Abstract
The acid-fastness is the most important and the most specific characteristics in mycobacteria, the mechanism of which is not clear but may be attributed to the lipid rich cell wall of this bacterium. While the exact component(s) responsible for this staining method remained unidentified, a Mycobacterium tuberculosis mutant, attenuated strain that produced shorter mycolic acids with defects in trans-cyclopropanation was shown to be acid fast negative. In this study, we examined the ultrastructure of the cell envelope (CE) of the mutant strain ΔkasB (missing a beta-ketoacyl-ACP synthase involved in mycolic acid biosynthesis), the parental CDC1551 (wild type strain) and kasB complemented strain, and compared ultrastructural differences among them with conventional transmission electron microscopy (TEM) and cryo-transmission electron microscopy (CEM). Conventional TEM revealed that there were no detectable differences in the thickness of the cell envelope among three strains (wild-type: 43.35 ± 6.13 nm; ΔkasB: 45.98 ± 11.32 nm; complement: 40.71 ± 6.3 nm). However, CEM data demonstrated that the region between the inner and outer membranes of the mutant strain, which is composed mainly of cell wall anchored mycolic acids (MA), showed a significant decrease in electron density as compared to the wild type and kasB complement strain (567.1 ± 372.7 vs. 301.4 ± 262.1, or vs. 235.2 ± 174.9, p < 0.02 or p < 0.001, respectively). These results suggested that altered MA patterns in the kasB mutant may have affected the packing of the lipid rich layer of the M. tuberculosis cell envelope, resulting in a reduced electron density of this layer as seen by CEM and loss of acid-fastness in light microscopical observation, and we propose a novel model of the cell envelope structure in tubercle bacilli.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 351-357 |
| Number of pages | 7 |
| Journal | Tuberculosis |
| Volume | 92 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jul 1 2012 |
Fingerprint
Keywords
- Acid-fastness
- Cell envelope
- Mycobacterium tuberculosis
- Transmission electron microscopy
- Virulent strain
ASJC Scopus subject areas
- Microbiology
- Immunology
- Microbiology (medical)
- Infectious Diseases
Cite this
Non-acid-fastness in Mycobacterium tuberculosis ΔkasB mutant correlates with the cell envelope electron density. / Yamada, Hiroyuki; Bhatt, Apoorva; Danev, Radostin; Fujiwara, Nagatoshi; Maeda, Shinji; Mitarai, Satoshi; Chikamatsu, Kinuyo; Aono, Akio; Nitta, Koji; Jacobs, William R.; Nagayama, Kuniaki.
In: Tuberculosis, Vol. 92, No. 4, 01.07.2012, p. 351-357.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Non-acid-fastness in Mycobacterium tuberculosis ΔkasB mutant correlates with the cell envelope electron density
AU - Yamada, Hiroyuki
AU - Bhatt, Apoorva
AU - Danev, Radostin
AU - Fujiwara, Nagatoshi
AU - Maeda, Shinji
AU - Mitarai, Satoshi
AU - Chikamatsu, Kinuyo
AU - Aono, Akio
AU - Nitta, Koji
AU - Jacobs, William R.
AU - Nagayama, Kuniaki
PY - 2012/7/1
Y1 - 2012/7/1
N2 - The acid-fastness is the most important and the most specific characteristics in mycobacteria, the mechanism of which is not clear but may be attributed to the lipid rich cell wall of this bacterium. While the exact component(s) responsible for this staining method remained unidentified, a Mycobacterium tuberculosis mutant, attenuated strain that produced shorter mycolic acids with defects in trans-cyclopropanation was shown to be acid fast negative. In this study, we examined the ultrastructure of the cell envelope (CE) of the mutant strain ΔkasB (missing a beta-ketoacyl-ACP synthase involved in mycolic acid biosynthesis), the parental CDC1551 (wild type strain) and kasB complemented strain, and compared ultrastructural differences among them with conventional transmission electron microscopy (TEM) and cryo-transmission electron microscopy (CEM). Conventional TEM revealed that there were no detectable differences in the thickness of the cell envelope among three strains (wild-type: 43.35 ± 6.13 nm; ΔkasB: 45.98 ± 11.32 nm; complement: 40.71 ± 6.3 nm). However, CEM data demonstrated that the region between the inner and outer membranes of the mutant strain, which is composed mainly of cell wall anchored mycolic acids (MA), showed a significant decrease in electron density as compared to the wild type and kasB complement strain (567.1 ± 372.7 vs. 301.4 ± 262.1, or vs. 235.2 ± 174.9, p < 0.02 or p < 0.001, respectively). These results suggested that altered MA patterns in the kasB mutant may have affected the packing of the lipid rich layer of the M. tuberculosis cell envelope, resulting in a reduced electron density of this layer as seen by CEM and loss of acid-fastness in light microscopical observation, and we propose a novel model of the cell envelope structure in tubercle bacilli.
AB - The acid-fastness is the most important and the most specific characteristics in mycobacteria, the mechanism of which is not clear but may be attributed to the lipid rich cell wall of this bacterium. While the exact component(s) responsible for this staining method remained unidentified, a Mycobacterium tuberculosis mutant, attenuated strain that produced shorter mycolic acids with defects in trans-cyclopropanation was shown to be acid fast negative. In this study, we examined the ultrastructure of the cell envelope (CE) of the mutant strain ΔkasB (missing a beta-ketoacyl-ACP synthase involved in mycolic acid biosynthesis), the parental CDC1551 (wild type strain) and kasB complemented strain, and compared ultrastructural differences among them with conventional transmission electron microscopy (TEM) and cryo-transmission electron microscopy (CEM). Conventional TEM revealed that there were no detectable differences in the thickness of the cell envelope among three strains (wild-type: 43.35 ± 6.13 nm; ΔkasB: 45.98 ± 11.32 nm; complement: 40.71 ± 6.3 nm). However, CEM data demonstrated that the region between the inner and outer membranes of the mutant strain, which is composed mainly of cell wall anchored mycolic acids (MA), showed a significant decrease in electron density as compared to the wild type and kasB complement strain (567.1 ± 372.7 vs. 301.4 ± 262.1, or vs. 235.2 ± 174.9, p < 0.02 or p < 0.001, respectively). These results suggested that altered MA patterns in the kasB mutant may have affected the packing of the lipid rich layer of the M. tuberculosis cell envelope, resulting in a reduced electron density of this layer as seen by CEM and loss of acid-fastness in light microscopical observation, and we propose a novel model of the cell envelope structure in tubercle bacilli.
KW - Acid-fastness
KW - Cell envelope
KW - Mycobacterium tuberculosis
KW - Transmission electron microscopy
KW - Virulent strain
UR - http://www.scopus.com/inward/record.url?scp=84862017631&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84862017631&partnerID=8YFLogxK
U2 - 10.1016/j.tube.2012.02.006
DO - 10.1016/j.tube.2012.02.006
M3 - Article
C2 - 22516756
AN - SCOPUS:84862017631
VL - 92
SP - 351
EP - 357
JO - Tuberculosis
JF - Tuberculosis
SN - 1472-9792
IS - 4
ER -