Lab Test 1 Part 2
|what biological molecules can make up the bacterial capsule or slime layer||Capsules are composed of polysaccharides or proteins.|
- 1 What is the bacterial capsule made of?
- 2 What type of macromolecule makes up the bacteria capsule?
- 3 How are bacterial capsules formed?
- 4 Why the bacterial capsule is considered a virulence factor?
- 5 What is capsule microbiology?
- 6 What is a capsule give three possible functions of the capsule?
- 7 What type of macromolecule is bacteria?
- 8 What macromolecules make up the major part of bacterial cell wall?
- 9 What is Fimbriae microbiology?
- 10 How is capsule formation influenced by environmental conditions?
- 11 What are examples of encapsulated bacteria?
- 12 How does bacterial capsule prevent phagocytosis?
- 13 What is the function of the capsule formed by Bacillus?
- 14 What does capsule do in a bacterial cell?
- 15 How do capsules confer bacterial pathogenicity in bacteria?
What is the bacterial capsule made of?
The capsule is composed of polysaccharides that cover the cell wall, which is made up of peptidoglycan and teichoic acid, characterizing the classic gram positive structure; It acts as the principal antiphagocytic and protective element that prevents access of the leukocytes to the underlying cell wall elements.
What type of macromolecule makes up the bacteria capsule?
Most bacterial capsules are composed of polysaccharide, but some species use other materials, such as poly-D-glutamic acid in Bacillus anthracis.
How are bacterial capsules formed?
Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens.
Why the bacterial capsule is considered a virulence factor?
Capsules contain water which protects the bacteria against desiccation. They also exclude bacterial viruses and most hydrophobic toxic materials such as detergents and help the cells to adhere to surfaces. The capsule is considered a virulence factor because it enhances the ability of bacteria to cause disease.
What is capsule 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. The number of genes associated with capsule synthesis ranges from one in serotype 37 Streptococcus pneumoniae to >20 in serotype 38 S.
What is a capsule give three possible functions of the capsule?
– The capsule is a polysaccharide outer cover that some bacteria have. – It is used for attachment to the host cell. – Represents a determinant of pathogenicity. – It makes it hard for neutrophils to engulf it.
What type of macromolecule is bacteria?
The cell wall of gram-positive bacteria is a peptidoglycan macromolecule with attached accessory molecules such as teichoic acids, teichuronic acids, polyphosphates, or carbohydrates (302, 694).
What macromolecules make up the major part of bacterial cell wall?
Peptidoglycan is the major structural polymer in most bacterial cell walls and consists of glycan chains of repeating N -acetylglucosamine and N -acetylmuramic acid residues cross-linked via peptide side chains. Peptidoglycan hydrolases are produced by many bacteria, bacteriophages and eukaryotes.
What is Fimbriae microbiology?
Fimbriae are long filamentous polymeric protein structures located at the surface of bacterial cells. They enable the bacteria to bind to specific receptor structures and thereby to colonise specific surfaces.
How is capsule formation influenced by environmental conditions?
The size of the capsule is influenced by a variety of host and environmental factors that include host tissue location, CO 2 levels, serum, temperature, and the availability of nutrients such as iron and glucose 10, 12.
What are examples of encapsulated bacteria?
Examples of encapsulated bacteria
- Haemophilus influenzae type B (Hib)
- Streptococcus pneumoniae (pneumococcus)
- Neisseria meningitides (meningococcus)
- Group B streptococcus (GBS)
- Salmonella typhi.
How does bacterial 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 the function of the capsule formed by Bacillus?
The capsule of Bacillus anthracis, composed of poly-D-glutamic acid, serves as one of the principal virulence factors during anthrax infection. By virtue of its negative charge, the capsule is purported to inhibit host defence through inhibition of phagocytosis of the vegetative cells by macrophages.
What does capsule do in a bacterial cell?
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.
How do capsules confer bacterial pathogenicity in bacteria?
The capsule is the pathogen’s most important determinant of virulence because it allows the bacterial cells to escape phagocytes in the lung. anthracis capsule is composed of poly-D-glutamic acid. Its capsule is antiphagocytic, and it protects the bacteria from complement- mediated lysis in serum or blood.