Discodermia kiiensis Discodermin

Closely related are the discodermins, the first polypeptides isolated from Discodermia kiiensis. Discodermin A (186) promotes permeabilization of the plasma membrane of AlO cells to the nonpermeable flourescent probes ethidium homodimer-1 (MW = 857), calcein (MW = 623), as well as permeabilization of vascular tissuecells to Ca and ATP [178-183], Neopetrosiamides A (187) (Figure 24) and B are rather complex linear polypeptides, differing from each other by the sterochemistry of the sulfoxide group. Both peptides were active in an amoeboid invasion assay at 6 pg/mL [184]. 

Four antimicrobial peptides, discodermins A-D (383-386), isolated from the Japanese sponge Discodermia kiiensis also show inhibitory activity on the development of starfish embryos (317,318). Three ichthyo-toxic peptides, pardaxins P-1 through P-3 (387-389), were isolated from... 

Matsunaga, S., Fusetani, N., Konosu, S., (1985). Bioactive marine metabolites, IV. Isolation and the amino acid composition of discodermin A, an antimicrobial peptide, from the marine sponge Discodermia kiiensis. J. Nat. Prod. 48, 236-241. 

Matsunaga et al. 171-173) have described the first bioactive polypeptides derived from a sponge, the antimicrobial discodermins A, B, C, and D (286-289) from Discodermia kiiensis. Among other methods, fast atom bombardment (FAB) mass spectrometry was applied for determination of their structures. These were unusual since 286-289 contain several D-amino acids and 286-288 t-Leu residues. Discoder-min A (286), C (288), and D (289) also inhibited the development of starfish embryo. 

Discodermins A-H Discodermia kiiensis, Japan MatsunagaeJa/., 1984, 1985a,b Ryu etal., 1994a,b... 

Matsunaga, S., Fusetam, N., and Konosu, S. (1985a) Bioactive marine metabolites VII. Structures of discodermins B, C, and D antimicrobial peptides from the marine sponge Discodermia kiiensis. Tetrahedron Lett., 26,855-856. 

Ryu, G., Matstmaga, S., and Fusetani, N. (1994b) Disccxlermins F-H, cytotoxic and antimicrobial tetradecapeptides from the marine sponge Discodermia kiiensis stmcture revision of discodermins A-D. Tetrahedron. 50,13409-13416. 

The tridecapeptide polydiscamide A (309) was obtained from an unidentified Caribbean species of Discodermia [220], while discodermins A-H (298-305) were isolated from D. kiiensis. The structures deduced previously for discodermins A-E [221, 222] were later revised on the basis of NMR data and protein sequence analysis [223]. A number of closely related compounds, the tetradecapeptides halicylindramides A-C (306-308) [224], the tridecapeptide halicylindramide D (310) [225], and the truncated linear peptide halicylindramide E [225] (311) were obtained from the sponge Halichondria cylindrata. A microbial origin for these compounds was suggested [226]. 

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