Fig 8. In vivo effect of ΔeccA₁, ΔespG₁ and ΔespH in zebrafish larvae.

Graphs A-C show relative levels of infection as determined by automated pixel count software for infection of zebrafish larvae. The larvae were infected with ~75–150 CFU red fluorescent M. marinum mutant strains and analyzed at 4 dpi. Graphs show combined data of three independent biological replicates per mutant strain, each dot represents one larva. Bars represent mean and standard error of the mean. A. Systemic infection of zebrafish larvae with M. marinum ΔeccA₁, B. M. marinum ΔespG₁ and C. M. marinum ΔespH, * = <0.05, **** <0.001. Representative bright field and corresponding fluorescent images are depicted in: D. WT infection, F. eccCb₁ mutant infection, H. M. marinum ΔeccA₁, J. M. marinum ΔespG₁, L. M. marinum ΔespH. Confocal imaging of a single cluster of infected L-plastin labeled phagocytic cells (cyan) in the tail of infected larvae confirmed the phenotype seen in fluorescent imaging: E. WT infection, G. eccCb1 mutant infection, I. M. marinum ΔeccA₁, K. M. marinum ΔespG₁, M. M. marinum ΔespH, depicting a cording phenotype (closed arrows) and intense fluorescent spots suggestive for phagocytic cell debris (open arrows). Scale bar E, G, I, K, M = 50 μm.