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Biomedical subjects

N Fusetani

Publications and source records attributed to N Fusetani.

81 records · Page 5Linked to original sources

Occurrence of a water soluble toxin in a parrotfish (Ypsiscarus ovifrons) which is probably responsible for parrotfish liver poisoning.

The liver of the parrotfish Ypsiscarus ovifrons sometimes causes severe muscle pain, paralysis and dyspnea when ingested by humans. Individual livers, ovaries and digestive tracts and their contents were examined for lethal potency in mice. They were all toxic, except for livers obtained from April to June. Lethal potency ranged from 0.25 to 5.0 MU/g tissue. Livers were extracted with acidic aqueous ethanol and the extracts purified by charcoal treatment, gel filtration and partition and reversed phase column chromatography. Both the crude and partially purified toxin showed chemical and/or pharmacological properties different from those of tetrodotoxin or paralytic shellfish poisons.

Animals↗

[Toxic complex from parrotfish].

Clinical and epidemiological observations suggested that a complex toxic molecule is involved in the parrotfish flesh (Scarus gibbus) poisoning from Gambier Islands. The fat soluble extract obtained from the muscles upon ciguatoxin preparation showed two toxic substances after fractionation by DEAE cellulose column chromatography. The major toxin is different from ciguatoxin judging by its chromatographic behaviour. The other is closely similar to (or identical with) ciguatoxin from the moray eel Gymnothorax javanicus. They were named SG1 for the new toxin and SG2 for the ciguatoxin like compound. Successive filtrations on Sephadex LH-20 of SG1 and SG2 gave respectively a lethality to mice of 0.03 microgram/g and 0.06 microgram/g. SG1, specifically occurs in the muscles of the parrotfish family (scaritoxin) while it is absent from other ciguateric fishes. According to that specificity and the lack of SG1 in S. gibbus liver and gut contents, the origin of scaritoxin is briefly discussed.

Animals↗

Membrane permeabilization induced by discodermin A, a novel marine bioactive peptide.

The effects of discodermin A (DC-A), a novel marine bioactive peptide extracted from sea sponge Discodermia kiiensis, on the vascular smooth muscle cells and tissues were examined. Analysis with a confocal laser microscope showed that DC-A (0.1-30 microM) permeabilized the plasma membrane of A10 cells to the non-permeable fluorescent agents, ethidium homodimer-1 (MW = 857) and calcein (MW = 623), in a concentration-dependent manner. In the vascular tissue treated with 30 microM DC-A, addition of a micromolar concentration of Ca(2+) evoked a sustained contraction in the presence of ATP, suggesting that DC-A increased the permeability of the membrane to Ca(2+) and ATP. DC-A at higher concentrations (30 microM) significantly increased the leakage of lactate dehydrogenase (140 kD) from the vascular tissue. These results suggest that DC-A has a permeabilizing effect on the plasma membrane possibly by interacting with plasma membrane phospholipids with its six successive hydrophobic amino acid residues at N-terminal.

Adenosine Triphosphate↗

Bioactive marine metabolites, IV. Isolation and the amino acid composition of discodermin A, an antimicrobial peptide, from the marine sponge Discodermia kiiensis.

An antimicrobial peptide, discodermin A, has been isolated from the marine sponge Discodermia kiiensis. The peptide showed antimicrobial activity as well as an inhibition of starfish embryo development. It appeared to be a tetradecapeptide consisting of D-Cys(O3H), L-Asp, L-MeGlu, L-Thr (2 moles), Sar, D-Pro, D-Ala, D- and L-t-Leu, D-Leu, L-Phe, D-Trp, and L-Arg.

Amino Acids↗