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What is the difference between capsule and slime layer?
Many bacterial cells secrete some extracellular material in the form of a capsule or a slime layer. A slime layer is loosely associated with the bacterium and can be easily washed off, whereas a capsule is attached tightly to the bacterium and has definite boundaries.
Why is a capsule advantages to a bacteria?
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. Capsules also contain water which protects the bacteria against desiccation.
How does a capsule help bacteria survive?
The capsule helps the bacteria to adhere to surfaces, camouflages the bacteria from the immune system by mimicking the host tissues, and makes the bacteria resistant to complement invasiveness. A capsule protects cells from desiccation and toxic metabolites in the environment (heavy metal ions and free radicals).
What are three benefits bacteria gain from having a capsule quizlet?
Capsules prevent phagocytosis so it is a virulence factor because it makes the virulence higher. Capsules make bacteria more adhesive, resists dehydration so sticks to things like catheters, and is free to multiply in tissues.
What type of infections are generally caused by bacteria that have a capsule?
Capsule (also known as K antigen) is a major virulence factor of bacteria, e.g. all of the principal pathogens which cause pneumonia and meningitis, including Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Klebsiella pneumoniae, Escherichia coli, and group B streptococci have polysaccharide …
What diseases does Streptococcus pneumoniae cause?
Streptococcus pneumoniae (pneumococcus) can cause a range of different illnesses including sinusitis, otitis media, pneumonia, bacteraemia, osteomyelitis, septic arthritis and meningitis.
What is the importance of the capsule in food industry?
Applications for this technique have increased in the food industry since the encapsulated materials can be protected from moisture, heat or other extreme conditions, thus enhancing their stability and maintaining viability. Encapsulation in foods is also utilized to mask odours or tastes.
Do all bacteria have a slime layer?
While slime layers and capsules are found most commonly in bacteria, while rare, these structures do exist in archaea as well.
What is a slime layer made of?
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 Glycocalyx and slime layer?
The glycocalyx exists in bacteria as either a capsule or a slime layer. Item 6 points at the glycocalyx. The difference between a capsule and a slime layer is that in a capsule polysaccharides are firmly attached to the cell wall, while in a slime layer, the glycoproteins are loosely attached to the cell wall.
Can bacteria survive without a capsule?
There are a number of bacteria that lack capsule. In the respiratory tract and oral cavity there are several species without capsular material on their surface. Examples are most Gram-negative Haemophilus influenza strains are unencapsulated (or non-typeable).
Do all bacteria have Glycocalyx?
All bacteria secrete some sort of glycocalyx, an outer viscous covering of fibers extending from the bacterium. An extensive, tightly bound glycocalyx adhering to the cell wall is called a capsule.
What is bacterial motility?
Gliding motility is the ability of certain rod-shaped bacteria to translocate on surfaces without the aid of external appendages such as flagella, cilia, or pili.
What does a bacteria require for motility?
Flagellin is a structural protein of the flagellum, a surface filament dedicated to bacterial motility. The flagellar filament is composed of as many as 20,000 subunits of flagellin. In pathogenic bacteria, flagella and chemotaxis machinery contribute to virulence.
What do some bacteria use for motility?
Motile bacteria either swim, by using flagella, or glide over surfaces by mechanisms that remain a mystery. Bacteria that glide can move towards or away from a variety of stimuli, including chemicals and light.
What is meant by darting motility?
Darting motility is a type of movement pattern in some gram negative bacteria. such as Vibrio cholerae and Campylobacter jejuni. As the word indicates, it is a quick movement without a visible change in. position of the subject.
Which shows darting motility?
The two most common examples of microbes showing this kind of motility are Vibrio cholerae and Campylobacter jejuni. Both of them possess special surface structures called flagella. Vibrio cholerae are gram-negative bacteria that have a single polar flagellum which is responsible for the bacteria’s motility.
What are the 2 most common types of motility in bacteria?
2 EIGHTEEN MOTILITY SYSTEMS
| Type | Name | Distribution |
|---|---|---|
| 1 | Bacterial flagella swimming Spirochetes swimming | Leptospira |
| 2 | Bacterial pili motility | Widespread in Bacteria |
| 3 | Myxococcus A motility | Class Gammaproteobacteria |
| 4 | Bacterial gliding | Phylum Bacteroidetes |
What is spirochete motility?
Spirochetes, which are members of a group of gram-negative bacteria with a spiral or flat-wave cell body, also show flagella-dependent motility, but their flagella are hidden within the periplasmic space and are thus called periplasmic flagella (PFs).
Can spirochetes swim?
Spirochetes have a unique structure, and as a result their motility is different from that of other bacteria. These organisms can swim in a highly viscous, gel-like medium, such as that found in connective tissue, that inhibits the motility of most other bacteria.
What is corkscrew motility?
Corkscrew motility (lashing, flexion extension motility) Spirochete. Alcaligenes are motile by peritrichous flagella. Campylobacters are small delicate, spirally curved, motile Gram-negative bacteria. They show characteristic rapid corkscrew-like motility.
How do spirochetes reproduce?
The flagella, in spirochaetes, runs lengthwise between the inner and outer membranes in the periplasmic space. During reproduction, the spirochaete is capable of undergoing asexual reproduction via binary fission. The binary fission allows for production of two separate spirochaetes.
How do spirochetes get their shape?
The axial filament is rotated by the rotation of the flagella, causing the spirochete to move with a twisting motion.
Which is the bacteria that have no flagella?
Coliform and Streptococci are examples of non-motile bacteria as are Klebsiella pneumoniae, and Yersinia pestis.
Where is flagella found?
Flagella are filamentous protein structures found in bacteria, archaea, and eukaryotes, though they are most commonly found in bacteria. They are typically used to propel a cell through liquid (i.e. bacteria and sperm).