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Previous issue date: 2006-12-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Pitimbu River is located at the oriental portion of the State of Rio Grande do Norte, including three importants cities named Maca?ba, Parnamirim e Natal. Although its high importance as a water source, which supplys great part of the South Zone of the Natal city, this river receives a large quantity of domestic and industrial waste water without treatment. The Pitimbu River headhas its river-head located in the city of Macaiba, goes through Parnamirim, then it flowing into at the Jiqui Lake in Natal. The aim of this study was to evaluate, qualitatively and quantitatively, the environmental quality of the Pitimbu River by genotoxicity bio-assays, which are important tools for genetics toxicological evaluation. In this work, five samples sites, distributed along the river, were used to collect water samples. Another point site, located near Jiqui lake, was used to collect drinkable water, which was treated by CAERN, the water treatment entreprise of Rio Grande do Norte. The following assays where used to evaluate the quality of these samples: Allium cepa assay; Comet assay; Micronuclei (MN) assay; and Ames test. For the Allium cepa assay, sixteen specimes where used for each water sample from the sample sites. In this assay both microscopic, like cytogenetic damage, and macroscopic aspects, as morphological variation were evaluated. Red blood cells from periferical blood of the Crenicichla menezesi native specie were used not only for the MN assay, but also for the Comet assay. These fishes were collected at different points on the Pitimbu River and the negative control was developed using fishes of the same species that were bring to the laboratory and maintained for 100 days in the optimal experimental conditions. For the Ames test, TA100, YG1042, TA98 and YG1041 strains were used in the directed method without metabolic activation. The results found by the Allium cepa assay showed that two water sample sites induced increase of mitotic index (IM). Additionally, compared to the control, all the water samples increased the chromossomal aberrations frequency and/or micronucleus. Among the sample sites, two also showed an abnormal growth rate in its root and two samples induced morphological alteration. With the MN test in red blood cells, a high frequence of MN was observed in tree sample. By comparing all the results obtained on the water sample points and with the negative control, a significant variation on the MN frequency was observed. Positive results were also observed for the same sample to water test by the Comet assay. These results allow concluding that the proposed specie Crenicichla menezesi has a good profile as a bio-indicator for the evaluation of environmental water quality and the MN and comet test can be usuful for in situ evaluation. By the Ames test, it was possible to detect the mutagenic activity on the waters from the Pitimbu River in different levels of mutagenicity. This result suggests that this river has several substances that induced changes directly to the DNA. The mechanisms involved to this phenomenon could be by both processes, by changing of the reading frame and by nucleotide substitution. These data set indicate the presence of mutagenic agents, which can represent in risk to biot and human beens / O rio Pitimbu localiza-se no litoral oriental do Estado do Rio Grande do Norte, mais precisamente na grande Natal, nos munic?pios de Maca?ba, Parnamirim e Natal. Embora se trate de um importante manancial, abastecendo parte da zona sul da capital do Estado, suas ?guas t?m sido alvo de dejetos industriais e dom?sticos, os quais n?o recebem tratamento adequado. O rio Pitimbu tem sua nascente situada no munic?pio de Maca?ba e des?gua na lagoa do Jiqu?, e parte em dire??o a praia de Pirangi, lan?ando suas ?guas no mar. O presente estudo teve como objetivo avaliar quantitativamente e qualitativamente a qualidade das ?guas do rio Pitimb?, atrav?s de bioensaios de genotoxicidade que s?o ferramentas de grande import?ncia nos estudos de gen?tica toxicol?gica. Neste trabalho foram coletadas amostras de ?gua de cinco pontos distribu?dos ao longo do rio e amostras da ?gua da lagoa do Jiqui ap?s tratamento feito pela CAERN (Companhia de ?guas e Esgotos do Rio Grande do Norte). Essas amostras foram analisadas atrav?s dos seguintes ensaios: teste de Allium cepa; o ensaio Cometa; o teste de Micron?cleo (MN); e o teste de Ames. Para realiza??o do teste em Allium cepa foram utilizados 16 indiv?duos para cada amostra testada, foram feitas an?lises dos aspectos microsc?picos (danos citogen?ticos) e macrosc?picos (varia??es morfol?gicas). Eritr?citos de sangue perif?rico da esp?cie nativa Crenicichla menezesi, foram utilizados tanto para execu??o do teste de MN como para o ensaio Cometa, os exemplares desta esp?cie foram coletados em diferentes pontos do rio Pitimbu e o controle negativo foi realizado com peixes da mesma esp?cie que foram trazidos para o laborat?rio e mantidos por 100 dias em condi??es ideais. Para execu??o do teste de Ames foram utilizadas as linhagens TA100, YG1042, TA98 e YG1041, sem ativa??o metab?lica, o qual foi realizado pelo m?todo direto. Os resultados obtidos no teste de Alium cepa monstraram que dois pontos de coleta de ?gua induziram altera??es no ?ndice mit?tico (?ndice de prolifera??o celular); al?m disso, todas as amostras de ?gua do rio induziram aumento na freq??ncia de aberra??es cromoss?micas e/ou de MN, em rela??o ao grupo controle. Dois dos pontos de coleta tamb?m apresentaram altera??o no crescimento da raiz e dois pontos produziram modifica??es morfol?gicas. Com o teste MN em eritr?citos uma alta freq??ncia de MN foi observada para tr?s amostras coletadas. Resultados positivos nas mesmas amostras teste tamb?m foram obtidos com o ensaio cometa. Estes resultados sugerem que a esp?cie Crenicichla menezesi pode ser considerado como um bom bioindicador para an?lise de qualidade ambiental e que os testes de MN e cometa s?o vi?veis para an?lise in situ. No teste de Ames, foi poss?vel detectar a presen?a de atividade mutag?nica nas ?guas do rio Pitimbu em diferentes n?veis de mutagenicidade, sugerindo a presen?a de compostos que agem de forma direta no DNA tanto por mudan?a do quadro de leitura quanto por substitui??o de pares de bases. Em conjunto os dados indicam a presen?a de agentes mutag?nicos, o que pode representar risco para a biota e os seres humanos
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13375 |
| Date | 21 December 2006 |
| Creators | Egito, Lucila Carmem Monte |
| Contributors | CPF:00297997750, http://lattes.cnpq.br/1083882171718362, Uchoa, Adriana Ferreira, CPF:58024867320, http://lattes.cnpq.br/6644671747055211, Medeiros, Maria das Gra?as, CPF:05769396415, http://lattes.cnpq.br/5124795265404536, Andrade, Helo?sa Helena Rodrigues de, CPF:25482343049, http://lattes.cnpq.br/3814921559949687, S?badia, Jos? Ant?nio Beltr?o, CPF:24214876334, http://lattes.cnpq.br/0280662216554148, Lima, Lucymara Fassarela Agnez |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias da Sa?de, UFRN, BR, Ci?ncias da Sa?de |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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