| Range |
Table - link
|
| Organism |
Bacteria Escherichia coli |
| Reference |
Hobot JA, Carlemalm E, Villiger W, Kellenberger E. Periplasmic gel: new concept resulting from the reinvestigation of bacterial cell envelope ultrastructure by new methods. J Bacteriol. 1984 Oct160(1):143-52PubMed ID6207168
|
| Method |
E. coli B was maintained on nutrient
agar slants (1.5% [wt/vol] nutrient broth [Difco Laboratories,
Detroit, Mich.], 0.5% [wt/vol] NaCl, 2% [wt/vol] agar
[Difco]) grown overnight in liquid culture (1% [wt/vol]
tryptone [Difco], 0.5% [wt/vol] NaCl) at 37°C plus aeration
and subcultured the following day into fresh liquid culture
until exponentially growing cells were observed (ca. 1.5 h 2
x 10^8 cells/ml). Isolation of peptidoglycan and density determinations. Cell envelope preparation. Electron microscopy. |
| Comments |
Researchers felt that the new progressive lowering of temperature (PLT) embedding procedure for electron microscopy (13, 28) might counter some of the adverse influences of dehydration in a manner that would provide new and additional data concerning cell envelope ultrastructure (J. A. Hobot, E. Carlemalm, and E. Kellenberger, Experientia 37:1226, 1981). When E. coli is fixed with osmium and embedded in Epon, the envelope shows several layers: the double track of an outer membrane with an underlying intermediate layer (the G layer described by DePetris [15]). This intermediate layer was assumed to be composed of a compact peptidoglycan layer (layer g2 described by DePetris [15]) separated from the outer membrane by a globular protein layer (layer g1 described by DePetris [15]). This interpretation confirmed the observations of Murray et al. (35) for the location and thickness (2.0 to 3.0 nm) of the peptidoglycan layer, which is in agreement with the calculated thickness of a peptidoglycan monolayer in the E. coli envelope (11) and the model for a compact, crystalline layer of peptidoglycan based on X-ray data (19). Note: this value is in agreement with 0.16 fL given by link |
| Entered by |
Uri M |
| ID |
104946 |