Fig. 4

Intracellular colonization by Bd in zebrafish larvae.

(a) Zebrafish larvae bath water was inoculated with high (>200 zsp per μl) dose Bd zoospores and incubated for 72 h.p.i., then fixed and labelled with Hoechst (for DNA; blue) and mAb 5C4 (for Bd; green) for visualization by confocal microscopy. Images taken at 63 X, maximum intensity projection of Z-stack shown here. Cartoon depicts imaged region. Representative images with arrows highlight colocalization between Bd and blisters on larvae skin. Scale bar, 50 μm. (b) Zebrafish larvae bath water was inoculated with high dose Bd zoospores and incubated for 72 h.p.i., then fixed and labelled with Hoechst (for DNA; blue), mAb 5C4 (for Bd; green) and phalloidin (for F-Actin; red) for visualization by confocal microscopy. Images taken at × 63, maximum intensity projection of Z-stack shown here. Cartoon depicts imaged region. Representative images with insets highlight Bd adjacent to host cell actin rearrangements. Scale bar, 50 μm. See also Supplementary Fig. 4c for host cell actin in control treated larvae. (c) Zebrafish larvae bath water was treated as in a. Images taken at × 40 or × 63, maximum intensity projection of Z-stack shown here. Images showing different stages of Bd invasion and infection on larvae, also depicted using cartoons in the right column. 1, rhizoid-like germ tube attached to encysting zoospore, 2, chytrid thallus growth on zebrafish larvae skin, 3, encysted sporangium amongst hyperplasic epithelial cells. Scale bars, 10 μm.