4,201 research outputs found

    A database for the taxonomic and phylogenetic identification of the genus Bradyrhizobium using multilocus sequence analysis.

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    Biological nitrogen fixation, with an emphasis on the legume-rhizobia symbiosis, is a key process for agriculture and the environment, allowing the replacement of nitrogen fertilizers, reducing water pollution by nitrate as well as emission of greenhouse gases. Soils contain numerous strains belonging to the bacterial genus Bradyrhizobium, which establish symbioses with a variety of legumes. However, due to the high conservation of Bradyrhizobium 16S rRNA genes - considered as the backbone of the taxonomy of prokaryotes - few species have been delineated. The multilocus sequence analysis (MLSA) methodology, which includes analysis of housekeeping genes, has been shown to be promising and powerful for defining bacterial species, and, in this study, it was applied to Bradyrhizobium, species, increasing our understanding of the diversity of nitrogen-fixing bacteria. Description: Classification of bacteria of agronomic importance is relevant to biodiversity, as well as to biotechnological manipulation to improve agricultural productivity. We propose the construction of an online database that will provide information and tools using MLSA to improve phylogenetic and taxonomic characterization of Bradyrhizobium, allowing the comparison of genomic sequences with those of type and representative strains of each species. Conclusion: A database for the taxonomic and phylogenetic identification of the Bradyrhizobium, genus, using MLSA, will facilitate the use of biological data available through an intuitive web interface. Sequences stored in the on-line database can be compared with multiple sequences of other strains with simplicity and agility through multiple alignment algorithms and computational routines integrated into the database. The proposed database and software tools are available at http://mlsa.cnpso.embrapa.br, and can be used, free of charge, by researchers worldwide to classify Bradyrhizobium, strains; the database and software can be applied to replicate the experiments presented in this study as well as to generate new experiments. The next step will be expansion of the database to include other rhizobial species.Edição dos Proceedings of the 10th International Conference of the Brazilian Association for Bioinformatics and Computational Biology (X-Meeting 2014), Belo Horizonte, Oct. 2014

    Relationship of arterial and exhaled CO2 during elevated artificial pneumoperitoneum pressure for introduction of the first trocar.

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    The present study evaluated the correlation between arterial CO2 and exhaled CO2 during brief high-pressure pneumoperitoneum. Patients were randomly distributed into two groups: P12 group (n=30) received a maximum intraperitoneal pressure of 12mmHg, and P20 group (n=37) received a maximum intraperitoneal pressure of 20mmHg. Arterial CO2 was evaluated by radial arterial catheter and exhaled CO2 was measured by capnometry at the following time points: before insufflation, once intraperitoneal pressure reached 12mmHg , 5 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or 20mmHg for the P20 group, and 10 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or when intraperitoneal pressure had decreased from 20mmHg to 12mmHg, for the P20 group. During brief durations of very high intraperitoneal pressure (20mmHg), there was a strong correlation between arterial CO2 and exhaled CO2. Capnometry can be effectively used to monitor patients during transient increases in artificial pneumoperitoneum pressure

    Impact of Delftia tsuruhatensis and Achromobacter xylosoxidans on Escherichia coli dual-species biofilms treated with antibiotic agents

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    Recently it was demonstrated that for urinary tract infections species with a lower or unproven pathogenic potential, such as Delftia tsuruhatensis and Achromobacter xylosoxidans, might interact with conventional pathogenic agents such as Escherichia coli. Here, single- and dual-species biofilms of these microorganisms were characterized in terms of microbial composition over time, the average fitness of E. coli, the spatial organization and the biofilm antimicrobial profile. The results revealed a positive impact of these species on the fitness of E. coli and a greater tolerance to the antibiotic agents. In dual-species biofilms exposed to antibiotics, E. coli was able to dominate the microbial consortia in spite of being the most sensitive strain. This is the first study demonstrating the protective effect of less common species over E. coli under adverse conditions imposed by the use of antibiotic agents.This work was financially supported by the FCT/MEC with national funds and when applicable co-funded by FEDER in the scope of the P2020 Partnership Agreement [Project UID/ EQU/00511/2013-LEPABE]; FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE, O Novo Norte–North Portugal Regional Operational Programme – ON2 and National Funds through Foundation for Science and Technology – FCT [Project NORTE-07-0124- FEDER-000025–RL2_ Environment&Health and Project ‘DNAmimics’ PIC/IC/82815/2007]; PhD fellowship [SFRH/ BD/82663/2011]; and postdoctoral fellowship [SFRH/ BPD/74480/2010]

    Atividade anti-protozoários de Croton cajucara Benth. e do 7-Hidroxi-calameneno.

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    O objetivo deste trabalho foi avaliar a atividade anti-protozoários de óleos essenciais obtidos de 5 diferentes acessos de sacaca e do 7-hidroxi-calameneno isolado desses óleos contra parasitas do gênero Leishmania e Trypanosoma

    Divergência genêtica entre genótipos de amendoim forrageiro em relação a cacteres agronômicos e bromatológicos avaliados na época seca.

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    Este trabalho teve como objetivo estudar a divergência genética entre genótipos de amendoim forrageiro em relação a características agronômicas e bromatológicas avaliadas no período seco. O estudo foi realizado a partir de genótipos do Banco Ativo de Germoplasma de Amendoim Forrageiro na Embrapa Acre. Foram utilizados 18 genótipos de amendoim forrageiro, sendo 12 da espécie A. pintoi, quatro da espécie A. repens e dois híbridos interespecíficos de A. pintoi x A. repens. Foi utilizado o delineamento em blocos ao acaso com cinco repetições. A análise de variância foi realizada para todas as características e, posteriormente, o estudo da divergência genética foi obtido pelo método de otimização de Tocher. A medida de dissimilaridade utilizada nas análises de agrupamento foi a distância generalizada de Mahalanobis. Verificou-se que não houve um padrão no agrupamento com base nas espécies utilizadas. Concluiu-se que: (i) existe variabilidade genética para todas as características, exceto para praga; (ii) no estudo de divergência genética do amendoim forrageiro, as características que apresentam maior contribuição relativa foram proteína bruta e altura média; (iii) os agrupamentos estabelecidos podem auxiliar o melhorista na escolha dos genitores e cruzamentos a serem realizados nos programas de melhoramento genético do amendoim forrageiro
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