Fig. 2

HK-Spn exposure augments the expression of per2, cry1a, per3, and per1b on zebrafish cells. (a) After entrainment, Z3 cells were exposed to PBS or heat-killed Streptococcus pneumoniae (HK-Spn) and maintained in constant darkness (DDDD). RNA samples were collected every 4 h throughout 48 h, and the relative transcript expression of per2, cry1a, per3, and per1b was measured. (b) Z3 cells were exposed to PBS or heat-killed Streptococcus pneumoniae (HK-Spn) under 12-hour low-intensity light (~ 4.12 × 10¹⁸ photons/s/m²) followed by constant darkness (LDDD). RNA samples were collected every 4 h throughout 48 h, and the relative transcript expression of per2, cry1a, per3, and per1b was measured. All time points were compared against time zero samples. Yellow bar: light period. Grey bar: dark period. Means ± SD are shown. Asterisks (*) indicate statistically significant differences *p < 0.05,** p < 0.01,***p < 0.001, ****p < 0.0001, Two-way ANOVA with Šídák’s multiple comparisons test. Three replicates per group, one experiment.