609 research outputs found

    Survey of the genus Bursaphelenchus Fuchs, 1937 (Nematoda: Aphelenchoididae) in Romania

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    An overview of the occurrence of species of the genus Bursaphelenchus in Romania is presented. The data is based on recent surveys conducted for the first time throughout the country, to monitor and evaluate the potential entry of the pine wood nematode, Bursaphelenchus xylophilus. Wood samples were collected from declining trees, woodprocessing companies and imported wood packaging material. Of the 895 wood samples examined, 11 contained Bursaphelenchus specimens. Morphological and molecular analyses were carried out to characterize the species detected. With respect to the possible presence of B. xylophilus, all samples were negative, confirming the absence of this quarantine pest in Romania. Nevertheless, five Bursaphelenchus species were found: B. hofmanni, B. poligraphi, B. vallesianus, B. willibaldi, and one putative new species belonging to the sexdentati group, classified here as Bursaphelenchus sp. NR512. These results constitute the first report of the genus Bursaphelenchus in Romania

    Acute-Phase CD8 T cell responses that select for escape variants are needed to control live attenuated simian immunodeficiency virus

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    The overall CD8 T cell response to human/simian immunodeficiency virus (HIV/SIV) targets a collection of discrete epitope specificities. Some of these epitope-specific CD8 T cells emerge in the weeks and months following infection and rapidly select forsequence variants, whereas other CD8 T cell responses develop during the chronic infection phase and rarely select for sequence variants. In this study, we tested the hypothesis that acute-phase CD8 T cell responses that do not rapidly select for escapevariants are unable to control viral replication in vivo as well as those that do rapidly select for escape variants. We created a derivative of live attenuated SIV (SIVmac239Δnef) in which we ablated five epitopes that elicit early CD8 T cell responses and rapidly accumulate sequence variants in SIVmac239-infected Mauritian cynomolgus macaques (MCMs) that are homozygous for the M3 major histocompatibility complex (MHC) haplotype. This live attenuated SIV variant was called m3KOΔnef. Viremia was significantly higher in M3 homozygous MCMs infected withm3KOΔnef than in either MHC-mismatched MCMs infected with m3KOΔ nef or MCMs infected with SIVmac239Δnef. Three CD8 T cell responses, including two that do not rapidly select for escape variants, predominated during earlym3KOΔnef infection in the M3 homozygous MCMs, but these animals were unable to control viral replication. These re-sults provide evidence that acute-phase CD8 T cell responses that have the potential to rapidly select for escape variants in the early phase ofinfection are needed to establish viral control in vivo

    Creating knowledge environment during lean product development process of jet engine

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    Organizations invest intense resources in their product development processes. This paper aims to create a knowledge environment using trade-off curves during the early stages of the set-based concurrent engineering (SBCE) process of an aircraft jet engine for a reduced noise level at takeoff. Data is collected from a range of products in the same family as the jet engine. Knowledge-based trade-off curves are used as a methodology to create and visualize knowledge from the collected data. Findings showed that this method provides designers with enough confidence to identify a set of design solutions during the SBCE application

    Performance of ionospheric maps in support of long baseline GNSS kinematic positioning at low latitudes

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    Ionospheric scintillation occurs mainly at high and low latitude regions of the Earth and may impose serious degradation on GNSS (Global Navigation Satellite System) functionality. The Brazilian territory sits on one of the most affected areas of the globe, where the ionosphere behaves very unpredictably, with strong scintillation frequently occurring in the local postsunset hours. The correlation between scintillation occurrence and sharp variations in the ionospheric total electron content (TEC) in Brazil is demonstrated in Spogli et al. (2013). The compounded effect of these associated ionospheric disturbances on long baseline GNSS kinematic positioning is studied in this paper, in particular when ionospheric maps are used to aid the positioning solution. The experiments have been conducted using data from GNSS reference stations in Brazil. The use of a regional TEC map generated under the CALIBRA (Countering GNSS high-Accuracy applications Limitations due to Ionospheric disturbances in BRAzil) project, referred to as CALIBRA TEC map (CTM), was compared to the use of the Global Ionosphere Map (GIM), provided by the International GNSS Service (IGS). Results show that the use of the CTM greatly improves the kinematic positioning solution as compared with that using the GIM, especially under disturbed ionospheric conditions. Additionally, different hypotheses were tested regarding the precision of the TEC values obtained from ionospheric maps, and its effect on the long baseline kinematic solution evaluated. Finally, this study compares two interpolation methods for ionospheric maps, namely, the Inverse Distance Weight and the Natural Neighbor

    Pth4, an ancient parathyroid hormone lost in eutherian mammals, reveals a new brain-to-bone signaling pathway

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    Regulation of bone development, growth, and remodeling traditionally has been thought to depend on endocrine and autocrine/paracrine modulators. Recently, however, brain-derived signals have emerged as key regulators of bone metabolism, although their mechanisms of action have been poorly understood. We reveal the existence of an ancient parathyroid hormone (Pth)4 in zebrafish that was secondarily lost in the eutherian mammals' lineage, including humans, and that is specifically expressed in neurons of the hypothalamus and appears to be a central neural regulator of bone development and mineral homeostasis. Transgenic fish lines enabled mapping of axonal projections leading from the hypothalamus to the brainstem and spinal cord. Targeted laser ablation demonstrated an essential role for of pth4-expressing neurons in larval bone mineralization. Moreover, we show that Runx2 is a direct regulator of pth4 expression and that Pth4 can activate cAMP signaling mediated by Pth receptors. Finally, gain-of-function experiments show that Pth4 can alter calcium/phosphorus levels and affect expression of genes involved in phosphate homeostasis. Based on our discovery and characterization of Pth4, we propose a model for evolution of bone homeostasis in the context of the vertebrate transition from an aquatic to a terrestrial lifestyle.Spanish Economy and Competitiveness Ministry Project [ALG2011-23581, AGL2014-52473R]; Portuguese Foundation for Science and Technology [PTDC/BIA-ANM/4225/2012-phos-fate]; U. S. National Institutes of Health/Office of the Director Grant [R01OD011116, R01 RR020833]; Generalitat de Catalunya [SGR2014-290]; Spanish Economy and Competitiveness Ministry [BFU2010-14875]; Science and Innovation Ministry [AGL2010-22247-C03-01]; Campus do Mar Ph.D. grant; Xunta de Galicia (Santiago, Spain) [AGL2014-52473R]info:eu-repo/semantics/publishedVersio

    Chromosomal-level assembly of the Asian Seabass genome using long sequence reads and multi-layered scaffolding

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    We report here the ~670 Mb genome assembly of the Asian seabass (Lates calcarifer), a tropical marine teleost. We used long-read sequencing augmented by transcriptomics, optical and genetic mapping along with shared synteny from closely related fish species to derive a chromosome-level assembly with a contig N50 size over 1 Mb and scaffold N50 size over 25 Mb that span ~90% of the genome. The population structure of L. calcarifer species complex was analyzed by re-sequencing 61 individuals representing various regions across the species' native range. SNP analyses identified high levels of genetic diversity and confirmed earlier indications of a population stratification comprising three clades with signs of admixture apparent in the South-East Asian population. The quality of the Asian seabass genome assembly far exceeds that of any other fish species, and will serve as a new standard for fish genomics

    The bowfin genome illuminates the developmental evolution of ray-finned fishes.

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    The bowfin (Amia calva) is a ray-finned fish that possesses a unique suite of ancestral and derived phenotypes, which are key to understanding vertebrate evolution. The phylogenetic position of bowfin as a representative of neopterygian fishes, its archetypical body plan and its unduplicated and slowly evolving genome make bowfin a central species for the genomic exploration of ray-finned fishes. Here we present a chromosome-level genome assembly for bowfin that enables gene-order analyses, settling long-debated neopterygian phylogenetic relationships. We examine chromatin accessibility and gene expression through bowfin development to investigate the evolution of immune, scale, respiratory and fin skeletal systems and identify hundreds of gene-regulatory loci conserved across vertebrates. These resources connect developmental evolution among bony fishes, further highlighting the bowfin's importance for illuminating vertebrate biology and diversity in the genomic era
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