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Bacterial cell envelope and antibiotics efficacy
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The Cell Membrane selective permeability and transport of solutes
electron transport and oxidative phosphorylation in aerobic species excretion of hydrolytic exoenzymes bearing the enzymes and carrier molecules that function in the biosynthesis of DNA, cell wall polymers, and membrane lipids bearing the receptors and other proteins of the chemotactic and other sensory transduction systems
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Permeability and transport
transports Active transport Ion-coupled transport uniport symport antiport ABC transport Passive transport Simple diffusion Facilitated diffusion Channel proteins Group translocation Vectorial metabolism Special transport processes Fe transport
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Group translocation
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Excretion of hydrolytic exoenzymes and pathogenicity proteins
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Excretion of hydrolytic exoenzymes and pathogenicity proteins
Excretion protein Type l α-hemolysin E coli adenylyl cyclase Bordetella pertussis Type ll Elastase phospholipase C Pseudomonas aeruginosa exotoxin A Type lll Type lV protein–DNA complexes Agrobacterium tumefaciens pertussis toxin B pertussis interleukin-8–inducing factor H pylori Type V IgA protease Neisseria gonorrhoeae vacuolating cytotoxin Helicobacter pylori
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Special Components of Gram-Negative and Gram- positive Cell Walls
1. Outer membrane 2. Lipopolysaccharide (LPS) 3.Lipoprotein 4.The periplasmic space Gram-positive: 1.Teichoic acid 2.Lipoteichoic acid 3.Teichoronic acid
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Special Components of Gram-Positive Cell Walls
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Special Components of Gram-Negative Cell Walls
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The Peptidoglycan Layer
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Biosynthetic functions : Synthesis of Cell Wall Peptidoglycan
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D-Ala-D-Ala synthesis
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INHIBITION OF CELL WALL SYNTHESIS
antibiotics β-lactam drugs penicillin's cephalosporin's monobactams carpabenem glycopeptide Vancomycin other Cycloserine
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The mimicry of beta-lactam antibiotics to acyl-D-alanyl-D-alanine (D-Ala-D-Ala)
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Mechanism of action β-lactam
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The model of beta-lactamase induction in Gram-negative bacteria
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Beta-lactamase
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vancomycin
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cycloserine is an amino acid derivative with an unusual structure
As a cyclic analogue of D- alanine, cycloserine acts against two crucial enzymes important in the cytosolic stages of peptidoglycan synthesis: alanine racemase (Alr) and D-alanine:D- alanine ligase (Ddl)
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Bacitracin
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Lysozyme
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INHIBITION/ALTERATION OF CELL MEMBRANE FUNCTION
Polymyxins detergent-like Daptomycin permit rapid diffusion of specific cations through the membrane Novobiocin specifically interfere with biosynthetic functions of the cytoplasmic membranes
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Polymyxins
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Daptomycin
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Antimicrobial peptides
are part of the innate immune response found among all classes of life These peptides are potent, broad spectrum antibiotics Are cationic and bind to acidic bacterial membrane
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AMPs mechanism of action
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