RESUMO
Four bacterial strains isolated from peat bog soil or swampy meadow in Baden-Württemberg (Germany) and found to have rrs sequences close to that of Rouxiella chamberiensis were compared to this species by using multi-locus sequence analysis and phenotypic tests. The four strains constituted two discrete groups (referred to as the Baden and the Silva groups) belonging to the genus Rouxiella. These groups differed in their ability to grow at 37 °C, reduce nitrate into nitrite, and to produce acid from several carbohydrates. Two novel species are, therefore, proposed: Rouxiella badensis sp. nov. for the Baden group (type strain, 323T=CIP 111153T=DSM 100043T) and Rouxiella silvae for the Silva group (type strain, 213T=CIP 111154T=DSM 103735T). The definition of the genus Rouxiellahas also been emended in order to take these two novel species into account.
Assuntos
Gammaproteobacteria/classificação , Filogenia , Microbiologia do Solo , Áreas Alagadas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Alemanha , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Biofilms are the natural form of life of the majority of microorganisms. These multispecies consortia are intensively studied not only for their effects on health and environment but also because they have an enormous potential as tools for biotechnological processes. Further exploration and exploitation of these complex systems will benefit from technical solutions that enable integrated, machine-assisted cultivation and analysis. We here introduce a microfluidic platform, where readily available microfluidic chips are connected by automated liquid handling with analysis instrumentation, such as fluorescence detection, microscopy, chromatography and optical coherence tomography. The system is operable under oxic and anoxic conditions, allowing for different gases and nutrients as feeding sources and it offers high spatiotemporal resolution in the analysis of metabolites and biofilm composition. We demonstrate the platform's performance by monitoring the productivity of biofilms as well as the spatial organization of two bacterial species in a co-culture, which is driven by chemical gradients along the microfluidic channel.
Assuntos
Biofilmes , Dispositivos Lab-On-A-Chip , Bacillus subtilis/crescimento & desenvolvimento , Cromatografia/métodos , Escherichia coli/crescimento & desenvolvimento , Hibridização in Situ Fluorescente , Microscopia/métodos , Espectrometria de Fluorescência/métodos , Tomografia de Coerência Óptica/métodosRESUMO
Microorganisms produce a great variety of secondary metabolites that feature surface active and bioactive properties. Those possessing an amphiphilc molecular structure are also termed biosurfactant and are of great interest due to their often unique properties. Rouxiella sp. DSM 100043 is a gram negative enterobacter isolated from peat-bog soil and described as a new biosurfactant producing species in this study. Rouxiella sp. produces glycolipids, biosurfactants with a carbohydrate moiety in its structure. This study characterizes the composition of glycolipids with different hydrophobicities that have been produced during cultivation in a bioreactor and been extracted and purified from separated foam. Using two dimensional nuclear magnetic resonance spectroscopy, the hydrophilic moieties are elucidated as glucose with various acylation sites and as talose within the most polar glycolipids. The presence of 3' hydroxy lauroleic acid as well as myristic and myristoleic acid has been detected.