Figure 1. (A) SEM images of mature sclerites isolated from the colonies of Sinularia sp.

Two types of sclerites were identified; arrows 1 and 2 indicate egg-shaped and rod-like sclerites, respectively. (B) Enlarged view of an egg-shaped sclerite. (C) Enlarged view of rod-like sclerites. (D) Raman spectra with the different sclerite shapes (Fig. B and C show the enlarged view). Characteristic Raman bands on both “egg-shaped” (top) and “rod-like” (second and third from the top) sclerites showed calcitic crystals at 154, 282, 712 and 1086 cm⁻¹. Several points in each sclerite were used for Raman analysis with similar results for each point. (E) FTIR spectra of the powdered sclerite samples showing the various molecular conformations, pure mineral composition and diagnostic IR absorption frequencies for proteins and amide A. Three strong calcite bands were identified at 713 cm^–1 (v4), 873 cm^–1 (v2) and 1415 cm^–1 (v3). Structural proteins of amide A (3300–3600 cm^–1), amide I & II (1400–1800 cm^–1), and a triple bond (2523 cm^–1) were also identified.