1,033 research outputs found

    Rare earths, zirconium and hafnium distribution in coastal areas: The example of Sabella spallanzanii (Gmelin, 1791)

    Get PDF
    The Zr, Hf, Y and lanthanide (REE) distribution in biological tissues of Sabella spallanzanii and Styela plicata species collected from two harbours from the northern Sicily is studied for providing information regarding the Zr, Hf and REE uptake from the environment. Previous studies determined the fractionation of dissolved REE scavenged on binding sites onto biological surfaces. By comparing the recognised shale-normalised REE patterns of studied samples with evidence from reference data, the observed behaviour of these elements in biological tissues of Sabella spallanzanii and Styela plicata is interpreted to result from the preferential uptake of intermediate REE onto carboxylic sites. Moreover, the relationship observed between the Fe content and Zr/Hf ratio suggests that preferential Hf accumulation occurs via siderophore-like binding sites. Features of the REE bioaccumulation factors (BAF), in addition to the absolute La, Ce and Sm contents and Zr-Hf fractionation, allow definition of the different origins of studied elements in the investigated localities. Higher BAF values for La and Ce associated with larger REE contents and lower Zr/Hf values strongly suggest that the environmental REE distribution in the Termini Imerese harbour is influenced by the delivery of particles from industrial sources and power plants. On the contrary, the REE contents of biological tissues collected in the Cala tourist harbour are affected by the dust dissolution from automotive traffic. These results suggest that the geochemical behaviour of REE and Zr/Hf signature can be used in environmental studies of biological tissues for reconstructing the nature of anthropogenic contaminations

    DIVERSITY OF LECTIN-SUGAR RECOGNITION SYSTEMS IN THE EVOLUTION OF FISH INNATE IMMUNITY

    Get PDF
    Carbohydrate recognition and interactions mediated by lectins have been recognized involved in vertebrate innate immunity, not only for recognition of potential pathogens, but also acting in the agglutination, immobilization and other functional steps. Fish are equipped with a complex lectin repertoire that, like mammals, are involved almost all the immune reactions. On the basis of our results on the isolation, cDNA cloning, structural analysis, tissue expression and localization, and opsonic activity of F-type and RBL lectins from Dicentrarchus labrax and Sparus aurata we showed that: lectin repertoires in fish are highly diversified and include not only representatives of the lectin families; described in mammals, but also members of lectin families described for the first time in fish species like the F type lectins; the tissue-specific expression and localization of the diverse lectin repertoires and their molecular partners is consistent with their distinct biological roles in innate and adaptive immunity; although some lectins may bind endogenous ligands, others bind sugars on the surface of potential pathogens; in addition to pathogen recognition and opsonization, some lectins display additional effector roles, such as regulation of immune function

    Multiple Wesen

    Get PDF
    Abstract in tedesco del Poster Multiple Wesen, esposto al Simposio internazionale „Lunar Base. Bauen fuer ein Leben auf dem Mond” tenuto a Kaiserslautern il 12-13 Maggio 2009. Was baut man auf dem Mond? Wie baut der Erdmensch auf dem Mond? WofĂĽr wird gebaut? FĂĽr wem wird gebaut? Welche Nutzungen, wie groĂź, welche Materialien? Man kann weiter fragen,... Sind dieses ĂĽberhaupt die richtige Fragen? Kann man ĂĽberhaupt vom Bauen auf dem Mond sprechen? Oder geht es darum, was der Mensch auf den Mond mit bringt, aus seiner Kenntniss, seinen Vorstellungen, seinen Träumen, seiner Erfahrung: was bringt er von dem Reich des Bekannten (der Erde) in das Reich des nur Vorstellbaren (dem Mond). Also: sich mit dem Mond zu beschäftigen - ausgenommen fĂĽr die sehr wenigen, die schon dort waren – heiĂźt, sich mit sich selbst zu beschäftigen, mit dem eigenen Wissen und dem Bild vom Mond. Alle Voraussetzungen, die einem irdischen architektonischen Entwurf zu Grunde liegen, fehlen; zu diesem Zeitpunkt kann man sich arbiträr Rahmenbedingungen geben: (Größe, wo, welche Nutzung, welche Lebensdauer, welche Materialien) so zu sagen ein Mondprojekt in einem Erdprojekt zu entwickeln, dadurch schnell eine „abgesicherte“, unangreifbare Lösung zu erlangen. Aber macht dieses Sinn? Bedeutet dies, die Spannung und die Erforschung des Neuen sowie das kreative Potential örtlicher Schwierigkeiten im Vorfeld auszuschlieĂźen? Wir schlagen vor, anstatt auf hiesige Fragen irdische Antworten zu formulieren, Strukturen zum Mond zu bringen; Raumstrukturen, die durch mentale Konzepte begrĂĽndet sind, welche die vielen Fragen - auch welche die wir jetzt nicht zu fragen gewagt haben - aufnehmen können. Diese Strukturen, aber auch kleine räumliche Gebilde, helfen dem Vorstellungsvermögen der Forscher, Ingenieure, Wissenschaftler und alle Mondinteressenten. Neutrale Strukturen, ohne jetzt genau alle physische Eigenschaften festlegen zu wollen, sollen Raum werden können fĂĽr Wohnen, Arbeiten, Forschen, Landen, Binden, SchĂĽtzen, Aufbewahren, usw. - abhängig von den Fragen, die sich zu gegebener Zeit formulieren lassen und ständig ändern werden. Wir denken an sehr flexible Strukturen, die viel aufnehmen und aushalten können, sich sehr schnell transformieren lassen, also multiple Wesen, die zunächst die Vorstellung eines belebten Mondes anregen sollen. Dieser Strukturenkatalog soll dem Wissenschaftler zur VerfĂĽgung stehen, um das Mitdenken seiner räumlichen BedĂĽrfnisse zu stĂĽtzen. Comunicato stampa Contributo degli studenti di Architettura al Simposio “Lunar Base - Costruire per una vita sulla Luna” A Kaiserslautern in Germania è in corso (12-13-maggio) il Simposio “Lunarbase - Bauen fuer ein Leben auf dem Mond” (www.lunar-base.net) organizzato dalla DLR (Agenzia aerospaziale tedesca) e dalla TU Kaiserslautern. Scienziati, ingegneri, architetti e designer di tutto il mondo presentano i loro piani e le loro visioni per una possibile vita sulla Luna. Alcune nazioni tra le quali la Cina, la Russia e gli Stati Uniti stanno elaborando piani concreti per la costruzione di stazioni lunari come basi per missioni equipaggiate su Marte, con un orizzonte temporale intorno al 2020. La proposta degli studenti dei Laboratori di I anno di Progettazione architettonica, tenuti dal Prof. Gaetano Licata con la collaborazione del dottorando in Design Michele Cammarata nel nuovo corso di Laurea triennale in Scienze dell’Architettura (SdA) e nel Corso di Laurea quinquennale (4/s), è stata selezionata dal comitato organizzatore che ne ha richiesto l’elaborazione sotto forma di un Poster (A0) attualmente esposto durante il Simposio. Si tratta di un montaggio di modelli tridimensionali elaborati dagli studenti e denominati “multiple Wesen”. Questi modelli, in quanto concetti di architettura assolutamente astratti, si prestano a contribuire a quel bagaglio di conoscenze, visioni, sogni e immaginazione, che chiunque voglia “confrontarsi” con una realtĂ  solo immaginabile come quella della Luna, ha bisogno di “portare con sé” dalla Terra. Concetti mentali di spazi possibili – “Raumstrukturen” - a sostegno degli scienziati, per poter continuare a immaginare insieme sempre piĂą concretamene la vita e la ricerca direttamente sulla Luna. Pa, 13.05.2009 ([email protected]

    COMPORTAMENTO DI IMPALCATI DA PONTE A CASSONE IN ACCIAIO-CALCESTRUZZO CON ANIMA ONDULATA

    Get PDF
    La memoria riguarda il comportamento di un impalcato di ponte stradale a cassone avente le anime sagomate secondo una sinusoide, con soletta in c.a. collaborante. L'impalcato presenta schema statico longitudinale di trave continua su 4 appoggi.The paper concerns the behaviour of a box-girder bridge deck road having a steel box and a concrete slab. The steel webs are shaped according to a sine wave. The deck has a width of 13.70 m and a length of 182 m, with the longitudinal static scheme as a continuous beam on four supports. The study highlights the reliability of this constructive solution

    Seasonal changes in morpho-functional aspects of two Anemonia sulcata (Pennant, 1777) wild populations

    Get PDF
    Marine benthic organisms can be used as indicators of the quality of environmental status and as monitoring tools to detect natural or anthropogenic perturbations. In temperate waters, metabolic and biochemical responses may be governed by physiological changes driven by seasonal factors. Gathering baseline information on the mechanisms underlying seasonal acclimation patterns is therefore a critical step towards the understanding of the physiological responses of biological indicators. In poikilothermic metazoans, the production of regulatory metabolic enzymes can be used as tools for deciphering the acclimation potential. The aim of this study was to characterize the natural seasonal variability in biometric traits and enzymatic biomarkers over a 12-month period in the sea anemone, Anemonia sulcata (Anthozoa, Cnidaria), from two areas with different environmental and anthropic impacts. Seasonality and site factors affected enzymatic kinetics at tentacle levels, while seasonality, site and biometrical characteristics modulated the same enzymes in the body column of A. sulcata. The results showed a decrease in enzymatic activity in summer and an increased synthesis of enzymes in the late fall and winter months. The interaction between biometric features and temperature appeared significant for mesolittoral sea anemones but not for infralittoral specimens. This study showed seasonal patterns of variations of biochemical responses in A. sulcata, suggesting that this species, an abundant member of shallow rocky bottom communities in temperate European seas, may represent a sensitive bio-indicator organism worth considering for further ecological studies on climate change as well as for environmental monitoring programs

    Evidence of cytotoxic activity against mammalian red blood cell of Na+ channel neurotoxin (AE1) from sea anemone (actinia equina)

    Get PDF
    The diversification of anthozoan toxins played an important role in the ability to colonize various ecological niches. In this study we evaluated the hemolytic activity of HPLC separated fraction of tentacle extracts of sea anemone Actinia equina. Toxic components from acid tissue tentacle extracts were investigated by size exclusion and reverse phase HPLC to characterize cytolytic molecules. A novel low molecular weight active fraction was sequenced by MALDI TOF analysis and a protein correspondent to 5.4 kDa Sodium channel neurotoxin (Ae1) from A. equina was identified. Synthetic Ae1 was assayed and it showed an hemolytic activity against mammalian erythrocytes in a dose dependent manner. Cytolytic activity in addition to neuro-inhibitory function could be a further property of Ae1 toxin repertoire

    Unveiling the timescale of the R-T transition in human hemoglobin

    Get PDF
    Time-resolved wide-angle X-ray scattering, a recently developed technique allowing to probe global structural changes of proteins in solution, was used to investigate the kinetics of R–T quaternary transition in human hemoglobin and to systematically compare it to that obtained with time-resolved optical spectroscopy under nearly identical experimental conditions. Our data reveal that the main structural rearrangement associated with the R–T transition takes place 2 μs after the photolysis of hemoglobin at room temperature and neutral pH. This finding suggests that the 20 μs step observed with time-resolved optical spectroscopy corresponds to a small and localized structural change

    Molecular characterisation, evolution and expression analysis of g-type lysozymes in Ciona intestinalis

    Get PDF
    Lysozyme is an important defense molecule of the innate immune system. Known for its bactericidal properties, lysozyme catalyzes the hydrolysis of b-(1,4)-glycosidic bonds between the N-acetyl glucosamine and N-acetyl muramic acid in the peptidoglycan layer of bacterial cell walls. In this study, the complete coding sequence of four g-type lysozymes were identified in Ciona intestinalis. Phylogenetic analysis and modelling supported the hypothesis of a close relationship with the vertebrate g-type lysozymes suggesting that the C. intestinalis g-type lysozyme genes (CiLys-g1, Cilys-g2, CiLys-g3, CiLys-g4) share a common ancestor in the chordate lineage. Protein motif searches indicated that C. intestinalis gtype lysozymes contain a GEWL domain with a GXXQ signature, typical of goose lysozymes. Quantitative Real-Time PCR analysis results showed that transcripts are expressed in various tissues from C. intestinalis. In order to determine the involvement of C. intestinalis g-type lysozymes in immunity, their expression was analyzed in the pharynx, showing that transcripts were significantly up-regulated in response to a challenge with lipopolysaccharide (LPS). These data support the view that CiLys g-type are molecules with potential for immune defense system against bacterial infection
    • …
    corecore