Figure 3. Spatial expression patterns of genes coding for glutamine synthetase, Spot 14 and Na/Pi-transporter.

(A-F); Whole mount in situ hybridization using antisense (A–C) and sense probes (D-F; negative controls) for glutamine synthetase-1 (GS-1; left), Spot 14 (center) and Na/Pi-transporter (NaPi; right). Inserts show cross sections of the polyp’s body. (G–I) Relative expression levels of whole animal (whole), isolated endoderm (End) and isolated ectoderm (Ect) tissue of Hv_Sym (green bars) and Hv_Apo (orange bars). For each biological replicate (n = 3) 10–20 hydra polyps were used for total RNA extraction of endodermal and ectodermal tissue. T-test was performed between Hv_Sym and Hv_apo. Pvalue, *<0.05, **<0.01. (J) Expression change of genes GS-1, Spot14, NaPi, Sym-1 and Sym-2 following exposure to 25, 50 and 100 mM maltose in Hv_Apo. For each biological replicate (n = 3) 50 hydra polyps were used for total RNA extraction The vertical axis shows log scale (log2) fold changes of relative expression level of maltose-treated over the untreated Hv_Apo control. T-test was performed between maltose-treated in each concentration and control (*: p value <0.05) and Kruskal-Wallis test (†: p value <0.05) in the series of 48 hr treatment were performed. Error bars indicate standard deviation.

Figure 3—figure supplement 1. Tissue isolation of green hydra.

(A) Isolated endoderm (left) and isolated ectoderm (right). Scale bar, 1 mm. Expression levels of an endoderm-specific gene finalASM_15403 (B) and that of an ectoderm specific gene finalASM_344 (C) in whole hydra (Whole) and isolated endoderm (End) and ectoderm (Ect) were examined to confirm whether tissue isolation had performed properly. For each biological replicate (n = 3) 10–20 hydra polyps were used for total RNA extraction of endodermal and ectodermal tissue. Error bars indicate standard deviation.

Figure 3—figure supplement 2. Effects of sugars on Hydra growth.

Effects of growth in presence of maltose (A), glucose (B), sucrose (C) and galactose (D) on gene expression of GS-1, Spot14 and NaPi. Hv_Apo were cultured in medium containing 10, 25, 50 or 75 mM of each sugar for 48 hr, and 75 mM maltose (orange) and glucose (blue) for 6 hr (E). RNA was extracted from the polyps in the light condition. Expression difference of the genes was examined by qPCR. For each biological replicate (n = 3) 50 hydra polyps were used for total RNA extraction. The vertical axis is log scale (log2) fold change of relative expression level of sugar-treated hydras over controls. T-test (*: p-value<0.05) in each concentration and Kruskal-Wallis test (†: pvalue <0.05) in the series of 48 hr treatment were performed. Error bars indicate standard deviation.