1,720,969 research outputs found
Costruire dispositivi con un nanoLEGO bio-inorganico
No full textIl workshop tenuto il 26 gennaio 2016 presso il Centro della Casaccia ha affrontato la tematica dell'autoassemblaggio di dispositivi ibridi bio-inorganici di tipo sensoristico, elettronico e informatico, basati sulle proprietà di autoassemblaggio del DNA in forme programmabili. Queste nanostrutture di DNA possono poi essere utilizzate come basi di montaggio automatico e programmato per mezzo di connettori specifico quali peptidi, aptameri e anticorpi, di componentistica funzionale proteica, di quantum dota inorganici e nanoparticelle conduttrici di interesse fotonico, di singole catene di polimeri conduttori, e perfino di ulteriori nanostrutture prefabbricate come particelle virali.The workshop held at the Casaccia Research Center on Jan 26, 2016 addressed the issue of self assembly of hybrid bio-inorganic electronic, sensing and information devices, exploiting the DNA property of self assembling into programmable shapes. Such nano sized DNA structures can be used as breadboards to self-organize specific connectors, such as peptides, aptamers and antibodies, functional protein components, inorganic nanostructure such as quantum dots or metal nanoparticles, single conducting polymer chains, and even natural prefabricated structures such as viral particles. The relevant skills available in the ENEA laboratories have been reviewed and are reported here together with an introductory note and the abstracts of the short presentations
In vitro and in vivo toxicity evaluation of plant virus nanocarriers
No full textThe use of biological self-assembling materials, plant virus nanoparticles in particular, appears very intriguing as it allows a great choice of symmetries and dimensions, easy chemical and biological engineering of both surface and/or internal cavity as well as safe and rapid production in plants. In this perspective, we present an initial evaluation of the safety profile of two structurally different plant viruses produced in Nicotiana benthamiana L. plants: the filamentous Potato virus X and the icosahedral Tomato bushy stunt virus. In vitro haemolysis assay was used to test the cytotoxic effects, which could arise by pVNPs interaction with cellular membranes, while early embryo assay was used to evaluate toxicity and teratogenicity in vivo. Data indicates that these structurally robust particles, still able to infect plants after incubation in serum up to 24h, have neither toxic nor teratogenic effects in vitro and in vivo. This work represents the first safety-focused characterization of pVNPs in view of their possible use as drug delivery carriers
A biodistribution study of two differently shaped plant virus nanoparticles reveals new peculiar traits
No full textSelf-assembling plant virus nanoparticles (pVNPs) have started to be explored as nanometre-sized objects for biomedical applications, such as vaccine or drug delivery and imaging. Plant VNPs may be ideal tools in terms of biocompatibility and biodegradability endowed with a wide diversity of symmetries and dimensions, easy chemical/biological engineering, and rapid production in plants. Recently, we defined that icosahedral Tomato bushy stunt virus (TBSV) and filamentous Potato virus X (PVX) are neither toxic nor teratogenic. We report here the results of an interdisciplinary study aimed to define for the first time the biodistribution of unlabelled, unpegylated, underivatized TBSV and PVX by proved detecting antibodies. These data add new insights on the in vivo behaviour of these nano-objects and demonstrate that the pVNPs under scrutiny are each intrinsically endowed with peculiar properties foreshadowing different applications in molecular medicine
Production and Functional Characterization of a Recombinant Predicted Pore-Forming Protein (TVSAPLIP12) of Trichomonas vaginalis in Nicotiana benthamiana Plants
No full textPlant-Produced Viral Nanoparticles as a Functionalized Catalytic Support for Metabolic Engineering
No full textSubstrate channeling could be very useful for plant metabolic engineering; hence, we propose that functionalized supramolecular self-assembly scaffolds can act as enzymatic hubs able to perform reactions in close contiguity. Virus nanoparticles (VNPs) offer an opportunity in this context, and we present a functionalization strategy to display different enzymes on the outer surface of three different VNPs produced in plants. Tomato bushy stunt virus (TBSV) and Potato virus X (PVX) plant viruses were functionalized by the genetic fusion of the E-coil peptide coding sequence to their respective coat proteins genes, while the enzyme lichenase was tagged with the K-coil peptide. Immobilized E-coil VNPs were able to interact in vitro with the plant-produced functionalized lichenase, and catalysis was demonstrated by employing a lichenase assay. To prove this concept in planta, the Hepatitis B core (HBc) virus-like particles (VLPs) were similarly functionalized by genetic fusion with the E-coil sequence, while acyl-activating enzyme 1, olivetolic acid synthase, and olivetolic acid cyclase enzymes were tagged with the K-coil. The transient co-expression of the K-coil-enzymes together with E-coil-VLPs allowed the establishment of the heterologous cannabinoid precursor biosynthetic pathway. Noteworthy, a significantly higher yield of olivetolic acid glucoside was achieved when the scaffold E-coil-VLPs were employed
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Vaccine glycoproteins tagged with the human Fc domain as second generation vaccine candidates
No full textTraditional vaccines such as inactivated or live attenuated vaccines, are gradually giving way to more biochemically defined vaccines that are most often based on a recombinant antigen known to possess neutralizing epitopes. Such vaccines can offer improvements in speed, safety and manufacturing process but an inevitable consequence of their high degree of purification is that immunogenicity is reduced through the lack of the innate triggering molecules present in more complex preparations. Targeting recombinant vaccines to antigen presenting cells (APCs) such as dendritic cells however can improve immunogenicity by ensuring that antigen processing is as efficient as possible. Immune complexes, one of a number of routes of APC targeting, are mimicked by a recombinant approach, crystallizable fragment (Fc) fusion proteins, in which the target immunogen is linked directly to an antibody effector domain capable of interaction with receptors, FcR, on the APC cell surface. A number of virus Fc fusion proteins have been expressed in insect cells using the baculovirus expression system and shown to be efficiently produced and purified. Their use for immunization next to non-Fc tagged equivalents shows that they are powerfully immunogenic in the absence of added adjuvant and that immune stimulation is the result of the Fc-FcR interaction
Targeting of Tomato Bushy Stunt Virus with a Genetically Fused C-End Rule Peptide
No full textHoming peptides are widely used to improve the delivery of drugs, imaging agents, and nanoparticles (NPs) to their target sites. Plant virus-based particles represent an emerging class of structurally diverse nanocarriers that are biocompatible, biodegradable, safe, and cost-effective. Similar to synthetic NPs, these particles can be loaded with imaging agents and/or drugs and functionalized with affinity ligands for targeted delivery. Here we report the development of a peptide-guided Tomato Bushy Stunt Virus (TBSV)-based nanocarrier platform for affinity targeting with the C-terminal C-end rule (CendR) peptide, RPARPAR (RPAR). Flow cytometry and confocal microscopy demonstrated that the TBSV-RPAR NPs bind specifically to and internalize in cells positive for the peptide receptor neuropilin-1 (NRP-1). TBSV-RPAR particles loaded with a widely used anticancer anthracycline, doxorubicin, showed selective cytotoxicity on NRP-1-expressing cells. Following systemic administration in mice, RPAR functionalization conferred TBSV particles the ability to accumulate in the lung tissue. Collectively, these studies show the feasibility of the CendR-targeted TBSV platform for the precision delivery of payloads
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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