Extrameningeal Meningococcus Infections

Comparative Proteome Analysis of Spontaneous Outer Membrane Vesicles and Purified Outer Membranes of Neisseria meningitidis

“…The data were then searched by using Sorcerer-SEQUEST (ThermoFinnigan; version v.27, rev. 11) against the N. meningitidis strain MC58 (34) The cured search results were then used for parsing by the Census software (37) to obtain the relative quantitative data of 14 N peaks (sample) versus 15 N peaks (pooled reference). Quantification results were exported (R 2 values of Ͼ0.7; only unique peptides; proteins failing to be relatively quantified were checked manually in the graphical user interface for on/ off proteins).…”

“…To achieve reliable labeling of N. meningitidis proteins with 15 N, we developed a minimal medium for stable isotope labeling of N. meningitidis called MMM. Figure 1 summarizes the work flow for the preparation and analysis of SOMVs and the OM.…”

“…To determine differences in protein abundance between the SOMV and OM fractions, metabolically 15 N-labeled mixtures of SOMV and OMV preparations were used as internal standards. Equal protein amounts of either unlabeled (light, 14 N) SOMV or OM preparations were mixed with equal amounts of the metabolically labeled (heavy, 15 N) internal standard.…”

“…meningitidis is restricted to humans and frequently colonizes the upper respiratory tract. Progression of meningococcal sepsis is exceptionally quick (15). Fulminant meningococcal sepsis (FMS) is accompanied by high death rates (summarized in: reference 16).…”

“…By applying a novel approach to the metabolic labeling of meningococcal proteins with 15 N, we were able to precisely determine the protein compositions of SOMV and OM fractions. We observed an enrichment of numerous minor OM proteins in SOMVs, whereas the major OM proteins porins A and B and OM-anchoring proteins were depleted from SOMVs.…”