Peptidoglycan figure

Structure similar to that of eukaryotes and a thick, bagshaped cell wall. The cell wall, about 25 nm wide, consists of peptidoglycans (Figure 11-14) and polyol phosphate polymers known as teichoic acids. Gram-negative bacteria (e.g., Escherichia coli and Salmonella typhimurium) do not contain teichoic acids but have an outer membrane system external to the plasma membrane and the peptidoglycan. The constituents of this second outer... 

Microbial Cell Wall Polysaccharides Peptidoglycan (Figure 9.26)... 

FIGURE 8.18 Dolichol phosphate is an initiation point for the synthesis of carbohydrate polymers in animals. The analogous alcohol in bacterial systems, undecaprenol, also known as bactoprenol, consists of 11 isoprene units. Undecaprenyl phosphate delivers sugars from the cytoplasm for the synthesis of cell wall components such as peptidoglycans, lipopolysaccharides, and glycoproteins. Polyprenyl compounds also serve as the side chains of vitamin K, the ubiquinones, plastoquinones, and tocopherols (such as vitamin E). 

FIGURE 9.25 Teichoic acids are covalently linked to the peptidoglycan of Grampositive bacteria. These polymers of (a, b) glycerol phosphate or (c) ribitol phosphate are linked by phosphodiester bonds. 

Figure 6.7 Formation of cross-linkage between individual peptide chains in the peptidoglycan layer of S. aureus.

Figure 10. Schematic view of the uptake of ferric siderophores by Gram-positive and Gram-negative bacteria. Please note that the murein (peptidoglycan) network associated with the cytoplasmic membrane is not shown. For details see text...

Figure 2.7. The outer membrane of Gram-negative bacteria. Abbreviations LB, LamB protein LP, lipoprotein O, OmpA protein MP, membrane protein. The peptidoglycan backbone consists of alternating residues of A-acetylglucosamine and /V-acetylmuramic acid, which are cross-linked via short peptides.

When grouped on the basis of similarities in their chemical structure, most antibiotics fall into the categories listed in Table 1.17. S-Lactams, which include penicillins and cephalosporins, exhibit a characteristic /i-lactam core ring structure (a four-atom cyclic amide) (Figure 1.14). They induce their bacteriocidal activity by inhibiting the synthesis of peptidoglycan, an essential component of the bacterial cell wall. 

UDP-GlcNAC enolpyruvyltransferase (MurZ) catalyzes the reaction between the phosphate of the enol pyruvate and the UDP-GlcNAC to form the corresponding enolpyruvate. This reaction is the first stage of the biosynthesis of the peptidoglycan of the bacterial wall. Phosphates of mono- and difluoroenolpyruvates are substrates of MurZ (Figure 7.30). The tetrahedral intermediates formed after incubation... 

Figure 2.23 Effect of different doses of whole peptidoglycan (WPG) from Bifidobacterium infantis on the growth rate of Meth A tumour. Mice were inoculated subcutaneously with a mixture of 105 Meth A cells and 0 ( ), 10 (A), 20 (A), 25 (O), 50 ( ) or 100(D) M of WPG. (Modified from Tamura et al., 1993.)...

Figure 8-29 (A) Repeating unit of structure of a bacterial peptidoglycan (murein). Some connecting bridges are pentaglycine (Staphylococcus aureus), trialanylthreonine (Micrococcus roseum), and polyserine (S. epidermis).

Figure 20-9 Biosynthesis of bacterial peptidoglycans. See Fig. 8-29 for details of the peptidoglycan structures. Green arrows show alternative route used by gram-positive bacteria.

---