Bacterial Killing Flashcards
Where is the peptidoglycan in gram negative bacteria?
mycrobacteria?
What is peptidoglycan made of?
what can T6SS do to the cell wall? how does the bacteria look after?
what do antibiotics do?
how does the cell wall protect bacteria?
inner membrane of it surrounded by outer membrane
single membrane of thin peptidoglycan = gram +, but has thick mycolic acid layer outside of it attached so inner layer
glycan sugar linked by short peptides of NAG N-acetylglucosamine & NAM N-acetylmuramic acid
deliver peptidoglycan hydrolase- cleaves peptide linkers & cut some glycan chains. becomes ball
block forming of peptide linkage in peptidoglycan
osmotic pressure
what is cool about the ß-lactam antibiotic structure?
what is a bacteriostatic antibiotic?
bacteriocidal?
so what kind of antibiotic are ß-lactams?
lactam structure resembles the linkages that form between peptidoglycan- when synthesising these attach & synthesis stops
when you add it, growth is inhibited, but when wash it growth continues again
after add it to bacteria = permanently destroyed until reach 0 bacteria
when they are all growing they permanently lyse = bacteriocidal- but there are some bacteria growing slower = presister cells which can wake up & grow after antibiotic washed away
what could T6SS systems deliver to degrade cell membranes?
what happens to the cell on rupturing?
what is Triclosan antibiotic used for?
what type of cases are these antibiotics? (using these to poke holes in membrane)
what type of pyocin can form holes?
what does MAC complement membrane attack complex do to poke holes in membrane?
what does polymyxin B do?
what do antimicrobial peptides do?
lipases- causes membranes to shrink until osmotic pressure ruptures them
tries to recover by compressing the cell- causes more rupturing so all contents leak out
inhibits fatty acid biosynthesis- so can prevent repair cell membranes
bacteriocidal- but depends on concentration of holes poked- e.g if it’s little they can close off & produce new cell
R-type
proteins insert into bacteria membrane & produce a pore so contents leak out (used in immune systems)
antibiotic- inserts into membrane & destabilises it so content flows out
insert into membrane & produce hole
which enzymes could you target in bacteria to stop translation? how?
what do bacteriostatic antibiotics do? but what happens if you wash away?
bacteriocidal antibiotics?
which T6SS toxin can degrade DNA? what happens if DNA ligase is inhibited?
is this bacteriocidal or bacteriostatic?
tRNAses & rRNAses- bacteriocins/T6SS toxins & antibiotics
prevent new amino acids growing on peptide chain by disrupting tRNAses- can make proteins again
disrupt protein synthesis by allowing incorrect proteins to be made- which consumes all bacteria resources & bad proteins interact badly with cell functions
quinolones- targets DNA helicase, lygase, topoisomerase. it’s used to relieve supercoiling- so means chromosome can’t separate/or there is lots of twisting = ruptures DNA
bacteriocidal for GROWING cells as they are actively replicating & separating chromosomes- if it’s inactive, then stress doesn’t result in permanent damage & when they are washed can be repaired
