Figure 5.

npsn deficiency affects neutrophil recruitment to bacteria. (a) The infection site of the zebrafish muscle (the red arrow). DsRed⁺ E. coli were injected subcutaneously over one somite into WT and npsn^smu5 mutant embryos with Tg(mpx:eGFP) background, and images were captured at 0.5, 3 and 24 hpi. All images are maximum-intensity projection at an interval of 2 µm. The white triangle indicated the neutrophil with phagosomes. (b) Quantification of recruited mpx:eGFP⁺ neutrophil numbers (green bar) and phagocytosing neutrophil numbers (red net bar) in the infection site at each time point in bacterial injected WT and npsn^smu5 mutants. Average numbers with means in WT and npsn^smu5 mutant groups at 0.5, 3, 24 hpi (green bar: 19.7 ± 2.6 versus 21.7 ± 0.8; 28.6 ± 4.1 versus 47.0 ± 2.3; 17.5 ± 4.8 versus 42.8 ± 7.5); (red net bar: 16.9 ± 2.6 versus 16.83 ± 1.2; 26.4 ± 3.6 versus 39.8 ± 2.1; 5.9 ± 2.2 versus 8.2 ± 1.1). (Mean±s.e.m., n ≥ 6 in each group, triplicated). Statistical significance was determined using the two-way ANOVA with Bonferroni's multiple comparisons adjustment. **p < 0.01. ***p < 0.001. n.s., not significant. (c) Bacterial burden of embryos at 24 hpi in npsn^smu5 mutant embryos and WT controls. (Mean±s.e.m., n = 50 in each group, triplicated). Statistical significance was determined using the unpaired t-test. ***p < 0.001.