DNA damage of erythrocytes of fish Oreochromis niloticus (Perciformes, Cichlidae), after acute exposure to river water receiving effluent from an oil refinery

The comet assay was applied to erythrocytes of fish Oreochromis niloticus (Perciformes, Cichlidae), exposed in the laboratory to water samples taken from the Paraiba do Sul (Brazil), a river that receives effluents from an oil refinery. Water samples were collected at three points: point 1 – upstream from the discharge of effluent from the oil refinery; point 2 – the dump location of the effluent from the oil refinery, and point 3 - downstream from the oil refinery dump. Artesian well water was used as the control. Samples were collected in May and August of 2004 (dry season) and in November of 2004 and January of 2005 (rainy season). The data obtained indicated the presence of genotoxic substances in points 2 and 3 in all the sampling months. We conclude that the final effluent from the oil refinery, even after treatment, can affect the quality of the Paraíba do Sul River.Keywords: aquatic biomonitoring, comet assay, genotoxicity, Nile tilapia

An evaluation for the standardization of the Allium cepa test as cytotoxicity and genotoxicity assay

A general report on the use of the Allium test as cytotoxicological and genotoxicological assay is proposed, with particular emphasis about the standardization of the test in several common applications. The intraspecific variation in Allium cepa has been overlooked, as in most investigations no mention is made about origin and denomination of the onion cultivar used. A standardization of the used material would allow a better generalization of the results, since we cannot be sure that all cultivars would give the same response. A more frequent use of transmission electron microscopy (TEM) investigation is proposed. Even if relatively time consuming and not available in all laboratories, it may help to better understand the mechanism of cytotoxicity, since many morphological characters may appear similar but be arisen from different processes observable only with TEM. About statistical testing, tests other than chi-squared may be used in case of a lower amount of data. The most commonly used statistical tests are the parametric tests ANOVA and Student’s t, and the nonparametric tests Kruskal–Wallis and Mann–Whitney U, for analysis of variance. Tests should be used also to assess the minimal sample dimension for obtaining significance, since data collection (microscope observation) appears to be one of the main bottle necks of the test. Also the use of the Allium test for testing liposomes and other nanovectors for drug delivery is proposed, in order to assess the cytotoxicity of these types of medium and the possible increase in cytotoxicity of the associated drug

Morphohistological study of testicles of the Brazilian diplopod Pseudonannolene tricolor Brolemann, 1901 (Pseudonannolenidae, Pseudonannolenida)

:The morphology and histology of testicles of the Brazilian species of diplopod Pseudonannolene tricolor Brolemann, 1901 are presented. The study is based in testicular vesicles that show differentiated spermatozoa in their interior

Ultrastructural features of the fat body and oenocytes of Rhinocricus padbergi Verhoeff (Diplopoda, Spirobolida)

The fat body of the diplopod Rhinocricus padbergi is located in two preferential areas of its body: a) immediately below the tegument, denominated parietal, and b) filling the body cavity, close to the viscera, mainly the ovaries and alimentary canal, denominated perivisceral.Ultrastructurally, its cells, the adipocytes, presented varied morphology and contained organelles indicating that they are cells that mainly produce and store lipids and proteins. The presence of cells similar to the oenocytes found in insects was observed for the first time in diplopods, associated to the fat body of R. padbergi. Our observations suggest that this tissue probably maintains activity cycles, since the presence of cells undergoing apoptosis was detected