197 research outputs found

    Cadmium uptake, localization and stress-induced morphogenic response in the fern Pteris vittata.

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    Cadmium uptake, tissue localization and structural changes induced at cellular level are essential to understand Cd tolerance in plants. In this study we have exposed plants of Pteris vittata to different concentrations of CdCl2 (0, 30, 60, 100 ÎŒM) to evaluate the tolerance of the fern to cadmium. Cadmium content determination and its histochemical localization showed that P. vittata not only takes up, but also transports and accumulates cadmium in the aboveground tissues, delocalizing it mainly in the less bioactive tissues of the frond, the trichomes and the scales. Cadmium tolerance in P. vittata was strictly related to morphogenic response induced by the metal itself in the root system. Adaptive response regarded changes of the root apex size, the developmental pattern of root hairs, the differentiation of xylem elements and endodermal suberin lamellae. All the considered parameters suggest that, in our experimental conditions, 60 ÎŒM of Cd may represent the highest concentration that P. vittata can tolerate; indeed this Cd level even improves the absorbance features of the root and allows good transport and accumulation of the metal in the fronds. The results of this study can provide useful information for phytoremediation strategies of soils contaminated by Cd, exploiting the established ability of P. vittata to transport, delocalize in the aboveground biomass and accumulate polluting metals

    Ovatoxin-a, a palytoxin analogue isolated from Ostreopsis cf. ovata Fukuyo: cytotoxic activity and ELISA detection

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    This study provides the first evaluation of the cytotoxic effects of the recently identified palytoxin (PLTX) analog, ovatoxin-a (OVTX-a), the major toxin produced by Ostreopsis cf. ovata in the Mediterranean Sea. Its increasing detection during Ostreopsis blooms and in seafood highlights the need to characterize its toxic effects and to set up appropriate detection methods. OVTX-a is about 100 fold less potent than PLTX in reducing HaCaT cells viability (EC50 = 1.1 7 10 129 M vs 1.8 7 10 1211 M, MTT test) in agreement with a reduced binding affinity (Kd = 1.2 7 10 129 vs 2.7 7 10 1211 M, saturation experiments on intact cells). Similarly, OVTX-a hemolytic effect is lower than that of the reference PLTX compound. Ost-D shows the lowest cytotoxicity toward HaCaT keratinocytes, suggesting the lack of a hydroxyl group at C44 as a critical feature for PLTXs cytotoxic effects. A sandwich ELISA developed for PLTX detects also OVTX-a in a sensitive (LOD = 4.2 and LOQ = 5.6 ng/mL) and accurate manner (Bias = 0.3%), also in O. cf. ovata extracts and contaminated mussels. Although in vitro OVTXa appears less toxic than PLTX, its cytotoxicity at nanomolar concentrations after short exposure time rises some concern for human health. The sandwich ELISA can be a viable screening method for OVTXs detection in monitoring program

    First Finding of Ostreopsis cf. ovata Toxins in Marine Aerosols

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    Since the late 1990s, a respiratory syndrome has been repetitively observed in humans concomitant with Ostreopsis spp. blooms (mainly O. cf. ovata) in the Mediterranean area. Previous studies have demonstrated that O. cf. ovata produces analogues of palytoxin (ovatoxins and a putative palytoxin), one of the most potent marine toxins. On the basis of the observed association between O. cf. ovata blooms, respiratory illness in people, and detection of palytoxin complex in algal samples, toxic aerosols, containing Ostreopsis cells and/or the toxins they produce, were postulated to be the cause of human illness. A small scale monitoring study of marine aerosol carried out along the Tuscan coasts (Italy) in 2009 and 2010 is reported. Aerosols were collected concomitantly with O. cf. ovata blooms, and they were analyzed by both PCR assays and LC-HRMS. The results, besides confirming the presence of O. cf. ovata cells, demonstrated for the first time the occurrence of ovatoxins in the aerosol at levels of 2.4 pg of ovatoxins per liter of air. Given the lack of toxicological data on palytoxins by inhalation exposure, our results are only a first step toward a more comprehensiveunderstanding of the Ostreopsis-related respiratory syndrome

    Azimuthal correlation between beauty particles produced in 350 GeV/c π−\pi^{-}-Cu interactions

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    Using a sample of 10810^8 triggered events, produced in 350 GeV/c350\, \hbox{GeV}/c π−\pi^- interactions in a copper target, we have identified 2626 b\=b events. These include 1313 events where the decays of both BB and B‟\overline{B} are well reconstructed. We measure the azimuthal \hbox{correlation} between beauty particles, and compare our result with predictions based on perturbative QCD

    Surgical site infection after caesarean section. Space for post-discharge surveillance improvements and reliable comparisons

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    Surgical site infections (SSI) after caesarean section (CS) represent a substantial health system concern. Surveying SSI has been associated with a reduction in SSI incidence. We report the findings of three (2008, 2011 and 2013) regional active SSI surveillances after CS in community hospital of the Latium region determining the incidence of SSI. Each CS was surveyed for SSI occurrence by trained staff up to 30 post-operative days, and association of SSI with relevant characteristics was assessed using binomial logistic regression. A total of 3,685 CS were included in the study. A complete 30 day post-operation follow-up was achieved in over 94% of procedures. Overall 145 SSI were observed (3.9% cumulative incidence) of which 131 (90.3%) were superficial and 14 (9.7%) complex (deep or organ/space) SSI; overall 129 SSI (of which 89.9% superficial) were diagnosed post-discharge. Only higher NNIS score was significantly associated with SSI occurrence in the regression analysis. Our work provides the first regional data on CS-associated SSI incidence, highlighting the need for a post-discharge surveillance which should assure 30 days post-operation to not miss data on complex SSI, as well as being less labour intensive

    Measurements of charmed-meson production in interactions between 350 GeV/c π−\pi^- particles and nuclei

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    Charmed-meson production by 350350~GeV/cc {π−\pi^-} particles incident on copper and tungsten targets has been studied in the WA9292 experiment, performed at the CERN Ωâ€Č\Omega^\prime spectrometer. Results obtained are reported and discussed. Reconstruction of decays from the set D0→K−π+{\rm D}^0 \rightarrow {\rm K}^- \pi^+, D0→K−π−π+π+{\rm D}^0 \rightarrow {\rm K}^- \pi^- \pi^+ \pi^+, D+→K−π+π+{\rm D}^+ \rightarrow {\rm K}^- \pi^+ \pi^+, Ds+→ϕπ+{{\rm D}_{\rm s}}^+ \rightarrow \phi \pi^+ and charge conjugates has yielded a sample of 7280±1087280 \pm 108 charmed mesons, produced with \xf > 0, \langle \xf \rangle = 0.18 and \langle {\pt}^2 \rangle = 1.86~{\rm (GeV/}c{\rm )}^2. Assuming a relationship σ=σ0Aα\sigma = \sigma_0 A^\alpha between the cross-section, σ\sigma, per nucleus of mass AA and the nucleonic cross-section, σ0\sigma_0, the α\alpha value found for the detected charmed particles is 0.95±0.06±0.030.95 \pm 0.06 \pm 0.03. Taking α=1\alpha = 1, the measured cross-sections per nucleon for \xf > 0 production are 7.78±0.14±0.527.78 \pm 0.14 \pm 0.52~ÎŒ\mubarn for D0{\rm D}^0/Dˉ0\bar{\rm D}^0, 3.28±0.08±0.293.28 \pm 0.08 \pm 0.29~ÎŒ\mubarn for D+{\rm D}^+/D−{\rm D}^- and 1.29±0.16±0.331.29 \pm 0.16 \pm 0.33~ÎŒ\mubarn for Ds+{{\rm D}_{\rm s}}^+/Ds−{{\rm D}_{\rm s}}^-. Differential cross-sections with respect to \xf and {\pt}^2 have been determined for the various types of charmed meson, and particle-antiparticle asymmetries have been analysed

    Mapping targets for small nucleolar RNAs in yeast

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    Background: Recent analyses implicate changes in the expression of the box C/D class of small nucleolar RNAs (snoRNAs) in several human diseases. Methods: Here we report the identification of potential novel RNA targets for box C/D snoRNAs in budding yeast, using the approach of UV crosslinking and sequencing of hybrids (CLASH) with the snoRNP proteins Nop1, Nop56 and Nop58. We also developed a bioinformatics approach to filter snoRNA-target interactions for bona fide methylation guide interactions. Results: We recovered 241,420 hybrids, out of which 190,597 were classed as reproducible, high energy hybrids. As expected, the majority of snoRNA interactions were with the ribosomal RNAs (rRNAs). Following filtering, 117,047 reproducible hybrids included 51 of the 55 reported rRNA methylation sites. The majority of interactions at methylation sites were predicted to guide methylation. However, competing, potentially regulatory, binding was also identified. In marked contrast, following CLASH performed with the RNA helicase Mtr4 only 7% of snoRNA-rRNA interactions recovered were predicted to guide methylation. We propose that Mtr4 functions in dissociating inappropriate snoRNA-target interactions. Numerous snoRNA-snoRNA interactions were recovered, indicating potential cross regulation. The snoRNAs snR4 and snR45 were recently implicated in site-directed rRNA acetylation, and hybrids were identified adjacent to the acetylation sites. We also identified 1,368 reproducible snoRNA-mRNA interactions, representing 448 sites of interaction involving 39 snoRNAs and 382 mRNAs. Depletion of the snoRNAs U3, U14 or snR4 each altered the levels of numerous mRNAs. Targets identified by CLASH were over-represented among these species, but causality has yet to be established. Conclusions: Systematic mapping of snoRNA-target binding provides a catalogue of high-confidence binding sites and indicates numerous potential regulatory interactions

    Measurement of the beauty production cross-section in 350 GeV/c π−\pi^- -Cu interactions

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    Using a sample of 10810^8 triggered events, produced in π−\pi^--- \,Cu interactions at 350~GeV/c/c, we have identified 26 beauty events. The estimated background in this sample is 0.6±0.60.6 \pm 0.6 events. From these data, assuming a linear A-dependence, we measure a beauty production cross-section integrated over all xFx_F of 5.7+1.3−1.1 (stat.)+0.6−0.5 (syst.) 5.7 {+1.3 \atop -1.1}~{\mathrm {(stat.)}} {+0.6 \atop -0.5}~{\mathrm {(syst.)}}~nb/N

    WA92: a fixed target experiment to trigger on and identify beauty particle decays

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    We describe the detectors and trigger system used in the CERN WA92 experiment. The experiment was designed to study the production and decay of beauty particles from 350 GeV/c c\,  π−\,\pi^- interactions in copper and tungsten targets. Charged particle tracking is performed using the Omega spectrometer. Silicon microstrip detectors are used to provide precise tracking information in the region of the production and the decay of heavy-flavoured particles and to trigger on the resulting high impact parameter tracks. The precision of vertex reconstruction corresponds to ±3.7%\pm 3.7\% of the mean B-decay proper lifetime. Lepton and high transverse momentum hadron signals are also used in the trigger, which accepts 29\% of B-decays and rejects 98\% of non-beauty interactions

    How to do an evaluation: pitfalls and traps

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    The recent literature is replete with papers evaluating computational tools (often those operating on 3D structures) for their performance in a certain set of tasks. Most commonly these papers compare a number of docking tools for their performance in cognate re-docking (pose prediction) and/or virtual screening. Related papers have been published on ligand-based tools: pose prediction by conformer generators and virtual screening using a variety of ligand-based approaches. The reliability of these comparisons is critically affected by a number of factors usually ignored by the authors, including bias in the datasets used in virtual screening, the metrics used to assess performance in virtual screening and pose prediction and errors in crystal structures used
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