Flashcards in Pathogens Host Defenses Deck (103)
What does the release of the extracellular enzyme leucocidin target & cause the lysis of?
Leucocytes (white blood cells) produced by staphylococci, streptococci, and some gram neg bacteria
What are leucocytes?
White blood cells
What do the extracellular proteins, Proteases, do once they are released?
The degrade complement proteins and/or antibodies
What produces the extracellular enzyme coagulase?
What do coagulase enzymes cause? What does this do?
insoluble fibrin to be deposited on bacterial cells. This blocks the bacteria from the immune system
What are invasins?
Surface proteins, or injected proteins, that allow microorganisms to enter cells (invade host cells)
What is one major virulence factor of intracellular pathogens?
How does the invasion of host cells benefit bacterial pathogens?
It protects them against the host immune system and is a good source of nutrients
What are 4 examples of pathogens that have invasins?
Mycobacterium, Salmonella, Listeria, Chlamydia
In what 4 ways do pathogens modify the properties and behaviors of host cells in order for them to grow inside of host cells?
1. block phagosome maturation (block digestion)
2. Increase size of vacuole
3. Acquire nutrients
4. Block detection of intracellular infection and response (host defense)
What is a phagosome?
a vacuole in the cytoplasm of a cell, containing a phagocytosed particle enclosed within a part of the cell membrane.
What two type of secretion systems do a lot of gram-negative pathogens use?
Type 3 (T3SS) and Type 4 (T4SS)
What does a T3SS do?
It forms a channel through the bacterial cytoplasmic membrean + periplasm + outer membrane + host cell membrane so bacterial proteins can be injected into the host cell cytosol
What are the 3 functions of T3SS?
1. Invasion of host cells
2. Block phagosome maturation
3. Take control of host cells
How is T4SS different from T3SS?
T4SS does not have a needle-like structure
What are T3SS and T4SS's also called?
What are toxins?
Extracellular enzymes that cause damage
Is toxin production always necessary for an organism to be highly virulent? What else can be the cause of damage to an organism?
No. Damage can be caused by the host's own immune system or be a result of the large # or pathogens present
What are the 2 categories of diseases that bacterial pathogens are associated with?
1. Infectious diseases
What do infectious disease result from?
The pathogen's growth
What do intoxication's result from?
The presence of a specific toxin
What are 3 examples of infectious diseases?
What is an examples of an intoxication?
What 2 categories are toxins divided into?
Exotoxins & endotoxins
What is an exotoxin?
A toxin secreted into the surroundings as the bacterial pathogen grows
What is an endotoxin?
A toxin that is part of the bacterial pathogen
Are exotoxins soluble or insoluble?
When are exotoxins secteted/released?
When the organism is lysed
What macromolecule are exotoxins normally?