Bernard Tursch

Chemical protection of a fish (Abudefduf leucogaster bleeker) by a soft coral (Litophyton viridis May).

Around Laing Island (Bismarck Sea), juveniles of the fishAbudefduf leucogaster are associated with the alcyonarianLitophyton viridis which, on mechanical stimulation, can release a potent ichthyotoxin and appears to be accordingly disliked by large predators. The fish has no special immunity to high levels of toxin but is affected more slowly than others. This has been interpreted in terms of an original strategy wherebyA. leucogaster plays its long reaction time against the diffusion of the toxin, allowing the fish to remain around the soft coral and benefit from indirect chemical protection. Possible biological implications of the toxin release are discussed.

Acansterol: a cyclopropane-containing marine sterol from Acanthaster planci

From an extract of Acanthaster planci a new cyclopropane-containing sterol has been isolated and its structure elucidated.

Effects of the organic layer of Hashish smoke extract and preliminary results of its chemical analysis

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Triterpènes XVI1. Fréquence et site d'oxygénation des triterpènes naturels

Comparison of the known tetracyclic andβ-amyrenic triterpenes shows that natural oxygenation of the skeleton occurs preferentially at certain carbon atoms that are biogenetically equivalent in the 2 series.