Eating habits - 8th set Flashcards
(113 cards)
Toxins (ramirez - kitchen table)
harmful substances made by some pathogenic bacteria species - cause tissue injury / trigger host immune response
Toxoid
altered or inactive toxins, mainly secreted exotoxins, often used as vaccines bc they can still retain property to stimulate the immune system and antibody production.
Toxemia
the presence of toxin in blood.
Antitoxin (ant horse - desk)
proteins or antibodies that bind to toxins and would block its action. if someone has tenanus, takes time to make antibodies. best bet to give them antitetanus antibodies from plasma
Toxigenicity
the ability of the bacteria to produce toxin.
Why bacteria makes and secretes toxin? (3 reasons)
3 main reasons. - shed, immune compromised, and iron.
Helps bacteria to be shedded out of body - mechanism for spreading and transmission
Location of the toxin genes - chromosome (chrome car)
Chromosome - pneumolysin (secreted by strep pneumonia), shiga toxin .
What’s the advantage of prophage gene encoding the toxin as a virulence factor? (pro gene)
it enhances gene mobility, more representation of the virulence factor gene in bacterial population
Why other genes don’t benefit ? (prophage gene encoding) (spread)
No clear answer
Possibly phages could amplify virulence factors (ex toxin) to spread during disease progression by infecting other similar bacteria present in the same location
exotoxin - gram + and negative (Exxon - backyard)
high toxicity. unstable at high temp - used as toxic vaccine. labile (can be altered) proteins. vaccines are heat treated exotoxins. The effects on the host vary. ex - botulism - one of most lethal toxins.
endotoxin - lipid A (lip - kitchen sink)
toxicity is low bc you have some control - body defense cells try to kill. stable can withstand heat for an 1hr, 120ºC (catheter - no endotoxin until opened)
Toxic actions - Plasma membrane disruption (nose plasma)
inserts onto host cell membrane and forms channels ( disrupts osmoregulation ) S aureus (α) alpha toxin. forms channels and hemolysis, cell dies
Toxic actions - Cellular cytoskeleton alteration ( microfilament – actin ) (skeleton - corner)
forces host membrane to surround pathogen; can now enter cell because the pathogen is protected from host defense cells
Disruption/targets of protein synthesis - toxic action (dip and shig are protein)
ex. diphtheria toxin, shiga. targets step in protein synthesis.
Block exocytosis - toxic actions and ex.
blocks exocytosis (release of neurotransmitters) of vesicle contents ex. tetanus and botulism
Disruption of signal transduction - toxic actions (traffic light highjack- tv)
hijacks host cell’s messenger system (usually cyclic Amp (CAMP) by either increasing or decreasing synthesis of critical molecules - CAMP controls channels in and out of cell, usually results in loss of electrolytes
Excessive activation - toxic actions
of immune response as with super antigens (tampons) and there is a disregulated cytokine secretion
exotoxin (exit kitchen)
Proteins made and secreted by Gram ( +) / (-)ve ; part of their normal growth and metabolism.
Cytotoxin - (cyto padsb)
PADSB
kills / affects host cell functions Ex: pneuomolysin, diptheria, anthrax, shiga like toxin, bordetella (whooping cough)
Neurotoxin (mattias) and ex.
impairs neuronal cells function; causes flaccid or spastic paralysis Ex: tetanus, botulism
Enterotoxin (think entero) and ex.
alters gastrointestinal cell lining functioning, cause intestinal disturbances Ex: cholera, E.coli.
shiga - like toxin
Made by S dysenteriae ( as well as some strains of E. coli (shiga toxin e.coli), STEC - potent cytotoxin
A part - shiga like toxin actions - (A dresser)
shigela enters endothelial cells, mostly kidney’s blood vessel, reacts w/ ribosomes which are RNA, and protein synthesis stops.
Bacterial ribosomes vs eukaryotic ribosomes
Bacterial ribosomes - 70S
eukaryotic ribosomes 80S
