Full text loading...
Abstract
The complex cell envelope profile of the anaerobic, spore-forming, xylanolytic eubacterium Clostridium xylanolyticum ATCC 49623 (G. M. Rogers and A. A. W. Baecker, Int. J. Syst. Bacteriol. 41:140-143, 1991) was investigated in greater detail. Although growing cells of this organism produced a gram-negative staining reaction, electron microscopy of thin sections of cells clearly revealed a gram-positive cell envelope profile. The cell wall consists of a thin peptidoglycan layer with a regularly arranged surface layer outside it. Older cells in the stationary phase may have surface layers on both sides of the peptidoglycan, providing a multilayer thin-section profile. Freeze-etched preparations of whole cells revealed an oblique surface layer lattice (a = 6.6 nm; b = 5.3 nm; γ ∼ 78°). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of a solubilized whole-cell extract indicated that the molecular mass of the surface layer monomer was approximately 180 kDa. Treatment of the gels with periodic acid-Schiff reagent resulted in a weak, but unambiguously positive staining reaction. Our data indicate that a glycosylated surface layer protein is present on the cell surface of C. xylanolyticum.
- Published Online: