Bacterial Capsule: structure, function and examples of Capsulated bacteria

The mucous layer is loosely attached to the cell wall and is lost during intense washing and subculture

In anthrax: A capsule consists of a polypeptide (D-glutamic acid polymer) and streptococci, which is an L-amino acid.

Prevent drying and drying of cells: capsular polysaccharides combine with large amounts of water to prevent cell dryness.

Accessories: Capsules help attach to the surface. For example. Streptococcus mutant strain carrying tooth is attached to the surface of the tooth through its film

Cell vesicles are a very large structure of prokaryotes such as bacterial cells. It is a layer of polysaccharide located outside the outer membrane of bacterial cells and is therefore considered part of the outer shell of bacterial cells. It is a well organized layer that is not easy to wash away, it may be the cause of various diseases. Capsules found in gram-negative and gram-positive bacteria should not be confused with the second lipid membrane (or bacterial outer membrane) containing lipopolysaccharide and lipoprotein, but only in Gram-negative bacteria. . If the amorphous viscous secretion (constituting the capsule) diffuses into the surrounding medium and retains loose secreted secretions, it is called the mucous layer.

Bacterial capsules are typically hydrated polysaccharide structures that cover the outer layer of the cell wall and in most bacteria it consists of monosaccharides joined together by glycosidic linkages. However, amino acid (peptide) and protein-carbohydrate capsules are also described. Capsules are believed to play a role in the pathogenicity and colonization of many pathogenic bacteria as they are exposed to the environment. Capsules help prevent bacterial dryness, prevent phagocytosis by host cells, or reduce complement-mediated lysis. Aeromonas sphaeroides are generally described as non-capsules, but the capsules have been identified in both A. and A. mobilis, the first of which is A. salmonicida when grown in glucose-rich medium in vitro . (Garrote, Bonet, Merino, Simonpujol, and Congregado, 1992) and Atlantic Salmon (Garduno and Kay, 1995). Garrote et al

It has been assigned to bacterial capsules of many different functions, including adhesion, transmission, resistance to congenital host defense, resistance to host adaptive immune response, and intracellular survival (Roberts, 1996). In some cases, the function of the bacterial capsule may be directly related to the chemical structure of the capsular polysaccharide. For example, adhesion between group A streptococci and pharyngeal cells is mediated by the interaction between hyaluronic acid capsules and CD44 (hyaluronan binding protein) (Cywes and Wessels, 2001). In the case of invasive pathogens it is important to be able to survive in native host defense. Although its mechanism is not always clear, it has long been known that the expression of polysaccharide capsules confer some resistance to complement-mediated killing (Roberts, 1996).