Total structure and biological properties of laxaphycins A and B, cyclic lipopeptides from the marine cyanobacteriumLyngbya majuscula

Abstract

SUMMARYThe tropical marine cyanobacterium Lyngbya majuscula produces a series of cytotoxic and antimicrobial cyclic peptides. The total structure of the two major components, laxaphycins A and B, was determined by interpretation of physical data, principally high field NMR, FAB MS and MS/MS, in combination with chemical derivatization and degradation schemes. Absolute stereochemistries of the natural and 'exotic' amino acids were determined. The two cyclic peptides exhibited an unusual biological synergism when tested for antifungal or cytotoxic effects.

Trichormamides C and D, antiproliferative cyclic lipopeptides from the cultured freshwater cyanobacterium cf. Oscillatoria sp. UIC 10045

“…A comparison of UIC 10045 to strains that produce structurally related peptides revealed a high degree of phylogenetic and geographic diversity. For example, hormothamnin A was obtained from the tropical marine species Hormothamnion enteromorphoides ; 18 laxaphycins were isolated from a marine species Anabaena torulosa and a terrestrial species Anabaena laxa ; 14,19,20 trichormamides A and B were isolated from a freshwater strain Trichormus sp. 7 These strains all belong to the order of Nostocales .…”

Filamentous tropical marine cyanobacteria: a rich source of natural products for anticancer drug discovery

“…10) are a series of cyclic lipopeptides that contain either 11 or 12 amino acid residues. The former compound was isolated from the Puerto Rican marine cyanobacterium, Hormothamnion enteromorphoides, while the laxaphycins were originally isolated from the freshwater cyanobacterium, Anabaena laxa and later re-isolated from the French Polynesian marine cyanobacterium, L. majuscula (Gerwick et al 1994;Frankmolle et al 1992;Bonnard et al 1997). The chemical structures of these macrocyclic molecules were determined by extensive 2D NMR experiments, mass spectroscopic data, as well as chemical degradative analysis.…”

A bloom of Lyngbya majuscula in Shoalwater Bay, Queensland, Australia: An important feeding ground for the green turtle (Chelonia mydas)

“…Harmful algal blooms (HABs) have been most extensively studied in cases where acute (human) poisoning occurs or where secondary metabolites produced by the blooming species may provide novel compounds with application in the biopharmaceutical industry (e.g., Bonnard et al, 1997;Orjala and Gerwick, 1997;Márquez et al, 1998;Singh et al, 1999;Milligan et al, 2000;Mitchell et al, 2000). The ecological impacts of HABs and the fate of the toxins they produce are not well understood, especially in terms of their implications for wildlife.…”