Figure 5

Blood flow analysis reveals reduced cardiac performance upon Flii deficiency, including a developmental arrest in the systolic hemodynamic force.

(A–C) Analysis of blood flow velocity (BFV) in the dorsal aorta by spinning disk microscopy at 72 hpf through 6 dpf. (A) Blood flow videos (400 frames/s, total of 500 frames shown) are visualized as kymographs, which show dynamics of blood cells that move distance x over frames y. Relative speeds are determined by measuring the angle of blood flow in the kymographs, with a steeper downward angle representing slower blood flow. In the systolic phase (blue box), blood cells move faster than in the diastolic phase (orange box). (B and C) Quantification of kymograph angles in systolic and diastolic phases, respectively. Note that the systolic blood cell speed does not increase in flii^D110fs mutants with developmental time (B). In contrast, the diastolic blood cell speed increases in flii^D110fs mutants but is still significantly reduced compared with that of wild-type and heterozygous siblings (C). One-way ANOVA coupled with Holm-Šídák multiple-comparison test was used to test for significance; values represent means ± SEM; (72 hpf flii^+/? siblings n = 7, flii^{D110fs/D110fs}n = 9); (96 hpf flii^+/? siblings n = 9, flii^{D110fs/D110fs}n = 8); (120 hpf flii^+/? siblings n = 9, flii^{D110fs/D110fs}n = 8); (6 dpf flii^+/? siblings n = 8, flii^{D110fs/D110fs}n = 6). (D and E) Quantification of absolute blood cell speed by single-cell tracking at 6 dpf reveals a normal sinus rhythm of heartbeats in both flii^{D110fs/D110fs} and flii^+/? siblings. Bar graphs display maximum velocity of blood cells in the dorsal aorta. Unpaired t test; values represent means ± SEM.