Single-Step Production of a Recyclable Nanobiocatalyst for Organophosphate Pesticides Biodegradation Using Functionalized Bacterial Magnetosomes

Enzymes are versatile catalysts in laboratories and on an industrial scale; improving their immobilization would be beneficial to broadening their applicability and ensuring their (re)use. Lipid-coated nano-magnets produced by magnetotactic bacteria are suitable for a universally applicable single-step method of enzyme immobilization. By genetically functionalizing the membrane surrounding these magnetite particles with a phosphohydrolase, we engineered an easy-to-purify, robust and recyclable biocatalyst to degrade ethyl-paraoxon, a commonly used pesticide. For this, we genetically fused the opd gene from Flavobacterium sp. ATCC 27551 encoding a paraoxonase to mamC, an abundant protein of the magnetosome membrane in Magnetospirillum magneticum AMB-1. The MamC protein acts as an anchor for the paraoxonase to the magnetosome surface, thus producing magnetic nanoparticles displaying phosphohydrolase activity. Magnetosomes functionalized with Opd were easily recovered from genetically modified AMB-1 cells: after cellular disruption with a French press, the magnetic nanoparticles are purified using a commercially available magnetic separation system. The catalytic properties of the immobilized Opd were measured on ethyl-paraoxon hydrolysis: they are comparable with the purified enzyme, with Km (and kcat) values of 58 µM (and 178 s−1) and 43 µM (and 314 s−1) for the immobilized and purified enzyme respectively. The Opd, a metalloenzyme requiring a zinc cofactor, is thus properly matured in AMB-1. The recycling of the functionalized magnetosomes was investigated and their catalytic activity proved to be stable over repeated use for pesticide degradation. In this study, we demonstrate the easy production of functionalized magnetic nanoparticles with suitably genetically modified magnetotactic bacteria that are efficient as a reusable nanobiocatalyst for pesticides bioremediation in contaminated effluents

Antiviral activities of extracts and phenolic components of two Spondias species against dengue virus

In recent years, the search for natural plant products to fight viral diseases has been increasing. In this work, two Spondias species, namely S. mombin and S. tuberosa, found in Ceará state (Brazil), and their main phenolic components were evaluated against dengue virus. In vitro antiviral tests were performed against type-2 dengue virus by the MTT method and standard cytopathic effect reduction assay in C6/36 cells. Cytotoxicity was also evaluated by MTT. The presence of phenolic compounds quercetin, rutin, and ellagic acid in plant extracts was characterized by HPLC analysis. Both Spondias species extracts and components were nontoxic to the cells whereas rutin and quercetin displayed relevant antiviral activity with IC50 of 362.68 µg/mL and 500 µg/mL, respectively

Inquéritos Nacionais de Saúde: experiência acumulada e proposta para o inquérito de saúde brasileiro

As informações oriundas das fontes de dados secundários dos sistemas de informação em saúde existentes são fundamentais, mas insuficientes para responder às necessidades atuais da gestão do Sistema Único de Saúde na identificação dos problemas e necessidades de saúde da população brasileira. Os inquéritos populacionais são instrumentos utilizados como subsídios à formulação e avaliação das políticas públicas, tornando-se crescente a sua utilização nos diversos países como ferramenta de apoio ao planejamento em saúde. O artigo realiza uma breve revisão das iniciativas de realização de inquéritos no âmbito internacional e no Brasil, e propõe um roteiro para a realização do Inquérito Nacional de Saúde.<br>The information from secondary data sources of existing health information systems are fundamental but insufficient to answer to the current needs of management in the Brazilian Health System (SUS) to identify problems and health needs of the population of Brazil. The population surveys are instruments used as subsidies for formulating and evaluating public policy, its use is increasing in several countries as a support tool in planning health. The paper makes a short revision of survey initiatives in International scope and in Brazil, it proposes a schedule for the realization of the National Health Survey