Cassava diversity in Brazil: the case of carotenoid-rich landraces

In Brazil, the center of cassava origin, cassava landraces have acquired through their domestication a large diversity in relation to many economic traits such as high content of carotenoids and excellent palatability among other characters. One of these clones, which has been grown by indigenous Brazilian farmers and is now being maintained in the University of Brasília gene bank, showed a high level of lycopene content (5 mg/kg viz. a viz. zero in common cultivars, and 12-20 mg/kg in tomato, a lycopene-rich vegetable). A second landrace called UnB 400 had a high content of b-carotene, which reached 4 mg/kg.

Toxicity of puffer fish - two species(Lagocephalus laevigatus, LINAEUS 1766 and Sphoeroides spengleri, BLOCH 1785) from the southeastern Brazilian coast

In Brazil, where puffer fish are considered poisonous, there are few documented cases on human consumption and consequent poisoning. In this study, toxicity of two puffer fish species from the Brazilian coast was examined. Specimens of Sphoeroides spengleri and Lagocephalus laevigatus were caught in Säo Sebastiäo Channel (North coast of Säo Paulo State, Brazil) between January 1996 and May 1997. Acidic ethanol extracts from muscle and skin plus viscera were tested for mice acute toxicity using the standard method of Kawabata. Polar extracts of S. spengleri showed high toxicity up to 946 MU/g. Extracts from L. laevigatus showed very low levels of toxicity, never exceeding 1.7 MU/g. All extracts from both species blocked amielinic nerve fiber evoked impulses of crustacean legs; this effect reverted on washing similar to the standard tetrodotoxin TTX. The aqueous extract solutions were partially purified using an ionic exchange column (Amberlit GC-50) followed by treatment with activated charcoal (Norit-A). The presence of TTX and their analogs in the semi-purified extracts were confirmed by HPLC and mass spectrometry (MALDI-TOF).