAs quantum-dot-in-nanowires for single photon emitters
Authors: Tatebayashi J. , Ota Y. , Ishida S. , Nishioka M. , Iwamoto S. , Arakawa Y.
Published: June 2012

We report the demonstration of site-controlled InAs/GaAs quantum dots (QDs) embedded in GaAs nanowires (NWs) by selective metalorganic chemical vapor deposition. InAs/GaAs quantum-dot-in-nanowires (QD-in-NWs) with various InAs thicknesses are realized on patterned GaAs(111)B substrates in the form of InAs/GaAs heterostructures and identified by structural analyses using scanning transmission electron microscopy and photoluminescence characterization. Sharp excitonic emission peaks at 10 K from single QD-in-NWs with the narrowest exciton linewidth of 87 μeV are observed. Light emission from the single QD-in-NW shows photon antibunching, along with biexciton-exciton cascaded emission process, which evidences single photon emission from high-quality QD-in-NWs.
Sieve element occlusion(SEO) genes encode structural phloem proteins involved in wound sealing of the phloem
Authors: Ernst Antonia M. , Jekat Stephan B. , Zielonka Sascia , Müller Boje , Neumann Ulla , Rüping Boris , Twyman Richard M. , Krzyzanek Vladislav , Prüfer Dirk , Noll Gundula A.
Published: June 2012

Thesieve element occlusion(SEO) gene family originally was delimited to genes encoding structural components of forisomes, which are specialized crystalloid phloem proteins found solely in the Fabaceae. More recently,SEOgenes discovered in various non-Fabaceae plants were proposed to encode the common phloem proteins (P-proteins) that plug sieve plates after wounding. We carried out a comprehensive characterization of two tobacco (Nicotiana tabacum)SEOgenes (NtSEO). Reporter genes controlled by theNtSEOpromoters were expressed specifically in immature sieve elements, and GFP-SEO fusion proteins formed parietal agglomerates in intact sieve elements as well as sieve plate plugs after wounding. NtSEO proteins with and without fluorescent protein tags formed agglomerates similar in structure to native P-protein bodies when transiently coexpressed inNicotiana benthamiana, and the analysis of these protein complexes by electron microscopy revealed ultrastructural features resembling those of native P-proteins.NtSEO-RNA interference lines were essentially devoid of P-protein structures and lost photoassimilates more rapidly after injury than control plants, thus confirming the role of P-proteins in sieve tube sealing. We therefore provide direct evidence thatSEOgenes in tobacco encode P-protein subunits that affect translocation. We also found that peptides recently identified in fascicular phloem P-protein plugs from squash (Cucurbita maxima) represent cucurbit members of the SEO family. Our results therefore suggest a common evolutionary origin for P-proteins found in the sieve elements of all dicotyledonous plants and demonstrate the exceptional status of extrafascicular P-proteins in cucurbits.
Structure and permeation mechanism of a mammalian urea transporter
Authors: Levin Elena J. , Cao Yu , Enkavi Giray , Quick Matthias , Pan Yaping , Tajkhorshid Emad , Zhou Ming
Published: June 2012

As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urinary space and the hyperosmotic interstitium. Here we report the first X-ray crystal structure of a mammalian UT, UT-B, at a resolution of 2.36 Å. UT-B is a homotrimer and each protomer contains a urea conduction pore with a narrow selectivity filter. Structural analyses and molecular dynamics simulations showed that the selectivity filter has two urea binding sites separated by an approximately 5.0 kcal/mol energy barrier. Functional studies showed that the rate of urea conduction in UT-B is increased by hypoosmotic stress, and that the site of osmoregulation coincides with the location of the energy barrier.
Does participation in research lead to changes in attitudes among clinicians? Report on a survey of those involved in a French practice research network
Authors: Thurin Jean-Michel , Thurin Monique , Midgley Nick
Published: June 2012

Background/Objective: With increasing awareness of some of the limitations of randomised controlled trials as the ‘gold standard’ of psychotherapy evaluation, researchers at the start of the twenty‐first century have focused on a number of new priorities: developing studies in natural conditions; investigating the psychotherapeutic process to better understand the conditions, causes and mechanisms of change; and reducing the gap between clinicians and researchers. Can these three interrelated objectives be combined? Method: A French psychotherapy practice‐based research network (PRN) is used as a field of research for these issues. A survey was used to investigate the conditions that encouraged the clinicians to participate in the PRN study within the context of clinicians’ general opposition to research. Results: Several elements emerged as the key to clinicians’ positive involvement in research: the methodology implemented (intensive case studies during one year); the choice of measures; the constant attention to the practicalities and the potential contribution of studies to clinical practice; the organisation of work in peer groups; the training methods; the use of new information technologies and the sense of participation in a project that would support the profession. Implications: These elements are briefly discussed in relation to the question of how best to encourage clinicians to engage with research.
Eye movements and parafoveal preview of compound words: Does morpheme order matter?
Authors: Angele Bernhard , Rayner Keith
Published: June 2012

Recently, there has been considerable debate about whether readers can identify multiple words in parallel or whether they are limited to a serial mode of word identification, processing one word at a time (see, e.g., Reichle, Liversedge, Pollatsek, & Rayner, 2009). Similar questions can be applied to bimorphemic compound words: Do readers identify all the constituents of a compound word in parallel, and does it matter which of the morphemes is identified first? We asked subjects to read compound words embedded in sentences while monitoring their eye movements. Using the boundary paradigm (Rayner, 1975), we manipulated the preview that subjects received of the compound word before they fixated it. In particular, the morpheme order of the preview was either normal ( cowboy) or reversed ( boycow). Additionally, we manipulated the preview availability for each of the morphemes separately. Preview was thus available for the first morpheme only ( cowtxg), for the second morpheme only ( enzboy), or for neither of the morphemes ( enztxg). We report three major findings: First, there was an effect of morpheme order on gaze durations measured on the compound word, indicating that, as expected, readers obtained a greater preview benefit when the preview presented the morphemes in the correct order than when their order was reversed. Second, gaze durations on the compound word were influenced not only by preview availability for the first, but also by that for the second morpheme. Finally, and most importantly, the results show that readers are able to extract some morpheme information even from a reverse order preview. In summary, readers obtain preview benefit from both constituents of a short compound word, even when the preview does not reflect the correct morpheme order.
‘Laboring in my Books’: A Religious Reader in Nineteenth Century New Hampshire
Authors: Westphall Allan F.
Published: June 2012

This essay examines the book collecting habits and annotation practices of Thomas Connary, an Irish immigrant farmer who lived in New Hampshire in the latter half of the nineteenth century. Connary led a pious life that revolved around the use, annotation and sharing of religious books: his extant annotated books provide a revealing glimpse into the book collecting habits of that elusive category of ‘the common reader’, and into how non-elite readers imagined book utilities and the iconic status of religious books. The first part provides an overview of the many ways in which Thomas Connary interacts with his books. Here a profile is established of a somewhat eccentric reader-cum-annotator who gives us insight into the range of opportunities provided by the material book for recording and communicating readerly intensity and religious fervour. In the second part the focus is on the broader, shared cultural setting in which books are seen as precious testimonies of personal faith, and come to function as tools of social interaction in both domestic and public spheres. Underlying Connary's many and varied interactions with books is a belief that physical objects can materialize belief, and that working in them can be a devout exercise instrumental in human salvation.
Functional Attributes of Proteins Withdrawn from Different Stages of a Commercial Ethanol Fuel/Distillers Dried Grains with Solubles Process Using a Wheat Feedstock
Authors: Stone Andrea , Avramenko Nicole , Abbott Dawn , Classen Hank , Nickerson Michael
Published: June 2012

The functional attributes of proteins withdrawn from different stages of a commercial ethanol fuel/distillers dried grains with solubles (DDGS) process that used a wheat feedstock were investigated. Specifically, protein coproducts were examined postliquefaction (PL), postdistillation (PD), and postdrying (DDGS) and related to those from the native wheat feedstock (WF). Water hydration, oil holding, foaming, and emulsifying properties of all materials were assessed. The WF and the PL coproduct showed similar water hydration capacities (WHCs), ranging between 80 and 110%, whereas WHCs for the PD and DDGS coproducts were significantly higher (ranging between 264 and 356%). WHC for all products was found to be independent over the pH range of 2.00–10.00. A similar trend was found for the oil holding capacities, for which both WF and PL materials showed lower values (≈120%) than both the PD (203%) and DDGS (171%) materials. Foam capacity and stability for the WF were found to be 32.8 and 61.4%, respectively, whereas no coproducts were foam forming. Emulsion stability decreased from ≈45% for the WF to <10% in all other materials. Findings indicated that initial changes to the protein's functional attributes occurred in the PL stage of ethanol/DDGS processing.
Stress Relaxation of Wheat Kernels and Their Relationship with Milling, Rheological, and Breadmaking Quality of Wheat
Authors: Figueroa J. D. C. , Manuel C. I. , Hernández‐Estrada Z. J. , Ramírez‐Wong B.
Published: June 2012

The stress relaxation behaviors of soft and bread‐type wheat kernels were studied using the generalized Maxwell model. The data showed two phases, a fast phase at short times of about 1.52–16.88 sec (τ1 and τ2) and a slow phase with longer times of about 81.28–793.81 sec (τ3 and τ4). The shorter decay of σ1 can be explained by very weak forces that affect mainly the rheological properties. The slow decay (σ4) located at longer relaxation times resulted from strong forces. The first derivative obtained from the stress relaxation curve of intact wheat kernels was quite similar in shape to the dough farinograms. The stress relaxation parameters showed differences in springs, relaxation times, and viscosities of bread wheat compared with soft‐type wheat kernels. The stresses σ1 and σ4 were correlated with wheat kernel, flour, rheological, and breadmaking properties; so especially were the elasticity of the spring (σ0) and viscosity of the fourth Maxwell element (η4), which were significantly correlated with all the quality properties, whereas σ2, σ3, η1, and η2 did not show correlation at all, except that η2 was correlated with falling number and volume of CO2.
A Novel Two-Component System PdeK/PdeR Regulates c-di-GMP Turnover and Virulence ofXanthomonas oryzaepv.oryzae
Authors: Yang Fenghuan , Tian Fang , Sun Lei , Chen Huamin , Wu Maosen , Yang Ching-Hong , He Chenyang
Published: June 2012

Two-component systems (TCS) consisting of histidine kinases (HK) and response regulators (RR) play essential roles in bacteria to sense environmental signals and regulate cell functions. One type of RR is involved in metabolism of cyclic diguanylate (c-di-GMP), a ubiquitous bacterial second messenger. Although genomic studies predicted a large number of them existing in different bacteria, only a few have been studied. In this work, we characterized a novel TCS consisting of PdeK(PXO_01018)/PdeR(PXO_ 01019) from Xanthomonas oryzae pv. oryzae, which causes the bacterial leaf blight of rice. PdeR (containing GGDEF, EAL, and REC domains) was shown to have phosphodiesterase (PDE) activity in vitro by colorimetric assays and high-performance liquid chromatography analysis. The PDE activity of full-length PdeR needs to be triggered by HK PdeK. Deletion of pdeK or pdeR in X. oryzae pv. oryzae PXO99Ahad attenuated its virulence on rice. ΔpdeK and ΔpdeR secreted less exopolysaccharide than the wild type but there were no changes in terms of motility or extracellular cellulase activity, suggesting the activity of PdeK/PdeR might be specific.
Genome Sequencing and Mapping Reveal Loss of Heterozygosity as a Mechanism for Rapid Adaptation in the Vegetable Pathogen Phytophthora capsici
Authors: Lamour Kurt H. , Mudge Joann , Gobena Daniel , Hurtado-Gonzales Oscar P. , Schmutz Jeremy , Kuo Alan , Miller Neil A. , Rice Brandon J. , Raffaele Sylvain , Cano Liliana M. , Bharti Arvind K. , Donahoo Ryan S. , Finley Sabra , Huitema Edgar , Hulvey Jon , Platt Darren , Salamov Asaf , Savidor Alon , Sharma Rahul , Stam Remco , Storey Dylan , Thines Marco , Win Joe , Haas Brian J. , Dinwiddie Darrell L. , Jenkins Jerry , Knight James R. , Affourtit Jason P. , Han Cliff S. , Chertkov Olga , Lindquist Erika A. , Detter Chris , Grigoriev Igor V. , Kamoun Sophien , Kingsmore Stephen F.
Published: June 2012

The oomycete vegetable pathogen Phytophthora capsici has shown remarkable adaptation to fungicides and new hosts. Like other members of this destructive genus, P. capsici has an explosive epidemiology, rapidly producing massive numbers of asexual spores on infected hosts. In addition, P. capsici can remain dormant for years as sexually recombined oospores, making it difficult to produce crops at infested sites, and allowing outcrossing populations to maintain significant genetic variation. Genome sequencing, development of a high-density genetic map, and integrative genomic or genetic characterization of P. capsici field isolates and intercross progeny revealed significant mitotic loss of heterozygosity (LOH) in diverse isolates. LOH was detected in clonally propagated field isolates and sexual progeny, cumulatively affecting >30% of the genome. LOH altered genotypes for more than 11,000 single-nucleotide variant sites and showed a strong association with changes in mating type and pathogenicity. Overall, it appears that LOH may provide a rapid mechanism for fixing alleles and may be an important component of adaptability for P. capsici.
The Requirement of Multiple Defense Genes in SoybeanRsv1–Mediated Extreme Resistance toSoybean mosaic virus
Authors: Zhang Chunquan , Grosic Sehiza , Whitham Steven A. , Hill John H.
Published: June 2012

Soybean mosaic virus (SMV) is a major viral pathogen of soybean. Among the three SMV resistance genes, Rsv1 mediates extreme resistance (ER) against most SMV strains, including the β-glucuronidase-tagged G2 isolate that was previously used in studies of Rsv1. Using virus-induced gene silencing (VIGS), we screened 82 VIGS constructs to identify genes that play a role in Rsv1-mediated ER to SMV infection. The target genes included putative Rsv1 candidate genes, soybean orthologs to known defense-signaling genes, and 62 WRKY transcription factors. We identified eight VIGS constructs that compromised Rsv1-mediated resistance when the target genes were silenced, including GmEDR1, GmEDS1, GmHSP90, GmJAR1, GmPAD4, and two WRKY transcription factors. Together, our results provide new insight into the soybean signaling network required for ER against SMV.
Functional Analysis of Gene-Silencing Suppressors from Tomato Yellow Leaf Curl Disease Viruses
Authors: Luna Ana P. , Morilla Gabriel , Voinnet Olivier , Bejarano Eduardo R.
Published: June 2012

Tomato yellow leaf curl disease (TYLCD) is caused by a complex of phylogenetically related Begomovirus spp. that produce similar symptoms when they infect tomato plants but have different host ranges. In this work, we have evaluated the gene-silencing-suppression activity of C2, C4, and V2 viral proteins isolated from the four main TYLCD-causing strains in Spain in Nicotiana benthamiana. We observed varying degrees of local silencing suppression for each viral protein tested, with V2 proteins from all four viruses exhibiting the strongest suppression activity. None of the suppressors were able to avoid the spread of the systemic silencing, although most produced a delay. In order to test the silencing-suppression activity of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) proteins in a shared (tomato) and nonshared (bean) host, we established novel patch assays. Using these tools, we found that viral proteins from TYLCV were able to suppress silencing in both hosts, whereas TYLCSV proteins were only effective in tomato. This is the first time that viral suppressors from a complex of disease-causing geminiviruses have been subject to a comprehensive analysis using two economically important crop hosts, as well as the established N. benthamiana plant model.
Ethylene Signaling Pathway Modulates Attractiveness of Host Roots to the Root-Knot Nematode Meloidogyne hapla
Authors: Fudali Sylwia L. , Wang Congli , Williamson Valerie M.
Published: June 2012

Infective juveniles of the root-knot nematode Meloidogyne hapla are attracted to the zone of elongation of roots where they invade the host but little is known about what directs the nematode to this region of the root. We found that Arabidopsis roots exposed to an ethylene (ET)-synthesis inhibitor attracted significantly more nematodes than control roots and that ET-overproducing mutants were less attractive. Arabidopsis seedlings with ET-insensitive mutations were generally more attractive whereas mutations resulting in constitutive signaling were less attractive. Roots of the ET-insensitive tomato mutant Never ripe (Nr) were also more attractive, indicating that ET signaling also modulated attraction of root-knot nematodes to this host. ET-insensitive mutants have longer roots due to reduced basipetal auxin transport. However, assessments of Arabidopsis mutants that differ in various aspects of the ET response suggest that components of the ET-signaling pathway directly affecting root length are not responsible for modulating root attractiveness and that other components of downstream signaling result in changes in levels of attractants or repellents for M. hapla. These signals may aid in directing this pathogen to an appropriate host and invasion site for completing its life cycle.
First Report of Powdery Mildew Caused by Podosphaera pannosa on Prunus cerasus in France
Authors: Hubert J. , Fourrier C. , Payen C. , Fournié J. L. , Ioos R.
Published: June 2012

Podosphaera pannosa (Wallr.:Fr.) de Bary (anamorph Oïdium leucoconium Desm.) is described as the most frequent species causing powdery mildew of members of the Rosaceae family, especially on Rosa spp. and Prunus spp. P. pannosa is reported as cosmopolitan, but its occurrence on Prunus cerasus (cherry) is limited to Hungary (3). During spring 2011, typical symptoms of powdery mildew were observed in a Prunus cerasus orchard located in La Roche de Glun (southeastern France). On average, 25% of the shoots per individual tree were affected by this disease. Although several different cultivars were grown in the orchard, cultivar Bigalise alone displayed powdery mildew symptoms. The lower surface of the leaves was covered with superficial, white, dense mycelium, whereas the upper side showed discoloration, necrosing patches, and blisters. Microscopic slides were prepared from fresh material by gently pressing a clear adhesive tape onto the lower surface covered by mycelium, which was further stained with lactic acid/methyl blue. The presence of powdery mildew was confirmed by the observation of typical microscopic features of the anamorphic stage of the fungus (2). Conidiophores were erect. Conidia (oïdia) were hyaline and keg-shaped, and developed basipetally in chains of six to eight conidia. Conidial dimensions were 17 to 29 (23) × 9 to 17 (14) μm. No cleistothecia (teleomorphic state of the fungus) were observed. Species identity was determined by sequencing the ITS region of the rDNA followed by comparison with reference sequences available on GenBank (1). Fungal material was collected from infected leaves by scraping the mycelium with a sterile needle, and was transferred into 2-ml microtubes. Fungal total DNA was then extracted using a commercial plant DNA extraction kit and the ITS region was amplified by PCR using the ITS1-ITS4 primer pair (4). Nucleotide sequence was determined and deposited in GenBank (Accession No. JN654341). Analysis of the sequence by BLAST showed 100% identity with Podosphaera pannosa. To our knowledge, this is the first report of Podosphaera pannosa on Prunus cerasus in France. This species was hitherto scarcely reported on cherry trees, and may deserve more attention in the future.

References: (1) M. Gàbor et al. Eur. J. Plant Pathol. 131:135, 2011. (2) G. Grove et al. Page 12 in: Compendium of Stone Fruit Diseases. American Phytopathological Society, St Paul, MN, 1995. (3) L. Vajna et al. New Dis. Rep. 12:15, 2005. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications, 1990.
Production of DAPG and HCN by Pseudomonas sp. LBUM300 Contributes to the Biological Control of Bacterial Canker of Tomato
Authors: Lanteigne Carine , Gadkar Vijay J. , Wallon Thérèse , Novinscak Amy , Filion Martin
Published: June 2012

Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis is known to cause significant economic losses to tomato production worldwide. Biological control has been proposed as an alternative to current chemical containment methods, which are often inefficient and may leave adverse effects on the environment. However, only little headway has so far been made in developing biocontrol strategies against C. michiganensis subsp. michiganensis. To address this knowledge gap, we investigated the antagonistic capacity of PCA, produced by Pseudomonas sp. LBUM223, and DAPG and HCN, both produced by Pseudomonas sp. LBUM300, on C. michiganensis subsp. michiganensis under in vitro and in planta conditions. Nonsynthesizing isogenic mutants of the producer strains were also developed to further dissect the role of each individual metabolite on C. michiganensis subsp. michiganensis biological control. Novel specific quantitative polymerase chain reaction TaqMan assays allowed quantification of C. michiganensis subsp. michiganensis in tomato plants and rhizospheric soil. Pseudomonas spp. LBUM223 and LBUM300 significantly repressed C. michiganensis subsp. michiganensis growth in vitro, while their respective nonproducing mutants showed less or no significant antagonistic activity. In planta, only Pseudomonas sp. LBUM300 was capable of significantly reducing disease development and C. michiganensis subsp. michiganensis rhizospheric population, suggesting that the production of both DAPG and HCN was involved. In summary, simultaneous DAPG/HCN production by Pseudomonas sp. LBUM300 shows great potential for controlling bacterial canker of tomato.
Comparative Effectiveness of Regional versus General Anesthesia for Hip Fracture Surgery in Adults
Authors: Neuman Mark D. , Silber Jeffrey H. , Elkassabany Nabil M. , Ludwig Justin M. , Fleisher Lee A.
Published: June 2012

Background

Hip fracture is a common, morbid, and costly event among older adults. Data are inconclusive as to whether epidural or spinal (regional) anesthesia improves outcomes after hip fracture surgery.

Methods

The authors examined a retrospective cohort of patients undergoing surgery for hip fracture in 126 hospitals in New York in 2007 and 2008. They tested the association of a record indicating receipt of regional versus general anesthesia with a primary outcome of inpatient mortality and with secondary outcomes of pulmonary and cardiovascular complications using hospital fixed-effects logistic regressions. Subgroup analyses tested the association of anesthesia type and outcomes according to fracture anatomy.

Results

Of 18,158 patients, 5,254 (29%) received regional anesthesia. In-hospital mortality occurred in 435 (2.4%). Unadjusted rates of mortality and cardiovascular complications did not differ by anesthesia type. Patients receiving regional anesthesia experienced fewer pulmonary complications (359 [6.8%] vs. 1,040 [8.1%], P < 0.005). Regional anesthesia was associated with a lower adjusted odds of mortality (odds ratio: 0.710, 95% CI 0.541, 0.932, P = 0.014) and pulmonary complications (odds ratio: 0.752, 95% CI 0.637, 0.887, P < 0.0001) relative to general anesthesia. In subgroup analyses, regional anesthesia was associated with improved survival and fewer pulmonary complications among patients with intertrochanteric fractures but not among patients with femoral neck fractures.

Conclusions

Regional anesthesia is associated with a lower odds of inpatient mortality and pulmonary complications among all hip fracture patients compared with general anesthesia; this finding may be driven by a trend toward improved outcomes with regional anesthesia among patients with intertrochanteric fractures.
Toll-like Receptor 4 Signaling in Ventilator-induced Diaphragm Atrophy
Authors: Schellekens Willem-Jan M. , van Hees Hieronymus W. H. , Vaneker Michiel , Linkels Marianne , Dekhuijzen P. N. Richard , Scheffer Gert Jan , van der Hoeven Johannes G. , Heunks Leo M. A.
Published: June 2012

Background

Mechanical ventilation induces diaphragm muscle atrophy, which plays a key role in difficult weaning from mechanical ventilation. The signaling pathways involved in ventilator-induced diaphragm atrophy are poorly understood. The current study investigated the role of Toll-like receptor 4 signaling in the development of ventilator-induced diaphragm atrophy.

Methods

Unventilated animals were selected for control: wild-type (n = 6) and Toll-like receptor 4 deficient mice (n = 6). Mechanical ventilation (8 h): wild-type (n = 8) and Toll-like receptor 4 deficient (n = 7) mice.Myosin heavy chain content, proinflammatory cytokines, proteolytic activity of the ubiquitin-proteasome pathway, caspase-3 activity, and autophagy were measured in the diaphragm.

Results

Mechanical ventilation reduced myosin content by approximately 50% in diaphragms of wild-type mice (P less than 0.05). In contrast, ventilation of Toll-like receptor 4 deficient mice did not significantly affect diaphragm myosin content. Likewise, mechanical ventilation significantly increased interleukin-6 and keratinocyte-derived chemokine in the diaphragm of wild-type mice, but not in ventilated Toll-like receptor 4 deficient mice. Mechanical ventilation increased diaphragmatic muscle atrophy factor box transcription in both wild-type and Toll-like receptor 4 deficient mice. Other components of the ubiquitin-proteasome pathway and caspase-3 activity were not affected by ventilation of either wild-type mice or Toll-like receptor 4 deficient mice. Mechanical ventilation induced autophagy in diaphragms of ventilated wild-type mice, but not Toll-like receptor 4 deficient mice.

Conclusion

Toll-like receptor 4 signaling plays an important role in the development of ventilator-induced diaphragm atrophy, most likely through increased expression of cytokines and activation of lysosomal autophagy.
Ondansetron Reverses Antihypersensitivity from Clonidine in Rats after Peripheral Nerve Injury
Authors: Hayashida Ken-ichiro , Kimura Masafumi , Yoshizumi Masaru , Hobo Shotaro , Obata Hideaki , Eisenach James C.
Published: June 2012

Introduction

Monoaminergic pathways, impinging an α2-adrenoceptors and 5-HT3 serotonin receptors, modulate nociceptive transmission, but their mechanisms and interactions after neuropathic injury are unknown. Here we examine these interactions in rodents after nerve injury.

Methods

Male Sprague-Dawley rats following L5-L6 spinal nerve ligation (SNL) were used for either behavioral testing, in vivo microdialysis for γ-aminobutyric acid (GABA) and acetylcholine release, or synaptosome preparation for GABA release.

Results

Intrathecal administration of the α2-adrenoceptor agonist (clonidine) and 5-HT3 receptor agonist (chlorophenylbiguanide) reduced hypersensitivity in SNL rats via GABA receptor-mediated mechanisms. Clonidine increased GABA and acetylcholine release in vivo in the spinal cord of SNL rats but not in normal rats. Clonidine-induced spinal GABA release in SNL rats was blocked by α2-adrenergic and nicotinic cholinergic antagonists. The 5-HT3 receptor antagonist ondansetron decreased and chlorophenylbiguanide increased spinal GABA release in both normal and SNL rats. In synaptosomes from the spinal dorsal horn of SNL rats, presynaptic GABA release was increased by nicotinic agonists and decreased by muscarinic and α2-adrenergic agonists. Spinally administered ondansetron significantly reduced clonidine-induced antihypersensitivity and spinal GABA release in SNL rats.

Conclusion

These results suggest that spinal GABA contributes to antihypersensitivity from intrathecal α2-adrenergic and 5-HT3 receptor agonists in the neuropathic pain state, that cholinergic neuroplasticity after nerve injury is critical for α2-adrenoceptor-mediated GABA release, and that blockade of spinal 5-HT3 receptors reduces α2-adrenoceptor-mediated antihypersensitivity via reducing total GABA release.
Cast adrift on an island: introduced populations experience an altered balance between selection and drift
Authors: O'Neill Eric M. , Beard Karen H. , Pfrender Michael E.
Published: June 2012

A long-standing question in evolutionary biology is what becomes of adaptive traits when a species expands its range into novel environments. Here, we report the results of a study on an adaptive colour pattern polymorphism (stripes) of the coqui frog,Eleutherodactylus coqui, following its introduction to Hawaii from Puerto Rico. We compared population differentiation () for thestripeslocus—which underlies this colour pattern polymorphism—with neutral microsatellite loci to test for a signature of selection among native and introduced populations. Among native populations,forstripeswere lower than expected under the neutral model, suggesting uniform balancing selection. Alternatively, among introduced populations,forstripesdid not differ from the neutral model. These results suggest that the evolutionary dynamics of this previously adaptive trait have become dominated by random genetic drift following the range expansion.
The effect of resveratrol on longevity across species: a meta-analysis
Authors: Hector Katie L. , Lagisz Malgorzata , Nakagawa Shinichi
Published: June 2012

Resveratrol has shown evidence of decreasing cancer incidence, heart disease, metabolic syndrome and neural degeneration in animal studies. However, the effects on longevity are mixed. We aimed to quantify the current knowledge of life extension from resveratrol. We used meta-analytic techniques to assess the effect resveratrol has on survival, using data from 19 published papers, including six species: yeast, nematodes, mice, fruitflies, Mexican fruitflies and turquoise killifish. Overall, our results indicate that resveratrol acts as a life-extending agent. The effect is most potent in yeast and nematodes, with diminished reliability in most higher-order species. Turquoise killifish were especially sensitive to life-extending effects of resveratrol but showed much variation. Much of the considerable heterogeneity in our analysis was owing to unexplained variation between studies. In summary, we can report that few species conclusively show life extension in response to resveratrol. As such, we question the practice of the substance being marketed as a life-extending health supplement for humans.
Songbirds learn songs least degraded by environmental transmission
Authors: Peters Susan , Derryberry Elizabeth P. , Nowicki Stephen
Published: June 2012

Communication depends on accurate reception of signals by receivers, and selection acts on signals to transmit efficiently through the environment. Although learnt signals, such as birdsong, vary in their transmission properties through different habitats, few studies have addressed the role of cultural selection in driving acoustic adaptation. Here, we present a test of the hypothesis that song-learning birds choose to copy songs that are less degraded by transmission through the environment, using swamp sparrows (
Melospiza georgiana
) as our study species. We found that all subjects discriminated between undegraded and naturally degraded song models, and learnt only from undegraded song models, demonstrating a role for cultural selection in acoustic adaptation of learnt signals.
The value of reputation
Authors: Pfeiffer Thomas , Tran Lily , Krumme Coco , Rand David G
Published: June 2012

Reputation plays a central role in human societies. Empirical and theoretical work indicates that a good reputation is valuable in that it increases one's expected payoff in the future. Here, we explore a game that couples a repeated Prisoner's Dilemma (PD), in which participants can earn and can benefit from a good reputation, with a market in which reputation can be bought and sold. This game allows us to investigate how the trading of reputation affects cooperation in the PD, and how participants assess the value of having a good reputation. We find that depending on how the game is set up, trading can have a positive or a negative effect on the overall frequency of cooperation. Moreover, we show that the more valuable a good reputation is in the PD, the higher the price at which it is traded in the market. Our findings have important implications for the use of reputation systems in practice.
Revealing mechanisms underlying variation in malaria virulence: effective propagation and host control of uninfected red blood cell supply
Authors: Metcalf C. J. E. , Long G. H. , Mideo N. , Forester J. D. , Bjørnstad O. N. , Graham A. L.
Published: June 2012

Malaria parasite clones with the highest transmission rates to mosquitoes also tend to induce the most severe fitness consequences (or virulence) in mammals. This is in accord with expectations from the virulence–transmission trade-off hypothesis. However, the mechanisms underlying how different clones cause virulence are not well understood. Here, using data from eight murine malaria clones, we apply recently developed statistical methods to infer differences in clone characteristics, including induction of differing host-mediated changes in red blood cell (RBC) supply. Our results indicate that the within-host mechanisms underlying similar levels of virulence are variable and that killing of uninfected RBCs by immune effectors and/or retention of RBCs in the spleen may ultimately reduce virulence. Furthermore, the correlation between clone virulence and the degree of host-induced mortality of uninfected RBCs indicates that hosts increasingly restrict their RBC supply with increasing intrinsic virulence of the clone with which they are infected. Our results demonstrate a role for self-harm in self-defence for hosts and highlight the diversity and modes of virulence of malaria.