Avaliação da expressão de um suposto gene responsável pela síntese de sideróforo em mycobacterium massiliense, em diferentes condições de disponibilidade de ferro
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2014-05-21
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Universidade Federal de Goiás
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Mycobacterium massiliense (MM) has been associated as the causative agent of many nosocomial outbreaks related to laparoscopy, arthroscopic and wound infections. Several outbreaks have been reported in Brazil. The cities of Goiânia, Rio de Janeiro and Belem reported a high number of cases in 2006 and 2007. The iron ion (Fe) is extremely important for many biochemical processes in all organisms and, in the case of microorganisms, the success of the infection. Microorganisms synthesize molecules called siderophores (SD) to aid Fe uptake. Micobactin and carboximicobactin are the SDs that has been described in mycobacteria. One of the genes responsible for the assembly of these SD in M. tuberculosis is the mbtb. A MM strain, which belongs to the outbreak that happened in Goiânia (MM GO06) had its genome sequenced and the analysis revealed that the species has a putative gene with high similarity to M. tuberculosismbtb, which could be an indication that MM also synthesizes a siderophore molecule and that this can be helping this mycobacteria to install the infection in the host. It is known that in the absence of mbtb gene M. tuberculosis do not synthesize their SD. To estimate whether a gene similar to mbtb and with the same function is present in MM (smbtb) will assist in the understanding of the infection mechanisms of MM and discover new drug targets for treating infections with this microorganism. Total RNA was obtained from cultures grown at different concentrations of Fe. Real time PCR was performed targeting the smbtb to evaluate the expression of this gene during bacterial growth in each condition. The expression of smbtb was higher with the increase of the availability of iron. In vivo studies with mice supplemented with or chelated fromiron showed expression profile of smbtb different from those obtained in in vitro studies. In mice, M. massiliense smbtb expressed at higher levels when the animal were treated for iron depletion. Thus, we have evidence that smbtb is involved in iron uptake both for subsequent storage, when this ion is available, and for prompt use in the metabolism of the bacteria when it is not in an environment where there is availability of this ion.
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ROCHA, V. L. Avaliação da expressão de um suposto gene responsável pela síntese de sideróforo em mycobacterium massiliense, em diferentes condições de disponibilidade de ferro. 2014. 95 f. Dissertação (Mestrado em Medicina Tropical e Saúde Publica) - Universidade Federal de Goiás, Goiânia, 2014.