The Cell wall Peptidoglycan G+ Bacteria G- Bacteria(10%) Gram PositivE Bacteri! Cell Wall Gram Negative Bacterial cell wall Lipoteichoic Acid Outer Lipid Membrane Peptidoglycan Cell Wall peptidoglycan Plasma Membrane Plasma Membrane Alternating copolymer o (1-4)-N-acetyl-D-glucosami and N-acetylmuramic acid L-Ala-D-GLU. Penta glycine cross-link L-Lys-D-Ala tetrapeptide
G+ Bacteria (~90%) G- Bacteria(~10%) Peptidoglycan The Cell Wall
The Cell wall Peptidoglycan Peptidoglycan Polymer (amino acids sugars) Unique to bacteria Sugars; NAG NAM(backbone) muram N-acetylglucosamine act N-acetyl lucosam N-acetylmuramic acid (The same in all bacterial species) 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
1上上1王 Pen cillin bi protein protein 2上⊥21夏 ●● Aame可 calycine Chsr o●● Alanine or D) 3 NAM 34 44卫 551非 13
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1 Penicillin Cell wall synthesis inhibitor in growth medium 2○ rupture late Bacterium 4 owww.scienceaidco,uk Spheroplast 5○ Sensitive to osmatic pressure
Sensitive to osmatic pressure 14
Beta lactam antibiotics Penicillin(over 50 compounds Share 4-sided ring(beta lactam ring) Natural penicillins Penicillin Mold Fungus Narrow range of action inactive against gram bacteria, no penetration of outer membrane Susceptible to penicillinase(beta lactamase) β- actam ring CH. S、/CH R-C-NH-CH+CH C Penicillinase R-C-NH-CH-HC C CH 11cH3 C-N CH- COOH O=C N—CH-cooH H OH Penicillin Penicilloic acid open theβ- actam ring of penicillins and cephalosporin 15
Beta lactam antibiotics • Penicillin (over 50 compounds) – Share 4-sided ring (beta lactam ring) • Natural penicillins - Narrow range of action, inactive against Grambacteria, no penetration of outer membrane - Susceptible to penicillinase (beta lactamase) open the β-lactam ring of penicillins and cephalosporin 15