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How does capsule protect the bacteria?
Capsules can protect a bacterial cell from ingestion and destruction by white blood cells (phagocytosis). While the exact mechanism for escaping phagocytosis is unclear, it may occur because capsules make bacterial surface components more slippery, helping the bacterium to escape engulfment by phagocytic cells.
What is the function of capsule in the bacteria?
Function. The capsule is considered a virulence factor because it enhances the ability of bacteria to cause disease (e.g. prevents phagocytosis). The capsule can protect cells from engulfment by eukaryotic cells, such as macrophages. A capsule-specific antibody may be required for phagocytosis to occur.
What type of staining is used for capsules?
Bacterial capsules are non-ionic, so neither acidic nor basic stains will adhere to their surfaces. Therefore, the best way to visualize them is to stain the background using an acidic stain and to stain the cell itself using a basic stain. We use India ink and Gram crystal violet.
What is the purpose of a capsule stain quizlet?
It is used to spread bacteria and India ink across the slide, forming a thin smear. Capsule staining requires several passes through the Bunsen burner to dry the smear. the background of the slide. the background of the slide.
How does capsule prevent phagocytosis?
Capsules can resist unenhanced attachment by by preventing pathogen-associated molecular patterns or from binding to endocytic pattern-recognition receptors on the surface of the phagocytes. The capsules of some bacteria interfere with the body’s complement pathway defenses.
What is capsule in microbiology?
Capsules are the outmost structures of bacterial and fungal cells. The capsules protect microbial cells from immune recognition and killing during infection of mammalian hosts. Except for the poly-γ-glutamate (PGA) capsule of Bacillus anthracis, other known capsules are all composed of polysaccharides.
What is the importance of the capsule in pathology?
Capsules have a significant role in determining access of certain molecules to the cell membrane, mediating adherence to surfaces, and increasing tolerance of desiccation. Furthermore, capsules of many pathogenic bacteria impair phagocytosis (22, 29, 30) and reduce the action of complement-mediated killing (7, 31, 35).
What are two things that are stained in a capsule stain?
Capsule stain is a type of differential stain which involves the use of two stains; primary stain and the counterstain.
What is a capsule microbiology?
What is the procedure for the capsule stain described in the staining lab?
The capsule stain employs an acidic stain and a basic stain to detect capsule production….Procedure of Capsule Staining
- Place a small drop of a negative stain (India Ink, Congo Red, Nigrosin, or Eosin) on the slide.
- Using sterile technique, add a loopful of bacterial culture to slide, smearing it in the dye.
Which reagent is responsible for staining the cell in the capsule staining technique?
The acetic acid lowers the pH in the sample and causes the Congo red to change from a red color to blue. The acid fuchsin (a basic dye) interacts with the bacterial cell, staining the cell bright red. The acetic acid serves as a mordant to stabilize the capsule structure.
What is the function of capsule in prokaryotic cell?
The capsule helps prokaryotes cling to each other and to various surfaces in their environment, and also helps prevent the cell from drying out. In the case of disease-causing prokaryotes that have colonized the body of a host organism, the capsule or slime layer may also protect against the host’s immune system.