24 research outputs found

    Induced plant-defenses suppress herbivore reproduction but also constrain predation of their offspring

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    Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid (JA). On tomato plants, most genotypes of the herbivorous generalist spider mite Tetranychus urticae induce JA defenses and perform poorly on it, whereas the Solanaceae specialist Tetranychus evansi, who suppresses JA defenses, performs well on it. We asked to which extent these spider mites and the predatory mite Phytoseiulus longipes preying on these spider mites eggs are affected by induced JA-defenses. By artificially inducing the JA-response of the tomato JA-biosynthesis mutant def-1 using exogenous JA and isoleucine (Ile), we first established the relationship between endogenous JA-Ile-levels and the reproductive performance of spider mites. For both mite species we observed that they produced more eggs when levels of JA-Ile were low. Subsequently, we allowed predatory mites to prey on spider mite-eggs derived from wild-type tomato plants, def-1 and JA-Ile-treated def-1 and observed that they preferred, and consumed more, eggs produced on tomato plants with weak JA defenses. However, predatory mite oviposition was similar across treatments. Our results show that induced JA-responses negatively affect spider mite performance, but positively affect the survival of their offspring by constraining egg-predation

    Identification of regulatory variants associated with genetic susceptibility to meningococcal disease

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    Non-coding genetic variants play an important role in driving susceptibility to complex diseases but their characterization remains challenging. Here, we employed a novel approach to interrogate the genetic risk of such polymorphisms in a more systematic way by targeting specific regulatory regions relevant for the phenotype studied. We applied this method to meningococcal disease susceptibility, using the DNA binding pattern of RELA - a NF-kB subunit, master regulator of the response to infection - under bacterial stimuli in nasopharyngeal epithelial cells. We designed a custom panel to cover these RELA binding sites and used it for targeted sequencing in cases and controls. Variant calling and association analysis were performed followed by validation of candidate polymorphisms by genotyping in three independent cohorts. We identified two new polymorphisms, rs4823231 and rs11913168, showing signs of association with meningococcal disease susceptibility. In addition, using our genomic data as well as publicly available resources, we found evidences for these SNPs to have potential regulatory effects on ATXN10 and LIF genes respectively. The variants and related candidate genes are relevant for infectious diseases and may have important contribution for meningococcal disease pathology. Finally, we described a novel genetic association approach that could be applied to other phenotypes

    Estudio de la estructura cortical en la Isla de Tierra del Fuego a partir de datos sismológicos

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    La Isla de Tierra del Fuego (TdF) se encuentra ubicada en el extremo sur de la Cuenca de Magallanes, donde el borde transformante entre la Placa de Scotia y la Sudamericana define el Sistema de Fallas Magallanes-Fagnano (MFS), cuya falla principal tiene un movimiento sinestral. Con el fin de obtener información de la corteza, se realizó un análisis de funciones receptoras (FR) a partir de datos registrados en cinco estaciones sismológicas instaladas en la Isla. Una FR es el resultado de un proceso matemático de deconvolución de la componente vertical de un sismograma con la componente radial, y permite obtener información acerca de las discontinuidades en la corteza y en el manto. Posteriormente estas FR son sumadas mediante un proceso de H-K stacking con el cual es posible estimar valores de H y Vp/Vs a partir de un modelo de referencia. Se obtuvieron valores de H y Vp/Vs comprendidos entre 26-34 km y 1.68-1.85 respectivamente. La presencia de diferentes unidades geológicas y de diversas fallas que componen el MFS serían los responsables del ambiente geotectónico complejo presente en la zona y de los distintos valores obtenidos dependiendo de la ubicación de la estación y de la dirección de los telesismos seleccionados para el análisis.Peer Reviewe

    Crustal structure beneath Tierra del Fuego, Argentina, inferred from seismic P-wave receiver functions and ambient noise autocorrelations

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    We investigate the structure of the crust beneath the main island of Tierra del Fuego through a teleseismic receiver function analysis and ambient seismic noise autocorrelation using data of four available broad-band stations. The area is situated in a remote region of southern Argentina where the interaction between the South American and Scotia plates define the Magallanes-Fagnano Fault System. Crustal thickness, Vp/Vs ratios and S-wave velocity models were estimated using the H-k stacking method and the inversion of receiver functions with the Neighbourhood Algorithm. Furthermore, we applied an ambient seismic noise autocorrelation procedure to identify PmP Moho reflections at all stations. The three methods provide consistent estimates for the crustal thickness which ranges from about 24.5 km in the northern part of the Island to about 39.2 km in the south. The lowest and highest values of S-wave velocity found, in the most superficial layers of the crust, correlate with the presence of Tertiary and upper Cretacic sediments in the north and with older geological units composed by more consolidated lithologies in the south, respectively. Despite the diverse geological and tectonic settings present, our results do not change significantly for different parameters or subsidiary data sets, i.e., showing the robustness of our models which likely represent closely the local structure beneath the Island. This area is considered a very seismically active one and its crustal structure has been little explored demonstrating the importance of having new models and the necessity to increase the station coverage to allow a more detailed study of the region. Furthermore, the models presented here provide better constraints on the crustal structure, and will facilitate studies of the regional seismicity that can improve our understanding of the seismic hazard posed by earthquakes such as the magnitude 7.5 and 7.8 events that occurred in 1949. © 2018The data used in this study was obtained from scientific projects funded by the National Agency for the Promotion of Science and Technology, Argentina (ANPCyT), the National University of La Plata, Argentina (UNLP) and the National Institute of Oceanography and Experimental Geophysics, Italy (OGS). We would like to thank the staff of the Astronomical Station of Rio Grande (EARG) for the installation and maintenance of seismic stations and Marcelo Moreno from the National Institute of Seismic Prevention (INPRES) for operational support in getting data. Furthermore we are grateful to Larminat and Henninger families for allowing us to install the stations DSPA and ELCA and for providing collaboration with EARG. This work was partially supported by a grant from the National Scientific and Technical Research Council (CONICET). MS acknowledges the Spanish Project MISTERIOS CGL2013-48601-C2-1-R.Peer reviewe

    The impact of type of manual medication cart filling method on the frequency of medication administration errors: A prospective before and after study

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    Background: The medication cart can be filled using an automated system or a manual method and when using a manual method the medication can be arranged either by round time or by medication name. For the manual methods, it is hypothesized that the latter method would result in a lower frequency of medication administration errors because nurses are forced to read the medication labels, but evidence for this hypothesis is lacking. Objectives: The aim of this study was to compare the frequency of medication administration errors of two different manual medication cart filling methods, namely arranging medication by round time or by medication name. Design: A prospective, observational study with a before-after design. Participants and settings: Eighty-six patients who stayed on an orthopaedic ward in one university medical centre in the Netherlands were included. Methods: Disguised observation was used to detect medication administration errors. The medication cart filling method in usual care was to fill the cart with medication arranged by round time. The intervention was the implementation of the second medication cart filling method, where the medication cart was filled by arranging medicines by their names. The primary outcome was the frequency of medication administrations with one or more error(s) after the intervention compared with before the intervention. The secondary outcome was the frequency of subtypes of medication administration errors. Results: After the intervention 170 of 740(23.0%) medication administrations with one or more medication administration error(s) were observed compared to 114 of 589(19.4%) before the intervention (odds ratio 1.24 [95% confidence interval 0.95-1.62]). The distribution of subtypes of medication administration errors before and after the intervention was statistically significantly different (p < 0.001). Analysis of subtypes revealed more omissions and wrong time errors after the intervention than before the intervention. Unauthorized medication errors were detected more frequently before the intervention than after the intervention. Conclusion: The frequency of medication administration errors with the medication cart filling method where the medication is arranged by name was not statistically significantly different compared to the medication cart filling method where the medication is arranged by round time. (C) 2010 Elsevier Ltd. All rights reserved

    Spider mites suppress tomato defenses downstream of jasmonate and salicylate independently of hormonal crosstalk.

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    Plants respond to herbivory by mounting a defense. Some plant-eating spider mites (Tetranychus spp.) have adapted to plant defenses to maintain a high reproductive performance. From natural populations we selected three spider mite strains from two species, Tetranychus urticae and Tetranychus evansi, that can suppress plant defenses, using a fourth defense-inducing strain as a benchmark, to assess to which extent these strains suppress defenses differently. We characterized timing and magnitude of phytohormone accumulation and defense-gene expression, and determined if mites that cannot suppress defenses benefit from sharing a leaf with suppressors. The nonsuppressor strain induced a mixture of jasmonate- (JA) and salicylate (SA)-dependent defenses. Induced defense genes separated into three groups: 'early' (expression peak at 1 d postinfestation (dpi)); 'intermediate' (4 dpi); and 'late', whose expression increased until the leaf died. The T. evansi strains suppressed genes from all three groups, but the T. urticae strain only suppressed the late ones. Suppression occurred downstream of JA and SA accumulation, independently of the JA-SA antagonism, and was powerful enough to boost the reproductive performance of nonsuppressors up to 45%. Our results show that suppressing defenses not only brings benefits but, within herbivore communities, can also generate a considerable ecological cost when promoting the population growth of a competitor

    Induced plant-defenses suppress herbivore reproduction but also constrain predation of their offspring

    No full text
    Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid (JA). On tomato plants, most genotypes of the herbivorous generalist spider mite Tetranychus urticae induce JA defenses and perform poorly on it, whereas the Solanaceae specialist Tetranychus evansi, who suppresses JA defenses, performs well on it. We asked to which extent these spider mites and the predatory mite Phytoseiulus longipes preying on these spider mites eggs are affected by induced JA-defenses. By artificially inducing the JA-response of the tomato JA-biosynthesis mutant def-1 using exogenous JA and isoleucine (Ile), we first established the relationship between endogenous JA-Ile-levels and the reproductive performance of spider mites. For both mite species we observed that they produced more eggs when levels of JA-Ile were low. Subsequently, we allowed predatory mites to prey on spider mite-eggs derived from wild-type tomato plants, def-1 and JA-Ile-treated def-1 and observed that they preferred, and consumed more, eggs produced on tomato plants with weak JA defenses. However, predatory mite oviposition was similar across treatments. Our results show that induced JA-responses negatively affect spider mite performance, but positively affect the survival of their offspring by constraining egg-predation
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