OCCURRENCE OF TETRODOTOXIN AND PARALYTIC SHELLFISH TOXINS IN Phallusia nigra (TUNICATA, ASCIDIACEA) FROM THE BRAZILIAN COAST

J. C. FREITAS(1), T. OGATA(2), C. H. VEIT(1), M. KODAMA(2)

1 Department of General Physiology and Marine Biology Center, Institute of Biosciences, University of São Paulo, State of São Paulo, Brazil, 2 Department of Marine Biochemistry, School of Fisheries Sciences, Kitasato University, Iwate 022-01, Japan.

ABSTRACT: We have already shown the presence of guanidine neurotoxins in calcareous red algae and mussels collected in the São Sebastião channel (State of São Paulo, Brazil).  It is known that these neurotoxins comprise more than 25 analogues such as tetrodotoxin (TTX) and derivatives plus the paralytic shellfish toxins (PST) found in a variety of marine, freshwater and amphibious species.  Filter feeding animals generally possess large amounts of these neurotoxins.  The tunicates are sessil marine animals with a high rate of sea water filtration.  The tunics and siphons of 50 specimens of Phallusia nigra  were dissected and the visceral organs were immersed in methanol containing acetic acid 0.02 N pH 5.0.  The extract was prepared by homogenization, filtration and the methanolic phase was concentrated under reduced pressure and defatted with chloroform.  The polar phase was evaporated and the residue dissolved in deionized water for further purification in ionic-exchange resin column (Bio-Gel P-2) and HPLC analysis.  The extract showed paralytic effects on mouse assay (26.9 MU/100mg) and on crustacean isolated nerve preparations.  The chemical analysis for TTX and PST revealed toxins with retention times similar to gonyautoxins, saxitoxins and TTX. These findings are important to explain future toxin envenoming outbreaks on the Brazilian coast.

KEY WORDS: Phallusia nigra, tunicate, paralytic shellfish toxins, tetrodotoxin.

CORRESPONDENCE TO:

J.C. FREITAS, Departamento de Fisiologia Geral e Centro de Biologia Marinha, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Travessa 14, nº 321, Cidade Universitária, Caixa Postal 11461, CEP 05422-970, São Paulo, Brasil.