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33 Cards in this Set

  • Front
  • Back
How is a biofilm synthesized?
Ceel-cell communication between bacteria using phermones causes synthesis of biofilms
What is the function of a biofilm?
Numerous bacteria live together in them protecting them from degradative detergents.
How are biofilms combated clinically?
Using drugs that block cell-cell communication

What are the three other names for a bacterial capsule?
1. mucoid layer
2. slime layer
3. glycocalyx
What is a bacterial capsule? What kind of bacteria require capsule?
A thick layer of polysaccharide not required for a non-pathogenic life style and is often produced only by virulent strains of bacteria.
What three things can capsule do that make them virulence factors?
1. protect bacteria from host defenses (ie phagocytosis, block drug entry)
2. attach to host tissue (VIP)
3. they can be harmful to the host on their own
Is the surface area of the capsule greater than that of the bacteria it surrounds?
Yes, significantly
Is a capsule required for life out the host?
Is the capsule porous or completely closed?
It is porous, letting nutrients in and out

In what 3 ways are bacterial flagella very important?
1. allows for swimming
2. it is polymorphic
3. it is also immunostimulatory
4. provides diagnostic info allowing us to look at patients bld, at bacterium, and see the appearance of the flaggellum to identify the kind of bacterium it is.

What is the main function of a pilli?
Mediate attachment between bacterium and host cell
Which is longer a flaggellum or a pilli?
Compare a pilli and a sex pillus:
Pilli: used for attachment
Sex pilli: used to transfer genetic information
How to pilli's and capsules interact with hosts?
Using adhesins bacteria can radically motify host cell to trick it into taking up the bacteria into its cell via the formation of a pedistal.
Who mediates the uptake a the bacterium when the host is in contact with the bacteriums pilli and capsule?
The HOST mediates the uptake of the bacterium
Do flaggellum mediate attachment?

How do pili confer virulence?
By attaching to the host
What are two types of bacteria cell envelopes?
Gram - and Gram +
What does a cell envelop consist of?
1. an innermembrane
2. cell wall (the pepidoglycan)
3. outer membrane (gram -)
What does an inner membrane contain and do? Does gram - or gram + have it?
An inner membrane consists of a lipid bilayer comprising phospholipids and proteins that are VIP since they sit on the membrane and allow for transport across it.

It is found in both gram - and gram +
What does a cell wall contain and do? Does gram (-) or gram (+) have it?
Cell wall contains peptidoglycan and is unique to bacteria. It contains sugar chains crosslinked together to give cell its shape.

Both gram - and gram + have a cell wall.
Describe four characteristics of a bacteria's cell wall:
1. antibiotics can act to disrupt cell wall biosynthesis resulting in cell lysis
2. peptidoglycan of some bacteria is toxic
3. gram + cell wall: thick with multiple layers of peptidoglycan and additional molecules called teichoic and lipoteichioc.
4. Gram - cell wall: Thin layer of peptidoglycan
What is the function of teichoic and lipoteichoic molecules found in the cell wall of gram + bacteria?
Teichoic acid - extend the surface of the peptidoglycan layer

Lipoteichioc- can bind to targets and activate killing mechanisms

Both are important molecules used to diagnose gram + bacteria.
In what cells, gram - or +, does a periplasmic space exist? What does it do?
Gram -:

It is the area between outer and inner membrane where enzymatic activity exists and where drugs are degraded
What is peptidoglycan an excellent target for?
What is the function and composition of the outer membrane? Does gram - or gram + have it?
It is unique to gram - bacteria.

Like the inner membrane it has a lipid layer but also has lipopolysaccharide (LPS) molecules instead of phospholipids. The outer membrane is a strong barrier to most molecules that might enter the cell.

What are the three major components of LPS?
1. a lipid portions - lipid A makes LPS highly toxic causing endotoxic shock
2. a polysaccaride portion
3. an O antigen polysaccharide side chain - major surface antigen of gram (-) providing an important antigenic marker. It is highly variable - allowing for serro typing.
The spread of plasmids, and thus virulence factors, is facilitated by the use of what?

Describe how multidrug resistance occurs?
1. a bacterium with a relatively impermeable outer membrane (selected for in hospitals) has a mutation of its cellular pumps (structure that spans the outer and inner membrane).
2. This mutation causes the small amount of drug able to get into cell to be rapidly pumped out using these cellular pumps.

Describe what spores do (in general) and what do they look like?
Spores are a dormant cell type formed by certain bacteria as a response to stress. They lack a peptidoglycan layer so they lack shape and can thus take on any shape. They are highly resistant, making disinfection very difficult.

Describe the mechanism of pore formation during starvation:
Under stressed conditions (ex. starvation)
1. cell divides in half
2. a small compartment of the cell gets pinched off to form an interior compartment that is dormant.
3. However, once there is food this interior compartment can germinate.
4. spores are then released into the environment

Describe the mechanism of pore formation during spoilage of food:
1. A spore can get into food and germinate
2. eat spoiled food - sporulation happens in your body
3. with every spore that is made a toxin is also made causing diarrhea
4. because of diarrhea spores are dispersed and linger in environment until they are picked up by host.
What are mycoplasmas? Why are these difficult to combat?
A nonstandard cell type, like spores, but are very simple - containing only an innermembrane that lacks peptidoglycan. This makes them unable to be targeted by antipeptidoglycan therapy (front-line therapy)