L26 - High Yield

______: Thin, hollow, helical rods used for motility; governed by chemotactic responses 

Flagella

3 components of the flagella?

Basal body, hook, and filament

• ________ - Small central rod spanning entire cell wall; spins (motor) flagellum

• Basal Body

______ connects the rotary motor (basal body) to the whip-like propeller (filament

Hook

_____ Protein filaments; extend like long tails from cell membranes

Filament

Species of bacteria can be identified by use of specific antibodies against ______ proteins

flagellar

Virulence Factor = ?

Motility of bacteria allows for spread of infection

________: Single flagellum

• Monotrichous

• ________: Two flagellum

• Amphitrichous

• _________: Two or more flagella at one or both ends

• Lophotrichous

• _________: Flagella all over the surface

• Peritrichous

What type of flagella is this?

Monotrichous

What type of flagella is this?

Amphitrichous and Lophotrichus

What type of flagella is this?

Amphitrichous and Lophotrichus

What type of flagella is this?

Peritrichous

how does flagella impact virulence factor?

Motility of bacteria allows for spread of infection

Pseudomonas aeruginosa would be an example of what type of flagella?

Monotrichous

Spirillum voltans would be an example of what type of flagella

Amphi and Lophtrichus

Proteus vulgaris would be an example of what flagella type?

Peritrichous flagella

_____: Short, filamentous non-motile protein 

Pili

types of pili?

 

• Attachment Pili: Adheres to surfaces

• Conjugation (Sex) Pili

how does pili act as a virulence factor

Serves as an adherence factor (adhesins)

Neisseria gonorrhoeae (bind to cervical & buccal cells), E. coli and Campylobacter jejuni (bind to intestinal epithelium)

This would be an example of?

Pili

_______: Polysaccharides; form loosely assoc. outer layer attached to cell wall

Capsule

_______: Formed due to depletion of essential nutrients, can lie dormant for years

Endospores

how do endospores serve as a virulence factor?

Activated then exposed to favorable nutrient environment

Bacillus would be an example of? (bacterial structure/adaptation)

Is it aerobic or anaerobic?

Endospore - Aerobic

Clostridium would be an example of?

Is it aerobic or anaerobic?

endospore - Anaerobic

__________: Organisms that survive in immune cells unharmed

Facultative Intracellular Organisms

what is the virulence factor of Facultative Intracellular Organisms?

inhibits phagosome-lysosome fusion

escapes deadly H₂O₂ and superoxide radicals

pathway of endospore formation (6 steps)

• Spore septum forms, isolating replicated DNA and some cytoplasm.

• Plasma membrane surrounds the isolated DNA and cytoplasm.

• Spore septum encloses the isolated portion, forming a forespore.

• Peptidoglycan layer forms between the two membranes.

• Spore coat forms.

• Endospore is released from the cell.

________: Proteins that are released by both gram positive and gram negative bacteria. 

• Released by all major gram _____ bacteria 

• Some gram _____ bacteria (e.g. Vibrio cholerae, E. coli) can secrete exotoxins

Exotoxins

• positive

• negative

• ______: Act on nerves or motor end plates to cause paralysis

• Neurotoxins

• ______: Act on GI tract to cause diarrhea

• Enterotoxins

________: Stimulates release of cytokines causing rash, fever, and toxic shock syndrome

• Pyrogenic Exotoxins

• _________: Bacteria destroys and tunnels through tissues

• Tissue Invasive Exotoxins

• _________: Disease unique to individual bacteria

• Miscellaneous Exotoxins

Botulism would be an example of what type of exotoxin?

Neurotoxin

Tetanus would be an example of what type of toxin?

Neurotoxin

Symptoms and cuases of botulism?

Sym: lethal, rapidly fatal food poisoning

Cause: Spores in canned food not cooked through then placed in anaerobic conditions

mechanism of botulism?

Spores germate → bacteria release exotoxin that block Ach in nerve → flacid muscle paralysis

Sym and cause of tetanus?

Sym: lockjaw

Cause: Spores in soil enter skin through trauma

Mechanism of tetanus?

Toxin causes sustained contraction of skeletal muscle

Cholera would be an example of? (what type of toxin)

what does it cause?

Enterotoxins - causes infection Diarrhea

Bacillus cerus would be an example of? (what type of toxin is it?)

Enterotoxins

Staph. aureus would be an example of? (what type of toxin is it?)

Enterotoxins

what do Bascillus cerus and staph. aureus cause?

food poisening

What is a type I toxin?

Toxin binds to receptors on target host cells, but is not internalized within the cell

TSST-1 of Staph. Aureus would be an example of?

Type I toxin

How do superantigen exotoxins (Like Type 1 toxin - TSST-1 of Staph. Aureus) cause toxic shock? pathway

• Bind to the high affinity T cell receptor–MHC Class II antigen complex.

• Stimulate an enhanced T lymphocyte response.

• Activate T cells, causing massive cytokine release (via IL-2, TNF, and IFN).

• Excess cytokines can lead to toxic shock.

What is a type II toxin?

Toxins that mechanically destabilizes the integrity of host cell plasma membranes.

Phospholipases would be an example of what type of toxin?

type 2

How do Type II toxins damage host cells? pathway

• Phospholipases or pore-forming cytotoxins disrupt host cell membranes.

• Damaged host cells release damage-associated molecular patterns (DAMPs).

• DAMPs bind to pattern-recognition receptors (PRRs), triggering inflammatory cytokine release.

• Inflammatory cytokines can cause further tissue damage.

(disruption → dAMP released → PRR binding → inflammatory cytokines released)

What are type III toxins?

Toxins that binds to the surface of target host cells and a portion becomes internalized within the cell.

Cholera toxin would be an example of?

Type 3 (A-B) toxins

Q: How does cholera toxin cause active secretion of ions and water as a type III (A-B) toxin?

• Cholera toxin binds to the GM1 ganglioside receptor on membrane.

• A subunit enters the cell and activates the Gs protein, which activates adenylate cyclase.

• Adenylate cyclase increases cAMP production.

• Elevated cAMP causes active secretion of ions and water.

(binding to GM1 + integration → Gs activation → aden cyclase activation → cAMP production → releases ions + water)

___________ (endotoxin) is a very toxic toxin released when bacteria undergoes lysis.

it is usually only present in gram (negative or positive) bacteria

Lipid A endotoxin - gram negative

Lipid A can be ____ from living bacteria in steady amounts

How is this endotoxin different than exotoxins?

shed

its not a protein that is excreted from cells

_________: Deadly response to both gram positive and gram negative bacteria

Septic Shock

WHat is the localized site of infection in septic shock called?

Bacteremia

Q: What is the mechanism of septic shock?

• Organisms release toxins into the bloodstream, stimulating immune cells.

• TNF triggers IL-1 release, leading to cytokine and prostaglandin production.

• The immune system, initially defending against microbes, begins damaging the body's organs.

• Organ damage contributes to septic shock.

how to treat septic shock?

• Broad spectrum antibiotics

• Fluids, drugs, and oxygenation to support B/P

• Recombinant activated Protein C - modest reduction in multi-organ failure and mortality

• Hydrocortisone - increases blood pressure & increases survival

• Polyclonal IVIG - reduced mortality among adults with sepsis

would monoclonal Ab, TNF, IL-1, or anti-inflammatory agents be successeful at blocking the inflammatory cascade in septic shock?

no

Antibodies bound to bacterial capsule (______) enable macrophages or neutrophils to bind to the FC portion of the antibody and phagocytize the bacteria.

opsonization

______ bound to bacterial capsule (opsonization) enable _______ or ______ to bind to the FC portion of the antibody and phagocytize the bacteria.

Antibodies; macrophages or neutrophils

Antibodies bound to bacterial capsule (opsonization) enable macrophages or neutrophils to bind to the ______ of the antibody and _______ the bacteria.

FC portion; phagocytize

______ – structural component (LPS) of gram-negative bacteria.

Endotoxins

Endotoxins are not actively secreted by ______.

Endotoxins are lipopolysaccharides (LPS) and cause ______ sepsis.

bacteria (they are located on the outer membrane of gram negative LPS and “shed”)

Gram- negative

Endotoxins are are seen in gram ___

negative

septic shock is a Deadly response to both _____ and ______

bacteria.

gram +ive; gram –ive

in septic shock, organisms release toxins (_______) that circulate in the bloodstream and stimulate _______ via ____ from TNF

endo/exotoxins; immune cells via IL-1

Endogenous mediators of sepsis?

TNF

what does TNF do in septic shock?

triggers the release of IL-1 from macrophages and

endothelial cells triggering the release of other cytokines

and prostaglandins.

Monotrichous, amphitrichous, lophitrichous, or peritrichous?

Pseudomonas

monotrichous - single flagellum

Monotrichous, amphitrichous, lophitrichous, or peritrichous?

Spirillum

amphitrichous - two flagella and lophotrichous - two or more flagella

Monotrichous, amphitrichous, lophitrichous, or peritrichous?

Salmonella

peritrichous - flagella all over the surface

Monotrichous, amphitrichous, lophitrichous, or peritrichous?

Proteus

peritrichous - flagella all over the surface

A gram-negative bacteria is able to mechanistically destabilize the integrity of a host cell membrane. What type of toxin is this?

Type II toxins

Can both Gram + and - do septic shock

yes

which bacteria (aerobic) gram pos can form endospores?

bacillus

which anaerobic bacteria (gram pos) can form endospores?

Clostridium

what is able to bind to prosthetic devices like IV catheters and form a mechanincal scaffold?

Which bacteria would you expect to do this in the hospital?

biofilms

Staphylococcus epidermidis.

which bacteria would you expect to Inhibit phagosome-lysosome fusion and escape host’s deadly H₂O₂ and superoxide radicals (facultative)

Listeria and Salmonella

which bacteria would you expect to secrete exotoxins

cholerae and e.coli

_____ are not actively secreted by bacteria

these are structural components in?

Endotoxins

LPS

disease manifestation of V. Cholerae?

infection diarrhea

disease manifestation of Bacillus cereus?

Food Poisoning

disease manifestation of staphylococcus aureus.?

Food Poisoning

TSST-1 of Staphylococcus aureus is associated with that type of toxins?

Type I

phospholipases are associated with what type of toxins?

type II

cholera is associated with what type of toxins?

Type 3 (A - B)

Example of a bacteria that uses pili that binds to cervical/buccal cells?

Gonorrhoeae

example of bacteria that uses pili that cause diarrheas using its adhesions to bind to intestinal epi? (theres 2)

E coili and Campy

Examples of capsules that use rough and smooth colonies?

Streptococcus pneumoniae

Examples of Facultaticve intracellular organisms? (theres 2)

Listeria and salmonella

What cell structures make the bacteria unable to be phagocytosed from macrophages and neutrophils

capsules

What type of toxins release for exotoxins?

Type 1 - 3 Toxins

mechanism of release for exotoxins

shed from living bacteria in steady amounts. Only seen in endo