Capsule is the structure that acts like an invisible cloak and helps the bacteria from phagocytosis.
Characteristics of capsule:
The characteristics of capsule are as follows:
This capsule can be found either on gram positive or gram negative bacteria. Capsule is 0.2µm thick viscous layer. Capsule is present outside to the cell wall of bacteria. The capsule is different from the cell wall of bacteria. It is usually composed of polysaccharide but sometimes it is composed of glycoproteins. This capsule can’t be washed by using alcohol or other chemicals. This capsule can be stain separately to visualize the bacteria. This capsule can be loosely attach or tightly attach to the cell wall. Bacteria that have capsule outer to the cell wall is called as encapsulated bacteria. Composition of capsule:
The capsule composition is different from bacteria to bacteria. Capsule have 2% polysaccharide and 98% water. Mostly, capsule is composed of polysaccharide. Polysaccharides are the long chains of carbohydrate. Monomeric subunit is combined to form long chains of carbohydrate. The glycosidic linkages are responsible for the binding of different monomeric units. On hydrolysis, they give the monomeric components that constitute the polysaccharide unit.
Some bacterial capsule is composed of glycoproteins. Glycoproteins are the structure in which the amino acids of proteins are attached with the carbohydrate group. Carbohydrate groups attach with the chain of polypeptides by covalently bonding. These oligosaccharides attach with the peptide chains during translation and post-translation modification
some of the weak-acid component of the buffer will dissociate and turn into the conjugate base (which is the weak-base component of the buffer) thus replenishing most of the protons removed.
