BIOL 318 Lecture Notes - Lecture 6: Opsonin, Phagosome, Phagolysosome
28 Oct 2018
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Document Summary
Opsonins form nice linking bridges between the phagocyte and the material to be ingested: step 3. Ingestion: membrane protrusions (pseudopodia) extend to engulf attached bacterium, tips meet and fuse phagosome, phagosome: internal vacuole of cell membrane containing engulfed particle(s, phagosome separates from cell membrane and becomes an internal structure, step 4. Phagosome fuses with lysosome: phagosome fuses with lysosome (containing microbiocidal chemicals) phagolysosome, antimicrobial agents found in phagolysosomes, low ph, acid-activated hydrolytic enzymes (degrade cellular proteins) Lysozyme: attack cell wall of gram + Proteases: break down proteins: antimicrobial proteins and peptides. Defensins: produce ion permeable holes in microbial cell membrane = destroys osmotic stability. Killing and digestion: usually bacterial death occurs in ~ 30 min with subsequent digestion of remains, step 6. It is good that c" (complement) proteins need to be activated before they can function! Anaphylatoxins: complement (c") split products: induce degranulation of mast cells/basophils increase in inflammation, release of inflammatory mediators, ex.
