734 research outputs found
Molecular Interactions of Human Plasminogen with Fibronectin-binding Protein B (FnBPB), a Fibrinogen/Fibronectin-binding Protein from Staphylococcus aureus
none7siStaphylococcus aureus is a commensal bacterium that has the ability to cause superficial and deep-seated infections. Like several other invasive pathogens, S. aureus can capture plasminogen from the human host where it can be converted to plasmin by host plasminogen activators or by endogenously expressed staphylokinase. This study demonstrates that sortase-anchored cell wall-associated proteins are responsible for capturing the bulk of bound plasminogen. Two cell wall-associated proteins, the fibrinogen- and fibronectin-binding proteins A and B, were found to bind plasminogen, and one of them, FnBPB, was studied in detail. Plasminogen captured on the surface of S. aureus- or Lactococcus lactis-expressing FnBPB could be activated to the potent serine protease plasmin by staphylokinase and tissue plasminogen activator. Plasminogen bound to recombinant FnBPB with a KD of 0.532 ÎĽm as determined by surface plasmon resonance. Plasminogen binding did not to occur by the same mechanism through which FnBPB binds to fibrinogen. Indeed, FnBPB could bind both ligands simultaneously indicating that their binding sites do not overlap. The N3 subdomain of FnBPB contains the full plasminogen-binding site, and this includes, at least in part, two conserved patches of surface-located lysine residues that were recognized by kringle 4 of the host protein.openPietrocola, G; Nobile, G; Gianotti, V; Zapotoczna, M; Foster, Tj; Geoghegan, Ja; Speziale, P.Pietrocola, Giampiero; Nobile, Giulia; Gianotti, Valentina; Zapotoczna, M; Foster, Tj; Geoghegan, Ja; Speziale, Pietr
Ultrathin random copolymer-grafted layers for block copolymer self-assembly
Hydroxyl-terminated P(S-r-MMA) random copolymers (RCPs) with molecular weights (Mn) from 1700 to 69000 and a styrene unit fraction of approximately 61% were grafted onto a silicon oxide surface and subsequently used to study the orientation of nanodomains with respect to the substrate, in cylinder-forming PS-b-PMMA block copolymer (BCP) thin films. When the thickness (H) of the grafted layer is greater than 5-6 nm, a perpendicular orientation is always observed because of the efficient decoupling of the BCP film from the polar SiO2 surface. Conversely, if H is less than 5 nm, the critical thickness of the grafted layer, which allows the neutralization of the substrate and promotion of the perpendicular orientation of the nanodomains in the BCP film, is found to depend on the Mn of the RCP. In particular, when Mn = 1700, a 2.0 nm thick grafted layer is sufficient to promote the perpendicular orientation of the PMMA cylinders in the PS-b-PMMA BCP film. A proximity shielding mechanism of the BCP molecules from the polar substrate surface, driven by chain stretching of the grafted RCP molecules, is proposed
Thymus vulgaris Essential Oil in Beta-Cyclodextrin for Solid-State Pharmaceutical Applications
: Antimicrobial resistance related to the misuse of antibiotics is a well-known current topic. Their excessive use in several fields has led to enormous selective pressure on pathogenic and commensal bacteria, driving the evolution of antimicrobial resistance genes with severe impacts on human health. Among all the possible strategies, a viable one could be the development of medical features that employ essential oils (EOs), complex natural mixtures extracted from different plant organs, rich in organic compounds showing, among others, antiseptic properties. In this work, green extracted essential oil of Thymus vulgaris was included in cyclic oligosaccharides cyclodextrins (CD) and prepared in the form of tablets. This essential oil has been shown to have a strong transversal efficacy both as an antifungal and as an antibacterial agent. Its inclusion allows its effective use because an extension of the exposure time to the active compounds is obtained and, therefore, a more marked efficacy, especially against biofilm-producing microorganisms such as P. aeruginosa and S. aureus, was registered. The efficacy of the tablet against candidiasis opens their possible use as a chewable tablet against oral candidiasis and as a vaginal tablet against vaginal candidiasis. Moreover, the registered wide efficacy is even more positive since the proposed approach can be defined as effective, safe, and green. In fact, the natural mixture of the essential oil is produced by the steam current method; therefore, the manufacturer employs substances that are not harmful, with very low production and management costs
Rationalization of dye uptake on titania slides for dye-sensitized solar cells by a combined chemometric and structural approach
Antioxidant Composition of a Selection of Italian Red Wines and Their Corresponding Free-Radical Scavenging Ability
This study correlates the antioxidant composition profiles and the overall antioxidant capacities of 36 Italian red wine samples. The samples were fully characterized by chromatographic and spectrophotometric techniques. The overall antioxidant capacity was determined by titrating a solution of the semistable free radical DPPH (1,1-diphenyl-2-picrylhydrazyl) with each wine sample followed by Electron Paramagnetic Resonance (EPR) spectroscopy and then measuring the resulting decrease in DPPH-signal. The antioxidant activities of the samples were expressed as (+)-catechin equivalents and related to their antioxidant composition profiles. Samples with a high polyphenol content showed a high DPPH scavenging ability as well. Seven well-defined groups, mainly constituted by wines coming from the same cultivar, were evidenced by PCA analysis. Alcohol content and pH did not influence the wine DPPH scavenging ability. The most important variables contributing to the wines’ antioxidant power are total flavonoid, total phenol, and proanthocyanidin indices together with fertaric acid, trans-caftaric acid, trans-coutaric acid, and both quercetin glucoside and quercetin glucuronide. EPR is demonstrated to be faster than the other analytical methods (spectrophotometric and chromatographic analyses) to determine the wine overall antioxidant activity
The DAQ system support to the AIV activities of the ASTRI camera proposed for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA), the next generation ground-based observatory for very high-energy gamma rays, is being built and will be operated by an international consortium. Two arrays will be located in the northern and southern hemispheres. Each telescope array will operate different numbers and types of telescopes. The Italian National Institute for Astrophysics (INAF) is leading the ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) project in the framework of the small size class of telescopes (SST). A first goal of the ASTRI project is the realization of an end-to-end prototype in dual-mirror configuration (SST-2M). The ASTRI camera focal plane is composed of a matrix of silicon photo-multiplier sensors managed by innovative front-end and back-end electronics. The ASTRI SST2M prototype is installed in Italy at the INAF "M.G. Fracastoro" observing station located at Serra La Nave, 1735 m a.s.l. on Mount Etna, Sicily. The ASTRI Data AcQuisition (DAQ) system acquires, packet by packet, the camera data from the back-end electronics. The packets are then stored locally in one raw file as soon as they arrive. During the acquisition, the DAQ system groups the packets by data type (scientific, calibration, engineering) before processing and storing the data in FITS format. All the files are then transferred to the on-site archive. In addition, we implemented a quick-look component the allows the operator to display the camera data during the acquisition. A graphical user interface enables the operator to configure, monitor and control the DAQ software. Furthermore, we implemented the control panel algorithms within the framework of the Alma Common Software, in order to integrate the DAQ software within the ASTRI control software. The ASTRI DAQ system supports the camera AIV activities and operations. We provide the instrument workstation to support the AIV activities in the laboratory, and the camera server on-site. In this paper, we assess the ASTRI DAQ system as it has performed the AIV tasks for the ASTRI SST-2M prototype
The AGILE Pipeline for Gravitational Waves Events Follow-up
The first direct detection of gravitational waves (GW) by Advanced LIGO detectors in September 2015 has drawn the attention of the astrophysical community that is now searching for the electromagnetic counterparts of the detected GW events. The AGILE (Astro-Rivelatore Gamma a Immagini Leggero) mission is primarily devoted to the high-energy astrophysical study of gamma-ray sources in the 30 MeV to 30 GeV energy range. The capability of the AGILE satellite for the discovery of transients is unique: the actual spinning configuration of the satellite, together with a large field of view and a good sensitivity of F =(1-2) Ă—10-8ergcm-2 s-1 for 100s integrations, provides a coverage of 80% of the sky, with each position exposed for 100 seconds, 200 times a day. The AGILE team signed a memorandum of understanding (MoU) with the LIGO/Virgo collaboration to follow the GW notices provided through the GCN network. In this paper we describe our automated pipeline that reacts to LIGO/Virgo GW notices and performs different kind of automated analysis to boost the search for of GW event counterparts
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