Microbiology Procedure
Home Link to us Resources Site map Search Language

Index >> Staining Methods in Microbiology >> Cell Wall Stains

Back to Home

Cell Wall Stains

Cell Wall Stains
Cell wall is a rigid structure which gives definite shape to the cell, situated between the outer most slime or capsule and cytoplasmic membrane. It has got thickness in the range from 10-25 nm. It comprises of about 10-40% of dry weight of cell. It is involved in growth and cell division of bacteria, apart from giving protection to the cell. Cell wall of bacteria contains diaminopimelic acid (DAP), muramic acid and teichoic acid. These substances are joined together to give rise to a complex polymeric structure known as peptidoglycan
which provides rigidity to the cell.

The structure of part of the peptidoglycan of E. coli N­ acetylmUl1lmic acid (MurNAc)­, L-alanine (L-ala), D-alanine (D-ala), D-glutamate (D-glu), meso-diaminopimelic acid (m-dap) and N-acetylglucosamine (GlcNAc)

negative cells peptidoglycan constitutes much smaller fraction of total cell wall than in cell wall of Gram positive bacteria. Bacterial cell wall imparts antigenicity (O-antigen). It has also the recepter site for the specific phage.

The cell wall- has low affinity for stain and therefore, it is not stained with most of the staining procedures used to stain cytoplasm. In cell wall staining techniques mordant is applied, which increases the affinity of cell wall for stain. It also increases the apparent thickness of cell wall due to deposition of fine precipitates.
Back to Home
Home | Site map | Submit Article | Resources | Search
  Language >> English | Français | Español | Deutsch | Italiano | Portugues | Japanese | Korean | Sim-Chinese