Acids Of Gram-positive Bacteria Research Articles

Biosynthesis of linkage units for teichoic acids in gram-positive bacteria: distribution of related enzymes and their specificities for UDP-sugars and lipid-linked intermediates.

The distribution and substrate specificities of enzymes involved in the formation of linkage units which contain N-acetylglucosamine (GlcNAc) and N-acetylmannosamine (ManNAc) or glucose and join teichoic acid chains to peptidoglycan were studied among membrane systems obtained from the following two groups of gram-positive bacteria: group A, including Bacillus subtilis, Bacillus licheniformis, Bacillus pumilus, Staphylococcus aureus, and Lactobacillus plantarum; group B, Bacillus coagulans. All the membrane preparations tested catalyzed the synthesis of N-acetylglucosaminyl pyrophosphorylpolyprenol (GlcNAc-PP-polyprenol). The enzymes transferring glycosyl residues to GlcNAc-PP-polyprenol were specific to either UDP-ManNAc (group A strains) or UDP-glucose (group B strains). In the synthesis of the disaccharide-bound lipids, GlcNAc-PP-dolichol could substitute for GlcNAc-PP-undecaprenol. ManNAc-GlcNAc-PP-undecaprenol, ManNAc-GlcNAc-PP-dolichol, Glc-GlcNAc-PP-undecaprenol, Glc-GlcNAc-PP-dolichol, and GlcNAc-GlcNAc-PP-undecaprenol were more or less efficiently converted to glycerol phosphate-containing lipid intermediates and polymers in the membrane systems of B. subtilis W23 and B. coagulans AHU 1366. However, GlcNAc-GlcNAc-PP-dolichol could not serve as an intermediate in either of these membrane systems. Further studies on the exchangeability of ManNAc-GlcNAc-PP-undecaprenol and Glc-GlcNAc-PP-undecaprenol revealed that in the membrane systems of S. aureus strains and other B. coagulans strains both disaccharide-inked lipids served almost equally as intermediates in the synthesis of polymers. In the membrane systems of other B. subtilis strains as well as B. licheniformis and B. pumilus strains, however, the replacement of ManNAc-GlcNAc-PP-undecaprenol by Glc-GlcNAc-PP-undecaprenol led to a great accumulation of (glycerol phosphate)-Glc-GlcNAc-PP-undecaprenol accompanied by a decrease in the formation of polymers.

On the relationship between glycerophosphoglycolipids and lipoteichoic acids in gram-positive bacteria: I. The occurrence of phosphoglycolipids

1. 1. Gram-positive bacteria out of the families of Streptococcaceae, Lactobacillaceae, Micrococcaceae and Bacillaceae were investigated with respect to the occurrence and the concentration of phosphoglycolipids. 2. 2. Phosphatidylglycolipids occur exclusively in group D Streptococci and in Streptococcus hemolyticus D-58. Phosphatidyl-α-kojibiosyldiacylglycerol, the prevalent species, accounts for up to 28% of the polar lipids. The related glycerophospho-phosphatidyl-α-kojibiosyldiacylglycerol is restricted to Streptococcus faecalis. 3. 3. Glycerophosphoglycolipids, usually minor components, comprise thirteen compounds most of which have so far not been described. Except Micrococcus lysodeikticus all examined bacteria contained one or more glycerophosphoglycolipids. Their occurrence parallels, therefore, that of lipoteichoic acids, which supports the hypothesis of a metabolic relationship between these two membrane components.

On the relationship between glycerophosphoglycolipids and lipoteichoic acids in gram-positive bacteria: II. Structures of glycerophosphoglycolipids

1. 1. Eight glycerophosphoglycolipids were isolated from six Gram-positive bacteria. Besides sn-glycero-1-phospho-β-gentiobiosyldiacylglycerol (i) and sn-glycero-1-phospho-α-kojibiosyldiacylglycerol (ii), three novel structures have been established: 1,2- di- O-acyl-3- O-[6-( sn-glycero-1-phospho)- α- D-glucopyranosyl-(1 → 2)-(6- O-acyl- α- D-glucopyranosyl)]glycerol ( iii), 1,2- di- O-acyl-3- O-[6-( sn-glycero-1-phospho)- β- D-glucopyranosyl- → 6)- α- D-galactopyranosyl-(1 → 2)- α- D-glucopyranosyl]glycerol (iv),and 1,2- di- O-acyl-3- O-[6-( sn-glycero-1-phospho)- β- D-glucopyranosyl-(1 → 6)- α- D-galactopyranosyl-(1 → 2)-(6- O-acyl- α- D-glucopyranosyl)]iglycerol ( v). 2. 2. Compound i was isolated from Bacillus licheniformis, Bacillus subtilis and Staphylococcus aureus, compound ii from a group B Streptococcus, compounds ii and iii from Streptococcus lactis, compounds iv and v from Lactobacillus casei. Lactobacillus plantarum contained besides compounds iv and v a glycerophosphate derivative of 1,2- di- O-acyl-3- O-[ α- D-galactopyranosyl (1 → 2)- α- D- glucopyranosyl] glycerol. 3. 3. Identical structural features of the described glycerophosphoglycolipids and the corresponding lipoteichoic acids are discussed.

Occurrence of glucomuramic acid in gram-positive bacteria.

Analyses of 48 gram-positive bacteria indicate only glucomuramic acid and no galactomuramic acid in cell walls.

Function of teichoic acids and effect of novobiocin on control of Mg2+ at the bacterial membrane.

ALTHOUGH the occurrence of both wall and membrane teichoic acids in Gram-positive bacteria has been known for a considerable time and it is believed that they are essential for normal cellular activity, their main function has been somewhat obscure. Confirmatory evidence for the proposal1 that teichoic acids participate in ion-exchange in the outer regions of the bacterial cell has been described recently2. It has been shown that the phosphate groups of the wall teichoic acid are responsible for the capacity of isolated walls to bind magnesium ions; but whole cells of Gram-positive bacteria also invariably contain a poly-glycerol phosphate-teichoic acid located in the region between the wall and the cytoplasmic membrane3 and it is believed that this must be able to bind Mg2+ as does the wall polymer. These two regions of anionic polymer might thus constitute an integrated cation-exchange system between the exterior of the cell and the cytoplasmic membrane, where relatively high concentrations of Mg2+ are required for a variety of processes. We report here experiments with a membrane-bound enzyme system that requires Mg2+, obtained from a broken cell preparation and in which the close contact between the outer layers of the cell is preserved. In this preparation the enzyme system displays maximum activity in the presence of Mg2+ bound to the endogenous teichoic acid and is insensitive to changes in the concentration of added Mg2+, in marked contrast to the behaviour of the enzyme system in isolated cytoplasmic membrane. These results provide the first direct demonstration of the function of teichoic acids in concentrating Mg2+at the cytoplasmic membrane. They lead to the conclusion that failure of teichoic acid biosynthesis in the whole cell would cause inhibition of membrane function through magnesium starvation. In view of this the effect of novobiocin, an antibiotic shown to inhibit teichoic acid biosynthesis in vitro4–6, is discussed.