Staphylococcal capsule is made up of:
Ref: Ananthanarayan, Paniker CJ. Textbook of Microbiology. 6th Ed, London: John Wiley & Sons: 2000. & Prescott LM. Microbiology. 5th Ed. London: McGraw-Hill: 2002.Explanation:Capsules usually are composed of polysaccharides, but they may be constructed ot other materials.But, Bacillus anthracis has a capsule of poly-D- glutamic acid (polypeptide).Capsules and Slime LayersSome bacteria have a layer of material lying outside the cell wall.When the layer is well organized and not easily washed off. it is called a capsule.A slime layer is a zone of diffuse, unorganized material that is removed easily.Capsules and slime layers usually are composed of polysaccharides, but they may be constructed of other materials. For example. Bacillus anthracis has a capsule of poly-D-glutamic acid.Capsules are clearly visible in the light microscope when negative stains or special capsule stains are employedThey help bacteria resist phagocytosisCapsules contain a great deal of water and can protect bacteria against desiccationAlso aids bacterial attachmentGliding bacteria often produce slime, which presumably aids in their motilityS-LayersMany gram-positive and gram-negative bacteria have a regularly structured layer called an S-layer on their surface.The S-layer has a pattern something like floor tiles and is composed of protein or glycoproteinIn gram-negative bacteria the S-layer adheres directly to the outer membrane; it is associated with the peptidoglycan surface in gram-positive bacteria.It may protect the cell against ion and pH fluctuations, osmotic stress, enzymes.The S-layer also helps maintain the shape and envelope rigidity of at least some bacterial cells.It can promote cell adhesion to surfaces.The layer seems to protect some pathogens against complement attack and phagocytosis.
Hyaluronic acid
Polysaccharide
Polypeptide
Poly-D-glutamic acid
Staphylococci