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. 2022 Aug 8;6(10):1438–1448. doi: 10.1038/s41559-022-01835-7

Fig. 4. Functional characterization and receptor prediction of ctenophore neuropeptides.

Fig. 4

a, Synthetic NPWa neuropeptide (IGSDIKLVPGAGGNPWa) induced contraction of the adradial canal (orange arrowheads) and mouth opening of B. mikado larvae. A peptide with the reverse AA sequence was used as a negative control. b, Typical change in the relative length of the adradial canal following treatment with seawater, 10 µM reverse peptide and 10 µM NPWa peptide. The time points at which the changes of medium took place are indicated by blue (seawater), light blue (reverse peptide) and orange (NPWa peptide) arrows. c, Quantitative analysis of the effect of increasing peptide concentrations on adradial canal contraction (n = 5 biologically independent animals for each concentration). Error bars represent the s.e.m. (**P < 0.01). d, Synthetic VWYa neuropeptide (ARVYKGYNGGNRVWYa) induced expansion of the epithelium (orange arrowheads). e, Quantitative analysis of the effect of VWYa on body volume (n = 5 biologically independent animals for each concentration). Error bars represent the s.e.m. (*P < 0.05, **P < 0.01). f, Cell cluster distribution of putative peptide GPCR expression. The representative peptide sequences from each peptide gene (in parentheses) in M. leidyi are shown on the left. The dot plot shows the normalized expression values (molecules per 10,000 UMIs) scaled by gene. Dot size from smallest to largest corresponds to lowest and highest expression, respectively. Dots are coloured according to the cluster category. g, Cell targets of representative peptides based on the expression of their predicted GPCRs (Methods). Scale bars, 50 µm (a,d). Statistics for c: two-tailed paired t test (1 µM: t = 2.448, d.f. = 4, P = 0.07059, 95% CI = −0.01615414, 0.25699004; 10 µM: t = 11.521, d.f. = 4, P = 0.0003241, 95% CI = 0.4416221, 0.7220451; 100 µM: t = 8.6694, d.f. = 4, P = 0.0009742, 95% CI = 0.3668352, 0.7125043); **P < 0.01. Statistics for e: two-tailed paired t test (10 µM: t = −3.0913, d.f. = 4, P = 0.03653, 95% CI = −0.4612434, −0.1623270; 100 µM: t = −5.792, d.f. = 4, P = 0.004417, 95% CI = −0.129532465, −0.006951329); *P < 0.05, **P < 0.01. Rev., reverse.