Cytotoxic potential of waters of the streams Mandacaru, Maringá, Miosótis and Nazareth in the urban area of Maringá, Paraná State, Brazil / Investigação do potencial citotóxico das águas dos ribeirões Mandacaru, Maringá, Miosótis e Nazareth, localizados na área urbana de Maringá, Estado do Paraná, Brasil

Streams Mandacaru, Maringá, Miosótis and Nazareth in the urban area of Maringá, Estado do Paraná, Brazil are affected by the local population's polluting practices. Meristemic cells of Allium cepa L. roots were used as test system to evaluate the cytotoxic effects of the streams' water. Onion roots were prepared by Feulgen reaction and stained with Schiff's reagent. Statistical analysis of the mitotic index was undertaken with the chi-square test. Results did not show significant cytotoxic effect of water samples. Results may dependent on climate variations, concentration of harmful substances, and on the time and samples sites evaluated. A deeper awareness of the population should be underscored for the proper use, preservation and maintenance of soil and water, with particular emphasis to this region.

Os Ribeirões Mandacaru, Maringá, Miosótis e Nazareth estão localizados na zona urbana da cidade de Maringá, Estado do Paraná, e por isso, recebem influência das práticas poluentes da população local. Com o objetivo de avaliar os efeitos citotóxicos das águas desses ribeirões, foi utilizado como sistema-teste de células meristemáticas de raízes de Allium cepa L. As raízes de cebola foram preparadas pela reação de Feulgen e coradas com o reativo de Schiff. Os índices mitóticos foram analisados estatisticamente utilizando o teste do Qui-quadrado. Os resultados obtidos não mostram efeito citotóxico significativo das águas amostradas avaliadas. Os resultados obtidos podem ser dependentes das variações climáticas, da concentração das substâncias nocivas, e da época e local das amostragens avaliadas. Além disso, vale destacar a necessidade de ser realizada, principalmente na área de estudo, conscientização da população em geral, no sentido de uso, preservação e manutenção do solo e das águas.

Allozyme differentiation of two populations of the genus Neoplecostomus Eigenmann & Eigenmann, 1888 (Teleostei, Loricariidae) from the upper Paraná River basin, Brazil

Allozyme electrophoresis was used to examine 12 enzymatic systems in two populations of the genus Neoplecostomus from the Paraná River basin. Samples of Neoplecostomus sp. 1 were collected in Paraitinguinha stream of the Tietê River basin, in the municipality of Salesópolis, São Paulo State, and those of Neoplecostomus sp. 2 from São Domingos stream of the Rio Grande River basin, in the municipality of Muzambinho, Minas Gerais State. The genetic variability of the two populations was estimated by Nei's expected heterozygosity and was considered lower than average for populations of freshwater fish. The proportion of polymorphic loci was low (only 5.26 percent for the locus Idh). The low frequency of heterozygosity for both populations revealed a high fixation of alleles for each locus. Homozygote excess was observed in both populations. The values of Nei's genetic identity and the presence of loci with different allele frequencies in both populations may imply that the two populations belong to different species. The genetic variability between populations was compared to other data for loricariids.