70 research outputs found

    Analysis of Increasing Flash Flood Frequency in the Densely Urbanized Coastline of the Campi Flegrei Volcanic Area, Italy

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    Climate change is affecting the frequency and severity of extreme meteorological and geo-hydrological events hitting the coastal zone of the Campi Flegrei volcanic district (southern Italy), which is prone to a wide spectrum of natural hazards, including volcanism, earthquakes, ground deformation, flash floods, landslides, and coastal erosion. This study documents the trend of flash floods affecting the town of Pozzuoli, located along the coastline of the Campi Flegrei volcanic area, during the 1970–2014 time period. An archive research together with the collection of data published on news websites and social media allowed understanding of the triggering and evolution mechanisms of flash floods in the area, as well as the most recurrent damages. Rainfall data collected by the rain gauge located within the Pozzuoli watershed were also analyzed. Results of this study show an increased frequency of flash flood events occurred in the study area. The variation in flash flood frequency is likely not related to urbanization changes, as no increase of the urban area occurred after the year 2000. The observed increase of flash flood events in recent years (2000–2014) can be reasonably ascribed to variations in the rainfall regime. Our research provides a contribution for the understanding of flash flood processes in the study area as well as relevant information for hazard and risk assessment

    Fast Detection of Two Smenamide Family Members Using Molecular Networking.

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    Caribbean sponges of the genus Smenospongia are a prolific source of chlorinated secondary metabolites. The use of molecular networking as a powerful dereplication tool revealed in the metabolome of S. aurea two new members of the smenamide family, namely smenamide F (1) and G (2). The structure of smenamide F (1) and G (2) was determined by spectroscopic analysis (NMR, MS, ECD). The relative and the absolute configuration at C-13, C-15, and C-16 was determined on the basis of the conformational rigidity of a 1,3-disubstituted alkyl chain system (i.e., the C-12/C-18 segment of compound (1). Smenamide F (1) and G (2) were shown to exert a selective moderate antiproliferative activity against cancer cell lines MCF-7 and MDA-MB-231, while being inactive against MG-63

    ATP-evoked intracellular Ca2+ transients shape the ionic permeability of human microglia from epileptic temporal cortex

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    BACKGROUND: Intracellular Ca2+ modulates several microglial activities, such as proliferation, migration, phagocytosis, and inflammatory mediator secretion. Extracellular ATP, the levels of which significantly change during epileptic seizures, activates specific receptors leading to an increase of intracellular free Ca2+ concentration ([Ca2+]i). Here, we aimed to functionally characterize human microglia obtained from cortices of subjects with temporal lobe epilepsy, focusing on the Ca2+-mediated response triggered by purinergic signaling.METHODS: Fura-2 based fluorescence microscopy was used to measure [Ca2+]i in primary cultures of human microglial cells obtained from surgical specimens. The perforated patch-clamp technique, which preserves the cytoplasmic milieu, was used to measure ATP-evoked Ca2+-dependent whole-cell currents.RESULTS: In human microglia extracellular ATP evoked [Ca2+]i increases depend on Ca2+ entry from the extracellular space and on Ca2+ mobilization from intracellular compartments. Extracellular ATP also induced a transient fivefold potentiation of the total transmembrane current, which was completely abolished when [Ca2+]i increases were prevented by removing external Ca2+ and using an intracellular Ca2+ chelator. TRAM-34, a selective KCa3.1 blocker, significantly reduced the ATP-induced current potentiation but did not abolish it. The removal of external Cl- in the presence of TRAM-34 further lowered the ATP-evoked effect. A direct comparison between the ATP-evoked mean current potentiation and mean Ca2+ transient amplitude revealed a linear correlation. Treatment of microglial cells with LPS for 48h did not prevent the ATP-induced Ca2+ mobilization but completely abolished the ATP-mediated current potentiation. The absence of the Ca2+-evoked K+ current led to a less sustained ATP-evoked Ca2+ entry, as shown by the faster Ca2+ transient kinetics observed in LPS-treated microglia.CONCLUSIONS: Our study confirms a functional role for KCa3.1 channels in human microglia, linking ATP-evoked Ca2+ transients to changes in membrane conductance, with an inflammation-dependent mechanism, and suggests that during brain inflammation the KCa3.1-mediated microglial response to purinergic signaling may be reduced

    An integrated approach for rock slope failure monitoring: The case study of Coroglio tuff cliff (Naples, Italy) - Preliminary results

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    The paper re ports the i mple mentation of an integrate d syste m ai me d at the real-ti me monitoring of a series of physical parame ters controlling the r ock slope stability. The system has bee n installe d on the Cor oglio tuff cliff, loc ate d in the highly ur banize d coastal area of Naples (Italy) at the bor der of the acti ve volcanic cal der a of Campi Flegrei. Preliminar y results obtai ne d during the first ye ar of data ac quisition and monitoring acti vi ty (Dece mber 2014 – January 2016) are also discussed on the basis of statistical models. (3) (PDF) An integrated approach for rock slope failure monitoring: the case study of Coroglio tuff cliff (Naples, Italy) – preliminary results. Available from: https://www.researchgate.net/publication/299340773_An_integrated_approach_for_rock_slope_failure_monitoring_the_case_study_of_Coroglio_tuff_cliff_Naples_Italy_-_preliminary_results [accessed Feb 27 2020].Published242-2471IT. Reti di monitoraggio e sorveglianzaN/A or not JC

    Fatty Acid Substitutions Modulate the Cytotoxicity of Puwainaphycins/Minutissamides Isolated from the Baltic Sea Cyanobacterium Nodularia harveyana UHCC-0300

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    Puwainaphycins (PUW) and minutissamides (MIN) are structurally homologous cyclic lipopeptides that exhibit high structural variability and possess antifungal and cytotoxic activities. While only a minor variation can be found in the amino acid composition of the peptide cycle, the fatty acid (FA) moiety varies largely. The effect of FA functionalization on the bioactivity of PUW/MIN chemical variants is poorly understood. A rapid and selective liquid chromatography-mass spectrometry-based method led us to identify 13 PUW/MIN (1-13) chemical variants from the benthic cyanobacterium Nodularia harveyana strain UHCC-0300 from the Baltic Sea. Five new variants identified were designated as PUW H (1), PUW I (2), PUW J (4), PUW K (10), and PUW L (13) and varied slightly in the peptidic core composition, but a larger variation was observed in the oxo-, chloro-, and hydroxy-substitutions on the FA moiety. To address the effect of FA substitution on the cytotoxic effect, the major variants (3 and 5-11) together with four other PUW/MIN variants (14-17) previously isolated were included in the study. The data obtained showed that hydroxylation of the FA moiety abolishes the cytotoxicity or significantly reduces it when compared with the oxo-substituted C-18-FA (compounds 5-8). The oxo-substitution had only a minor effect on the cytotoxicity of the compound when compared to variants bearing no substitution. The activity of PUW/ MIN variants with chlorinated FA moieties varied depending on the position of the chlorine atom on the FA chain. This study also shows that variation in the amino acids distant from the FA moiety (position 4-8 of the peptide cycle) does not play an important role in determining the cytotoxicity of the compound. These findings confirmed that the lipophilicity of FA is essential to maintain the cytotoxicity of PUW/MIN lipopeptides. Further, a 63 kb puwainaphycin biosynthetic gene cluster from a draft genome of the N. harveyana strain UHCC-0300 was identified. This pathway encoded two specific lipoinitiation mechanisms as well as enzymes needed for the modification of the FA moiety. Examination on biosynthetic gene clusters and the structural variability of the produced PUW/MIN suggested different mechanisms of fatty-aryl-AMP ligase cooperation with accessory enzymes leading to a new set of PUW/MIN variants bearing differently substituted FA.Peer reviewe

    In silico analysis and theratyping of an ultra-rare CFTR genotype (W57G/A234D) in primary human rectal and nasal epithelial cells

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    Mutation targeted therapy in cystic fibrosis (CF) is still not eligible for all CF subjects, especially for cases carrying rare variants such as the CFTR genotype W57G/A234D (c.169T>G/c.701C>A). We performed in silico analysis of the effects of these variants on protein stability, which we functionally characterized using colonoids and reprogrammed nasal epithelial cells. The effect of mutations on cystic fibrosis transmembrane conductance regulator (CFTR) protein was analyzed by western blotting, forskolin-induced swelling (FIS), and Ussing chamber analysis. We detected a residual CFTR function that increases following treatment with the CFTR modulators VX661±VX445±VX770, correlates among models, and is associated with increased CFTR protein levels following treatment with CFTR correctors. In vivo treatment with VX770 reduced sweat chloride concentration to non-CF levels, increased the number of CFTR-dependent sweat droplets, and induced a 6% absolute increase in predicted FEV1% after 27 weeks of treatment indicating the relevance of theratyping with patient-derived cells in CF

    Stereostructural studies and biological activities of secondary metabolites from marine sources

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    Within the marine ecosystem, the sessile organisms such as Porifera are considered the most interesting phylum by the natural products chemists. Because these organisms live fixed on a substrate and are lacking of any physical defence against predators, they have acquired, during their evolution, the ability to synthesize bioactive compounds that can be used as chemical weapons. Sponge derived natural products belong to many different chemical classes, including polyketides, terpenoids, peptides and alkaloids, and show a wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiviral and anti-inflammatory activities. For this reason these compounds can be used as lead compounds in drug discovery. In the last years, several drugs derived from marine natural products have appeared in the market, and others are in clinical trials. The research work described in this PhD thesis belongs to this research field. In particular, my attention was focused on the chemical analysis of the sponge of the genus Smenospongia. Two new bioactive secondary metabolites with a hybrid structure peptide/ polyketide, smenothiazoles A and B, were isolated from the sponge Smenospongia aurea. Smenothiazoles were tested against four solid tumor cell lines and showed a potent cytotoxic activity at nanomolar levels with selectivity against ovarian cancer cells and a pro-apoptotic mechanism. The analysis of the congeneric sponge species, Smenospongia conulosa, revealed the presence of two additional chlorinated compounds, conulothiazoles A and B together with smenothiazoles. However, the anticancer activity of these compounds cannot be evaluated because of the low amount isolated from the sponge. My work during these three years regarded also the chemical analysis of the MeOH crude extract of the sponge Achantostrongylophora ingens which revealed protein kinase inhibitory activity. The bioguided fractionation of this extract led to the isolation of a new halogenated alkaloid, chloromethylhalicyclamine B, together with the known natural compound halicyclamine B. The new compound is the result of the reaction between halicyclamine B and CH2Cl2 used for the extraction. However, in contrast to the known halicyclamine B, the new derivative revealed to be a selective CK1δ/ε inhibitor with an IC50 value of 6 μM. The absolute configuration of chloromethylhalicyclamine B was determined by quantum mechanical prediction of its ECD spectrum. The conformation assumed by the new molecule was also determined by computational studies and was validated by NOESY data. Docking studies were also performed in order to evaluate the accommodation of the molecule in the ATP binding site of CK1δ. Even if the globular structure of this compound is very different from that of already known CK1δ inhibitors, the analysis revealed that the accommodation in the binding site is good. Therefore, these data showed chloromethylhalicyclamine B as a new structural type of CK1δ/ε inhibitor. A deeper analysis of the chemical composition of A. ingens revealed also the presence of additional new halicyclamine derivatives but their activity has not yet been evaluated. Another part of my work has been addressed to the search for molecules involved in quorum sensing mechanism in order to control the communication between bacteria and thus their virulence. The most frequent molecules involved in this process are the acylated homoserinelactone compounds (AHLs). In collaboration with the group of Prof. Laura Steindler at the University of Haifa, Israel, I analyzed the extracts of the marine bacteria Paracoccus sp. in order to detect the presence of AHLs. Twelve saturated long-chain AHLs (3-OH-C10-HSL, 3-OH-C12-HSL, C10-HSL, 3-OH-C14-HSL, C12-HSL, 3-O-C16-HSL, 3-OHC16-HSL, C14-HSL, 3-OH-C18-HSL, C16-HSL, 3-O-C18-HSL, and C18-HSL), along with four putative unsaturated long-chain AHLs (C10 :1-HSL, 3-OH-C18 :1-HSL, C16 :1-HSL, and C18 :1-HSL) were found in Paracoccus extract confirming the possibility to have quorum sensing in particular conditions. It is noteworthy that other small molecules like diketopiperazines (DKPs) are able to influence the quorum sensing mechanism. For this reason, we determined the absolute configuration by Marfey’s method of 7 known diketopiperazine isolated from the marine sponge Acanthostrongylophora ingens. In this way we created a library of DKPs that were evaluated for their quorum quenching activity. Preliminary results showed that all compounds exhibit QS inhibitory activity against E.coli pSB1075 (long chain gene reporter) with MIC of 70 µM, while none compounds show QS inhibitory activity against E.coli pSB401 (short chain gene reporter) at low concentrations where in addition the bioluminescence increases at high concentration ≥ 70 µM

    Do You Know That Microbes Use Social Networks?

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