Production of siderophores by Serratia marcescens and the role of MacAB efflux pump in siderophores secretion

© 2016, Springer Science+Business Media New York.Human opportunistic pathogen Serratia marcescens secrete siderophores to enable growth under iron-limiting conditions. Iron acquisition genes are among a few known virulence factors of S. marcescens. Siderophore export systems in Gram-negative bacteria are not fully understood. There is some evidence for involvement of efflux pumps in the export of synthesized enterobactin-like molecules. The goal of this study was to characterize siderophore production by two different strains of S. marcescens, SM6 and SR41-8000, and to evaluate the role of efflux pump MacAB in siderophore secretion by these strains. We showed that both strains produced siderophores in CAS agar assay. We further showed that both strains were able to secrete catecholate siderophores in response to iron starvation. MacAB efflux pump played a role in siderophore secretion of S. marcescens SR41-8000 strain but was dispensable for accumulation of these molecules in the culture supernatant of S. marcescens strain SM6

Comparative metagenomic analysis of electrogenic microbial communities in differentially inoculated swine wastewater-fed microbial fuel cells

Bioelectrochemical systems such as microbial fuel cells (MFCs) are promising new technologies for efficient removal of organic compounds from industrial wastewaters, including that generated from swine farming. We inoculated two pairs of laboratory-scale MFCs with sludge granules from a beer wastewater-treating anaerobic digester (IGBS) or from sludge taken from the bottom of a tank receiving swine wastewater (SS). The SS-inoculated MFC outperformed the IGBS-inoculated MFC with regard to COD and VFA removal and electricity production. Using a metagenomic approach, we describe the microbial diversity of the MFC planktonic and anodic communities derived from the different inocula. Proteobacteria (mostly Deltaproteobacteria) became the predominant phylum in both MFC anodic communities with amplification of the electrogenic genus Geobacter being the most pronounced. Eight dominant and three minor species of Geobacter were found in both MFC anodic communities. The anodic communities of the SS-inoculated MFCs had a higher proportion of Clostridium and Bacteroides relative to those of the IGBS-inoculated MFCs, which were enriched with Pelobacter. The archaeal populations of the SS- and IGBS-inoculated MFCs were dominated by Methanosarcina barkeri and Methanothermobacter thermautotrophicus, respectively. Our results show a long-term influence of inoculum type on the performance and microbial community composition of swine wastewater-treating MFCs

Microbial diversity and mineral composition of weathered serpentine rock of the Khalilovsky massif

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Influence of divalent metal ions of biofilm formation by Bacillus subtilis

Статья посвящена исследованию регуляции формирования биопленки на рекомбинантных штаммах B, subtilis в условиях стресса521-52

Production of siderophores by Serratia marcescens and the role of MacAB efflux pump in siderophores secretion

© 2016, Springer Science+Business Media New York.Human opportunistic pathogen Serratia marcescens secrete siderophores to enable growth under iron-limiting conditions. Iron acquisition genes are among a few known virulence factors of S. marcescens. Siderophore export systems in Gram-negative bacteria are not fully understood. There is some evidence for involvement of efflux pumps in the export of synthesized enterobactin-like molecules. The goal of this study was to characterize siderophore production by two different strains of S. marcescens, SM6 and SR41-8000, and to evaluate the role of efflux pump MacAB in siderophore secretion by these strains. We showed that both strains produced siderophores in CAS agar assay. We further showed that both strains were able to secrete catecholate siderophores in response to iron starvation. MacAB efflux pump played a role in siderophore secretion of S. marcescens SR41-8000 strain but was dispensable for accumulation of these molecules in the culture supernatant of S. marcescens strain SM6

Arabidopsis thaliana Metabolites Secreted by Roots during Plant Growth in Phosphorus-Limiting Conditions

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