Browsing by Author "Medeiros, Mafalda Vieira"
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- Evaluation of the effects of obesogenic compounds on microorganismsPublication . Medeiros, Mafalda Vieira; Sousa, Ana Catarina Almeida; Alexandre, Ana; Rato, Luís PedroThousands of chemical compounds are generated as a result of human activity, many of which have a high potential for accumulation in both vertebrates and invertebrates. Some chemicals interfere with the way the body stores and processes lipids by acting as metabolic disruptors, promoting adipogenesis by, for example, increasing the size and number of adipocytes, increasing adipose tissue and interfering with the hormonal control of appetite and satiety. These compounds are called obesogenic compounds and have been suggested as possible causes for the increase in the number of cases of obesity. Numerous studies have been carried out to demonstrate the effect of obesogenic compounds, mainly in vertebrates, but to prove that the effect of these compounds crosses different taxonomic levels, it is important to add evidence at the level of prokaryotic organisms by studying different types of bacteria. On the other hand, it is also important to study the impact of obesogenic compounds on bacteria that interact with eukaryotic hosts. In this sense, it is essential to choose a well-established system that is easy to work with, such as the rhizobium-legume mutualistic symbiosis. The aim of this study is to evaluate the effect of exposure to an obesogenic compound, tributyltin (TBT), on model bacteria (Escherichia coli DSM 5698, Bacillus subtilis DSM 10T, Pseudomonas fluorescens DSM 50090T) and on different rhizobium species (Mesorhizobium loti MAFF303099, Mesorhizobium mediterraneum UPM-Ca36T, Mesorhizobium sp. PMI-6-Portimão, Mesorhizobium sp. V-15b-Viseu, Mesorhizobium sp. BR15-Bragança, Mesorhizobium sp. LMS-1). The aim is to assess the sensitivity of these bacteria to TBT and its effect on lipid accumulation, as well as the impact of this compound on the prokaryote-eukaryote interaction (namely, the rhizobium-legume interaction). The results show that tributyltin affects the growth of the different model bacteria studied as well as the different rhizobia evaluated, and it was possible to establish a range of sublethal concentrations for the study of lipid accumulation, namely 0.25 µM; 1.5 µM; 2.5 µM TBT. Regarding lipid accumulation, evaluated in Escherichia coli DSM 5698 and Mesorhizobium sp. V-15b-Viseu it was possible to observe that exposure to 2.5 µM TBT was responsible for a significant increase in the amount of lipids, demonstrating that the obesogenic potential of TBT extends to these microorganisms. Regarding the prokaryote-eukaryote interaction, curling, the initial phase of this interaction, in which a morphologic change in the root hairs occurs was analyzed. Few curling events were observed in the roots of chickpea inoculated with the bacterium Mesorhizobium sp. V-15b-Viseu, so it is not possible to evaluate the effect of TBT on this interaction. Further studies are necessary to understand the potential effects of TBT on the prokaryote-eukaryote interactions.