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Where are mucosal surfaces washed by fluids?
-in the mouth, small intestine, and bladder.
Many pathogens have mechanisms of attaching themselves to host ______________.
Specific receptors infect _______ parts of the body.
human strains of a particular bacterial species may NOT adhere to __________ cells of an animal and vice versa.
What is required to get to any structure in the first place?
What are specialized structures that provide motility?
- -Fimbriae / Pilli also involved in motility
What is chemotaxis?
-directed movement of an organism toward (+) or away from (-) a chemical gradient.
Flagellum have the same basic structure between _____________ & __________.
Bacteria & Archaea
flagellum all around the flagella
one flagellum at one end
several flagellums at one end
How do peritrichously and lophotrichous flagellated organisms move?
move in a slow, straight line
some bacteria can move at ___ cell lengths/sec.
(cheetah - 25 lengths/sec)
polar flagellated organisms move in a .....
rapid, spinning motion
How many genes are involved in movement of flagellas?
What genes are involved in movement of flagellas?
regulation genes (synthesis and control)
structural proteins (makeup the flagella itself)
chaperone proteins (mediate export of flagella proteins thru cytoplasmic membrane to outside of cell to construct flagellum itself)
What are regulation genes?
for synthesis and control
Structural proteins are...
- proteins that help movement of flagella.
- These proteins make up the flagella itself.
Chaperones proteins mediate...
export of flagella proteins thru cytoplasmic membrane to outside of cell to construct the flagellum itself.
Flagella consists of several components:
base & filament
Several "rings" make the ____ body. (Gram (-))
an outer L in LPS, P in peptidoglycan, MS and C rings are located in Cytoplasmic Membrane and Cytoplasm.
What does the flagella lack?
-lack outer membrane so no outer L ring. (Gram(+))
What is located at the base that rotates the flagella that is anchored in the cytoplasmic membrane and cell wall?
What acts as motors that switch (reverse) mechanisms that are anchored in the cytoplasmic membrane?
Mot and Fli
Motion from the basal body uses ____________ Force.
Proton Motive Force; protons across cytoplasmic membrane thru Mot complex (1000-1200 ions per revolution)
Smooth "runs" means....
cell stops and jigs about, changes direction then "runs" in a new direction
in a gradient, fewer '______' and more 'runs' and bacteria moves attractant or way from a repellant.
Anticlockwise = _____________
clockwise = ____________________
bundle of flagella pushes apart
forward motion cease and cells _________.
How do polar flagellated cells move?
reverse direction of rotation results in backwards motion
what are chemoreceptors?
sensory proteins in the cytoplasmic membrane sense the chemical gradients.
Surface structures involved in
- Slime Layers
- Specialized Proteins
What do Fimbriae and Pili have in common?
rod shaped protein structures
What are the differences of Fimbriae and Pili?
-differ in thickness and length (often on Gram (-) organisms)
Fimbriae tends to be used for shorter, thinner structures
Pili used for longer thicker structures.
Pili are used for....
longer thicker structures
Fimbriae tends to be used for....
shorter, thinner structures
How is a cylindrical structure formed?
-an orderly array of single subunits aka pilin packed in a helical way
How does the pili make contact ? (2-step progress)
retract and "pull" bacterial close to host cell where adhesins take over and pili depolymerize.
Signal Transduction of pili envokes what?
attachment of pili envokes a whole range of "gene switching" of virulence genes .
what are ushers ?
add'l proteins that interact with chaperones and guide the subunits (pili) to cell surface.
What is the chaperone-usher system?
-present in periplasm, prevent pilus from folding into their final configuration until ready to be extruded from outer membrane
What signals the end of the extrusion process?
-a periplasmic protein (H)
Assembly of pili is undertaken in what space?
What are the functions of Fimbriae / pili ?
twitching motility. Rapid extension/retraction enables cell to "Crawl" along surface.
key colonization factor in Neisseria menigitidis (bacterial meningitis) and Vibrio cholerae (cholera)
avoid host defenses. Pili break easily and when bound by host antibodies can break away (E,F and G proteins). Once body recognizes pili another type of pili w/ diff tip is produced by bacteria.
What is twitching motility?
rapid extension/retraction enables cell to "crawl" along surface.
What are key colonization factors?
Neisseria meningitidis (bacterial mengiditis)
Vibrio cholerae (cholera)
How does the function that avoid host defenses work?
Pili break easily and when bound by host antibodies can break away (E,F and G proteins). Once the body recognizes the pili another type of pili with a different tip is produced by the bacteria.
List of Pili (Fimbriae) of Gram + bacteria
- Strep. salvivarius
- Strep. gordonii
- Strep. oralis
- Actinomyces naeslundii
- Strep. parasanguis
Strep. salvivarius, Strep. gordonii, Step. oralis, Corynebacterium, Actinomyces naeslundii and Strep. parasanguis are lists of .... ?
pili (fimbriae) that are oral strains able to adhere to form biofilms.
-covalent attachment of subunits to each other and to peptidoglycan cell wall.
Strep. salvivarius, Strep. gordonii, Step. oralis, Corynebacterium, Actinomyces naeslundii and Strep. parasanguis morphology...
Many prokaryotes secrete a loose, unstructured network of polysaccharide / protein-carbohydrate that may be .... ?
rigid (capsule) or flexible (slime), thick or thin
What are biofilms important for?
important in pre-infection and establishing colonization/disease.
examples: Pseudomonas aeruginosa in Cystic Fibrosis
Legionella pneumophilia in Legionnaire's disease
Streptococcus, Bacteroides, Fusobacterium in Dental Plaque (endocarditis)
S. epidermidis, Enterococcus faecalis, E. coli, Proteus mirabilis, P. aeruginosa, K. pneumoniae -medical catheters
What are biofilms?
-matrices of organisms where gradients of nutrients exist.
Most Frequent Entry Portals
and many others...
What are preferred portals?
specific places for microbes to cause disease
ex: Vibrio cholera infects the GI tract therefore, rubbing an infected oyster on a wound of the skin will not cause cholera.
Tick, mouse, deer interactions -Borrelia burgdoferi -Lyme Disease is an example of ?
penetration of skin or epithelial layer
microorganisms are deposited into tissues below skin mucous membranes.....
splitting of skin due to swelling or dryness.
What happens first for infections?
enter the body:
-penetration of skin
-penetration of epithelial and mucin layers
What are Rickettsial Diseases ?
small bacteria, strictly obligate intracellular in vertebrates and have life-cycle associated with fleas, lice or ticks.
Rickettsia prowazekii causes ... ?
Bite of louse punctures skin, makes a trough, blood pools (pool feeding) and bacterium enters from louse fecal matter, which is aided by what?
In Neisseria gonorrhoeae (STD), how does it attach to urogenital epithelia more tightly than other tissues?
via a protein Opa (opacity associated protein) that binds specifically to the protein CD66 (only found in human epi. cells)
What is mucin?
network of protein and polysaccharide
What does mucin do?
- prevent bacteria reaching mucosal cells
- GI and vaginal tracts act as lubricants - Goblet cells
- respiratory tract - ciliated cells expel bacteria caught in mucin
Some bacteria can actively __________ mucin as a nutrient.