Gram Positive Bacteria Cell Wall Characteristics

Characteristics

• Peptidoglycan (also known as murein) layer is thick (up to 50 layers)
• Teichoic acids and lipoteichoic acids are present in the cell wall
• Have a single membrane (monoderm)
• Stain purple with Gram stain due to the thick peptidoglycan layer

Cell Wall Structure

• Peptidoglycan layer:
  • Made up of repeating units of N-acetylglucosamine and N-acetylmuramic acid
  • Cross-linked by peptide chains
• Teichoic acids:
  • Polymers of glycerol or ribitol phosphate
  • Covalently linked to peptidoglycan
• Lipoteichoic acids:
  • Amphipathic molecules
  • Anchored to the membrane and extend into the peptidoglycan layer

Examples of Gram Positive Bacteria

• Firmicutes:
  • Bacillus (e.g. B. subtilis, B. anthracis)
  • Clostridium (e.g. C. difficile, C. perfringens)
  • Staphylococcus (e.g. S. aureus, S. epidermidis)
  • Streptococcus (e.g. S. pneumoniae, S. pyogenes)
• Actinobacteria:
  • Mycobacterium (e.g. M. tuberculosis)
  • Corynebacterium (e.g. C. diphtheriae)

Importance of Gram Positive Bacteria

• Some are pathogenic, causing diseases such as tuberculosis, pneumonia, and food poisoning
• Others are beneficial, used in food production (e.g. cheese, yogurt), biofuel production, and bioremediation
• Some produce antibiotics and other secondary metabolites

Characteristics of Gram Positive Bacteria

• Thick peptidoglycan (murein) layer, up to 50 layers
• Presence of teichoic acids and lipoteichoic acids in the cell wall
• Single membrane (monoderm)
• Stain purple with Gram stain due to thick peptidoglycan layer

Cell Wall Structure of Gram Positive Bacteria

• Peptidoglycan layer composed of repeating units of N-acetylglucosamine and N-acetylmuramic acid
• Peptidoglycan layer cross-linked by peptide chains
• Teichoic acids are polymers of glycerol or ribitol phosphate, covalently linked to peptidoglycan
• Lipoteichoic acids are amphipathic molecules, anchored to the membrane and extending into the peptidoglycan layer

Examples of Gram Positive Bacteria

• Firmicutes:
  • Bacillus (e.g. B. subtilis, B. anthracis)
  • Clostridium (e.g. C. difficile, C. perfringens)
  • Staphylococcus (e.g. S. aureus, S. epidermidis)
  • Streptococcus (e.g. S. pneumoniae, S. pyogenes)
• Actinobacteria:
  • Mycobacterium (e.g. M. tuberculosis)
  • Corynebacterium (e.g. C. diphtheriae)

Importance of Gram Positive Bacteria

• Some species are pathogenic, causing diseases such as tuberculosis, pneumonia, and food poisoning
• Others are beneficial, used in food production (e.g. cheese, yogurt), biofuel production, and bioremediation
• Some species produce antibiotics and other secondary metabolites