The gram-negative cell wall PM Cell The gram-positive cell wall OM wall M Outer membrane PM Peptidoglycan Peptidoglyc Plasma membrane Plasma membrane enplasmIc Cell wall space Source: Brooks GF, Carroll KC, Butel JS, Morse SA, Mietzner TA: Jawetz, Melnick, Adeiberg's MedicalMicrobiology26thEdition:www.accessmedicine.com Copyright O The McGraw-Hill Companies, Inc. All rights reserved Chapter 2 p. 24
Chapter 2 p. 24 11
The Cell wall Gram Flagellum Cell membrane Nucleoid Cell wall 厂■□■ peptidoglycan Gram Pili Granule Capsule Cell (inner) membrane Outer membrane Ribosomes Cell wall -peptidoglycan 12
Gram - Gram + Cell wall -peptidoglycan Cell membrane Nucleoid Flagellum Cell (inner) membrane Outer membrane Ribosomes Granule Cell wall -peptidoglycan Capsule Pili The Cell Wall 12
The Cell wall Peptidoglycan G+ Bacteria (-90%) G- Bacteria(-10%) Gram Positive bacterial Cell Wall Gram Negative Bacterial Cell Wall Lipoteichoic Acid Outer Lipid Membran Peptidoglycan Cell Wall Peptidoglycan Plasma Membrane Plasma Membrane Alternating copolymer of 1-4)-N-acetyl-D-glucosamin and N-acetylmuramic acid Ala.D-GLI Pentaglycine cross-link L-LyS-D-Ala tetrapeptide
G+ Bacteria (~90%) G- Bacteria(~10%) Peptidoglycan The Cell Wall
The Cell wall Peptidoglycan Staphylococcus aureus peptidoglycan D-nlutame Dante D More than 40 sheets in Gram positive bacteria E coli peptidoglycan Only 1-2 sheets n Gram negative bacteria
Peptidoglycan More than 40 sheets in Gram positive bacteria Only 1-2 sheets In Gram negative bacteria The Cell Wall
The Cell wall Peptidoglycan Peptidoglycan Polymer (amino acids sugars) Unique to bacteria Sugars; NAG NAM(backbone) -ac uram N-acetylglucosamine N-acetyl- lucosamin N-acetylmuramic acid (The same in all bacterial species) G Basic structural unit of peptidoglycan Tetrapeptide(vary from species) -D form of Amino acids(not L form) Hard to break down d form Pentapeptide(vary from species) Amino acids cross link nag NAM
• Peptidoglycan Polymer (amino acids + sugars) • Unique to bacteria • Sugars; NAG & NAM (backbone) – N-acetylglucosamine – N-acetylmuramic acid (The same in all bacterial species) • Tetrapeptide (vary from species) -D form of Amino acids (not L form) Hard to break down D form • Pentapeptide (vary from species) -Amino acids cross link NAG & NAM Peptidoglycan The Cell Wall