HomeCoursesMEDSCI 203: Mechanisms of DiseaseLecture 15 Lecture 15 1. What is bacterial transformation? When a bacteria takes in fragments of DNA from other bacteria and incorpororate it into their DNAWhat is bacterial transformation?== When a bacteria takes in fragments of DNA from other bacteria and incorpororate it into their DNA 2. What is transduction? When a virus transfers DNA from one bacteria to anotherWhat is transduction?== When a virus transfers DNA from one bacteria to another 3. What is conjugation? When bacteria unite through pili and share DNA plasmidsWhat is conjugation?== When bacteria unite through pili and share DNA plasmids 4. What are the sources of transmission? (6) Self/others, food/drink/ environment, air, fomites, insects/animalsWhat are the sources of transmission? (6)== Self/others, food/drink/ environment, air, fomites, insects/animals 5. What are the modes of transmission? Airborne, eating/drinking, bodily fluids, direct contact, insect bite, surgeryWhat are the modes of transmission?== Airborne, eating/drinking, bodily fluids, direct contact, insect bite, surgery 6. What are the steps to infection? (4) Colonisation, evade host defences, proliferate, cause damageWhat are the steps to infection? (4)== Colonisation, evade host defences, proliferate, cause damage 7. What are some risk factors for infection? (5) Age, medical conditions, genetics, surgery, medicationWhat are some risk factors for infection? (5)== Age, medical conditions, genetics, surgery, medication 8. Why do bacteria stick? (2) Prevent elimination, anchor at preferred nicheWhy do bacteria stick? (2)==Prevent elimination, anchor at preferred niche 9. How do bacteria stick? (2) Non specific adhesion molecules, specific adhesinsHow do bacteria stick? (2)== Non specific adhesion molecules, specific adhesins 10. What are some non-specific adhesins? (2) Techoic acids (S. aureus), alginate capsule (P. aeruginosa)What are some non-specific adhesins? (2)== Techoic acids (S. aureus), alginate capsule (P. aeruginosa) 11. What are some gram negative specific adhesins? (2) Pili/fimbrae, outer membrane adhesinsWhat are some gram negative specific adhesins? (2)== Pili/fimbrae, outer membrane adhesins 12. What are some gram positive specific adhesins?= =MSCRAMMS What are some gram positive specific adhesins?= =MSCRAMMS 13. What is the mechanism of pili adhesin? (3) Pili attach to receptor, pili retract, outer membrane adhesins bind receptors on cellWhat is the mechanism of pili adhesin? (3) ==Pili attach to receptor, pili retract, outer membrane adhesins bind receptors on cell 14. What is the mechanism for lipoteichoic acid attachment? Lipoteichoic acids attach, MSCRAMMS bind matrix proteins (fibrinogen, fibronectin, collagen)What is the mechanism for lipoteichoic acid attachment?== Lipoteichoic acids attach, MSCRAMMS bind matrix proteins (fibrinogen, fibronectin, collagen) 15. What is our primary barrier defense against microbes? (2) Skin, mucous membranesWhat is our primary barrier defense against microbes? (2)== Skin, mucous membranes 16. What is an additional protective defense mechanism of mucos membranes (besides barrier)? Contains antimicrobial compoundsWhat is an additional protective defense mechanism of mucos membranes (besides barrier)?== Contains antimicrobial compounds 17. What is a metabolic defense against microbes? Iron restrictionWhat is a metabolic defense against microbes?== Iron restriction 18. What are the immune defences? (3) Complement, phagocytes, antibodiesWhat are the immune defences? (3)== Complement, phagocytes, antibodies 19. How can microbes resist antimicrobial fluids? (3) Altering surface charge (repel antimicrobial peptides), producing proteases (cleave sIgA), barrier (capsule etc.)How can microbes resist antimicrobial fluids? (3)== Altering surface charge (repel antimicrobial peptides), producing proteases (cleave sIgA), barrier (capsule etc.) 20. How can microbes evade the immune system? Masking/hidingHow can microbes evade the immune system? ==Masking/hiding 21. What are the methods of hiding/masking? (3) Capsule, invasion of host cell, mimicking host (self)What are the methods of hiding/masking? (3)== Capsule, invasion of host cell, mimicking host (self) 22. How does a microbe employ mimicry with Ig? Protein A of S. aureus binds FC region of Ig antibody, inhibiting binding of Ig to immune systemHow does a microbe employ mimicry with Ig?== Protein A of S. aureus binds FC region of Ig antibody, inhibiting binding of Ig to immune system 23. How does a microbe employ mimicry with MSCRAMMS? S. aureus binds extracellular matrix proteins which cover the cell presenting it as selfHow does a microbe employ mimicry with MSCRAMMS?== S. aureus binds extracellular matrix proteins which cover the cell presenting it as self 24. How does a capsule enable hiding/masking? Prevents opsonisation/contact by immune systemHow does a capsule enable hiding/masking?== Prevents opsonisation/contact by immune system 25. How does invading enable a microbe to evade the immune system?== The microbe lives within host cell and remains undetected by immune system 26. How does binding factor H facilitate immune evasion by microbes? S. pyogenes and N. meningitidis bind factor H (produced by the body to protect from autoimmune attack) and degrade C3bHow does binding factor H facilitate immune evasion by microbes?== S. pyogenes and N. meningitidis bind factor H (produced by the body to protect from autoimmune attack) and degrade C3b 27. How can a microbe destroy a phagocyte? (2) Phagocyte ingests microbe, microbe produces toxin which kills phagocyteHow can a microbe destroy a phagocyte? (2)== Phagocyte ingests microbe, microbe produces toxin which kills phagocyte 28. How do microbes detoxify phagocytes? M. tuberculosis is ingested by phagocyte, detoxifies reactive oxygen speciesHow do microbes detoxify phagocytes?== M. tuberculosis is ingested by phagocyte, detoxifies reactive oxygen species 29. How do microbes disrupt complement? S. aureus inhibits chemotaxis by blocking C5a receptors on immune cells (C5a antagonist) through secretion of CHIPSHow do microbes disrupt complement?== S. aureus inhibits chemotaxis by blocking C5a receptors on immune cells (C5a antagonist) through secretion of CHIPS 30. What is antigenic variation? Where a microbe (N. meningitidis) stimulates production of immune antibodies, then mutates so the antibodies don’t recognise itWhat is antigenic variation?== Where a microbe (N. meningitidis) stimulates production of immune antibodies, then mutates so the antibodies don’t recognise it 31. What are decoys used to confuse the immune system? Lipopolysaccharide blebs of outer membrane decoy immune systemWhat are decoys used to confuse the immune system?== Lipopolysaccharide blebs of outer membrane decoy immune system 32. How can microbes physically resist the immune response? By producing long O-antigens which prevent complement adhesionHow can microbes physically resist the immune response?== By producing long O-antigens which prevent complement adhesion 33. How can the host restrict iron availability to microbes? (2) Lactoferrin, transferrinHow can the host restrict iron availability to microbes? (2)== Lactoferrin, transferrin 34. How do microbes overcome iron restriction? (3) Siderophores (transport iron across membranes), transferrin binding proteins, haemolysis/proteaseHow do microbes overcome iron restriction? ==(3) Siderophores (transport iron across membranes), transferrin binding proteins, haemolysis/protease Loading...
