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Novosphingobium sp. PP1Y as a novel source of outer membrane vesicles
Federica De Lise,Francesca Mensitieri,Giulia Rusciano,Fabrizio Dal Piaz,Giovanni Forte,Flaviana Di Lorenzo,Antonio Molinaro,Armando Zarrelli,Valeria Romanucci,Valeria Cafaro,Antonio Sasso,Amelia Filip 한국미생물학회 2019 The journal of microbiology Vol.57 No.6
Outer membrane vesicles (OMVs) are nanostructures of 20– 200 nm diameter deriving from the surface of several Gramnegative bacteria. OMVs are emerging as shuttles involved in several mechanisms of communication and environmental adaptation. In this work, OMVs were isolated and characterized from Novosphingobium sp. PP1Y, a Gram-negative non-pathogenic microorganism lacking LPS on the outer membrane surface and whose genome was sequenced and annotated. Scanning electron microscopy performed on samples obtained from a culture in minimal medium highlighted the presence of PP1Y cells embedded in an extracellular matrix rich in vesicular structures. OMVs were collected from the exhausted growth medium during the mid-exponential phase, and purified by ultracentrifugation on a sucrose gradient. Atomic force microscopy, dynamic light scattering and nanoparticle tracking analysis showed that purified PP1Y OMVs had a spherical morphology with a diameter of ca. 150 nm and were homogenous in size and shape. Moreover, proteomic and fatty acid analysis of purified OMVs revealed a specific biochemical “fingerprint”, suggesting interesting details concerning their biogenesis and physiological role. Moreover, these extracellular nanostructures do not appear to be cytotoxic on HaCaT cell line, thus paving the way to their future use as novel drug delivery systems.
Kim, Jiyeun Kate,Jang, Ho Am,Kim, Min Seon,Cho, Jae Hyun,Lee, Junbeom,Di Lorenzo, Flaviana,Sturiale, Luisa,Silipo, Alba,Molinaro, Antonio,Lee, Bok Luel American Society for Biochemistry and Molecular Bi 2017 The Journal of biological chemistry Vol.292 No.47
<P>Lipopolysaccharide, the outer cell-wall component of Gram-negative bacteria, has been shown to be important for symbiotic associations. We recently reported that the lipopolysaccharide O-antigen of <I>Burkholderia</I> enhances the initial colonization of the midgut of the bean bug, <I>Riptortus pedestris</I>. However, the midgut-colonizing <I>Burkholderia</I> symbionts lack the O-antigen but display the core oligosaccharide on the cell surface. In this study, we investigated the role of the core oligosaccharide, which directly interacts with the host midgut, in the <I>Riptortus–Burkholderia</I> symbiosis. To this end, we generated the core oligosaccharide mutant strains, Δ<I>wabS</I>, Δ<I>wabO</I>, Δ<I>waaF,</I> and Δ<I>waaC,</I> and determined the chemical structures of their oligosaccharides, which exhibited different compositions. The symbiotic properties of these mutant strains were compared with those of the wild-type and O-antigen–deficient Δ<I>wbiG</I> strains. Upon introduction into <I>Riptortus</I> via the oral route, the core oligosaccharide mutant strains exhibited different rates of colonization of the insect midgut. The symbiont titers in fifth-instar insects revealed significantly reduced population sizes of the inner core oligosaccharide mutant strains Δ<I>waaF</I> and Δ<I>waaC</I>. These two strains also negatively affected host growth rate and fitness. Furthermore, <I>R. pedestris</I> individuals colonized with the Δ<I>waaF</I> and Δ<I>waaC</I> strains were vulnerable to septic bacterial challenge, similar to insects without a <I>Burkholderia</I> symbiont. Taken together, these results suggest that the core oligosaccharide from <I>Burkholderia</I> symbionts plays a critical role in maintaining a proper symbiont population and in supporting the beneficial effects of the symbiont on its host in the <I>Riptortus–Burkholderia</I> symbiosis.</P>