231 research outputs found

    On the Correspondence between Display Postulates and Deep Inference in Nested Sequent Calculi for Tense Logics

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    We consider two styles of proof calculi for a family of tense logics, presented in a formalism based on nested sequents. A nested sequent can be seen as a tree of traditional single-sided sequents. Our first style of calculi is what we call "shallow calculi", where inference rules are only applied at the root node in a nested sequent. Our shallow calculi are extensions of Kashima's calculus for tense logic and share an essential characteristic with display calculi, namely, the presence of structural rules called "display postulates". Shallow calculi enjoy a simple cut elimination procedure, but are unsuitable for proof search due to the presence of display postulates and other structural rules. The second style of calculi uses deep-inference, whereby inference rules can be applied at any node in a nested sequent. We show that, for a range of extensions of tense logic, the two styles of calculi are equivalent, and there is a natural proof theoretic correspondence between display postulates and deep inference. The deep inference calculi enjoy the subformula property and have no display postulates or other structural rules, making them a better framework for proof search

    Automated Synthesis of Tableau Calculi

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    This paper presents a method for synthesising sound and complete tableau calculi. Given a specification of the formal semantics of a logic, the method generates a set of tableau inference rules that can then be used to reason within the logic. The method guarantees that the generated rules form a calculus which is sound and constructively complete. If the logic can be shown to admit finite filtration with respect to a well-defined first-order semantics then adding a general blocking mechanism provides a terminating tableau calculus. The process of generating tableau rules can be completely automated and produces, together with the blocking mechanism, an automated procedure for generating tableau decision procedures. For illustration we show the workability of the approach for a description logic with transitive roles and propositional intuitionistic logic.Comment: 32 page

    Transient glyco-engineering to produce recombinant IgA1 with defined N-and O-glycans in plants

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    [EN] The production of therapeutic antibodies to combat pathogens and treat diseases, such as cancer is of great interest for the biotechnology industry. The recent development of plant-based expression systems has demonstrated that plants are well-suited for the production of recombinant monoclonal antibodies with defined glycosylation. Compared to immunoglobulin G (IgG), less effort has been undertaken to express immunoglobulin A (IgA), which is the most prevalent antibody class at mucosal sites and a promising candidate for novel recombinant biopharmaceuticals with enhanced anti-tumor activity. Here, we transiently expressed recombinant human IgA1 against the VP8* rotavirus antigen in glyco-engineered XT/FT Nicotiana benthamiana plants. Mass spectrometric analysis of IgA1 glycopeptides revealed the presence of complex biantennary N-glycans with terminal N-acetylglucosamine present on the N-glycosylation site of the CH2 domain in the IgA1 alpha chain. Analysis of the peptide carrying nine potential O-glycosylation sites in the IgA1 alpha chain hinge region showed the presence of plant-specific modifications including hydroxyproline formation and the attachment of pentoses. By co-expression of enzymes required for initiation and elongation of human O-glycosylation it was possible to generate disialylated mucin-type core 1 O-glycans on plant-produced IgA1. Our data demonstrate that XT/FT N. benthamiana plants can be engineered toward the production of recombinant IgA1 with defined human-type Nand O-linked glycans.This work was supported by a grant from the Austrian Federal Ministry of Transport, Innovation and Technology (bmvit) and Austrian Science Fund (FWF): TRP 242-B20 and by the Austrian Research Promotion Agency (Laura Bassi Center of Expertise "Plant produced Bio-Pharmaceuticals" Grant Nr. 822757).Dicker, M.; Tschofen, M.; Maresch, D.; Koenig, J.; Juarez, P.; Orzáez Calatayud, DV.; Altmann, F.... (2016). Transient glyco-engineering to produce recombinant IgA1 with defined N-and O-glycans in plants. Frontiers in Plant Science. 7(18):1-12. https://doi.org/10.3389/fpls.2016.00018S11271

    Metabolic profiling and antibacterial activity of Eryngium pristis Cham. & Schltdl. - prospecting for its use in the treatment of bacterial infections

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    Morbidity and mortality of the infected patients by multidrug-resistant bacteria have increased, emphasizing the urgency of fi ght for the discovery of new innovative antibiotics. In this sense, natural products emerge as valuable sources of bioactive compounds. Among the biodiversity, Eryngium pristis Cham. & Schltdl. (Apiaceae Lindl.) is traditionally used to treat thrush and ulcers of throat and mouth, as diuretic and emmenagogue, but scarcely known as an antimicrobial agent. With this context in mind, the goals of this study were to investigate the metabolic profi le and the antibacterial activity of ethanolic extract (EE-Ep) and hexane (HF-Ep), dichloromethane (DF-Ep), ethyl acetate (EAF-Ep) and butanol (BF-Ep) fractions from E. pristis leaves. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to stablish the metabolic profi le and revealed the presence of 12 and 14 compounds in EAF-Ep and HF-Ep, respectively. β-selinene, spathulenol, globulol, 2-methoxy-4-vinylphenol, α-amyrin, β-amyrin, and lupeol derivative were some of phytochemicals identifi ed. The antibacterial activity was determined by Minimal Inhibitory Concentration (MIC) using the broth micro-dilution against eight ATCC® and fi ve methicillin-resistant Staphylococcus aureus (MRSA) clinical strains. HF-Ep was the most eff ective (MIC ≤ 5,000 μg/μL), being active against the largest part of tested Gram-positive and Gram-negative bacterial strains, including MRSA, with exception of Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 9027) and (ATCC 27853). These results suggest that E. pristis is a natural source of bioactive compounds for the search of new antibiotics which can be an interesting therapeutic approach to recover patients mainly infected by MRSA strains.info:eu-repo/semantics/publishedVersio

    Pioderma gangrenoso secundário à infecção por Sarcoptes Scabei: relato de caso

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    O Pioderma Gangrenoso é considerado uma dermatose inflamatória de baixa prevalência, com clínica de lesões ulcerosas, pustulosas, bolhosas ou vegetantes dispersas pelo corpo. Geralmente são crônicas e podem simular outras lesões, sendo difícil seu diagnóstico. Sua causa pode ser primária idiopática ou secundária à outras patologias, principalmente autoimunes, como a Doença de Crohn e algumas Artrites. Seu diagnóstico pode ser feito por exame anatomopatológico da lesão ou exclusão de outras afecções dermatológicas de clínica semelhante. Relata-se um caso de apresentação atípica de Pioderma Gangrenoso secundário a escabiose, em paciente do sexo masculino, 73 anos, com queixa de prurido em membros superiores, tronco e abdome, associado à lesões ulceradas em membros inferiores. As hipóteses diagnósticas iniciais foram farmacodermia, porfiria cutânea tarda, escabiose associada à ectima, pênfigo bolhoso ou “PLECTS” (paracoccidioidomicose, leishmaniose, esporotricose, cromomicose, tuberculose cutânea). Feito biópsia das lesões cujo diagnóstico foi Pioderma Gangrenoso secundário à infecção por Sarcoptes scabiei. Por ser uma afecção dermatológica rara, idiopática e muitas vezes de causa secundária; torna-se cada vez mais importante o diagnóstico precoce da lesão para o sucesso do seu tratamento

    GoldenBraid: An Iterative Cloning System for Standardized Assembly of Reusable Genetic Modules

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    Synthetic Biology requires efficient and versatile DNA assembly systems to facilitate the building of new genetic modules/pathways from basic DNA parts in a standardized way. Here we present GoldenBraid (GB), a standardized assembly system based on type IIS restriction enzymes that allows the indefinite growth of reusable gene modules made of standardized DNA pieces. The GB system consists of a set of four destination plasmids (pDGBs) designed to incorporate multipartite assemblies made of standard DNA parts and to combine them binarily to build increasingly complex multigene constructs. The relative position of type IIS restriction sites inside pDGB vectors introduces a double loop (“braid”) topology in the cloning strategy that allows the indefinite growth of composite parts through the succession of iterative assembling steps, while the overall simplicity of the system is maintained. We propose the use of GoldenBraid as an assembly standard for Plant Synthetic Biology. For this purpose we have GB-adapted a set of binary plasmids for A. tumefaciens-mediated plant transformation. Fast GB-engineering of several multigene T-DNAs, including two alternative modules made of five reusable devices each, and comprising a total of 19 basic parts are also described
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