Raul Henrique da Silva Pinheiro

Studies of micronuclei and other nuclear abnormalities in red blood cells of Colossoma macropomum exposed to methylmercury

The frequencies of micronuclei (MN) and morphological nuclear abnormalities (NA) in erythrocytes in the peripheral blood of tambaqui (Colossoma macropomum), treated with 2 mg.L−1 methylmercury (MeHg), were analyzed. Two groups (nine specimens in each) were exposed to MeHg for different periods (group A - 24 h; group B - 120 h). A third group served as negative control (group C, untreated; n = 9). Although, when compared to the control group there were no significant differences in MN frequency in the treated groups, for NA, the differences between the frequencies of group B (treated for 120 h) and the control group were extremely significant (p < 0.02), thus demonstrating the potentially adverse effects of MeHg on C. macropomum erythrocytes after prolonged exposure.

Detecção de larvas de Anisakidae parasitando Plagioscion squamosissimus e Pellona castelnaeana no Estado do Pará, Brasil

Five specimens of Plagioscion squamosissimus from Xingu River and ten specimens of Pellona castelnaeana from Mosqueiro Island, both in the State of Para, Brazil, were examined to investigate the presence of anisakid nematodes, due to their zoonotic potential. Their parasitism indices and sites of infection were also determined. This is the first record of Anisakidae parasitizing Pellona castelnaeana . Four-hundred and eighty-four third-stage larvae (L 3 ) of Anisakidae were found, of which 42 were found in P. squamosissimus and 442 in P. castelnaeana . The parasitism indices of the anisakid collected from the P. squamosissimus comprised prevalence (P) of 100%, mean infection intensity (MI) of 8.4, range of infection (RI) of 1-13, mean abundance (MA) of 8.4, and infection site (IS) in the abdominal cavity. P. castelnaeana showed P = 100%, MI = 44.2, RI = 10-114, MA = 44.2, and IS = abdominal cavity, cecum and stomach. The life cycle of these nematodes can be completed in the Amazon basin, since the two hosts fish are part of the cetacean diet of the region, which participate as final hosts. These findings have an important consequence on epidemiology of anisakiasis, so attention should be extended to human protection against this public health risk.

Investigation into the cytotoxicity and mutagenicity of the Marajó Archipelago waters using Plagioscion squamosissimus (Perciformes: Sciaenidae) as a bioindicator.

Maintaining water quality within tolerable limits is a basic need of the riverside communities in the Amazon. Using endemic aquatic organisms as biological models is useful for monitoring the environment. In this study, potential cytotoxic and genotoxic damages in Plagioscion squamosissimus (commonly known as silver croaker) from the Marajó Archipelago were evaluated using a flow cytometry assay and a survey of micronuclei (MN) frequency as well as other nuclear abnormalities (NA). P. squamosissimus specimens were collected at four locations in the Marajó Archipelago. Blood samples from these fish were used in the flow cytometry assay and piscine micronucleus test, and the resulting data were analyzed using analysis of variance (ANOVA). We did not observe a difference in the erythrocyte cell cycle distribution among the samples (P=0.9992), which suggests the absence of cytotoxic agent-induced apoptosis. The piscine micronucleus test exhibited differences in the samples from São Sebastião da Boa Vista (SSBV), and those from Anajás produced the highest mutagenicity indices. The MN frequencies were low for all groups, but the groups exhibited significantly different frequencies (P=0.0033). Reniform nuclei, nuclei with extensions, and lobed nuclei were combined and considered NA. The frequency differences for these NA were significant among sampling sites (P <0.0001). This report is the first to use flow cytometry in fish to evaluate cytotoxic agent-induced apoptosis. The micronucleus test results indicate the presence of pollutants that can change the genetic material of the fish studied. We also demonstrate that the Amazonian fish P. squamosissimus is important not only as a comestible species but also as an adequate model for biomonitoring in aquatic environments.