Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus

Hutchinson et al. 10.1073/pnas.0610785104.

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SI Figure 6
SI Table 2
SI Table 3
SI Figure 7
SI Figure 8

Fig. 6. ¹H-NMR spectra of prey fed to hatchling R. tigrinus. Green bars indicate the three areas diagnostic of bufadienolides. (A) Full spectrum, showing evidence of large quantities of bufadienolides in the parotoid gland secretion from an adult toad (B. terrestris), pieces of which were fed to some hatchling R. tigrinus. (B) Aromatic region of spectra showing the lack of bufadienolides in whole-skin extracts of metamorphic B. terrestris; bufadienolides were present in the parotoid gland secretions of juvenile B. fowleri and the skin extracts of juvenile B. quercicus. (C) Aromatic region of spectra from extracts of nonbufonid prey fed to hatchling R. tigrinus. Whole-body extract of the fish (P. promelas) and skin extracts of the nonbufonid frogs (Spea multiplicata and Scaphiopus holbrookii) show no evidence of bufadienolides.

Fig. 7. HPLC chromatograms of pooled samples of nuchal gland fluid from toad-fed R. tigrinus. (A) Hatchlings from clutch no. 1 that were fed toads for 13-42 days. (B) Hatchlings from clutch no. 2 that were fed toads for 11-12 days. (C) Hatchlings from clutch no. 3 that were fed toads for 2-51 days. Bufadienolides are identified by number (see Fig. 5). mAU, milli-absorbance units at 280 nm.

Fig. 8. HPLC chromatograms of nuchal gland fluid from R. tigrinus. (Upper) Dam no. 4 fed a nonbufonid diet in captivity. (Lower) Pooled samples from unfed hatchlings born to dam no. 4. Bufadienolides are identified by number (see Fig. 5). mAU, milli-absorbance units at 280 nm. A chromatogram of pooled samples from toad-fed hatchlings born to dam no. 4 is presented in Fig. 4.