unit 1 Flashcards
describe gram neg structure
PM, PG with no gly5, OM with porins made of Lipid A, KDO, Core, O antigen (LPS)
gram staining. whats each colour?
positive - purple
negative - pink
4 gram staining steps
- crystal violet
- iodine
- alcohol
- safranin
mycolic acid is found where
arabinogalactan layer of acid fast bacteria
autoclave conditions
121degrees, 15psi, 20 mins
flagella biosynthesis genes
early: flhc and flh d make FlhD2C2, which recruits sigma 70 and RNA pol to make middle gene
middle: sigma F and FlgM (anti-sigma factor, gets excreted through T3SS once structures built), then sigmaF binds late gene promoter
describe transformation, transduction, conjugation and transposition
transformation: DNA taken up from environment and incorportaed in genome
transduction: DNA from bacteriophage gets incorporated into genome or stays in own plasmid
conjugation: DNA enters via pilus cell-cell contact (usually F plasmid transfered)
transposition: DNA (transposon) cut from one location and move to another
name an antibiotic resistance test that compares gradients
kirby bauer test
purpose of clavulanic acid
synthetic b lactamase competitor. added to antibiotics so b lactam ring cant get chopped by b lactamase
What’s SCC Mec?
large genetic element that has mecA gene, makes PBP2a and inhibits B lactam antibiotics
what drug works on MRSA? how?
teixobactin: affects PG synthesis of gram +
molecular koch postulates vs organismal
- gene linked to disease in animal
- removal of gene = loss or reduction of virulence
- returing gene in organism restores full virulence
organismal:
1. agent absent in healthy and present in diseased.
2. agent isolated and grown in culture
3. causes disease when reintroduced in person
4. agent must be re-isolated
give an example of an AB toxin and describe how it works
Diphtheria toxin - inhibits protein synthesis.
A subunit inactivates elongation factor 2 by transferring ADP-ribose on it. thus stops protein elongation, killing the cell
shiga toxin is an example of an ab or ab5 toxin? what disease causes it?
ab5 caused by pathogenic E.coli (0157:h7)
ab5 toxin example and mechanism
cholera toxin.
a1 cleaved after phag, adp-ribosilated G protein, acenylyl cyclase activated, cAMP increased, cell secretes fluit and salt
pathogenicity islands have high ______ content
GC
describe STEC infection process
pili attaches to host, activates T3SS, Tir inserts into host, acts as receptor for intimin, then actin-based pedestal formed, curli aids in biofilm formation, stec releases shiga toxins which binds Gb3, stx binds ribosome and stops protein synthesis
the purpose of ____ secreting gbpA is ____
v.cholerae ; facilitate binding to chitin or small intestine
cholera process
cholera binds to GbpA, uses TCP to make stronger attachment, forms biofilm, secretes toxin, B5 binds GM1, toxin taken into cell where activates adenyl cyclase and increases cAMP, water and salt secreted from cell, diarrhea
listeria is a gram ___ bacteria
positive
3 listeria monocytogenese virulence factors
- internalin B: binds to met to internalize listeria
- LLO (exotoxin) forms pore in vacuole when pH drops to let lysteria out
- ActA - actin modulating protein that moves bacteria in cell
staph aureus bacteria type
gram positive
