Preparation Of Sio2/nb2o5/zno Mixed Oxide By Sol-gel Method And Its Application For Adsorption Studies And On-line Preconcentration Of Cobalt Ions From Aqueous Medium

A new Nb2O5/ZnO mixed oxide dispersed in a silica matrix (i.e., SiO2/Nb2O5/ZnO) was synthesized via sol-gel method and used as an adsorbent of cobalt ions (Co2+). The material presented a high surface area (323m2g-1) and the maximum adsorption capacity was found to be 0.518mgg-1, determined from the non-linear Langmuir-Freundlich isotherm model. The material was used as a chelating agent free-solid phase extractor (CAF-SPE) in an on-line preconcentration procedure, based on the adsorption of Co2+ ions (16.0mL, pH 7.4) at a high flow rate (8.0mLmin-1) onto a mini-column packed with the adsorbent (200mg). The analyte was then eluted with 1.0molL-1 HCl and transported toward the FAAS detector. Linear calibration range was obtained from 0.96 up to 150.0μgL-1, with a limit of detection of 0.28μgL-1. The precision of method, estimated as relative standard deviation of ten replicate measurements of 30 and 150μgL-1 analyte solutions, was found to be 4.6% and 3.1%, respectively. 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Análise Genômica de Burkholderia mallei e Burkholderia pseudomallei: Dois Patógenos de Primeira Grandeza e de Genomas Surpreendentemente Complexos

The Burkholderia genus holds over 40 species of Gram-negative bacteria, including genomovars early identified as part of B. cepacia complex (Bcc), besides B. mallei (causative agent of equine glanders) and B. pseudomallei (causative agent of human melioidosis or pseudoglanders). Natural B. mallei and B. pseudomallei zoonotic infections have largely been eradicated/controlled and human infection is extremely rare, but renewed interest in these organisms parallels their classification as category B biothreat agents, the lack of any effective vaccine available for them and the serious risk of aerosol transmission, a great concern for public health surveillance. Both diseases are very ancient, but relatively little is known about details concerning virulence mechanisms in glanders and melioidosis. Here we apply bioinformatics resources and tools to investigate B. mallei and B. pseudomallei sequenced genomes, their putative genes (and coded proteins) in a pathogenomics approach aiming at the in silico identification of virulence genes potentially associated with a key-lesion of both diseases, the granuloma (or piogranuloma) formation. Granulomas are localized chronic inflammatory responses that are able to keep the pathogen inside of them and are, thus, critical sites of infection. Our results help to build a panel of eighteen (18) putative ortologs, which can be excellent targets for future experimental screenings that might lead to genetic characterizations of their functions in terms of granulomatous genesis within Burkholderia infections.O gênero Burkholderia constitui mais de 40 espécies, incluindo genomovares entre bactérias identificadas anteriormente como parte do complexo B. cepacia (Bcc), além de B. mallei (agente causal do mormo) e a B. pseudomallei (agente causal da melioidose ou pseudomormo). B. mallei e B. pseudomallei foram escolhidos como alvos deste trabalho exatamente pela incrível capacidade zoonótica (de certo modo, compartilhada na letalidade potencial para humanos e animais) e risco iminente à saúde pública em geral, assim como também por serem potenciais agentes bioterroristas, principalmente pela habilidade de infecção por aerossóis e a inexistência de vacinas efetivas. Ressalta-se, aqui, o caráter de re-emergência das zoonoses em geral, não só no Brasil, mas no mundo inteiro, em que aproximadamente 75% das doenças infecciosas humanas recém-emergentes são de origem animal; com a incrível porcentagem de cerca 60% de todos os patógenos humanos serem, em essência, zoonóticos. Apesar da relativa antiguidade das duas doenças, pouco se sabe sobre os detalhes e mecanismos de virulência e patogenicidade em mormo e melioidose. Neste trabalho foram usadas vários recursos e ferramentas de Bioinformática para investigar genes e produtos gênicos putativos em cromossomos e replicons seqüenciados dos genomas de B. mallei e B. pseudomallei, numa abordagem patogenômica visando a identificação de genes representativos de fatores de virulência associados com uma lesão-chave nas duas doenças, a formação de granulomas/piogranulomas. Granulomas são respostas localizadas de inflamação crônica capazes de reter os patógenos em seu interior, sendo, assim, sítios estratégicos da infecção. Os resultados in silico ajudaram a formar um painel preliminar contendo dezoito (18) ortólogos putativos, excelentes alvos para futuros screenings experimentais que venham a caracterizar precisamente suas funções na atividade granulomatogênica de Burkholderia