Question | Answer |
infection (definition) | when a parasite is multiplying in/on a host |
infectious disease (definition) | when a host cannot function normally |
pathogens (definition) | cause disease |
pathogenicity (definition) | organism's ability to cause disease |
virulence (definition) | degree or intensity of pathogenicity |
three factors affecting outcome of host/parasite relationship | # organisms, virulence, host's resistance |
symptoms | unobservable |
signs | observable changes |
disease syndrome | collection of signs and symptoms |
infectivity (definition) | ability of an organism to start an infection |
invasiveness (definition) | ability of an organism to spread |
pathogenic potential (definition) | ability of an organisms to cause symptoms (toxins!) |
3 factors affecting virulence | infectivity, invasiveness, pathogenic potential |
infectivity affected by (4) | ability to be transmitted, ability to adhere, ability to grow, ability to avoid immune response |
fomite (definition) | inanimate objects that are contaminated (like a doorknob) |
4 ways of direct transmission | airborne, horizonal, vertical, vector |
horizontal direct transmission | kissing etc |
vertical direct transmission | pregnancy |
vector direct transmission | insects |
indirect transmission (3) | airborne (from soil etc), contaminated food/water, contact (fomites) |
5 places adhesins are found | fimbriae, capsule/glycocalyx/slime layer, s-layer, teichoic acid, viral capsids and envelopes |
teichoic acid | for attachment; found in gram positive bacteria |
s-layer | may be used for attachment; protein layer around cells |
host must have correct ___ for parasite to grow | pH, oxygen, temperature |
microbial products to avoid immune system (3) | IgA protease, leukocidins, capsule |
IgA protease | cleaves IgA |
leukocidins | kill lysosomes in WBCs |
how to hide within a host cell? (2) | escape phagosome before fuses w/ lysosome; prevent phagosome from fusing with lysosome |
M-cell targeting | (salmonella)-> releases enzyme that makes these ruffle (immune cells in GI tract) so bacteria sink into them and get taken up |
macrophage targeting | (Tuberculosis)-> tricks cells into spreading across mucous membranes and into circulation (hides in macrophages) |
microbial products involved in invasion (definition) | all break down tissue so more space for microbe |
Leishmaniasis | protozoal skin infection that can become visceral |
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neurotoxin treatment | antiserum (aka antitoxin) AND antibiotics |
botulism causes | flaccid paralysis |
tetanus causes | spastic paralysis |
tetanus toxin | tetanospasmin |
enterotoxins (definition) | affect GI tract |
enterotoxin examples (2) | Vibrio cholera, E. coli |
cytotoxin (definition) | affects cellular functions |
cytotoxin (examples) | Corynebacterium diptheriae, C. perfringens |
Corynebacterium diptheriae | diptheria toxin; creates pseudomembrane of dead bacteria+neutrophils which clogs throat |
Clostridium perfringens | releases a-toxin-> removes head from phospholipids, breaks down muscle tissue (causes gas gangrene) |
superantigen (definition) | over-stimulates the immune system; causes similar response to endotoxins |
superantigen example | S. aureus TSST1 (toxic shock syndrome); shock dilates blood vessels, causes rashes (>20% of T-cells activated) |
exotoxin genes (3) | plasmid, lysogenic phage, chromosomal |
which disease must have phage to be virulent? | Diptheria |
toxoids | inactivated toxins |
DPT vaccine | toxoids-> diphtheria, pertussis, tetanus |
why is there no vaccine for lipid A? | the immune system doesn't recognize it and launch a response |
septic shock cascade | caused by lipid A; blood clotting factor that over stimulates 4 systems; unregulated blood clotting which leads to organ failure **vasodilation |
pelvic inflammatory disease | Neisseria gonorrhea; adhesins stick to sperm, scar tissue that blocks fallopian tubes |
damage caused by inflammation | macrophages/neutrophils release toxic molecules that cause tissue damage |
damage caused by antibodies | antigen/antibody complexes settle in kidneys and joints that elicits an immune response -> tissue damage |
how does herpes evade immune system? | prevent MHC I on cell surface |
skin as an innate physical barrier | keratinocytes (keratin is H2O repellant), dry, top layer is dead, acidic, salty |
fungal infection that invades skin | ringworm |
Streptococcus pyogenes | exotoxin A= shock; exotoxin B= melts tissue/muscle underneath skin |
mucosa | columnar cells that form barrier, release mucous (prevents adhesions and traps microbes) |
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problems that weaken mucous defense | smoking (kills cilia), asthma, cystic fibrosis |
mucociliary escalator | ciliated cells and mucous trap and propel microbes away from lungs and into throat |
how microbes evade GI tract (4) | resist saliva, strong adhesins, capsules, slime layers |
microbes response to stomach acid | pH resistant (produce base), resistant spores |
cervical mucous, prostatic fluid, tears contain ___ | lysozyme and lactoferrin |
defensins | punch holes in membrane |
lactoferrin/transferrin | sequester iron away from microbes |
bacteriocin | produced by normal flora; kill other bacteria |
complement 3 functions | opsonization, MAC, inflammation |
cytokines | protein communication molecules |
interferon response | infected cell releases it, other cells have receptors and synthesize antiviral proteins |
granulocytes (definition) | contain toxic molecules |
agranuloytes (definition) | do not contain toxic molecules |
macrophages are called ___ in blood | monocytes |
dendritic cells | phagocytosis; present in skin and mucosa |
neutrophils | first responders (in blood) |
inflammation (4) | bacteria introduced; histamine released; neutrophils roll and stop; extravassation |
death from fever occurs at ___ | 109.4 degrees F |
two substances that cause fever | pyrogens (exogenous= LPS etc; endogenous=interleukin-1) |
why are fevers good? (4) | slows microbial growth, inactivates some toxins, increases immune activity, forces person to feel ill |
two immunological responses | primary= first exposure; secondary= memory response |
antigen | a substance that the body sees as foreign and mounts an immune response |
epitopes | short AA sequences that are recognized by antibodies and T-cells |
when active, CD8 cells are called (and activated by whom?) | CTL (cytotoxic T lymphocytes) *activated by t-helper CD4 |
CD4 aka | (bossy) T helper cells |
CD8 cells are important for | fighting viruses and tumor cells |
how do C8 cells kill? | make pore, insert enzymes, apoptosis |
B-cells | recognize and bind to antigen using the BCR (surface bound antibody) after receiving cytokine signal |
memory B cells | stay in lymph nodes until second infection |
IgM | secreted after infection, pentameric |
IgD | unknown function, stays bound to B-cell |
IgG | most abundant during 2nd infection, *crosses placenta (monomeric), blood! |
IgA | mucosal surfaces (dimeric) |
IgE | allergies (binds to mast cells), monomeric |
5 functions of antibodies | complement fixation, neutralization, opsonization, (agglutination, precipitation) |
complement fixation | antibodies trigger complement cascade |
opsonization (antibodies) | same process as complement does |
neutralization | antibodies surround microbe and prevent it from binding to a cell |
live attenuated vaccines | live culture no longer pathogenic (vaccine) *can mutate and be virulent |
activated/killed vaccines | killed with heat or chemicals |
toxoids | inactivated toxins (vaccines) |
polysaccharide capsules | vaccine type; copy of the coat of microbes |
what do B-cells do? | recognize an epitope, and make an antibody (IgM initially, IgG later) |
protein vaccines | recombinant or native (new) |
DNA vaccines | inject plasmids that express antigens in host tissues (in clinical testing) |
recombinant vector vaccines | use of viruses or bacteria to deliver genes of interest (in clinical testing) |
conjugate vaccines | link toxoid to polysaccharide component to help target T-cells |
how does HIV work? | kills CD4 cells (no antibody, no CTL) **increased cancer and opportunistic infections |
how does Epstein-Barr virus work? | over proliferation of B and T cells |
how do herpes/measles work? | hide antigens from surface of presenting cells |
how does the flu work? | changes antigens each year |
How does Tuberculosis work? | reproduce inside WBCs |
our definition for organic | 2 or more carbons |
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heterotrophs | use reduced organic molecules as carbon source |
trace element function | help in metabolic functions |
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phototrophs reduce or oxidize CO2? | reduce |
bioremediation | cleaning/plastic making using microbes |
Exxon Valdez oil spill | add P and N to stimulate oil-eating bacteria |
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chemical work | molecule synthesis |
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E0 values | more negative= give electrons; positive= receive electrons |
epidemiology | the study of distribution and determinants of disease frequency in human populations |
outbreak | higher than expected occurrence in a small group (WWII vets pneumonia) |
pandemic | occurrence higher than expected worldwide (influenza) |
nosocomial infection | illnesses associated with hospitalization |
endemic disease | steady but low frequency (herpes) |
epidemic | occurrence higher than expected (index case) |
zoonoses | animal disease transmitted to humans (80% of known diseases) |
prairie dogs transmit | the plague |
deer mice transmit | hanta virus (sheds) |
vectors and ___ are the same thing | carriers |
hepatitis A/E | transient |
hepatitis B/C | chronic |
convalescent | getting better, large # of microbes |
most infectious w/ flu when? | prodromal |
passive mechanical vector | vector carries it outside of its body |
passive biological vector | animal carries it inside its body |
active biological vector | bite, defecate, regurgitate in tissue |
antigenic drift | example mixing up H's and N's of influenza |
antigenic shift | example mutations in H and N antigens |
when do you for sure want antibiotics (4) | rash/stiff neck/fever, sore throat that doesn't go away, skin infections, bladder infections |
what did Bonnie Bassler study? | squid that used bacteria to hide its shadow; pumped 95% of them out in the morning; enough for quorum sensing by night time |
types of quorum sensing | species-specific and species-nonspecific |
what is the system that removes microbes from the lungs? | mucociliary escalator |
infections that one gets at hospitals | nosocomial |
mice= infected but cannot transmit to cats; fleas carry disease to cats and they get sick: mouse= ___; flea=____ | reservoir; vector |
you travel to Africa and develop Ebola, which antibody most effective in helping to clear it? | IgG (blood) |
2 antigens and 7 epitopes for a parasite- how many B cells specific for it? | 1 for each epitope (7) |
2 different antibodies specific for same epitope- they will have different __ | constant regions on the heavy chains |
roommate has hep A; you get gamma globulin shot; if they develop it 3 years later will you be protected? | no, it likely mutated (it's also acute) |
asked to develop a toxoid specific for the C difficile toxin- what will you create? | the toxin that is deactivated by chemicals or heat |
what would happen w/ complement deficiency? | lack of pore production on pathogens |
smoker gets lung infections why? | smoking kills cilia |
3 ways TSST an LPS are different | exotoxin/endotoxin; actively secreted/not; made of protein/made of lipopolysaccharides |
2 ways TSST and LPS same | both lead to shock and both have no vaccine |
which antibody inhibits toxin binding to receptors in the liver | IgG |
H2S-> S could be done by | aerobic chemolithotrophy or anaerobic chemolithotrophy |
NO3- -> NO2- could be done by | anaerobic chemolithotrophy or anaerobic respiration |
final electron acceptor in methanogenesis | CO2 |