Figure 1.
Induction of membrane vesicle formation in Corynebacterium glutamicum
(A) Structures of the cell envelope of Gram-negative (left), Gram-positive (middle), and mycolic acid-containing bacteria (right). OM, outer membrane; MM, mycomembrane; PG, peptidoglycan; IM, inner membrane; and AG, arabinogalactan; CM, cytoplasmic membrane.
(B and C) Membrane vesicle (MV) release by C. glutamicum under MV formation-inducing conditions. FM4-64 fluorescence of the purified MV fractions was normalized to (B) OD600 or (C) dried cell weight (DCW). All values indicated by the bars represent the mean value ± SD for three experiments. p values were calculated using unpaired t test with Welch's correction.
(D) Transmission electron microscopic (TEM) images of MVs released by C. glutamicum under the conditions shown in (B and C). Scale bars, 200 nm. Structures that are presumably MVs collapsed are indicated with blue arrowheads.
(E) Quick-freeze deep-etch (QFDE) electron microscopic images of MVs. Scale bars, 200 nm.
(F) MV release by wild-type C. glutamicum and NCgl1682 deletion mutant. White and blue bars indicate the presence or absence of MMC in the culture media, respectively. All values indicated by the bars represent the mean value ± SD for three experiments. p values were calculated using unpaired t test with Welch's correction.