Many cells and their outer barriers make up biofilms. Both capsules and slime layers have two primary functions: defense and adhesion.
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What is the function of the slime layer?
The slime layer is an easily removed, diffuse, unorganized layer of extracellular material which surrounds the bacterial cell. It is usually composed of polysaccharides and it may serve to trap nutrients, to aid in cell motility, to bind cells together or to adhere to smooth surfaces.
What is the difference between a capsule and a slime layer Why does the term glycocalyx usually encompass both?
Why does the term glycocalyx usually encompass both? Capsules are well organised layers, composed of polysaccharides, and present extending from the surface of the cell. … Slime layer is a zone of diffuse, unorganized, layer present encompassing the surface of the cell.
What is the function of slime capsule in bacteria?
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 possession of capsule makes some pathogenic bacteria resistant to phagocytosis.
What is the role of slime layer in eubacteria?
The function of the slime layer is to protect the bacteria cells from environmental dangers such as antibiotics and desiccation. The slime layer allows bacteria to adhere to smooth surfaces such as prosthetic implants and catheters, as well as other smooth surfaces like petri-dishes.
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 is capsule stain?
Capsule stain is a type of differential stain which uses acidic and basic dyes to stain background & bacterial cells respectively so that presence of capsule is easily visualized. Capsule is synthesized in the cytoplasm and secreted to the outside of the cell where it surrounds the bacterium.
What is the difference between a capsule and slime?
Slime layer is the extracellular layer that is loosely associated with the bacterial cell wall. It is a less discrete layer that can be easily washed off. Capsule is attached tightly to the cell wall, and it is a thick discrete layer.
Why is a capsule advantages to a bacterium?
A durable and dense mucilage covering is the capsule. It gives bacteria protection against the immune system of the host. … This protects a bacterial cell from white blood cell absorption and destruction (phagocytosis) and allows it to hide from the host immune system.
What is the difference between capsule and glycocalyx?
The key difference between capsule and glycocalyx is that capsule is an organized, well defined, condensed extracellular layer that is tightly bound to the cell envelope of bacteria, while glycocalyx is an additional layer composed of polysaccharides and/or polypeptides outside the cell wall of bacteria.
What are two functions of the capsule or slime layer in bacterial cells?
Biofilms are composed of many cells and their outer barriers. The primary functions of both capsules and slime layers are for protection and adhesion.
How do capsules and slime layers differ quizlet?
A capsule is closely associated with cells and does not wash off easily, while a slime layer is more diffuse and easily washed off. … An extraordinary resistance cell produce by some types of bacteria.
Is slime layer a virulence factor?
Capsule or slime layer is used to describe glycocalyx which is a thin, high molecular weight secretory substance present in many bacteria external to cell wall (Fig. … The capsule is considered a virulence factor because it enhances the ability of bacteria to cause disease.
Are S layers and slime layers the same?
The difference is that the S-layer is more organized. The slime layer is a mixture of various chemicals, including glycoproteins and glycolipids.
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.
Where are capsules found?
Capsule is located immediately exterior to the murein (peptidoglycan) layer of gram-positive bacteria and the outer membrane (Lipopolysaccharide layer) of gram-negative bacteria. In electron microscopy, capsule appears like a mesh or network of fine strands.
How does a 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 cell capsule?
The bacterial capsule is a layer of material, usually polysaccharide, attached to the cell wall possibly via covalent attachments to either phospholipid or lipid-A molecules. … It protects the cell from different environmental dangers such as phagocytosis, dessication, etc.
What is biofilm formation?
Biofilm formation is a process whereby microorganisms irreversibly attach to and grow on a surface and produce extracellular polymers that facilitate attachment and matrix formation, resulting in an alteration in the phenotype of the organisms with respect to growth rate and gene transcription.
What is meant by biofilm?
Biofilms are glycocalyx-containing materials secreted by individual microorganisms in which are encased communities of these microorganisms. Biofilms allow these microorganisms to adhere to a solid surface and be enveloped within a protective extracellular glycocalyx-containing matrix.
How is capsule staining done?
Procedure of Capsule Stain Prepare thin smears of bacterial culture on a microscope slide. Allow the smear to only air-dry. … Apply 1% crystal violet and allow it to remain on the slide for 2 minutes. With the slide over the proper waste container provided, gently wash off the crystal violet with 20% copper sulfate.
How are 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.
What type of staining is used for capsules and why?
The capsule stain employs an acidic stain and a basic stain to detect capsule production. Capsules are formed by organisms such as Klebsiella pneumoniae . Most capsules are composed of polysaccharides, but some are composed of polypeptides.
What is a 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 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 is the advantage of a capsule to bacterial survival quizlet?
Capsules may protect pathogenic bacteria from phagocytosis by macrophages. Bacteria may run or tumble depending on the rotation of their flagella.
Why was it not necessary to heat fix the smear for the capsule stain?
Capsular material is very moist (slimy) and any heating will cause it to shrink – it is for this reason that we will not heat fix the slide before staining.
What is the term Glycocalyx used for?
The glycocalyx is a type of identifier that the body uses to distinguish between its own healthy cells and transplanted tissues, diseased cells, or invading organisms.