Detailed Structural Characterization of the Lipooligosaccharide from the Extracellular Membrane Vesicles of Shewanella vesiculosa HM13.

Rossella Di Guida,Angela Casillo,Tatsuo Kurihara,Fumiaki Yokoyama,Jun Kawamoto,Maria Michela Corsaro

doi:10.3390/md18050231

Rossella Di Guida, Angela Casillo + Show 4 more

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https://doi.org/10.3390/md18050231

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Abstract

Bacterial extracellular membrane vesicles (EMVs) are membrane-bound particles released during cell growth by a variety of microorganisms, among which are cold-adapted bacteria. Shewanella vesiculosa HM13, a cold-adapted Gram-negative bacterium isolated from the intestine of a horse mackerel, is able to produce a large amount of EMVs. S. vesiculosa HM13 has been found to include a cargo protein, P49, in the EMVs, but the entire mechanism in which P49 is preferentially included in the vesicles has still not been completely deciphered. Given these premises, and since the structural study of the components of the EMVs is crucial for deciphering the P49 transport mechanism, in this study the complete characterization of the lipooligosaccharide (LOS) isolated from the cells and from the EMVs of S. vesiculosa HM13 grown at 18 °C is reported. Both lipid A and core oligosaccharide have been characterized by chemical and spectroscopic methods.

Highlights

Extracellular membrane vesicles (EMVs) are spherical membrane-bound particles produced during cell growth by a wide variety of Gram-negative bacteria [1]
EMVs were collected from the broth culture, as described in the experimental section
The rifampin-resistant mutant was used in this study because it is used as a parental strain mechanistic studies on the biogenesis of EMVs

Summary

Introduction

Extracellular membrane vesicles (EMVs) are spherical membrane-bound particles produced during cell growth by a wide variety of Gram-negative bacteria [1]. In the biogenesis of these EMVs, a small portion of the bacterial outer membrane (OM) bulges away from the cell. For this reason, in Gram-negative bacteria, they are primarily composed of lipopolysaccharides (LPSs), membrane phospholipids, and outer membrane proteins [2]. LPSs and membrane phospholipids are the major components of EMVs for their high surface–volume ratio. EMVs can contain different cargoes such as DNA, RNA, many different periplasmic and cytoplasmic proteins, and toxins. These molecules and cargoes confer to EMVs a role in diverse physiological and pathological functions [3]

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