175 research outputs found

    Evaluation of subsidence induced by long-lasting buildings load using InSAR technique and geotechnical data: The case study of a Freight Terminal (Tuscany, Italy)

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    This paper shows the results of the comparison between Multi-temporal Synthetic Aperture Radar (MTInSAR) products derived from different sensors (C-band ERS 1/2, Envisat, Sentinel-1 and X-band COSMO-SkyMed) and geotechnical data to investigate the driving factors of subsidence which affect a freight terminal located along the a coastal plain of Tuscany (central Italy). MTInSAR data have been acquired in a very long period, between 1992 and 2018 and were analyzed in terms of subsidence rates and deformation time series at building scale. The obtained results show that the oldest buildings are still affected by a deformation rate close to −5 mm/yr, whereas recent buildings register rates around −40 mm/yr. Time series of deformation suggest that the deformation rates decrease over time following time-dependent trend that approximates the typical consolidation curve for compressible soils. The geotechnical and stratigraphical analysis of the subsurface data (boreholes, cone penetration tests and dilatometer tests) highlights the presence of a 15 m thick layer formed of clay characterized by poor geotechnical characteristics. The comparison among InSAR data, subsurface geological framework and geotechnical reconstruction suggests a possible evaluation of the timing of the primary and secondary consolidation processes

    Interaction of short modified peptides deriving from glycoprotein gp36 of feline immunodeficiency virus with phospholipid membranes

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    A tryptophan-rich octapeptide, C8 (Ac-Trp-Glu-Asp-Trp-Val-Gly-Trp-Ile-NH2), modelled on the membrane-proximal external region of the feline immunodeficiency virus (FIV) gp36 glycoprotein ectodomain, exhibits potent antiviral activity against FIV. A mechanism has been proposed by which the peptide, being positioned on the surface of the cell membrane, inhibits its fusion with the virus. In the present work, peptide–lipid interactions of C8 with dimyristoyl phosphatidylcholine liposomes are investigated using electron spin resonance spectroscopy of spin-labelled lipids. Three other peptides, obtained from modifications of C8, have also been investigated, in an attempt to clarify the essential molecular features of the interactions involving the tryptophan residues. The results show that C8 adsorbs strongly on the bilayer surface. Membrane binding requires not only the presence of the Trp residues in the sequence, but also their common orientation on one side of the peptide that is engendered by the WX2 WX2 W motif. Membrane interaction correlates closely with peptide antiviral activity, indicating that the membrane is essential in stabilizing the peptide conformation that will be able to inhibit viral infection

    BK polyomavirus microRNA levels in exosomes are modulated by non-coding control region activity and down-regulate viral replication when delivered to non-infected cells prior to infection

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    In immunosuppressed patients, BKPyV-variants emerge carrying rearranged non-coding control-regions (rr-NCCRs) that increase early viral gene region (EVGR) expression and replication capacity. BKPyV also encodes microRNAs, which have been reported to downregulate EVGR-encoded large T-antigen transcripts, to decrease viral replication in infected cells and to be secreted in exosomes. To investigate the interplay of NCCR and microRNAs, we compared archetype- and rr-NCCR-BKPyV infection in cell culture. We found that laboratory and clinical rr-NCCR-BKPyV-strains show higher replication rates but significantly lower microRNA levels than archetype virus intracellularly and in exosomes. To investigate whether rr-NCCR or increased EVGR activity modulated microRNA levels, we examined the (sp1-4)NCCR-BKPyV, which has an archetype NCCR-architecture but shows increased EVGR expression due to point mutations inactivating one Sp1 binding site. We found that microRNA levels following (sp1-4)NCCR-BKPyV infection were as low as in rr-NCCR-variants. Thus, NCCR rearrangements are not required for lower miRNA levels. Accordingly, Sp1 siRNA knock-down decreased microRNA levels in archetype BKPyV infection but had no effect on (sp1-4)- or rr-NCCR-BKPyV. However, rr-NCCR-BKPyV replication was downregulated by exosome preparations carrying BKPyV-microRNA prior to infection. To explore the potential relevance in humans, urine samples from 12 natalizumab-treated multiple sclerosis patients were analysed. In 7 patients, rr-NCCR-BKPyV were detected showing high urine BKPyV loads but low microRNAs levels, whereas the opposite was seen in 5 patients with archetype BKPyV. We discuss the results in a dynamic model of BKPyV replication according to NCCR activity and exosome regulation, which integrates immune selection pressure, spread to new host cells and rr-NCCR emergence

    Co-circulation of the two influenza B lineages during 13 consecutive influenza surveillance seasons in Italy, 2004-2017

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    BACKGROUND: Since 1985, two antigenically distinct lineages of influenza B viruses (Victoria-like and Yamagata-like) have circulated globally. Trivalent seasonal influenza vaccines contain two circulating influenza A strains but a single B strain and thus provide limited immunity against circulating B strains of the lineage not included in the vaccine. In this study, we describe the characteristics of influenza B viruses that caused respiratory illness in the population in Italy over 13 consecutive seasons of virological surveillance, and the match between the predominant influenza B lineage and the vaccine B lineage, in each season. METHODS: From 2004 to 2017, 26,886 laboratory-confirmed influenza cases were registered in Italy, of which 18.7% were type B. Among them, the lineage of 2465 strains (49%) was retrieved or characterized in this study by a real-time RT-PCR assay and/or sequencing of the hemagglutinin (HA) gene. RESULTS: Co-circulation of both B lineages was observed each season, although in different proportions every year. Overall, viruses of B/Victoria and B/Yamagata lineages caused 53.3 and 46.7% of influenza B infections, respectively. A higher proportion of infections with both lineages was detected in children, and there was a declining frequency of B/Victoria detections with age. A mismatch between the vaccine and the predominant influenza B lineage occurred in eight out of thirteen influenza seasons under study. Considering the seasons when B accounted for >\u200920% of all laboratory-confirmed influenza cases, a mismatch was observed in four out of six seasons. Phylogenetic analysis of the HA1 domain confirmed the co-circulation of both lineages and revealed a mixed circulation of distinct evolutionary viral variants, with different levels of match to the vaccine strains. CONCLUSIONS: This study contributes to the understanding of the circulation of influenza B viruses in Italy. We found a continuous co-circulation of both B lineages in the period 2004-2017, and determined that children were particularly vulnerable to Victoria-lineage influenza B virus infections. An influenza B lineage mismatch with the trivalent vaccine occurred in about two-thirds of cases

    Modulation of the virus-receptor interaction by mutations in the V5 loop of feline immunodeficiency virus (FIV) following in vivo escape from neutralising antibody

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    <b>BACKGROUND:</b> In the acute phase of infection with feline immunodeficiency virus (FIV), the virus targets activated CD4+ T cells by utilising CD134 (OX40) as a primary attachment receptor and CXCR4 as a co-receptor. The nature of the virus-receptor interaction varies between isolates; strains such as GL8 and CPGammer recognise a "complex" determinant on CD134 formed by cysteine-rich domains (CRDs) 1 and 2 of the molecule while strains such as PPR and B2542 require a more "simple" determinant comprising CRD1 only for infection. These differences in receptor recognition manifest as variations in sensitivity to receptor antagonists. In this study, we ask whether the nature of the virus-receptor interaction evolves in vivo.<p></p> <b>RESULTS:</b> Following infection with a homogeneous viral population derived from a pathogenic molecular clone, a quasispecies emerged comprising variants with distinct sensitivities to neutralising antibody and displaying evidence of conversion from a "complex" to a "simple" interaction with CD134. Escape from neutralising antibody was mediated primarily by length and sequence polymorphisms in the V5 region of Env, and these alterations in V5 modulated the virus-receptor interaction as indicated by altered sensitivities to antagonism by both anti-CD134 antibody and soluble CD134.<p></p> <b>CONCLUSIONS:</b> The FIV-receptor interaction evolves under the selective pressure of the host humoral immune response, and the V5 loop contributes to the virus-receptor interaction. Our data are consistent with a model whereby viruses with distinct biological properties are present in early versus late infection and with a shift from a "complex" to a "simple" interaction with CD134 with time post-infection.<p></p&gt

    Selective expansion of viral variants following experimental transmission of a reconstituted feline immunodeficiency virus quasispecies

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    Following long-term infection with virus derived from the pathogenic GL8 molecular clone of feline immunodeficiency virus (FIV), a range of viral variants emerged with distinct modes of interaction with the viral receptors CD134 and CXCR4, and sensitivities to neutralizing antibodies. In order to assess whether this viral diversity would be maintained following subsequent transmission, a synthetic quasispecies was reconstituted comprising molecular clones bearing envs from six viral variants and its replicative capacity compared in vivo with a clonal preparation of the parent virus. Infection with either clonal (Group 1) or diverse (Group 2) challenge viruses, resulted in a reduction in CD4+ lymphocytes and an increase in CD8+ lymphocytes. Proviral loads were similar in both study groups, peaking by 10 weeks post-infection, a higher plateau (set-point) being achieved and maintained in study Group 1. Marked differences in the ability of individual viral variants to replicate were noted in Group 2; those most similar to GL8 achieved higher viral loads while variants such as the chimaeras bearing the B14 and B28 Envs grew less well. The defective replication of these variants was not due to suppression by the humoral immune response as virus neutralising antibodies were not elicited within the study period. Similarly, although potent cellular immune responses were detected against determinants in Env, no qualitative differences were revealed between animals infected with either the clonal or the diverse inocula. However, in vitro studies indicated that the reduced replicative capacity of variants B14 and B28 in vivo was associated with altered interactions between the viruses and the viral receptor and co-receptor. The data suggest that viral variants with GL8-like characteristics have an early, replicative advantage and should provide the focus for future vaccine development

    Linee guida per l’elaborazione del modello idrogeologico concettuale

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    Introduzione. Il presente quaderno tecnico affronta il tema del modello idrogeologico concettuale, ovvero di quel passaggio dalle categorie storicamente qualitative, naturalistiche della geologia classica, a quelle di un inquadramento stringente, coerente e quantificato dell’idrogeologia applicata e dei suoi corollari numerici. Vengono di seguito descritti metodi, strumenti e concetti per una corretta elaborazione del modello concettuale, ovvero come conglobare l’informazione meteo-climatica, idrochimica, geochimica, agronomica, litologica, petro- chimica ed idrologica in uno schema coerente che consenta la sintesi olistica della dinamica delle acque sotterranee e di quanto esse veicolano, in un quadro comprensibile anche ad altre categorie tecnico-professionali. Un modello concettuale, correttamente concepito, agevola la comprensione dei fenomeni accaduti e la previsione di cosa potrà succedere anche, ma non solo, in conseguenza di azioni antropiche in atto o in programmazione. Si è quindi affrontato anche il tema delle normative che trattano la materia in riferimento alla programmazione ter- ritoriale, alla progettazione di manufatti ed opere ed alla tutela ed al risanamento dell’ambiente. Il modello concettuale è base imprescindibile per ogni successiva valutazione quantitativa. In assenza di un modello verificato e robusto, non solo il passaggio all’implementazione di un modello numerico è velleitario, ma anche i semplici calcoli deterministico-analitici, più ampiamente diffusi ed applicati, rischiano di perdere ogni significato pratico. Ovviamente il quaderno non ha alcuna pretesa di esaustività né di formulare codici, ma cerca semplicemente di for- nire ai colleghi una traccia utile, ancorché insufficiente se non corredata dagli approfondimenti che ciascuno di noi è sempre tenuto a fare, per soddisfare in scienza e coscienza le esigenze dei committenti. Il paragrafo bibliografia e l’annesso glossario servono proprio a questo
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