Micro Exam 3a Flashcards
portals of entry
- mucous membranes
- skin
- parenteral route
adhesion
surface structure or macromolecule that binds a bacterium to specific surface
lectin
any protein that binds to a carbohydrate
ligand
surface molecule that exhibits specific binding to a receptor molecule on another surface
fimbriae
filamentous proteins on surface of bacterial cells that may behave as adhesions for specific adherence
glycocalyx
layer of fibers on the surface of bacterial cells which may be involved in adherence to surfaces
capsule
detectable layer of polysaccharide on surface of bacterial cell which may mediate specific or nonspecific attachment
lipopolysaccharide
distinct cell wall component of the outer membrane of gram-negative bacteria with potential structural diversity to mediate adherence
nonspecific adherence
reversible attachment of bacterium to eukaryotic surface
- hydrophobic interactions
- electrostatic interactions
- brownian movement
specific adherence
irreversible permanent attachment of microorganism to surface
- lock-and-key bonds
ID50
infectious dose for 50% of the test population
- skin: 10-50 endospores
- inhalation: 10000-20000 endospores
- ingestion: 250000-1000000 endospores
LD50
lethal dose of a toxin for 50% of test population
- botulinum: 0.03 ng/kg
- staphylococcal enterotoxin: 1350 ng/kg
capsule
- prevents phagocytosis
- components: M protein, Opa protein and mycolic acid
M protein
resists phagocytosis
Opa protein
inhibits T helper cells