RESUMO
Three individuals of silver carp (Hypophthalmichthys molitrix) were collected biweekly from Paranoá Lake (DF, Brazil) for analysis of microcystin (MC) concentrations in their muscle and liver tissue. Analysis by high performance liquid chromatography and mass spectrometry revealed MC masses and fragmentation patterns that were identified as MC-LR (995.04 m/z), MC-LA (909.01 m/z) and an unknown MC (987.07 m/z). Concentrations were calculated as MC-LR equivalents using a calibration curve prepared with a standard of MC-LR. May/06 was the month with the highest MC-LR equivalent concentrations in muscle and liver (3.83 ± 2.78, and 12.94 ± 10.51 µg g(-1), respectively). Our results show that during the drought months (April-September), consumption of fish with these MC concentrations would result in exposure to MCs that greatly exceed the World Health Organization's recommended tolerable daily intake limit of 0.04 µg MC kg(-1) body weight.
Assuntos
Carpas/metabolismo , Monitoramento Ambiental/métodos , Lagos/química , Microcistinas/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Cromatografia Líquida de Alta Pressão , Cianobactérias/crescimento & desenvolvimento , Lagos/microbiologia , Fígado/química , Toxinas Marinhas , Microcistinas/farmacocinética , Músculo Esquelético/química , Estações do Ano , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Poluentes Químicos da Água/farmacocinéticaRESUMO
Studies of genotoxicity in fish caused by cyanobacterial extracts containing microcystins (MCs) can be useful in determining their carcinogenic risk due to a genotoxic mechanism. An extract of cyanobacterial Microcystis ssp, containing MC-LR and -LA from a bloom collected in a eutrophic lake, showed genotoxicity to Oreochromis niloticus. DNA damage (comet assay) was significantly induced in peripheral erythrocytes with both tested concentrations of 6.90 µg kg(-1) bw and 13.80 µg kg(-1) bw through intraperitoneal injection (ip). There was no micronucleus induction after ip injection at concentrations of 6.90 µg kg(-1) bw and 13.80 µg kg(-1) bw. Body exposure resulted in micronucleus induction and DNA damage only at the highest tested concentrations of 103.72 µg L(-1). Thus, comet assay and ip injection revealed the highest levels of the genotoxicity of MCs. Apoptosis-necrosis test carried out at concentrations of 6.90 µg kg(-1) bw and 13.80 µg kg(-1) bw revealed that at low concentrations more apoptosis than necrosis occurred. At higher concentrations more necrosis than apoptosis occurred.
Assuntos
Ciclídeos/genética , Dano ao DNA , Microcistinas/toxicidade , Microcystis/patogenicidade , Micronúcleos com Defeito Cromossômico , Animais , Apoptose/efeitos dos fármacos , Microcystis/química , Testes de Mutagenicidade , NecroseRESUMO
Eight cassava (Manihot esculenta Crantz) cultivars, of which four are indigenous to the Amazon region, along with an interspecific hybrid, were assessed for their carotenoid content. They were propagated and are maintained in the living Manihot collection at the University of Brasília. The cultivar "Amarelinha do Amapá", which was collected from the State of Amapá, was found to have a very high content of beta-carotene: 27 mg per 100 mg, which is more than 50-fold higher than in other cassava cultivars. This cultivar, which also has excellent palatability, could be an important source of beta-carotene for cassava breeding.
Assuntos
Carotenoides/análise , Produtos Agrícolas/química , Manihot/química , Cromatografia Líquida de Alta Pressão , Raízes de PlantasRESUMO
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 beta-carotene, which reached 4 mg/kg.