BP Exam 2- stress and antibiotic resistance

when bacteria is grown at higher temps, what protein is made

heat shock (Hsps)

heat shock protein function

chaperone (folding and export)

which regulon encodes for a sigma factor that makes heat shock proteins

RpoH, mutants lacking it are unable to grow

the master regulator of stress responses

RpoS regulon

uv light causes _____ dimers, and ____ reverses it

thymine, photolyase

what cuts dna in nucleotide excision repair (caused by pyrimidine dimers)

uvrABC

in base excision repair, deaminated bases are fixed by

glycosylases

what cleaves the phosphodiester bond in base excision repair

AP endonuclease

what polymerizes in base excision repair

DNA pol I

recombination requires activity of rec_

A

the sos response is generated when

recA binds to ssDNA

sos regulon is induced when

inactivation of repressor lexa

oxidative stress happens when

cells are exposed to toxic forms

which enzymes can convert toxic oxygen to nontoxic forms

superoxide dismutase and catalase

oxidative stresss proteins

soxR and soxS

soxR

activated in response to superoxide, activates soxS gene

soxS

transcription of genes for resistance to toxic elements

oxyR

activated in response to hydrogen peroxide, activates several genes

katG

encodes for catalase and oxyS

flagella genes are repressed during

starvation, unfavorable osmolarity

what mutations result in resistance to a whole class of antibiotics

chromosomal

what gives resistant to multiple classes of antibiotics

plasmids

cassettes of resistance genes are organized into

integrons

chromosomes have an _____ site for integrons

attachment

integrons can ____ resistance genes to spread others

rearrange

three mechanisms of resistance

alter target site, alter access to target site, enzymes that modify or destroy the drug

3 mechanisms of b lactam resistance

decrease concentratoin at cell wall target site, decrease binding of PBP, b lactamases

target sites in gram negative cells can alter ___ genes to decrease permeability of outer membrane

porin

mrsa encodes

PBP2a

gram postivies can release ____ into the environment

b lactamases

gram negative b lactamases stay in

periplasm

vancomycin disrupts

PG synthesis

glycopeptides interact with

d-ala-d terminal

vanA and vanB on plasmids confer resistance for

glycopeptides/vancomycin

aminoglycosides inhibit protein synthesis by binding to

30S ribosomal proteins

penetratoin of aminodglycosides depends on what

oxygen, energy

aminoglycosides cannot kill ___ bacteria

anaerobic

4 mechanisms of amnoglycoside resistance

mutation of ribosomal site, decreased uptake of drug into cell, increased expulsion of drug, enzymatic modification of antibiotic

quinolones inhibit

dna replicatoin

rifampicin inhibits

rna polymerase

sulfanomides and trimethoprim inhibit

precursor synthesis

quinolones inhibit what two replication enzymes

dna gyrase and topoisomerase

3 mechanisms of quinolone resistance

change target enzymes, change cell wall permeability, plasmid reistance with Qnr protein

rifamycin binds to ___ dependent rna pol

DNA

metronidazole is activated after ___. resistance involves an alteration of ____

entry, uptake

sulfanomides act in competition for

active sites that make purines and pyrimidines

trimethoprim is an analog of ____ synthesis

folic acid