Term
driving force for penicillin/cephalosporin biosynthesis:
Substrates/products: |
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Definition
atp hydrolysis -> AMP + PPi (irreversible)
substrate- 3 AA + ATP
Products: penicillins + AMP + PPi |
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Term
| Penicillin notatum uses a series of -- that is -- polyketide in --. |
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Definition
series of enzymes
NOT LIKE
Erythromycin |
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Term
| Why is ATP -> AMP is irreversible? Why is it important? |
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Definition
| it takes 2 enzymes to get back to ATP from AMP which is a lot of work. This forces a lot of energy outwards |
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Term
| How does penicillin enter the cell? |
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Definition
| it is charged so it can enter thru porins |
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Term
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Definition
| non ribosomal peptide synthetase (NRPS) driving force is ATP hydrolysis-> AMP |
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Term
| substrates / products for vancomycin |
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Definition
substrates: 7 AA + ATP
products: vancomycin precursor +AMP+ PPi |
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Term
| Why is vancomycin only G+ |
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Definition
| it is massive: made up of 7 AA = 2-3X larger than penicillin. |
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Term
| What completes the biosynthesis of vancomycin? |
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Definition
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Term
| Vancomycin is very hydro-- and -- making it -- |
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Definition
HYDROPHOBIC and not charged bc it formed amide bonds with original carboxylic acids.
Too big for porins- cant go thru membrane of G- |
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Term
innate/intrinsic resistance:
example= |
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Definition
microbe is normallly not susceptible to the drug
G- are not susceptible to vancomycin |
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Term
| Mechanisms for resistance: |
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Definition
mutation of target
drug inactivation
decreased uptake
increased elimination
plasmids |
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Term
Mechanism: Mutation of target-
ex- |
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Definition
| genetic change= spontaneous mutation or gene transfere. Faulty polymerase activity in bacteria lead to mutation in gene that affects abx (MRSA, vancomycin resistance) |
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Term
Mechanism: Drug inactivation-
ex: |
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Definition
modification/destruction of drug (MRSA)
Drug will not hit target- Beta lactamases secreted by microbe take out penicillin before it can get to transpepsidases |
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Term
| Mechanism: Decreased uptake example= |
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Definition
| Porins- bring in nutrients, but G- have evolved to be less permeable to the drugs= decreased uptake |
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Term
| Mechanism: increased elimination: |
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Definition
| Efflux pumps (G+ and G-) ATP dependent pumps that kick out abx and things the microbe doesn't want. Common in G- for tetracycline =protein synthesis inhibitor |
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Term
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Definition
| a lot of plasmids carry resistance genes and exchange between different species |
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Term
| MRSA genetic change caused: |
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Definition
| truncated version of the protein that causes cross bridges to form. Other resistance is from a change in the active site in the ezyme: harder for drug to bind and inactivate |
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Term
| Microbial control is focused on -- = |
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Definition
| sterilization= removing/destroying micro organisms and viruses anot necc. prions |
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Term
| Who had the germ theory of disease? |
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Definition
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Term
Joseph lister in GA?
what idea did he have? |
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Definition
in GA
first idea of steralization: used phenol/ carbolic acid for surgical instruments, wounds, hand washing |
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Term
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Definition
sterilize
germicide
disinfectant
antiseptic |
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Term
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Definition
Remove/destroy all living microorganism and viruses
Not prions/viroids |
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Term
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Definition
Kills ALL growing cells
May or may not destroy endospores
(lysol, chlorox, pinesol) |
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Term
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Definition
Removes most pathogens (microbes and viruses)
Usually too toxic to ingest |
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Term
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Definition
Skin, mouth/ external parts
Too toxic if ingested, ok to put on self for a breif time. Gargel lysterine vs toilet bowl cleaner. |
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Term
| considerations for microbial control: |
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Definition
| item composition and microbe itself |
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Term
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Definition
metal glass some plastic: autoclave
food- no lysol, no autoclave
can thing be around moisture/high temps? |
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Term
| Microbe considerations for control: |
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Definition
endospores might make it resitant
mycobacteria have a weird cell wall
viruses membrane or naked?
prions are hard to get rid of |
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Term
| endospore forming microbes: |
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Definition
| C. perfringens and B. anthracis |
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Term
| Membrane or naked viruses consideration: |
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Definition
| non enveloped is harder to destroy bc the lipid membrane is a good target to attack |
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Term
| Approaches to microbe control: |
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Definition
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Term
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Definition
mechanical (scrub)
heat (autoclave, pasteurize)
Filtration
Irradiation-DNA damage |
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Term
| Chemical methods of control: |
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Definition
| irreversible reactions with DNA proteins, lipids |
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Term
| Why type of control is lysol wipe? |
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Definition
| has chemical but you also have to scrub so also physical |
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