Fig. 3

Correlative light and electron microscopy of M. marinum infected blood vessels showing irregular blood vessel walls and invasion of endothelial cells. Tg(kdrl:mCherry)^is5 larva (9 dpf) with red fluorescent blood vessels infected with green fluorescent M. marinum after phagocyte depletion. To aid correlation of confocal and EM imaging, nuclei were stained with DAPI after fixation (cyan). (a) Electron microscopy and (b) correlative light and electron microscopy, and (c) confocal microscopy. Arrows indicate landmarks used to merge images obtained from consecutive slices in the same area of the zebrafish brain. Boxed area is enlarged in (f), scale bar a = 5 ?m (applies to b?d). (d) Single red channel illustrating the irregularity of the infected blood vessel and the more regular shape of the non?infected blood vessel (right upper corner). (e,f) High magnification EM image showing the irregular shaped infected blood vessels and basal lamina. Red dotted lines represent basal lamina found in this area. Boxed area is enlarged in (g). Scale bar = 1 ?m. (g) High magnification of area where mycobacteria can both be found intravascular as intracellular. Vesicles, indicative for intravascular localisation, can only be found left of the red dotted line. This suggest that mycobacteria right of the line are localised in an endothelial cell (*). Scale bar = 200 nm. M = M. marinum