Bacterial Properties Flashcards
name and describe the various forms of bacteria
bacilli - rod
cocci - spherical
spirilli - spiral
how are bacteria distinguished between and what is distinguished?
gram stain
gram +ive/-ive
how is a gram stain carried out?
stained with violet dye and iodine, rinsed in alcohol, stained with red dye
1st dye binds to peptidoglycan
what do stain results indicate?
pink = gram -ive as 1st dye is lost so cells absorb 2nd dye
deep violet = gram +ive as peptidoglycan retains 1st dye
what happens after gram stain?
culture and microscopy
biochemical and serological tests
antibiotic sensitivities
DNA techniques
what are the properties of pathogens?
colonise, persist, duplicate, disseminate within cells, tissue and host, cause disease
give examples of IC pathogen and how they survive
listeria, shigella - escape phagosome
salmonella, mycobacteria, chlamydia - prevent fusion with lysosome
coxiella - survive in phagolysosome
name key properties of salmonella
flagellum = locomotion injectisome = invasion and transfer of virulence proteins into host which causes actin polymerisation, membrane ruffling and bacterial internalisation
how does listeria use actin?
locomotion by hijacking cytoskeleton to move cell-to-cell
what makes up a gene repertoire?
core genes and accessory genes
how are accessory genes acquired? what do they allow?
horizontal gene transfer
evolution
what are the forms of HGT? give bacterium examples for each
transformation - neisseria, strep.
conjugation - many gram +ive/-ive
transduction - many gram +ive/-ive
what is pathogenicity island
horizontally acquire DNA that contribute to virulence
DNA selection, encodes proteins that contribute to virulence either by main injectosome, produce toxin, very widespread
