1,878 research outputs found

    Frutapin, a lectin from Artocarpus incisa (breadfruit): cloning, expression and molecular insights

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    Artocarpus incisa (breadfruit) seeds contain three different lectins (Frutalin, Frutapin and Frutackin) with distinct carbohydrate specificities. The most abundant lectin is Frutalin, an α-D-galactose-specific carbohydrate-binding glycoprotein with antitumour properties and potential for tumour biomarker discovery as already reported. Frutapin (FTP) is the second most abundant, but proved difficult to purify with very low yields and contamination with Frutalin frustrating its characterization. Here, we report for the first time high-level production and isolation of biologically-active recombinant FTP in E. coli BL21, optimizing conditions with the best set yielding >40 mg/L culture of soluble active FTP. The minimal concentration for agglutination of red blood cells was 62.5 µg/mL of FTP, a process effectively inhibited by mannose. Apo-FTP, FTP-mannose and FTP-glucose crystals were obtained and diffracted X-rays to a resolution of 1.58 (P212121), 1.70 (P3121) and 1.60 (P3121) Å, respectively. The best solution showed four monomers per asymmetric unit. Molecular Dynamics simulation suggested FTP displays higher affinity for mannose than glucose. Cell studies revealed FTP was non-cytotoxic to cultured mouse fibroblast 3T3 cells below 0.5 mg/mL and also capable of stimulating cell migration at 50 µg/mL. In conclusion, our optimized expression system allowed high amounts of correctly-folded soluble FTP to be isolated. This recombinant bioactive lectin will now be tested in future studies for therapeutic potential; for example, in wound healing and tissue regeneration

    Sphaerodoridae (Annelida: Polychaeta) from the Bellingshausen Sea (Antarctica) with the description of two new species

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    The examination of polychaete collections obtained during the Spanish Bentart 2006expedition to the Bellingshausen Sea (Antarctica) revealed the presence of several sphaerodorid species. In this work, species belonging to the genera Sphaerodorum Örsted, 1843, Ephesiella Chamberlin, 1919, Clavodorum Hartman and Fauchald, 1971 and Sphaerephesia Fauchald, 1972 are reported including two new species belonging to Sphaerodorum and Sphaerephesia, respectively. A specimen identified as Ephesiella sp. might also represent a new species but, due to its poor state of preservation, a formal description is not possible yet. Furthermore, Sphaerodoropsis polypapillata Hartmann-Schröder and Rosenfeldt, 1988 is transferred to the genus Clavodorum Hartman and Fauchald, 1971 after examination of the type series and specimens obtained from the Bellingshausen Sea.Comisión Interministerial de Ciencia y Tecnología; REN 2001-1074/ANTComisión Interministerial de Ciencia y Tecnología; CGL2004-0185

    Forest Fires Across Italian Regions and Implications for Climate Change: A Panel Data Analysis

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    In this paper, we analyze the determinants of monthly variations in forest fire frequency and on the size of the area burnt for Italian regions between 2000 and 2011. We employ panel data techniques, which allow capturing the dynamics of fire danger due to changes in past climatic conditions, after accounting for regional fixed effects to control region-specific unobserved and time-invariant factors. Results highlight a significant heterogeneity of the effects of driving factors across the Italian peninsula and weather seasons. Climatic conditions also show lasting effects within the year. Using climate change projections for 2016–2035, we then obtain the projected forest fire frequency and total area burnt across the Italian peninsula for the same period. Climate change is expected to increase the number of forest fires across the whole peninsula, which is more evident for the central part of Italy. Even though most of annual increases in fire events relate to the summer period, intensifications in frequency during autumn become more evident in the southern Italy. We extend finally our analysis to investigate the contribution of socio-economic factors to fire regime and the role of education and the containment of fraudulent activity is also highlighted.</p

    Three endo-β-mannanase genes expressed in the micropylar endosperm and in the radicle influence germination of Arabidopsis thaliana seeds

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    Mannans are hemicellulosic polysaccharides in the plant primary cell wall (CW). Mature seeds, specially their endosperm cells, have CWs rich in mannan-based polymers that confer a strong mechanical resistance for the radicle protrusion upon germination. The rupture of the seed coat and endosperm are two sequential events during the germination of Arabidopsis thaliana. Endo-β-mannanases (MAN; EC. 3.2.1.78) are hydrolytic enzymes that catalyze cleavage of β1 → 4 bonds in the mannan-polymer. In the genome of Arabidopsis, the endo-β-mannanase (MAN) family is represented by eight members. The expression of these eight MAN genes has been systematically explored in different organs of this plant and only four of them (AtMAN7, AtMAN6, AtMAN2 and AtMAN5) are expressed in the germinating seeds. Moreover, in situ hybridization analysis shows that their transcript accumulation is restricted to the micropylar endosperm and to the radicle and this expression disappears soon after radicle emergence. T-DNA insertion mutants in these genes (K.O. MAN7, K.O. MAN6, K.O. MAN5), except that corresponding to AtMAN2 (K.O. MAN2), germinate later than the wild type (Wt). K.O. MAN6 is the most affected in the germination time course with a t 50 almost double than that of the Wt. These data suggest that AtMAN7, AtMAN5 and specially AtMAN6 are important for the germination of A. thaliana seeds by facilitating the hydrolysis of the mannan-rich endosperm cell walls

    Inactivation of PNKP by mutant ATXN3 triggers apoptosis by activating the DNA damage-response pathway in SCA3.

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    Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is an untreatable autosomal dominant neurodegenerative disease, and the most common such inherited ataxia worldwide. The mutation in SCA3 is the expansion of a polymorphic CAG tri-nucleotide repeat sequence in the C-terminal coding region of the ATXN3 gene at chromosomal locus 14q32.1. The mutant ATXN3 protein encoding expanded glutamine (polyQ) sequences interacts with multiple proteins in vivo, and is deposited as aggregates in the SCA3 brain. A large body of literature suggests that the loss of function of the native ATNX3-interacting proteins that are deposited in the polyQ aggregates contributes to cellular toxicity, systemic neurodegeneration and the pathogenic mechanism in SCA3. Nonetheless, a significant understanding of the disease etiology of SCA3, the molecular mechanism by which the polyQ expansions in the mutant ATXN3 induce neurodegeneration in SCA3 has remained elusive. In the present study, we show that the essential DNA strand break repair enzyme PNKP (polynucleotide kinase 3'-phosphatase) interacts with, and is inactivated by, the mutant ATXN3, resulting in inefficient DNA repair, persistent accumulation of DNA damage/strand breaks, and subsequent chronic activation of the DNA damage-response ataxia telangiectasia-mutated (ATM) signaling pathway in SCA3. We report that persistent accumulation of DNA damage/strand breaks and chronic activation of the serine/threonine kinase ATM and the downstream p53 and protein kinase C-d pro-apoptotic pathways trigger neuronal dysfunction and eventually neuronal death in SCA3. Either PNKP overexpression or pharmacological inhibition of ATM dramatically blocked mutant ATXN3-mediated cell death. Discovery of the mechanism by which mutant ATXN3 induces DNA damage and amplifies the pro-death signaling pathways provides a molecular basis for neurodegeneration due to PNKP inactivation in SCA3, and for the first time offers a possible approach to treatment.This study was funded by NIH grant NS073976 to TKH and a John Sealy Grant to PSS

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Landscape determinants of European roller foraging habitat: implications for the definition of agri-environmental measures for species conservation

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    Across much of Europe, farmland birds are declining more than those in other habitats. From a conservation perspective, identifying the primary preferred habitats could help improve the foraging conditions of target species and, consequently, enhance their breeding success and survival. Here, we investigated the ranging behaviour and foraging habitat selection of the European roller (Coracias garrulus) during the breeding season in an agricultural landscape of South Iberia. The occurrence of foraging rollers was predicted to gradually increase with decreasing distance from the nest and increasing availability of perches, such as fences and electric wires. Traditional olive groves and stubble fields were positively and negatively associated with the occurrence of rollers, respectively. Additionally, analysis of hunting strikes showed that rollers highly prefer foraging in fallows rather than cereal or stubble fields. Prey surveys revealed that fallows had the highest abundance of grasshoppers, rollers’ preferred prey during chick-rearing. Pair home-ranges, obtained from 95% fixed Kernel estimators averaged 70.9 ha (range = 34–118 ha) and most foraging trips (80%) occurred in the close vicinity of the nest (<500 m). Number of chicks fledged was not affected by mean foraging distances travelled during the chick-rearing period. Overall, our results suggest that traditional extensive practices of cereal cultivation, with large areas of low-intensity grazed fallows, represent a high-quality foraging habitat for rollers and should be promoted through agri-environmental schemes within at least 1-km radius from the nest. These recommendations are targeted at the roller, but have been shown to apply broadly to several other steppe-bird species

    Heparan sulfate proteoglycans: structure, protein interactions and cell signaling

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    Heparan sulfate proteoglycans are ubiquitously found at the cell surface and extracellular matrix in all the animal species. This review will focus on the structural characteristics of the heparan sulfate proteoglycans related to protein interactions leading to cell signaling. The heparan sulfate chains due to their vast structural diversity are able to bind and interact with a wide variety of proteins, such as growth factors, chemokines, morphogens, extracellular matrix components, enzymes, among others. There is a specificity directing the interactions of heparan sulfates and target proteins, regarding both the fine structure of the polysaccharide chain as well precise protein motifs. Heparan sulfates play a role in cellular signaling either as receptor or co-receptor for different ligands, and the activation of downstream pathways is related to phosphorylation of different cytosolic proteins either directly or involving cytoskeleton interactions leading to gene regulation. The role of the heparan sulfate proteoglycans in cellular signaling and endocytic uptake pathways is also discussed.Proteoglicanos de heparam sulfato são encontrados tanto superfície celular quanto na matriz extracelular em todas as espécies animais. Esta revisão tem enfoque nas características estruturais dos proteoglicanos de heparam sulfato e nas interações destes proteoglicanos com proteínas que levam à sinalização celular. As cadeias de heparam sulfato, devido a sua variedade estrutural, são capazes de se ligar e interagir com ampla gama de proteínas, como fatores de crescimento, quimiocinas, morfógenos, componentes da matriz extracelular, enzimas, entreoutros. Existe uma especificidade estrutural que direciona as interações dos heparam sulfatos e proteínas alvo. Esta especificidade está relacionada com a estrutura da cadeia do polissacarídeo e os motivos conservados da cadeia polipeptídica das proteínas envolvidas nesta interação. Os heparam sulfatos possuem papel na sinalização celular como receptores ou coreceptores para diferentes ligantes. Esta ligação dispara vias de sinalização celular levam à fosforilação de diversas proteínas citosólicas ou com ou sem interações diretas com o citoesqueleto, culminando na regulação gênica. O papel dos proteoglicanos de heparam sulfato na sinalização celular e vias de captação endocítica também são discutidas nesta revisão.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo (UNIFESP) Departamento de BioquímicaUniversidade Federal de São Paulo (UNIFESP) Departamento de OftalmologiaUNIFESP, Depto. de BioquímicaUNIFESP, Depto. de OftalmologiaSciEL

    Approaches in biotechnological applications of natural polymers

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    Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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