English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Cells of theCorynebacterium-Nocardia-Mycobacterium group of bacteria are surrounded by an outer membrane (OM) containing mycolic acids that are covalently linked to the underlying arabinogalactan-peptidoglycan complex. This OM presumably acts as a permeability barrier that imparts high levels of intrinsic drug resistance to some members of this group, such asMycobacterium tuberculosis , and its component lipids have been studied intensively in a qualitative manner over the years. However, the quantitative lipid composition of this membrane has remained obscure, mainly because of difficulties in isolating it without contamination from the inner cytoplasmic membrane. Here we use the extraction, with reverse surfactant micelles, of intact cells ofCorynebacterium glutamicum and show that this method extracts the free OM lipids quantitatively with no contamination from lipids of the cytoplasmic membrane, such as phosphatidylglycerol. Although only small amounts of corynomycolate were esterified to arabinogalactan, a large amount of cardiolipin was present in a nonextractable form, tightly associated, possibly covalently, with the peptidoglycan-arabinogalactan complex. Furthermore, we show that the OM contains just enough lipid hydrocarbons to produce a bilayer covering the cell surface, with its inner leaflet composed mainly of the aforementioned nonextractable cardiolipin and its outer leaflet composed of trehalose dimycolates, phosphatidylinositol mannosides, and highly apolar lipids, similar to the Minnikin model of 1982. The reverse micelle extraction method is also useful for extracting proteins associated with the OM, such as porins.

Quantitative lipid composition of cell envelopes of Corynebacterium glutamicum elucidated through reverse micelle extraction