151 research outputs found

    FicD genes in invertebrates: A tale of transposons, pathogenic and integrated viruses

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    : Many gene families are shared across the tree of life between distantly related species because of horizontal gene transfers (HGTs). However, the frequency of HGTs varies strongly between gene families and biotic realms suggesting differential selection pressures and functional bias. One gene family with a wide distribution are FIC-domain containing enzymes (FicDs). FicDs catalyze AMPylation, a post-translational protein modification consisting in the addition of adenosine monophosphate to accessible residues of target proteins. Beside the well-known conservation of FicDs in deuterostomes, we report the presence of a conserved FicD gene ortholog in a large number of protostomes and microbial eukaryotes. We also reported additional FicD gene copies in the genomes of some rotifers, parasitic worms and bivalves. A few dsDNA viruses of these invertebrates, including White spot syndrome virus, Cherax quadricarinatus iridovirus, Ostreid herpesvirus-1 and the beetle nudivirus, carry copies of FicDs, with phylogenetic analysis suggesting a common origin of these FicD copies and the duplicated FicDs of their invertebrate hosts. HGTs and gene duplications possibly mediated by endogenous viruses or genetic mobile elements seem to have contributed to the transfer of AMPylation ability from bacteria and eukaryotes to pathogenic viruses, where this pathway could have been hijacked to promote viral infection

    Modulação do estado de polimerização in vitro dos filamentos intermediários em astrócitos pela fosforilação e proteína S100B

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    Intermediate filaments represent a major cytoskeleton constituent in eukaryotic cells. GFAP ("glial fibrillary acidic protein") is the monomer of these filaments in astrocytes and its polymerization is apparently modulated by phosphorylation and by interaction with S100B, a calcium-binding protein. In this study we investigate in vitro polymerization of GFAP, using an assay based on imidazol/high magnesium-induced sedimentation. In fact, soluble GFAP (nonpolymerized) increased about 25% in presence of S100B or PKA (protein kinase A). These data suggest that both mechanisms could be acting in the cycle of polymerization/depolymerization of GFAP at different times and/or conditions, therefore affecting glial plasticity.Os filamentos intermediários representam um dos principais componentes do citoesqueleto de células eucarióticas. O monômero desses filamentos em astrócitos é a GFAP (“glial fibrillary acidic protein”), cuja polimerização é modulada aparentemente pela fosforilação e pela interação com uma proteína ligante de cálcio, a S100B. Neste estudo investigamos a polimerização in vitro da GFAP, usando um ensino baseado na sedimentação induzida por imidazol/alto magnésio. De fato, a GFAP solúvel (não polimerizada) aumentou em cerca de 25% na presença de S100B ou PKA (proteína cinase A). Estes dados sugerem que ambos os mecanismos possam estar atuando no ciclo de polimerização/despolimerização da GFAP em momentos e/ou situações diferentes afetando a plasticidade glial

    Non-Commutative Gauge Theories and the Cosmological Constant

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    We discuss the issue of the cosmological constant in non-commutative non-supersymmetric gauge theories. In particular, in orbifold field theories non-commutativity acts as a UV cut-off. We suggest that in these theories quantum corrections give rise to a vacuum energy \rho, that is controlled by the non-commutativity parameter \theta, \rho ~ 1/theta^2 (only a soft logarithmic dependence on the Planck scale survives). We demonstrate our claim in a two-loop computation in field theory and by certain higher loop examples. Based on general expressions from string theory, we suggest that the vacuum energy is controlled by non-commutativity to all orders in perturbation theory.Comment: 11 pages, RevTex. 4 eps figures. v2: Typos corrected. To appear in Phys.Rev.

    Toward food waste reduction at universities

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    Food waste is a serious problem, which undermines the achievement of many sustainable development goals (SDGs), despite their consideration in the agendas of many countries and companies. Notoriously, food waste (FW) causes different kinds of pollution that affect public health and social justice, while contributing to economic losses. This waste phenomenon has causes, drivers, and impacts that require rigorous assessments and effective approaches to mitigate its noxious effects, which are a serious concern for universities. Within these institutions, reducing food waste becomes a circular economy strategy, which is being utilized to assist in promoting sustainable development. However, there is a need for urgent attention to the specific causes of food waste and for consistent actions to reduce it, while boosting awareness in the campus community and triggering a change in students’ eating habits. The purpose of this study is to analyze what can be done to reduce the levels of food waste at universities. To achieve this, a review of the theme’s state of the art, which is inclusive of an overview of food waste production at universities around the world, is presented. The study employed a qualitative methodology where a comprehensive review of the literature and case studies analyses from selected world regions were considered. The data indicate that a broad variance exists in producing food waste among universities, from 0.12 to 50 kg/capita/day. More factors influence the problem (e.g., gender, age, season, consumer behavior), as well as strategies to solve and prevent it (e.g., composting, recycling, new designs of packages, trayless meals, education), and benefits leading toward food waste reductions from 13 to 50%. Also, four priority actions were identified to reduce food waste at universities, and these consist of planning and awareness, food preparation and storage, services, and direct waste reuse. With appropriate adaptations, these recommended actions should be deployed as means for reducing food waste at universities around the world, while expanding learning and education in sustainability

    Two-loop Yang-Mills diagrams from superstring amplitudes

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    Starting from the superstring amplitude describing interactions among D-branes with a constant world-volume field strength, we present a detailed analysis of how the open string degeneration limits reproduce the corresponding field theory Feynman diagrams. A key ingredient in the string construction is represented by the twisted (Prym) super differentials, as their periods encode the information about the background field. We provide an efficient method to calculate perturbatively the determinant of the twisted period matrix in terms of sets of super-moduli appropriate to the degeneration limits. Using this result we show that there is a precise one-to-one correspondence between the degeneration of different factors in the superstring amplitudes and one-particle irreducible Feynman diagrams capturing the gauge theory effective action at the two-loop level.Comment: 42 pages plus appendices, 10 figure

    RESVERATROL INCLUSION COMPLEX WITH β-CYCLODEXTRIN (RCD): CHARACTERIZATION AND EVALUATION OF TOXICITY IN WISTAR RATS

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    Objective: The aim of this study was to characterise the resveratrol inclusion complex with β-cyclodextrin (RCD) and evaluate their toxicity in wistar rats.Methods: The RCD were prepared in ultra-turrax. For characterization of the RCD were used: Fourier transform infra-red Spectroscopy, Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) and X-ray powder diffraction. The RCD and others 4 treatments were performed by the chronic oral administration in 35 rats during 60 ds. After the treatments they were euthanized and the serum blood were collected to analyzed some hemogram and biochemical parameters including aspartyl aminotransferase (AST); alanine aminotransferase (AST); phosphatase alkaline (ALP); total bilirubin (TB); direct bilirubin (DB); total protein (TP); total cholesterol (TC), triacylglycerol (TAG), very low-density lipoprotein (VLDL), high-density lipoprotein (HDL), calcium, iron and phosphate using fully automated biochemistry analyzer.Results: The characterization results indicated a successful formation of the RCD. All hematological parameters analysed were within the normal values in all the groups. Furthermore, the hemogram and biochemical parameters were significantly (P>0.05) similar to the control group.Conclusion: The daily oral administration during 60 d of RCD are not harmful on blood parameters of Wistar rats. Thus, RCD can be used safely for treatment of some metabolic diseases

    Use of twitter data for waste minimisation in beef supply chain

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    Approximately one third of the food produced is discarded or lost, which accounts for 1.3 billion tons per annum. The waste is being generated throughout the supply chain viz. farmers, wholesalers/processors, logistics, retailers and consumers. The majority of waste occurs at the interface of retailers and consumers. Many global retailers are making efforts to extract intelligence from customer’s complaints left at retail store to backtrack their supply chain to mitigate the waste. However, majority of the customers don’t leave the complaints in the store because of various reasons like inconvenience, lack of time, distance, ignorance etc. In current digital world, consumers are active on social media and express their sentiments, thoughts, and opinions about a particular product freely. For example, on an average, 45,000 tweets are tweeted daily related to beef products to express their likes and dislikes. These tweets are large in volume, scattered and unstructured in nature. In this study, twitter data is utilised to develop waste minimization strategies by backtracking the supply chain. The execution process of proposed framework is demonstrated for beef supply chain. The proposed model is generic enough and can be applied to other domains as well

    Guanosine effect on cholesterol efflux and apolipoprotein E expression in astrocytes

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    The main source of cholesterol in the central nervous system (CNS) is represented by glial cells, mainly astrocytes, which also synthesise and secrete apolipoproteins, in particular apolipoprotein E (ApoE), the major apolipoprotein in the brain, thus generating cholesterol-rich high density lipoproteins (HDLs). This cholesterol trafficking, even though still poorly known, is considered to play a key role in different aspects of neuronal plasticity and in the stabilisation of synaptic transmission. Moreover, cell cholesterol depletion has recently been linked to a reduction in amyloid beta formation. Here we demonstrate that guanosine, which we previously reported to exert several neuroprotective effects, was able to increase cholesterol efflux from astrocytes and C6 rat glioma cells in the absence of exogenously added acceptors. In this effect the phosphoinositide 3 kinase/extracellular signal-regulated kinase 1/2 (PI3K/ERK1/2) pathway seems to play a pivotal role. Guanosine was also able to increase the expression of ApoE in astrocytes, whereas it did not modify the levels of ATP-binding cassette protein A1 (ABCA1), considered the main cholesterol transporter in the CNS. Given the emerging role of cholesterol balance in neuronal repair, these effects provide evidence for a role of guanosine as a potential pharmacological tool in the modulation of cholesterol homeostasis in the brain
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