91 research outputs found

    Molecular characterization of Listeria monocytogenes from beef samples and cattle slaughterhouses located in the Federal District, Brazil

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    Este trabalho teve como objetivo realizar a detecção de cepas de Listeria monocytogenes de cortes cárneos bovinos bem como no ambiente de abatedouros frigoríficos localizados no Distrito Federal, promover a sorotipificação pela reação em cadeia da polimerase (PCR), realizar antibiograma e submeter às cepas à eletroforese de campo pulsado (Pulsed-field gel electrophoresis - PFGE). Foram analisados um total de 125 cortes cárneos bovinos, 45 amostras de swabs de carcaças e 43 amostras de swabs em que foram detectados 13 cepas de Listeria monocytogenes, sendo 11 em cortes cárneos bovinos e 2 swabs de ambiente em um abatedouro frigorifico. Não foram isoladas cepas de swabs de carcaça. Dentre as 13 cepas de Listeria monocytogenes foram encontradas seis cepas do sorotipo 4b, cinco do sorotipo 1/2c e duas cepas do sorotipo 1/2a. Dentre as 11 cepas de L. monocytogenes encontradas em cortes cárneos bovino, uma (9,1%) cepa apresentou resistência a eritromicina, outra (9,1%) cepa a gentamicina e outra a ciprofloxacina (9,1%) e todas as cepas (100%) apresentaram resistência ao Ác. Nalidíxico. Das duas (2) cepas oriundas de ralos de abatedouro frigorífico, todas (100%) apresentaram resistência ao Ác. Nalidíxico e a sulfonamidas. A análise por eletroforese de campo pulsante (PFGE) demonstrou 13 diferentes pulsotipos, em que foram agrupados em 3 diferentes grupos clonais, que coincidentemente se correlacionavam com os 3 diferentes sorotipos encontrados sugerindo uma ampla disseminação desses perfis no Distrito Federal.The aim of the study was the analysis of Listeria monocytogenes strains in beef samples as well as slaughterhouse environment, located in the Federal District, promote serotyping by polymerase chain reaction (PCR), perform antibiotic susceptibility and submit the strains to Pulsed-field gel electrophoresis (PFGE). A total of 125 beef samples were analyzed, 45 samples of carcasses swabs and 43 swab samples. It detected 13 strains of Listeria monocytogenes, 11 in beef samples. and 2 in slaughterhouse environment. No carcass swabs strains were isolated. Among the 13 strains of L. monocytogenes six strains of serotype 4b were found, five serotype 1/2c and two strains of serotype 1/2a. Among the 11 strains of L. monocytogenes found in beef, one (9.1%) strain showed resistance to erythromycin, one (9.1%) strain to gentamicin, one to ciprofloxacin (9.1%) and all strains (100%) were resistant to nalidixic acid. The two strains coming from the slaughterhouse drains, all (100%) were resistant to nalidixic acid and Sulfonamides. The analysis by pulsed field gel electrophoresis (PFGE) showed 13 different pulsotypes; they were grouped into three different clonal groups, coincidentally correlated with the three different serotypes found, what suggests a widespread dissemination of these profiles in the Federal District, Brazil

    Sustainable plant polyesters as substrates for optical gas sensors

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    UIDB/04378/2020 PTDC/BII-BIO/28878/2017 PTDC/SAU-SER/30388/2017 SFRH-BD-110467-2015The fast and non-invasive detection of odors and volatile organic compounds (VOCs) by gas sensors and electronic noses is a growing field of interest, mostly due to a large scope of potential applications. Additional drivers for the expansion of the field include the development of alternative and sustainable sensing materials. The discovery that isolated cross-linked polymeric structures of suberin spontaneously self-assemble as a film inspired us to develop new sensing composite materials consisting of suberin and a liquid crystal (LC). Due to their stimuli-responsive and optically active nature, liquid crystals are interesting probes in gas sensing. Herein, we report the isolation and the chemical characterization of two suberin types (from cork and from potato peels) resorting to analyses of gas chromatography–mass spectrometry (GC-MS), solution nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS). The collected data highlighted their compositional and structural differences. Cork suberin showed a higher proportion of longer aliphatic constituents and is more esterified than potato suberin. Accordingly, when casted it formed films with larger surface irregularities and a higher C/O ratio. When either type of suberin was combined with the liquid crystal 5CB, the ensuing hybrid materials showed distinctive morphological and sensing properties towards a set of 12 VOCs (comprising heptane, hexane, chloroform, toluene, dichlormethane, diethylether, ethyl acetate, acetonitrile, acetone, ethanol, methanol, and acetic acid). The optical responses generated by the materials are reversible and reproducible, showing stability for 3 weeks. The individual VOC-sensing responses of the two hybrid materials are discussed taking as basis the chemistry of each suberin type. A support vector machines (SVM) algorithm based on the features of the optical responses was implemented to assess the VOC identification ability of the materials, revealing that the two distinct suberin-based sensors complement each other, since they selectively identify distinct VOCs or VOC groups. It is expected that such new environmentally-friendly gas sensing materials derived from natural diversity can be combined in arrays to enlarge selectivity and sensing capacity.publishersversionpublishe

    Mapping Molecular Recognition of β1,3-1,4-Glucans by a Surface Glycan-Binding Protein from the Human Gut Symbiont Bacteroides ovatus

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    This work was supported by Fundação para a Ciência e a Tecnologia (FCT-MCTES), Portugal, through project grant PTDC/BIA-MIB/31730/2017 (to A.S.P.), fellowships PD/BD/105727/2014 (to V.G.C.) and SFRH/BD/143494/2019 (to F.T.), and program contract DL-57/2016 (to B.A.P. and C.N.) and by Wellcome Trust Biomedical Resource grants number WT108430/Z/15/Z and WT218304/Z/19/Z, a March of Dimes (Arlington, VA, USA) Prematurity Research Center grant (number 22-FY18-821) for the funding to the Carbohydrate Microarray Facility, Associate Laboratory projects LAQV-REQUIMTE (UIDB/50006/2020) and CICECO-Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020), and by the Applied Molecular Biosciences Unit (UCIBIO), which is financed by Portuguese national funds from FCT-MCTES (UIDP/04378/2020 and UIDB/04378/2020).A multigene polysaccharide utilization locus (PUL) encoding enzymes and surface carbohydrate (glycan)-binding proteins (SGBPs) was recently identified in prominent members of Bacteroidetes in the human gut and characterized in Bacteroides ovatus. This PUL-encoded system specifically targets mixed-linkage β1,3-1,4-glucans, a group of diet-derived carbohydrates that promote a healthy microbiota and have potential as prebiotics. The BoSGBPMLG-A protein encoded by the BACOVA_2743 gene is a SusD-like protein that plays a key role in the PUL's specificity and functionality. Here, we perform a detailed analysis of the molecular determinants underlying carbohydrate binding by BoSGBPMLG-A, combining carbohydrate microarray technology with quantitative affinity studies and a high-resolution X-ray crystallography structure of the complex of BoSGBPMLG-A with a β1,3-1,4-nonasaccharide. We demonstrate its unique binding specificity toward β1,3-1,4-gluco-oligosaccharides, with increasing binding affinities up to the octasaccharide and dependency on the number and position of β1,3 linkages. The interaction is defined by a 41-Å-long extended binding site that accommodates the oligosaccharide in a mode distinct from that of previously described bacterial β1,3-1,4-glucan-binding proteins. In addition to the shape complementarity mediated by CH-π interactions, a complex hydrogen bonding network complemented by a high number of key ordered water molecules establishes additional specific interactions with the oligosaccharide. These support the twisted conformation of the β-glucan backbone imposed by the β1,3 linkages and explain the dependency on the oligosaccharide chain length. We propose that the specificity of the PUL conferred by BoSGBPMLG-A to import long β1,3-1,4-glucan oligosaccharides to the bacterial periplasm allows Bacteroidetes to outcompete bacteria that lack this PUL for utilization of β1,3-1,4-glucans. IMPORTANCE With the knowledge of bacterial gene systems encoding proteins that target dietary carbohydrates as a source of nutrients and their importance for human health, major efforts are being made to understand carbohydrate recognition by various commensal bacteria. Here, we describe an integrative strategy that combines carbohydrate microarray technology with structural studies to further elucidate the molecular determinants of carbohydrate recognition by BoSGBPMLG-A, a key protein expressed at the surface of Bacteroides ovatus for utilization of mixed-linkage β1,3-1,4-glucans. We have mapped at high resolution interactions that occur at the binding site of BoSGBPMLG-A and provide evidence for the role of key water-mediated interactions for fine specificity and affinity. Understanding at the molecular level how commensal bacteria, such as prominent members of Bacteroidetes, can differentially utilize dietary carbohydrates with potential prebiotic activities will shed light on possible ways to modulate the microbiome to promote human health.publishersversionpublishe

    Initial modelled outputs at field scale

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    This report comprises Deliverable 6.16 in the project, which contributes to the third objective as it presents field-scale evaluation of innovations, in order to adapt and evaluate agroforestry designs and practices for locations where agroforestry is currently not-widely practised or declining. The modelling of outputs at field scale to support best agroforestry practices is an ongoing activity during the AGFORWARD project. This report highlights some of the outputs which has been produced in the form of three papers (either submitted or about to be submitted to a peer-reviewed journal) or in four presentations at the Third European Agroforestry Conference in May 2016N/

    Current extent and stratification of agroforestry in the European Union

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    An accurate and objective estimate on the extent of agroforestry in Europe is critical for the development of supporting policies. For this reason, a more harmonised and uniform Pan-European estimate is needed. The aim of this study was to quantify and map the distribution of agroforestry in the European Union. We classified agroforestry into three main types of agroforestry systems: arable agroforestry, livestock agroforestry and high value tree agroforestry. These three classes are partly overlapping as high value tree agroforestry can be part of either arable or livestock agroforestry. Agroforestry areas were mapped using LUCAS Land Use and Land Cover data (Eurostat, 2015). By identifying certain combinations of primary and secondary land cover and/or land management it was possible to identify agroforestry points and stratify them in the three different systems. According to our estimate using the LUCAS database the total area under agroforestry in the EU 27 is about 15.4 million ha which is equivalent to about 3.6% of the territorial area and 8.8% of the utilised agricultural area. Of our three studied systems, livestock agroforestry covers about 15.1 million ha which is by far the largest area. High value tree agroforestry and arable agroforestry cover 1.1 and 0.3 million ha respectively. Spain (5.6 million ha), France (1.6 million ha), Greece (1.6 million ha), Italy (1.4 million ha), Portugal (1.2 million ha), Romania (0.9 million ha) and Bulgaria (0.9 million ha) have the largest absolute area of agroforestry. However the extent of agroforestry, expressed as a proportion of the utilised agricultural area (UAA), is greatest in countries like Cyprus (40% of UAA), Portugal (32% of UAA) and Greece (31% of UAA). A cluster analysis revealed that a high abundance of agroforestry areas can be found in the south-west quadrat of the Iberian Peninsula, the south of France, Sardinia, south and central Italy, central and north-east Greece, south and central Bulgaria, and central Romania. Since the data were collected and analysed in a uniform manner it is now possible to make comparisons between countries and identify regions in Europe where agroforestry is already widely practiced and areas where there are opportunities for practicing agroforestry on a larger area and introducing novel practices. In addition, with this method it is possible to make more precise estimates on the extent of agroforestry in Europe and changes over time. Because agroforestry covers a considerable part of the agricultural land in the EU, it is crucial that it gets a more prominent and clearer place in EU statistical reporting in order to provide decision makers with more reliable information on the extent and nature of agroforestry. Reliable information, in turn, should help to guide policy development and implementation, and the evaluation of the impact of agricultural and other policies on agroforestry

    Predicting site index from climate and soil variables for cork oak (Quercus suber L.) stands in Portugal

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    Site productivity, assessed through site index, was modelled using partial least squares regression as a function of soil and climatic variables. Two alternative models were developed: a full model, considering all available explanatory variables, and a reduced model, considering only variables that can be obtained without digging a soil pit. The reduced model was used for mapping the site index distribution in Portugal, on the basis of existing digital cartography available for the whole country. The developed models indicate the importance of water availability and soil water holding capacity for site index value distribution. Site index was related to climate, namely evaporation and frost, and soil characteristics such as lithology, soil texture, soil depth, thickness of the A horizon and soil classification. The variability of the estimated values within the map (9.5–16.8 m with an average value of 13.4 m) reflects the impact of soil characteristics on the site productivity estimation. These variables should be taken into consideration during the establishment of new plantations of cork oak, and management of existing plantations. Results confirm the potential distribution of cork oak in coastal regions. They also suggest the existence of a considerable area, located both North and South of the Tagus river, where site indices values of medium (]13;15]) to high (]15;17]) productivity classes may be expected. The species is then expected to be able to have good productivity along the northern coastal areas of Portugal, where presently it is not a common species but where, according to historical records, it occurred until the middle of the sixteenth century. The present research focused on tree growth. Cork growth and cork quality distribution needs to be further researched through the establishment of long term experimental sites along the distribution area of cork oak, namely in the central and northern coastal areas of the countryinfo:eu-repo/semantics/publishedVersio
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