Eating habits - 8th set Flashcards
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
shigatoxin also responsible for…(heme ur syn) and ex.
hemolytic uremic syndrome - children and elderly died when eating beef not cooked. Toxin is secreted by E.coli 0157:H7. Died from kidney failure
RBC break up in tiny blood vessels (caused by hemolytic uremic syndrome (shigatoxin) (shig and tu)
anemia, kidney failure (deposited in glomerulus) accompanied by paralysis and nervous system injury signs (all is due to oxygen deprivation)
Diptheria pathogen= pseudomembrane
pseudo membrane at back of throat. trying to scavenge iron from our bodies.
virulent diptheria have..(cut throat)
lysogenic phage - codes for diptheria toxin
avirulent diptheria
lacks prophage
Diptheria toxin (dip - hot tub)
dimeric cytotoxin with 2 peptides - A and B (a single polypeptide chain) joined by disulfide bonds
Immunotoxin = Antibody and Toxin conjugate
diptheria (sailor - couch)
ss bond is reduced and A enters cytoplasm (A - active portion). scientists conjugated (linked) A-subunit of toxin to an antibody. its called an immunotoxin. Then its endocytotized. A comes out, stops protein synthesis and cancer cell dies. Elongation factor becomes inactive.
this is only up to slide 14!!!
add the others before the final
main goal of diphtheria… (iron - closet door)
(stranglers disease) is to scavenge the iron in lungs. Iron involved in energy metabolism (FE.S proteins cytochromes)
toxins are normally…(lymph door) ex.
blood or lymph soluble; may be distributed globally - botulism - everywhere bc of blood
3 types of exotoxins - NEC - based upon….
NEC
the tissue cells they target - cytotoxin, neurotoxin, and enterotoxin
shiga make up (shig - alphabet - TV)
chromosomally coded AB toxin. stops translation (protein synthesis) by a mechanism similar to ricin toxin ( of castor bean seeds)
effects of shiga (shig - work - corner)
leads to host cell death ( cytotoxicity within 8 hours - toxin acts as a N (ACGT) glycosidase; splits specific A nucleotide base from 60 S ribosomal subunit
vaccine for diptheria
we have a good vaccine in US. can’t remove membrane may need tracheostomy. stranglers disease.
diptheria is a….and it targets….. (skeleton eyes - di - 2)
it’s a cytotoxin, it targets the eukaroyotic elongation factor 2 (eEF2) used in protein synthesis (also called translation)
some A subunits toxins (A poly)
can have a single polypeptide chain of A-B part. The A part may have ADP ribosyltransferase activity.
B subunit
it helps to bind target cells.
A is the active part of the toxin - pepsidase (bot w/ pepsi)
some have pepsidase or protease activity. ex botulism, tetanus toxin.
dtap
diphtheria, tetanus, and whooping cough (pertussis)
A-B toxins (what A and B stand for)
two parts: an “A” or active component, “B” or binding component that binds the exotoxin
3 steps in diphtheria (dip in pool)
initiation (initiation factors participate), elongation, and termination. Most important step is elongation.
A is the active part of the toxin - gylcosidase and ex.
gylcosidase activity ex shiga toxin.
A is the active part of the toxin - has ADP…(A camera - hall)
ADP ribosylation activity ex cholera, diptheria, whooping cough
endotoxin - effects on host
diptheria different that cholera, tetanus different that botulism. fever, shock, coagulation.
location of toxic genes - plasmid
virulence plasmid - anthrax toxin (2 virulence plasmid - 1 for poly d. and other for anthrax )
location of toxic genes - prophage - encoded -
viral dna integrated into bacterial dna.
endotoxemia is (endotoxin)
is the presence of lipid A or the endotoxin in blood
why bacteria make and secrete toxins? immune system (lois - hallway)
may induce state of compromised immune system - ex. super antigens. once they are secreted, it short circuits activation of T cells. massive release of cytokines. - least / minimal impact on bacteria by host defense system
why bacteria make and secrete toxins? iron and ex.
Scavenge important metabolite / element after killing and from dying cells ex diphtheria toxin.
exotoxin damage often occurs before…
an adequate immune response is initiated
phages
phages (viruses that infect bacterial cells)
diptheria - antibody and toxin conjugate (ant - ball - corner) - (this is ss)
it is a specific antibody to cell surface antigen expressed on cancer cell and its membrane.
diphtheria pseudomembrane has..(zombie)
dead epithelial cells (respiratory), bacteria, and inflammatory host cells (can be dead or alive)
iron is never..
free in our bloodstream.
B subunit - diphtheria (obvious)
cells of respiratory tract
B subunit - cholera (obvious)
only cells of intestinal epithelia. bc the B subunit recognizes specific receptors.
elongation (long race)
participate and facilitates the ribosome (moves forward) to the messenger RNA
some AB toxins have….and ex. (chiq - abs)
have a multi subunit AB toxin, ex. cholera.
exotoxins are coded by…(exit cpd)
chromosomal, plasmids or phage DNA
Why we get antitoxin despite the fact our body makes effective antitoxins ?
it takes some time to make antitoxins; often time the toxin effects are quick and antitoxins are the best way to neutralize the toxins
anthrax vaccine given to..
military personels, veternarians and leather industry workers. First choice as an biological weapon
super antigens cause
excessive immune response
anthrax - active as individual subunit?
NO
specifically targets tissue
diphtheria
Endotoxemia
presence of lipid A in blood
ex. of compromised immune system
super antigens
ex. of scavenge for iron
diphtheria
prophages change bacteria…
bacteria to make toxin.
usually AB type (x-abs)
exotoxins
A subunit in shiga has
gylocosidase activity
60s ribosomal subunit has
3 types of rRNA - 28S is the target for shiga toxin
ferritin and transferrin (ferret)
Ferritin - stored in the body’s cells until it’s time to make more red blood cells. The body will signal the cells to release ferritin. The ferritin then binds to another substance called transferrin. Transferrin is a protein that combines with ferritin to transport it to where new red blood cells are made
diphtheria is an ___toxin
AB
B subunit in diptheria binds to receptors and causes..(the end)
endocytosis. A and B acidified and separated and A is made free.
uncoated and neutral ph
diptheria
acidic ph (diptheria) (dip - fridge)
separates A and B subunit. A comes out. modifies eEF2 and then cell dies.
ex of toxin shed out of body
w/ cholera toxin
botulism is a…
exotoxin
diptheria is a…
cytotoxin
diptheria toxin is coded by…
phages
ex. of prophage encoded bacteria (pro - CBDSS)
cholera, diphtheria, botulism, super antigens, scarlet fever
all exotoxins (exit B D CAT)
diptheria, cholera, anthrax, tetanus and botulism
endotoxins (end SES)
Salmonella typhi, E. coli, Shigella
how acidified endosome promotes A subunit to dissociate from B subunit (sailor)
reduces the S-S bonds; that promotes the separation and entry into the cytoplasm
diptheria efficiently ADP…(dip on ladder)
ADP-ribosylates elongation factor-2 (EF-2) and thus blocks the translational machinery of target cells
targets protein synthesis
diptheria
cholera creates..(chiq acid)
metabolic acidosis (its basically a decrease in ph of body fluids). its mainly due to loss of the bicarbonate ions.
cholera initiates..and symptoms (chiq - potassium)
hypokalemia, loss of potassium ions, muscle cramps and irregular heartbeat.
cholera leads to..(chiq low volume)
hypovolumic shock - reduced blood volume, may have an affect on vital organ functioning. kidney, heart the demand a threshold of blood pressure. this in turn leads to death and coma.
cholera treatment options
hydration and replenishment of lost fluids and electrolytes is most important asap. Dont give antibiotics, they won’t help because the bacteria is already out of the body from diarrhea.
endotoxins on humans is the same signs and symptoms…(A - front door)
fever - sudden drop of blood pressure, leads to cardiovascular collapse.
most exotoxins are…
AB type. it is made up of 2 subunits - A subunit, and B subunit
A is the active part of the…
toxin
A part - peptidase or protease ex. (bot shot)
botulism, tetanus toxin
A part - glycosidase ex.
shiga toxin
A part - ADP ribosylation ex. (ribs in CDW)
(CDW)
cholera, diptheria, whooping cough
1st line of defense
physical, chemical, genetic barrier, normal microflora
2nd line of defense (PNM FC)
phagocytosis, neutrophils, macrophages, fever, cytokines
3rd line of defense
b and lymphocytes
B cells have..
BCRs - recognize and phagocotize
lymphocytes have…(nymph - tck)
TCR - T cell receptors. recognizes antigens which are presented by MHC II.
lethal factor w/ anthrax is..
protease
anthrax is encoded by…
plasmid
calmodulin
Calcium binding protein
general population not vaccinated for diptheria because..
not part of routine vaccine since disease risk is low to
minimal in general population
Toxin secreted by Clostridium botulinum…(ingest)
and the toxin is absorbed from digestive system. Many time we ingest spores of C botulinum
cholera bengal is the..
emerging strain
Bordetella / pertussis toxin (hot chocolate)
Modifies G protein, subsequently deregulates G protein and c AMP build up inside cells and excessive mucus accumulation in the upper respiratory tract.
codes for diptheria (dip - lice)
lysogenic phage
