Oxygen in animal intestine 15 min unclamped 30 min unclamped 15 min clamped[ 30 min clamped E coll expressing luciferase reporter grown anaerobically were injected with luciferase substrate into ligated rabbit ileal loops luciferase requires oxygen and aTP to produce detectable luminescence from substrate Martyn,B,eta!(2010), Nature465(7296):355358.11
Oxygen in animal intestine 11 E. coli expressing luciferase reporter grown anaerobically were injected with luciferase substrate into ligated rabbit ileal loops. Luciferase requires oxygen and ATP to produce detectable luminescence from substrate. Marteyn, B., et al. (2010). Nature 465(7296): 355-358
Oxygen gradient in animal intestine Lumen 70 um Villi LPS/actin GFP Merge/DAP Shigella flexneri expressing GFP reporter grown anaerobically were injected into rabbit ligated ileal loops. GFP covalently binds oxygen to fold into a mature fluorescent conformation. Immunofluorescent imaging of clamped loops shows little or no GFP signals(not shown) Martyn,B,eta!(2010). Nature465(7296):355-358
Oxygen gradient in animal intestine 12 Shigella flexneri expressing GFP reporter grown anaerobically were injected into rabbit ligated ileal loops. GFP covalently binds oxygen to fold into a mature, fluorescent conformation. Immunofluorescent imaging of clamped loops shows little or no GFP signals (not shown). Marteyn, B., et al. (2010). Nature 465(7296): 355-358
B. fragilis -an aerotolerant obligate anaerobe SOD+ catalase+ Key metabolism enzymes only reversibly inhibited by oxygen Some aerotolerance-related proteins are encoded on a single operon and induced by oxygen
B. fragilis - an aerotolerant obligate anaerobe 13 • SOD+ , catalase+ • Key metabolism enzymes only reversibly inhibited by oxygen • Some aerotolerance-related proteins are encoded on a single operon and induced by oxygen
B. fragilis-a anaerobe? a1010 0nMQ2合 108 10 1μMo E 10 2 uM O2 10 100 uM O2 102 25 50 75 B f encodes a high-affinity oxidase enabling it to grow in the presence of nanomolar oxygen Baughn, A D. and M. H. Malam(2004). Nature 427 (6973): 441-444
B. fragilis - a nanaerobe? 14 B. f. encodes a high-affinity oxidase enabling it to grow in the presence of nanomolar oxygen. Baughn, A. D. and M. H. Malamy (2004). Nature 427(6973): 441-444
B. fragilis-a anaerobe? 10 WT 10 l△oxe e102 △ oxe/oxe 10 10 106 五马 10 大大大大 10 0 020.52.05021.0 %oxygen(v/v) Inactivation of a single gene in B. f. enables growth at higher oxygen levels Meehan, B M, et al.(2012). Proc Natl Acad SciUsA109(30): 12153-12158
B. fragilis - a nanaerobe? 15 Inactivation of a single gene in B. f. enables growth at higher oxygen levels. Meehan, B. M., et al. (2012). Proc Natl Acad Sci U S A 109(30): 12153-12158