25 research outputs found

    East and west separation of Rhipicephalus sanguineus mitochondrial lineages in the Mediterranean Basin

    Get PDF
    Background: Rhipicephalus sanguineus belongs to a complex of hard tick species with high veterinary-medical significance. Recently, new phylogenetic units have been discovered within R. sanguineus, which therefore needs taxonomic revision. The present study was initiated to provide new information on the phylogeography of relevant haplotypes from less studied regions of Europe and Africa. With this aim, molecular-phylogenetic analyses of two mitochondrial markers were performed on 50 ticks collected in Hungary, the Balkans, countries along the Mediterranean Sea, Kenya and Ivory Coast. Results: In the "temperate lineage" of R. sanguineus, based on cytochrome c oxidase subunit 1 (cox1) and 16S rRNA genes, Rhipicephalus sp. I was only found in the eastern part of the Mediterranean Basin (with relatively homogenous haplotypes), whereas Rhipicephalus sp. II occurred in the middle-to-western part of this region (with phylogenetically dichotomous haplotypes). Ticks identified as R. leporis (based on morphology and cox1 gene) were found in Kenya and Ivory Coast. These clustered phylogenetically within R. sanguineus (s.l.) ("tropical lineage"). Conclusions: In the Mediterranean Basin two mitochondrial lineages of R. sanguineus, i. e. Rhipicephalus sp. I and Rhipicephalus sp. II exist, which show different geographical distribution. Therefore, data from this study confirm limited gene flow between Rhipicephalus sp. I and Rhipicephalus sp. II, but more evidence (analyses of nuclear markers, extensive morphological and biological comparison etc.) are necessary to infer if they belong to different species or not. The phylogenetic relationships of eastern and western African ticks, which align with R. leporis, need to be studied further within R. sanguineus (s.l.) ("tropical lineage")

    GRIPS - Gamma-Ray Imaging, Polarimetry and Spectroscopy

    Full text link
    We propose to perform a continuously scanning all-sky survey from 200 keV to 80 MeV achieving a sensitivity which is better by a factor of 40 or more compared to the previous missions in this energy range. The Gamma-Ray Imaging, Polarimetry and Spectroscopy (GRIPS) mission addresses fundamental questions in ESA's Cosmic Vision plan. Among the major themes of the strategic plan, GRIPS has its focus on the evolving, violent Universe, exploring a unique energy window. We propose to investigate γ\gamma-ray bursts and blazars, the mechanisms behind supernova explosions, nucleosynthesis and spallation, the enigmatic origin of positrons in our Galaxy, and the nature of radiation processes and particle acceleration in extreme cosmic sources including pulsars and magnetars. The natural energy scale for these non-thermal processes is of the order of MeV. Although they can be partially and indirectly studied using other methods, only the proposed GRIPS measurements will provide direct access to their primary photons. GRIPS will be a driver for the study of transient sources in the era of neutrino and gravitational wave observatories such as IceCUBE and LISA, establishing a new type of diagnostics in relativistic and nuclear astrophysics. This will support extrapolations to investigate star formation, galaxy evolution, and black hole formation at high redshifts.Comment: to appear in Exp. Astron., special vol. on M3-Call of ESA's Cosmic Vision 2010; 25 p., 25 figs; see also www.grips-mission.e

    Population Analysis of the Fusarium graminearum Species Complex from Wheat in China Show a Shift to More Aggressive Isolates

    Get PDF
    A large number of Fusarium isolates was collected from blighted wheat spikes originating from 175 sampling sites, covering 15 provinces in China. Species and trichothecene chemotype determination by multilocus genotyping (MLGT) indicated that F. graminearum s. str. with the 15-acetyl deoxynivalenol (15ADON) chemotype and F. asiaticum with either the nivalenol (NIV) or the 3-acetyl deoxynivalenol (3ADON) chemotype were the dominant causal agents. Bayesian model-based clustering with allele data obtained with 12 variable number of tandem repeats (VNTR) markers, detected three genetic clusters that also show distinct chemotypes. High levels of population genetic differentiation and low levels of effective number of migrants were observed between these three clusters. Additional genotypic analyses revealed that F. graminearum s. str. and F. asiaticum are sympatric. In addition, composition analysis of these clusters indicated a biased gene flow from 3ADON to NIV producers in F. asiaticum. In phenotypic analyses, F. asiaticum that produce 3ADON revealed significant advantages over F. asiaticum that produce NIV in pathogenicity, growth rate, fecundity, conidial length, trichothecene accumulation and resistance to benzimidazole. These results suggest that natural selection drives the spread of a more vigorous, more toxigenic pathogen population which also shows higher levels of fungicide resistance

    Expression and In Vivo Rescue of Human ABCC6 Disease-Causing Mutants in Mouse Liver

    Get PDF
    Loss-of-function mutations in ABCC6 can cause chronic or acute forms of dystrophic mineralization described in disease models such as pseudoxanthoma elasticum (OMIM 26480) in human and dystrophic cardiac calcification in mice. The ABCC6 protein is a large membrane-embedded organic anion transporter primarily found in the plasma membrane of hepatocytes. We have established a complex experimental strategy to determine the structural and functional consequences of disease-causing mutations in the human ABCC6. The major aim of our study was to identify mutants with preserved transport activity but failure in intracellular targeting. Five missense mutations were investigated: R1138Q, V1298F, R1314W, G1321S and R1339C. Using in vitro assays, we have identified two variants; R1138Q and R1314W that retained significant transport activity. All mutants were transiently expressed in vivo, in mouse liver via hydrodynamic tail vein injections. The inactive V1298F was the only mutant that showed normal cellular localization in liver hepatocytes while the other mutants showed mostly intracellular accumulation indicating abnormal trafficking. As both R1138Q and R1314W displayed endoplasmic reticulum localization, we tested whether 4-phenylbutyrate (4-PBA), a drug approved for clinical use, could restore their intracellular trafficking to the plasma membrane in MDCKII and mouse liver. The cellular localization of R1314W was significantly improved by 4-PBA treatment, thus potentially rescuing its physiological function. Our work demonstrates the feasibility of the in vivo rescue of cellular maturation of some ABCC6 mutants in physiological conditions very similar to the biology of the fully differentiated human liver and could have future human therapeutic application

    Transcriptional Regulation Is a Major Controller of Cell Cycle Transition Dynamics

    Get PDF
    DNA replication, mitosis and mitotic exit are critical transitions of the cell cycle which normally occur only once per cycle. A universal control mechanism was proposed for the regulation of mitotic entry in which Cdk helps its own activation through two positive feedback loops. Recent discoveries in various organisms showed the importance of positive feedbacks in other transitions as well. Here we investigate if a universal control system with transcriptional regulation(s) and post-translational positive feedback(s) can be proposed for the regulation of all cell cycle transitions. Through computational modeling, we analyze the transition dynamics in all possible combinations of transcriptional and post-translational regulations. We find that some combinations lead to ‘sloppy’ transitions, while others give very precise control. The periodic transcriptional regulation through the activator or the inhibitor leads to radically different dynamics. Experimental evidence shows that in cell cycle transitions of organisms investigated for cell cycle dependent periodic transcription, only the inhibitor OR the activator is under cyclic control and never both of them. Based on these observations, we propose two transcriptional control modes of cell cycle regulation that either STOP or let the cycle GO in case of a transcriptional failure. We discuss the biological relevance of such differences

    Both Positive and Negative Selection Pressures Contribute to the Polymorphism Pattern of the Duplicated Human CYP21A2 Gene.

    Get PDF
    The human steroid 21-hydroxylase gene (CYP21A2) participates in cortisol and aldosterone biosynthesis, and resides together with its paralogous (duplicated) pseudogene in a multiallelic copy number variation (CNV), called RCCX CNV. Concerted evolution caused by non-allelic gene conversion has been described in great ape CYP21 genes, and the same conversion activity is responsible for a serious genetic disorder of CYP21A2, congenital adrenal hyperplasia (CAH). In the current study, 33 CYP21A2 haplotype variants encoding 6 protein variants were determined from a European population. CYP21A2 was shown to be one of the most diverse human genes (HHe=0.949), but the diversity of intron 2 was greater still. Contrary to previous findings, the evolution of intron 2 did not follow concerted evolution, although the remaining part of the gene did. Fixed sites (different fixed alleles of sites in human CYP21 paralogues) significantly accumulated in intron 2, indicating that the excess of fixed sites was connected to the lack of effective non-allelic conversion and concerted evolution. Furthermore, positive selection was presumably focused on intron 2, and possibly associated with the previous genetic features. However, the positive selection detected by several neutrality tests was discerned along the whole gene. In addition, the clear signature of negative selection was observed in the coding sequence. The maintenance of the CYP21 enzyme function is critical, and could lead to negative selection, whereas the presumed gene regulation altering steroid hormone levels via intron 2 might help fast adaptation, which broadly characterizes the genes of human CNVs responding to the environment

    The Europeanization of Social Democracy in East Central Europe

    No full text
    'The Europeanization of social democratic parties in the new member states has reached a turning point with accession, especially in relation to the upcoming elections to the European Parliament (EP) in June 2004. At the same time, domestically the social construction of democracy is high on the agenda in East Central Europe (ECE) after a long decade of political and economic transformation which has brought the region to the stage of democratic consolidation. The ECE countries have arrived at a crossroads: in parallel with EU accession they must decide what kind of public sector they will create, almost from scratch, and how a new democratic state will be built. This paper focuses on the present situation of social democracy in ECE, particularly in respect of the connection between social interests and political parties in the Europeanization process. It tries to combine a bottom-up and a top-down approach, presenting the attempts of leftist party elites to solve social problems and represent societal interests on the one hand, and describing the forms and intensity of popular pressure from below on the other. The formation of political parties in ECE, indeed, has been to a great extent an elite-dominated process and the party elites have used several forms of political marketing to attract voter support without a meaningful social response. It is equally true that the ECE parties - at least in their rhetoric and mostly before elections - have tried to satisfy their constituencies' demands, so to some extent they have had to pursue social interest-driven politics. However, the main influence on ECE party formation has been the example of the Western European party system: only those have survived that could fit into the pre-existing party-types with an 'EU license', that is, have received an 'accreditation' from the West. This paper focuses on the changes in the external role and internal structure of left-wing parties in ECE, contrasting between external and internal Europeanization, also in respect of the painful road from politics to policy, that is, from ideologically-driven political battles to concrete policy-making processes. Our conclusion is that despite particular efforts to solve the problems of those who have lost out from systemic change and EU accession, the challenges they have faced have brought hard times for the Left everywhere in ECE, indicating a difficult start for social democracy in the westernmost part of the 'East,' namely Central Europe.' (extract)Die Europaeisierung der sozialdemokratischen Parteien in den neuen Mitgliedsstaaten hat mit dem Beitritt und besonders den Wahlen zum Europaeischen Parlament einen Wendepunkt erreicht. Gleichzeitig steht auf nationaler Ebene der soziale Aufbau der Demokratie nach einer langen Zeit politischer und oekonomischer Transformation an der Spitze der Tagesordnung in Mittel- und Osteuropa (ECE). Die ECE-Laender muessen sich mit dem Beitritt zur EU entscheiden, wie der oeffentliche Sektor ausgestaltet sein soll und wie ein neuer demokratischer Staat aufgebaut werden kann. Der vorliegende Beitrag konzentriert sich auf die Sozialdemokratie in den ECE-Laendern unter besonderer Beruecksichtigung der Beziehungen zwischen sozialen Interessen und politischen Parteien waehrend des Europaeisierungsprozesses. Der Autor verbindet dabei die Positionen der Parteielite und der Parteibasis. (ICDUebers)German title: Die Europaeisierung der Sozialdemokratie in OstmitteleuropaAvailable from Friedrich-Ebert-Stiftung e.V. Abt. Internationale Politikanalyse, Bonn (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
    corecore