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Fig. 2
Effect of yolk sac co-injection of Pu.1 morpholino and M. marinum on bacterial localization and proliferation within embryos.
(A and B) 3 day-old infected mpx-gfp transgenic embryos (A) with and (B) without Pu.1 morpholino (scale bar: 250 μm). Greater numbers of (extracellular) bacteria throughout body of morphant embryo seen in A contrast with lower amount of more localized (phagocytosed) bacteria seen in B. Very low number of mpx-gfp labelled neutrophils in A confirms Pu.1 morpholino effect. (C) Bright-field/fluorescence overlay and (D) confocal z-stack of mag49-GFP/mCherry bacteria in body of 2 dpi embryo (scale bar: 25 μm). Red-fluorescent bacteria form a cording structure adjacent to a few cells containing green-fluorescent (mag49-activated) bacteria. Lack of green fluorescence in cording bacteria indicates no phagocytosis by macrophages and extracellularity. (E) Close-up (digital zoom: 5.2) of cording structure formed by extracellular bacteria (scale bar: 10 μm; only red channel shown).