226 research outputs found

    Evidence of pyrite dissolution by Telephora terrestris Ehrh in the Libiola mine (Sestri Levante, Liguria, Italy)

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    Evidence of pyrite dissolution by Telephora terrestris Ehrh were observed for the first time in the abandoned sulphide Libiola mine in May 2017 (Sestri Levante, Liguria, Italy). This fungus is an ectomycorrhizal species able to colonize this extreme environment and bioaccumulate metals such as copper and silver in its fruiting bodies, and it is known to establish symbiosis with maritime pines present in the area, thus favouring their recolonization of the site. This paper presents evidence of T. terrestris promoted dissolution of sulphide minerals. This species can remove from soil not only metals possibly toxic to the pine trees, but it can also contribute to the ions bioaccumulation through the bioweathering of sulphide mineral grains (especially pyrite)

    FbsA-driven fibrinogen polymerization: a bacterial Deceiving Strategy.

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    We show that FbsA, a cell wall protein of the bacterium Streptococcus agalactiae, promotes large-scale aggregation of human plasma fibrinogen, leading to the formation of a semiflexible polymerlike network. This extensive aggregation process takes place not only in solution, but also on FbsA-functionalized colloidal particles, and leads to the formation of a thick layer on the bacterial cell wall itself, which becomes an efficient mask against phagocytosis

    Bottleneck genes and community structure in the cell cycle network of S. pombe.

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    The identification of cell cycle-related genes is still a difficult task, even for organisms with relatively few genes such as the fission yeast. Several gene expression studies have been published on S. pombe showing similarities but also discrepancies in their results. We introduce a network in which the weight of each link is a function of the phase difference between the expression peaks of two genes. The analysis of the stability of the clustering through the computation of an entropy parameter reveals a structure made of four clusters, the first one corresponding to a robustly connected M-G1 component, the second to genes in the S phase, and the third and fourth to two G2 components. They are separated by bottleneck structures that appear to correspond to cell cycle checkpoints. We identify a number of genes that are located on these bottlenecks. They represent a novel group of cell cycle regulatory genes. They all show interesting functions, and they are supposed to be involved in the regulation of the transition from one phase to the next. We therefore present a comparison of the available studies on the fission yeast cell cycle and a general statistical bioinformatics methodology to find bottlenecks and gene community structures based on recent developments in network theory

    Sulfide weathering processes mediated by microfungi

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    This study aimed to experimentally investigate the interactions, the bioalteration, and the biocorrosion of sulfides mediated by three microfungi (Trichoderma harzianum group, Penicillium glandicola, P. brevicompactum) isolated within the open-air waste-rock dumps from Libiola mine (Liguria, Italy). Unaltered samples of pyrite-mineralizations from the same waste-rock dumps were ground and sieved into size fraction of 150-63 \u3bc m which resulted composed by single crystals of pyrite (>80 wt%), with minor quartz and trace amount of chalcopyrite. The mineral bioalteration tests were carried out for six weeks using Czapek-Dox agar medium (CZA). In each plate, four pyrite crystals or crystal fragments were set into the solid medium. After one week, pyrite grains were almost completely covered by mycelia of the three different fungi. The samples were examined, before and after the experimental procedure, using plane-polarized optical microscopy (transmitted- and reflected-light) and environmental scanning electron microscopy (ESEM-EDS). The ESEM analyses were performed in low-vacuum mode for the micromorphological analyses to characterize the evolution of the mineralfungi interactions during the different experimental steps. After six weeks covered by mycelia, the pyrite grains were collected and analyzed revealing that the surface of pyrite crystals was strongly corroded in all experimental tests. ESEM images underlined how pyrite alteration was strictlty associated with biological patterns (curves, rounded cracks, and sinuous traces). Corrosion patterns and etching pits were not related to specific crystallographic planes or weakness, but were randomly distributed on the crystal surfaces, in particular in correspondence of the fungal hyphae attachment. Moreover, in the same temporal interval, the control experiment performed in abiotic conditions did not show any dissolution evidences thus suggesting that in absence of fungal interactions the pyrite weathering did not occur or was much slower. The experimental results evidenced the active role of fungi in the pyrite crystal weathering and suggested that sulfide alteration was not only the consequence of the interactions between metabolites secreted by fungi and minerals, but there was also a possible bio-mechanical role of hyphae in corrosion through penetration, boring, and burrowing along weak crystal planes or microfractures. Finally, the evidences of biocorrosion led to evaluate the important role of fungi in the iron and sulfur cycles in sulfide-bearing materials, since fungal alteration systematically triggers sulfide to sulfate oxidation, causing local gypsum and Fe-oxyhydroxides precipitation within mycelium structure

    DEGASSAMENTO DI RADON E MODIFICHE DEL DNA DELLA POPOLAZIONE SICILIANA: POSSIBILI RELAZIONI CON IL TERREMOTO DEL 1908

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    I risultati delle indagini condotte su base geochimica e genetica nell’area delle Stretto di Messina si incrociano proponendo uno scenario assolutamente nuovo su ciò che un terremoto può indurre anche come effetti sulla salute umana, con modifiche di tipo genetico. Le ricerche svolte nell’ambito del progetto INGV-Dipartimento Protezione Civile su “Valutazione del potenziale sismogenetico e probabilità dei forti terremoti in Italia”, hanno mostrato che nell’area dello Stretto di Messina persistono anomalie di degassamento dai suoli di CO2, metano e radon, diversi ordini di grandezza al di sopra dei valori normali, per esempio con concentrazioni dinamiche di Rn fino oltre 80.000 Bq/m3 La valutazione di un degassamento naturale di tale intensità in situazione di quiete sismica, ha assunto significato anche nella valutazione degli effetti del Rn sulla salute umana, che, sebbene conosciuti da tempo come seconda causa di tumore al polmone dopo il fumo, si mostrano sorprendentemente come i possibili protagonisti delle mutazioni genetiche riscontrate nella popolazione vivente intorno allo Stretto Radon e DNA La presenza di antigeni indicano di modifiche del DNA, ed uno in particolare denominato DR11 è presente con la frequenza più alta intorno a Messina e a Reggio (54% della popolazione) per poi diminuire verso Caltanissetta e Vibo Valentia (44%) con un minimo a Trapani (38%; figura 1). Una tale modifica del DNA è in contrasto con la Legge di Hardy –Weimberg, secondo la quale in una popolazione in cui gli accoppiamenti avvengono a caso, e in assenza di pressioni evolutive e di forti migrazioni dovrebbe essere mantenuta una generale omogeneità. Questo tipo di distribuzione, molto eterogenea, ma non irregolare e disordinata, non può essere attribuita a fluttuazioni casuali o a deriva genetica, e neanche alle invasioni che nel passato queste regioni hanno subito da parte di popoli stranieri.L’ordinata e graduale riduzione di frequenza del DR11, funzione dalla distanza dallo stretto, unitamente alle valutazioni basate sulla riduzione nel tempo della frequenza del DR11, portano a concentrare l’attenzione su un evento con epicentro nello stretto accaduto circa un secolo fa, identificabile come il terremoto del 1908. Tenuto conto che non ci sono effetti diretti di un sisma in grado di interagire con la saluteumana (se non ferite, paura) si ipotizza che non sia direttamente il terremoto come tale la causa scatenante della mutazione genetica osservata ma qualcosa che ad un forte evento sismico possa essere legata. Fluidi e terremoti I risultati ottenuti in varie aree sismiche italiane (p.e. Umbria, Friuli, Appennino Tosco Emiliano) hanno mostrato che i fluidi cambiamo composizione e intensità del rilascio durante l’evolversi della sismogenesi. Le modifiche si registrano prima, durante e dopo gli eventi sismici mostrando che oltre alla fratturazione anche le deformazioni della crosta provocano modificazioni nei fluidi circolanti. Una aumentata emissione di radon durante il processo che ha portato al terremoto del 1908 è assolutamente ipotizzabile in accordo con quanto osservato durante la crisi sismica dell’Umbria (1997-98) e con le misure effettuate nell’area dello Stretto (Figura 2). Una contaminazione da gas radon dovuta alla sismogenesi, che si è protratta per tempi probabilmente lunghi, prima durante e dopo il catastrofico evento, può essere la causa delle mutazioni genetiche osservate, avendo indotto gli organismi a reagire per tutelarsi rispetto ad una pressione esterna pericolosa.Un simile scenario, che vede i processi sismogenetici strettamente legati ai fluidi anche con attivi processi di degassamento, richiede ulteriori indagini che oltre a contribuire alla riduzione del rischio sismico permettono la conoscenza di quegli aspetti legati alle interazioni uomo-ambiente su medio-lungo termine anche come possibili responsabili di cambiamenti profondi come quelli identificati del DNA dei siciliani

    Controlled Quenching of Agarose Defines Hydrogels with Tunable Structural, Bulk Mechanical, Surface Nanomechanical, and Cell Response in 2D Cultures

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    : The scaffolding of agarose hydrogel networks depends critically on the rate of cooling (quenching) after heating. Efforts are made to understand the kinetics and evolution of biopolymer self-assembly upon cooling, but information is lacking on whether quenching might affect the final hydrogel structure and performance. Here, a material strategy for the fine modulation of quenching that involves temperature-curing steps of agarose is reported. Combining microscopy techniques, standard and advanced macro/nanomechanical tools, it is revealed that agarose accumulates on the surface when the curing temperature is set at 121 °C. The inhomogeneity can be mostly recovered when it is reduced to 42 °C. This has a drastic effect on the stiffness of the surface, but not on the viscoelasticity, roughness, and wettability. When hydrogels are strained at small/large deformations, the curing temperature has no effect on the viscoelastic response of the hydrogel bulk but does play a role in the onset of the non-linear region. Cells cultured on these hydrogels exhibit surface stiffness-sensing that affects cell adhesion, spreading, F-actin fiber tension, and assembly of vinculin-rich focal adhesions. Collectively, the results indicate that the temperature curing of agarose is an efficient strategy to produce networks with tunable mechanics and is suitable for mechanobiology studies

    A case report of myoid gonadal stromal tumor treated with testis sparing surgery

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    Background: Myoid gonadal stromal tumors (MGST) of the testis represent a very rare finding. They are an emerging clinicopathological entity with specific features and identity. Nowadays, pathological recognition and diagnosis of MGSTs still represents a difficult challenge in most cases and there are no data of specific radiological features of these tumors expect for what seen by ultrasound; besides a conservative surgical approach was never performed to treat these lesions.Case Description: We present the case of a 20-year-old young man patient with symptoms suspicious for left varicocele, who was incidentally diagnosed with right testicular nodule via scrotal doppler ultrasound powered with contrast enhancement infusion and subsequent multiparametric magnetic resonance imaging. Then, lesion was treated through a testis sparing surgical approach. Histopathology, which included an external revision by an experienced Center, revealed a MGST with benign features, so that no further treatment was considered. 3 and 12 months after surgery a contrast enhancement ultrasound was performed with no evidence of recurrence.Conclusions: Previous reported cases of MGST were all difficult to characterize as a specific pathological entity; treatment usually applied was radical orchiectomy and a subsequent total Body CT was performed for staging purpose. No metastatic spreading nor recurrence were ever reported. Considering the favorable behavior of this pathologic entity, testis-sparing surgery with no radiation exposure during follow-up is a safe and effective strategy

    A common approach to the conservation of threatened island vascular plants: First results in the mediterranean basin

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    The Mediterranean islands represent a center of vascular plant diversity featuring a high rate of endemic richness. Such richness is highly threatened, however, with many plants facing the risk of extinction and in need of urgent protection measures. The CARE-MEDIFLORA project promoted the use of ex situ collections to experiment with in situ active actions for threatened plants. Based on common criteria, a priority list of target plant species was elaborated, and germplasm conservation, curation and storage in seed banks was carried out. Accessions were duplicated in the seed banks of the partners or other institutions. Germination experiments were carried out on a selected group of threatened species. A total of 740 accessions from 429 vascular plants were stored in seed banks, and 410 seed germination experiments for 283 plants species were completed; a total of 63 in situ conservation actions were implemented, adopting different methodological protocols. For each conservation program, a specific monitoring protocol was implemented in collaboration with local and regional authorities. This project represents the first attempt to develop common strategies and an opportunity to join methods and methodologies focused on the conservation of threatened plants in unique natural laboratories such as the Mediterranean islands

    Detection of ST1702 Escherichia coli blaNDM-5 and blaCMY-42 genes positive isolates from a Northern Italian hospital

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    We describe two multi drug-resistant (MDR) carbapenemase-producing Escherichia coli clinical isolates from an acute hospital in Milan. Both strains, isolated from a surgical wound sample and a surveillance rectal swab respectively, were positive for a blaNDM-type gene by Xpert Carba-R test. The whole-genome sequence characterization disclosed several resistance determinants: blaNDM-5, blaCMY-42, blaTEM-198, rmtB, mphA. The two isolates belonged to phylogenetic group A, sequence type (ST) 1702 and serotype O89:H9. PCR-based replicon typing and conjugation assay demonstrated an IncI1 plasmid localization for both blaNDM-5 and blaCMY-42 genes. This is the first report of a ST1702 NDM-5 and CMY-42- producing E. coli clone in Italy
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