Fichas
13 - bacterial adhesion
Fichas del conjunto (39)
- 1define colonisationbacterial attachment and growth at site
- 2define adhesinsurface molecule binding to a receptor
- 3define receptorhost molecule complementary to an adhesin
- 4define invasinsurface or injeted virulence factor that enable cell invasion
- 5what are the obligatory steps in infection1. attachment or invasion
2. multiplication
3. invasion of the host defences
4. damage to the host (essential/collateral)
5. tranmission to new host - 6what are sites of microbial infection?skin
respiratory tract
urogenitary tract
gastrointestinal tract
eyes - 7what is the role of commensalsprevent colonisation of pathogens
- 8what produces antimicrobial products on the skinoils produced by skin are antimicrobial
commensals produce antimicrobial products - 9what is on the surface of skin that aids it as a barrier against pathogenic colonisationfatty acids at pH 5.5 which is too acidic for some pathogens
- 10what ways do pathogens move past the skin barrier1. physical damage to skin
2. UV damage
3. bites by insects or other things - 11how does the respiratory tract protect from the thousands of organisms inhaled /daylarge particles filtered out by nose hairs
trapped in mucus and moved by ciliary action - 12how do bacteria overcome these protective defenses of the respiratory tractadhesins on surface allow them to adhere to epithelial cells - cilia+mucus fail
production of ciliostatic substances inhibit ciliary action
muco-ciliary defects in humans - 13how is the urogenitary tract protected from infectionflushed every few hours (by pissing x)
strong sphincter prevents microbial entry into the bladder - 14why are women more likely to get a UTI than menurethra is closer to rectum than men - so more access of the bacteria
- 15what is cystisis pyelonephritis and prostatitiscystisis = bladder UTI
pyelonephritis = kidney UTI
prostatitis = inflamed prostate - 16what are the defenses against GI tract infectinsaliva contains antimicrobial substances + flushes mouth out
stomach is v acidic
large intestine peristalsis (flushing) + mucus + commensals - 17what does the flushing force stopbacterial adhesion to epithelial cells
- 18describe the process of bacterial attachmentbacterial adhesin binds to host receptor and colonisation can occur (growth)
- 19there is repulsion from host cells how is this overcomecomplementary adhesin binding
- 20give examples of adhesinsflagella
fimbrae
gram neg outer membrane proteins
gram pos cell wall proteins - 21how does flagella act as an adhesinfor motility
move through mucus etc to attachment site and can attach - 22how do fimbriae adhesin workshort projections (like flagella)
extend and contract
like neisseria type 4 pili
sense environment - adherence may activate immune system :( - 23how do gram negative adhesins workouter membrane proteins (OMP)
promote intimate attachment as they don't stick out so get really close
can promote invasion - 24how do gram positive adhesins workMSCRAMMS (microbial surface components recognising adhesive matrix molecules)
- 25give examples of MSCRAMMS receptorintegrins
carbohydrate moieties - 26what can adhesins help determine give an examplepathogenic location
type fimbriae cystitis binds in bladder not in kidney - 27what does adhesin binding cause formation of in enteropathogenic E.colipedestal formation
- 28how does EPEC insert infector proteins into host cellforms a needle shaped multiprotein complex
attaches and insert into host
injects infector proteins which translocate
they manipulate cell to promote infection - 29what specifically does EPEC inject into the cell to aid with infectionits own receptor called TIR
- 30what is the purpose of TIRintimin is produced by bacterium which binds to TIR and causes formation of pedestal
- 31how does salmonella attach to host cellthrough fimbiae and pili
- 32once attached how does salmonella inject infector proteins into host cellSPI1 needle inserts and injects salmonella specific infector proteins which invade host cell
- 33what do these salmonella specific proteins protect themselves from host defencesthey are in a salmonella containing vacuole
- 34how does salmonella stop the formation of phagolysosomes in host macrophage cellinjects SPI2 (type 3 secretion) which prevents fusion with lysosomes + prevents intracellular death
- 35how do salmonella then grow and spreadintracellular replication and then lysis out of the cell to infect other cells
- 36how are SPI1 and SPI2 delivered into host cellinjectosomes
needle injects them into the cell - 37what is salmonellas target cellmacrophages
- 38as well as SPI2 stopping lysosome fusion how else does salmonella avoid death inside the macrophageproduces enzymes which inactivate toxic macrophage compounds (nitric oxide + peroxide antagonists)
- 39summary of salmonella infection process1. binds to host
2. type 3 secretion injects effector proteins and enters host cell
3. fuses with endosomes
4. SPI2 protects from fusion with lysosomes
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- Descripción
- Year 2 (Immunity and infection ) Biomedicine Year 2 Fichas sobre 13 - bacterial adhesion, creado por Georgie Philpott el 24/12/2022.
- Creado por
- Georgie Philpott
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