Paul J. Scheuer

Bioorganic marine chemistry

Bioactive Polyethers.- Bioactive Phenolics and Related Compounds.- Bioactive Microalgal Metabolites: Mediation of Subtle Ecological Interactions in Phytophagous Suspension Feeding Marine Invertebrates.- DOPA Proteins: Versatile Varnishes and Adhesives from Marine Fauna.- Author Index Volumes 1-4.

Ciguatoxin: isolation and chemical nature.

Ciguatoxin, the agent responsible for ciguatera, a disease produced in humans from ingestion of certain fishes, has been isolated from specimens of the moray eel, Gymnothorax javanicus. The toxin is apparently a lipid containing quaternary nitrogen, hydroxyl, and carbonyl functions.

Manoalide, an antibiotic sesterterpenoid from the marine sponge (polejaeff)

Abstract The structure of manoalide ( 1 ), a new sesterterpenoid antibiotic isolated from a marine sponge, has been determined by spectral analysis and chemical transformations.

Tetrahedron perspective number 2: Ciguatera and its off-shoots—chance encounters en route to a molecular structures

Abstract The history of ciguatera research at the University of Hawaii during the past 35 years revolves around the search for a molecular structure and strays upon some unexpected paths, far removed from the original goal.

Ilimaquinone, a sesquiterpenoid quinone from a marine sponge

Abstract Ilimaquinone (1) is a new sponge metabolite of composition C22H30O4. Its structure, which was determined by spectral correlations and X-ray crystallography, comprises a rearranged drimane sesquiterpene moiety linked to a 2-hydroxy-5-methoxybenzoquinone at C-3.

OBSERVATIONS ON CIGUATERA‐TYPE TOXIN IN FISH*

This is an interim report on the progress of an investigation of ciguatera in the tropical Pacific that is being carried on at the Hawaii Marine Laboratory of the University of Hawaii. For almost two years these studies have been supported not only through grants1 but also through informal cooperation of the government of the United States Trust Territories, the United States Air Force, the medical services of the United States Army and Navy, and the Royal Air Force of Great Britain. This widespread support of the investigation reflects the gravity of the problem of poisonous fishes in the Pacific. These investigations have been limited primarily to the toxin from the flesh of the large red snapper, Lutjanzts bohar (Forskiil), from the Line Islands, south of the Hawaiian archipelago. All of the later studies dealing with bioassay and chemical extraction have been confined to this species from Palmyra Island in the Line Islands. This restriction was imposed to insure that only one type of toxin was being investigated. While it is unlikely that other fishes causing ciguatera have toxins differing from those of L. bohar from Palmyra, this could not be assumed. Lutjanus bohar was selected as the fish for study because it is reported to be one of the most consistently toxic fish throughout the Pacific. I t is generally abundant and easily caught, and it is large enough to provide adequate material for sampling. Palmyra Island was selected for logistic reasons and because of the high toxicity of the fishes there. This report covers the work that has been done on the definition of the problem, the development of a bioassay, the initial attempts a t extraction and purification of the toxin, and a preliminary inquiry into the relationship of ciguatera to toxin from a common alga.

Pahutoxin: A Fish Poison

The widespread occurrence of alarming and repellent substances among marine organisms is well known to biologists (1, 2), but the chemical nature of these substances has received little attention. Brock (3) had observed that the boxfish, Ostracion lentiginosus, a member of the trunkfish family (Ostraciontidae), when placed in a container, secreted a substance that rapidly killed other fish in its vicinity. Thomson (4) confirmed this observation and isolated

Photosynthetic Marine Mollusks: In vivo 14C Incorporation into Metabolites of the Sacoglossan Placobranchus ocellatus.

In seawater enriched with carbon-14-labeled sodium hydrogen carbonate the sacoglossan Placobranchus ocellatus when exposed to light incorporates carbon-14 at a rate 50-fold of that for animals kept in the dark. 9,10-Deoxytridachione, a secondary metabolite of the mollusk, undergoes a photorearrangement to photodeoxytridachione in vivo.

Electronic spectra of substituted naphthoquinones

Abstract Echinoderms elaborate many closely related structural pigments (spinochromes) based on a naphthoquinone skeleton. As an aid to structural elucidation of these compounds the electronic spectra of a large number of substituted naphthoquinones were examined. The bands in the 240–600 mμ region of the electronic spectra of 1,4-naphthoquinone, juglone, and naphthazarin have been assigned to either benzenoid or quinoid electronic excitations and the effect of substitution on the position of these bands has been systematically studied. As a result, a number of empirical correlations have been derived that are useful in the structure determination of unknown pigments.

Two interchangeable forms of ciguatoxin

Ciguatoxin, the principal toxin responsible for ciguatera, isolated from moray eel viscera, has been separated into two distinct components by alumina chromatography. A series of chromatographies showed that the two components are interchangeable. This proves that ciguatoxin is a single molecular entity. Both forms were crystallized and their 1H NMR spectra were recorded.