Bacterial lipopolysaccharide (LPS), which is generally considered to be an endotoxin, is the major constituent of the outer membrane of Gram-negative bacteria. The structure of LPS consists of three regions; lipid A, core oligosaccharide and O-antigen polysaccharide (O-PS). The structures of lipid A and core oligosaccharide are highly conserved among bacterial genera, but that of O-PS varies an...

Mutants of Escherichia coli susceptible to vancomycin were isolated after mutagenesis with nitrosoguanidine. One such mutant was studied extensively. Multiple regression analysis of the relationship between physical properties of 20 glycopeptides and their in vitro activities against the vancomycin-susceptible mutant revealed a significant correlation with molecular mass (P = 0.007). pI, hydrop...

The outer membrane (OM) of Gram-negative bacteria is asymmetric due to the presence of lipopolysaccharide (LPS) facing the outer leaflet of the OM and phospholipids facing the periplasmic side. LPS is essential for bacterial viability, since it provides a permeability barrier and is a major virulence determinant in pathogenic bacteria. In Escherichia coli, several steps of LPS biosynthesis and ...

The major permeability barrier in any membrane is the lipid bilayer structure, and its barrier property is inversely correlated with its fluidity. Bacteria cannot make this membrane much less fluid or it will start to interfere with the normal functions of the membrane proteins, so some bacteria have constructed an additional structure that surrounds the cell outside the cytoplasmic membrane. A...

The major permeability barrier in any membrane is the lipid bilayer structure, and its barrier property is inversely correlated with its fluidity. Bacteria cannot make this membrane much less fluid or it will start to interfere with the normal functions of the membrane proteins, so some bacteria have constructed an additional structure that surrounds the cell outside the cytoplasmic membrane. A...

The major permeability barrier in any membrane is the lipid bilayer structure, and its barrier property is inversely correlated with its fluidity. Bacteria cannot make this membrane much less fluid or it will start to interfere with the normal functions of the membrane proteins, so some bacteria have constructed an additional structure that surrounds the cell outside the cytoplasmic membrane. A...

Previous investigations of the incompatibility group F, P, and I plasmid systems revealed the important role of the outer membrane components in the conjugal transfer of these plasmids. We have observed variability in transfer frequency of three incompatibility group H plasmids (IncHI1 plasmid R27, IncHI2 plasmid R478, and a Tn7 derivative of R27, pDT2454) upon transfer into various Salmonella ...

Shigella flexneri is a gram-negative bacterium responsible for serious enteric infections that occur mainly in the terminal ileum and colon. High interest in Shigella, as a human pathogen, is driven by its antibiotic resistance and the necessity to develop a vaccine against its infections. Vaccines of the last generation use carbohydrate moieties of the lipopolysaccharide as probable candidates...

The core lipopolysaccharides (LPS) of Proteus mirabilis as well as those of Klebsiella pneumoniae and Serratia marcescens are characterized by the presence of a hexosamine-galacturonic acid disaccharide (αHexN-(1,4)-αGalA) attached by an α1,3 linkage to L-glycero-D-manno-heptopyranose II (L-glycero-α-D-manno-heptosepyranose II). In K. pneumoniae, S. marcescens, and some P. mirabilis strains, He...

introduction: legionnair's disease bacterium is a gram negative, facultative intracellular bacilli which parasitize human alveolar macropages as well as some species of free living amobae. this study was achieved in order to compare the cell wall composition in intracellular bacteria. whole cell and outer membrane proteins and the bacterial lipopolysacharide (lps) were analyzec on sds page syst...