Title Novosphingobium sp. PP1Y as a novel source of outer membrane vesicles
Author Federica De Lise1, Francesca Mensitieri1, Giulia Rusciano2, Fabrizio Dal Piaz3, Giovanni Forte4, Flaviana Di Lorenzo5, Antonio Molinaro5, Armando Zarrelli5, Valeria Romanucci5, Valeria Cafaro1, Antonio Sasso2, Amelia Filippelli3, Alberto Di Donato1, and Viviana Izzo3*
Address 1Department of Biology, University of Naples, Federico II, Italy, 2Department of Physics, University of Naples, Federico II, Italy, 3Department of Medicine, Surgery and Dentistry, University of Salerno, Italy, 4Department of Pharmacy, University of Salerno, Italy, 5Department of Chemical Sciences, University of Naples Federico II, Italy
Bibliography Journal of Microbiology, 57(6),498–508, 2019,
DOI 10.1007/s12275-019-8483-2
Key Words outer membrane vesicles, exocytosis, bacterial secretion, sphingomonadales, Novosphingobium, outer cell membrane
Abstract 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.